Many years ago, late 1950's, I read an article about a German engineer who built a high performance engine using roller bearings on the crankshaft. To get the bearings onto the journals he used hardened tubes as journals and then large screwed pins ti squeeze the webs onto them. The pins were threaded both ends with different pitch right hand threads. The coarse pitch thread traveled faster than the fine pitch thereby drawing the two components together. The effect was that of using a very fine pitch in terms of tightness but with the strength of deeper threads. For example a 2mm and 1mm pitch would give the tightness of a 0.5mm pitch. This is different from your example in as far as the two right hand threads slowed down the travel whereas the right and left combination gave a speeding up. The process is called differential threading.
I have heard but do not know if it's true that Rolls Royce engines used in WW2 Spitfire and Mustang fighter planes had ball bearings in the crank shaft bearings..
These are often called "differential" threads. The only application I had heard of before this video was for locking Hirth serrated face couplings together ; If you use a coarse and a very fine thread, it produces a gear reduction which is ideal for producing a lot of torque for a small angular displacement.
I know of no where else that this information could be shared in the fashion that you do. It is like talking to my father who was a machinist by trade but not nearly as patient as you. Thank you once again and keep them coming. BTW I would have to believe the Butterfield would have more surface engagement. Too bad all these good American tools and companies are gone.
I'm no engineer but I can see why Butterfield made their tap handles the way they did and it's pure genius. The jaws are both the same. Same shape, same thread. This means each handle requires one setup to make the jaws. I wonder if they also initially engineered their handle the way they did, in regards to the compound threading, as a way to avoid any patent infringement with the Greenfield design. Not knowing when each company released their products I can only speculate on that. Interesting video, I enjoyed it.
Also machining a cylindrical portion on a square block just adds more fuss in the machining of the part. Whereas putting the thread on the already cylindrical handle, just adds another operation to make the handle.
On pure aesthetic value, I like the Butterfield. Very pleasing to look at. Thanks for the discourse Mr Pete, very interesting. I would have enjoyed having you as a shop teacher.
I found a nice Greenfield No. 6 today, and was looking for information on it. Thank you for the complete explanation of how it works. I now know I found an excellent tool for my chest.
Love how you invite folks to "conclude the video right now". Odd how of all the old tools I've picked up at sales and auctions, you Sir, seem to make a video of them each in turn. By the end of the buying up of crap season (garage sale season)I found myself in the possession of 4 or 5 Greenfield handles. The weight of them and the overall aesthetic drew me in 1st time I picked one up. Great minds I suppose. Excellent video Mr. Pete, thank you.
Would you believe that I just came from an auction this afternoon? I Purchased a tap and die set reasonably priced simply because it had the GreeniField tap wrench. Watch for that video next week.
This "differential screw" system was used for the blade adjustment on the English Norris wood plane, it gives a very precise adjustment, we seem to be abandoning a lot of very good mechanical ideas in our modern world.
Great video, Mr. Pete! I picked up a Greenfield No.7 this past weekend at a flea market, and referred to this video to get it apart for cleaning. It's the older pattern design, that of your No. 5. Unfortunately the color from the case hardening is completely gone, and the movable jaw has also been chipped, though making a replacement jaw might make a fun project. Thanks again for the very informative video, it's much appreciated.
I thoroughly enjoyed this video! What brought me here is the recent thrift shop acquisition of a Greenfield No. 00x4 Tap Wrench. The overall length of the tap wrench is: 5-1/4", and its case-hardening is very much in evidence, as the tool shows that it has had very minimal (if any) actual use. Near as I can tell, it is for 1/16" -1/4" taps. It sure is 'a cute little bugger"! You now have another subscriber!
Enjoyed the video very much. I have Greenfield #0-#7 and some others. For those thinking of taking one apart, mark the orientation of the dynamic jaw. In order to minimize runout the jaws have to fit as they did from the factory. It may take you a while to reposition the static jaw. Ask me how I know. Better yet, don't take one apart if you don't have to. FWIW, in terms of lubricant, I've found that moly grease works best. Thin oil, not so much. Regarding the wrench that was cited as an older #5, IMO it's newer. I have one of them, as well. Greenfield was bought by TRW in the mid-50s and owned the company until the mid-80s. If ya take a look at a TRW tap wrench, its shape is essentially identical to the #5 in the video. I could be wrong, of course. It would be great if someone knew for sure. I don't have a Butterfield, but hope to one day. It was cool seeing it.
Just rewatched this video. Yes you have done a wonderful job of explaining as usual. I have a Greenfield No. 5 with the old beautiful case Harding. I’m guessing it to be 60+ years old. It still looks like new. I also have taken it apart since they get sluggish with age. Thanks for the refresher.
We've used compound screws to achieve the opposite effect in the high precision coating machines we built. There were just a few differences, however. Both threads were right-handed and one was a single thread pitch different than the other. The net effect was a whole bunch of turns to net a tiny amount of linear motion.
Two things: The compounded threading allows the threads to be self locking when tightened. On the small diameter, a 10TPI would be at a steep enough angle that, when lubricated, it could slip, like back-driving a leadscrew. An extreme example of this is the `spiral' screwdriver. Instead, the threads lock like a two stage screw jack. My opinion is that the Butterfield is a little stronger used the right way because, as stated by others, both jaws transfer force more directly to the frame. I doubt the difference is significant in service, since the force for both is primarily transferred near the corners of the tap end, and both jaw designs provide a straight line in the force direction (perpendicular to the face applying the force) through the jaw to the frame. Experience tells me that the Butterfield is certainly more resistant to a worn tap end skipping out of the jaws, when used in the correct direction.
A little late to the game here, but another example of compound thread to provide advance speed can be found on the clamp screws of Wild (later Leica) survey instrument tripod legs. I happened upon this video while searching for an good-quality but inexpensive tap handle that I could trim the arms on so I can use it on my 12" lathe. The Craftsman I was using to tap a 1/2-13 thread today is too big to clear the lathe ways, but I needed all the leverage I could get and my T-handle tap wrench just wasn't big enough. I've had the Craftsman for over 40 years and don't want to chop it, but after watching this video I guess I'm not going to be buying and cutting up a Greenfield, either.
An important note about the greenfield model is that, since the fixed jaw is retained with a set screw rather than the handle, you can remove one handle to tap holes in tight spaces without needing a different style of tap wrench, so long as you still have enough room for the tap body. And if I’m not mistaken, the ability to transfer torque should be roughly similar since the contact area is similar, and most importantly, both handles should be able to readily break your tap off while you’re tapping the last hole.
Even at 76 one learns something new every day. Very interesting how the double threads, LH & RH, are used together, very interesting. Many thanks for taking the time to explain. You make very nice, informative video's. From Missouri
Very interesting video. I have a Craftsman tap handle that looks something like that and I have had it since the 1970's and it has never occurred to me to want to take it apart. I guess I was just glad it stuck together all this time. =(;-) Now I expect that I will not make it all day without taking it apart. Keep on keeping on.
Douglas Corrigan once flew to Ireland after "intending" to fly to Los Angeles (he could not obtain permission for a transatlantic flight). He completed the flight despite the presence of a leaking fuel system.
Mr. Pete, the first time I took one of the apart, as a starting machinist, I was taken aback. The next day I immediately asked my instructor about these threads. Very nice video Sir.
I have a smaller Butterfield tap handle that belonged to my dad. Back in my early childhood of discovering how things went together and worked, I snapped the pin thread off the handle for the fixed jaw, not knowing it was left hand. Mixed up a bit of Epoxy and glued the handle in place and jaw was left loose. Don't know why I didn't glue the jaw in place. Fifty something years later, I still have that little tap handle and it gets used every now and then. Thanks for the video, Mr. Pete. Ken S.
Hi mrpete222 The thread system shown in the tap wrenches is also found on the Lee Valley adjuster mechanisms for their hand plane blades. Very smooth and positive.
Great video for tool nuts, the time flew by! A few thoughts: - The contact flats are basically the same in both tools, though with the butterfield it might be stronger in one direction of rotation than the other suggesting you would need to flip it to make sure the wider flats were resting rotation? The Greenfield would be "ambidextrous". - I'd expect the butterfield to be slightly more resistant to "blackout tendency" since it has the finer thread and the coarser partner thread would be fully pushed in to take up any backlash, suggesting the governor of backout tendency would be the finest thread in the stack. -I've seen these compound threads used on modern fanlight winders, the type where you use a hooked pole to reach the roof light and twiddle a nut. Perhaps I'm overthinking it! Love your videos.
+Ian Sanders I agree, I think the Butterfield would be strongest but you would have to pay attention to which direction you put the tap in (similar to the crescent wrench argument). Having the long flats as the driving side would be strongest, although either one would more than likely stronger than most taps
Sir, I am going to have to accuse you of thinking like a machinist... (compliment)... indeed, you sir, are an intellectual (no offense meant)... you put a great deal of contemplation and effort into these videos... so much detail on the complexity of what until today I was sure was a simple device... I turn it... it tightens... but NO, like almost everything in life; nothing is ever as simple as it first appears! Thanks.
Thank you once again for the detailed information, we all use tools like these regularly, but one does not often stop and think how much thought actually went into the design of a everyday used tool! Never too old to learn and look at something from a different aspect!
The Butterfield is the stronger one because of the larger clamping area on both jaws, but notice that it also cut 5+ operations (not counting the threaded holes), when making the Greenfield jaws, down to two operations for the Butterfield because both jaws have the same design. That's a real costsaver...
I disagree, the Butterfield design is directional, and only has more contact area when operating in one direction of torsion, in the other direction it has much less contact area in reference to the force direction. On the Greenfield jaws there is one full surface contact for each torque direction on one jaw, and the small surface contact areas on the second jaw are just for inward linear force instead of torque resistance.
the mechanical principle to use the advancement of two screws with a single rotating part is called "differential screw": en.wikipedia.org/wiki/Differential_screw In the majority of its applications the two advancements work against each other (hence the word differential) such as in microscopes to achieve minute advancements per turn. E.g one thread has a lead of 50 thou forward and the other 48 thou backward resulting in only 2 thou advancement per turn. In your example in the video the two advancements are added to achieve an extra long advancement. The same happens in turn buckles.
+mrpete222 You are very welcome. The differential screw is not very widely known and deserves more publicity. The differential pulley en.wikipedia.org/wiki/Differential_pulley is already better known. And the differential gear is the star. en.wikipedia.org/wiki/Differential_%28mechanical_device%29. All three are governed by the same principle: two opposed, slightly different movements. Considering your talent to visualize and explain technical principles this might be worthy material for a new video. I think you have covered the differential pulley and gear before. (BTW the car differential does not lend itself to easily explain that principle since the two opposed movements are equal. An ordinary planetary gear, which is also a differential gear, is easier to explain.)
Snap-on sells a tap wrench that looks very similar to the Butterfield. It appears to be about the same size as that #10. It sells for $91.00 on the site. It is tough to tell but it looks as though it is cast instead of machined. I have a T & E tap and die set. Both of the dismally inferior die cast wrenches from that set have been replaced by Greenfields.
I enjoyed it, and now understand why I have been outbid several times on E Bay. Maybe someday! I must keep using my "cheap," but workable imitations; but, there's nothing like the "real thing!"
Yes MrPete the color case hardening is beautiful ....BUT alas I'am sure that the process probably involved chemicals the EPA has banned for some reason .... great video as always
Thanks Mr. Pete! Interesting to many I'm sure. Glad you added the care and feeding of these fine old tools...with it they will last many life times. You inspired some great conversations below. I agree that the Butterfield is easier to manufacture, more simplistic in design and possibly stronger of the 2. The body design seems more substantial too. As for the right vs left hand tap strength on the Butterfield it may be stronger because of the overall capture length of the tap is possibly greater than the Greenfields...but without mic'ing them out and knowing the tap range for each it's only an earball thought. Would also like to know what % of thread engagement they have? Always appreciative of your gifts to education and us!! ~PJ
Hi Tublicain, I too have a No 7 & No. 5 GREEBFIELD Die's straight handles. Used White Vinegar to clean up. It's magic stuff.It Dose the job quit well. Thanks for the advice. Will keep watching RSA. Rob Schofield I will keep watching.
+Rob Schofield Hi Tublicain, I too have a No 7 & No. 6 GREEBFIELD Die's straight handles. Used White Vinegar to clean up. It's magic stuff.It Dose the job quit well. Thanks for the advice. Will keep watching RSA. Rob Schofield I will keep watching. Sorry about the above in error 5 should read 6. thanks
Great video Mr. Pete! Another one of those seemingly simple, but ingenious designs. Something not so ingenious, I got a Harbor Freight tap and die set many years ago. The taps and dies actually aren't that bad, they still do the job to this day, although admittedly I don't make a lot of threads here at home. But the tap wrench was the most abysmal piece of junk! It had no jaws at all, just a V cast in the opening on one side and the handle was a threaded rod on the other that would push the tap into the V. It never worked and it went in the garbage.
The jaw design on the Butterfield seems the superior one to me because the load is transferred to the frame as the tap end is clamped. In the Greenfield, the load is transferred to the screw alone.
It was interesting to see how the Butterfield did the compound threads versus the Greenfield. I have had my Greenfield apart to see how they did that. I see on the #4 that it looks like there is a small screw that holds the movable jaw on the shaft? It looks like the Greenfield would hold left and right hand taps equally, but the Butterfield would hold right hand taps better than left hand taps the way the V's in the jaws are shaped. Thanks for the vid. One of these days I'm going to make a tap handle as a fun project. Figuring how I would want to mill/turn the center part for looks is going to be an interesting thing to figure out.
also, since having seen your videos on threading: the "compound threading" seems to offer TWO mechanical advantages... travel *and* torque... over a double-cut thread (travel only)? GREAT STUFF - thank you!!!
The commonest place where a combination of RH and LH threads move something twice as fast is the simple turnbuckle. I like the design of the Butterfield a bit better. I think (no engineering; just a guess) the asymmetrical jaws will give a better grip in one direction (flip it to get a better grip in the other direction). But the really cool thing is that left hand thread in the fixed jaw. That (combined with the asymmetrical jaws) _makes the two jaws identical_. The company only needs to make and stock one part to cover both jaws. =======and here I digress (as usual)======== I was faced with making safety grilles for some low windows and wanted something with a stronger pull-out strength than a simple press fit for the cross bars and the uprights at each side. (This let me use very thin rods to avoid obscuring too much of the view, and still get the strength required by the building code.) I got a set of left-hand tap and die in 5/16-24 (from our old friends at McMaster-Carr) and fitted the left ends and side rail with left hand threads and the right side with right hand threads. Then it was just a matter of assembling both ends of 9 rods simultaneously. (It can be done. I did four of those grilles.)
+Peter W. Meek I thought about the holding of the Butterfield (actually it is symmetrical) and read until I found your comment. I agree, it will hold better in one direction. My logic is that with the Greenfield (and all the others I've seen), you get full contact on one side and a smaller amount of contact on the other; this is not going to hold as well as for example, full contact on both sides. Therefore, full contact along the side with the most pressure, duplicated on the other side, will logically work better or allow more force to be applied. And I like your two jaws identical conclusion. I have to say though, you mentioned that "The commonest place where.a combination of RH and LH threads move something twice as fast is the simple turnbuckle." Hold on, it doesn't speed up the action of the threads, just allows the thing to work while turning in one direction. Either both sides come together or both sides move away. The combination of RH and LH on the tapping tools "gears it up" in the right arrangement. If they are the same direction, the design changes like you pointed out enabling both jaws to be the same, just a different screw arrangement, both same handed. Interesting to see both tools use a different approach with the same end result. It's a good video. Reminds me of: "How exactly does a posi-traction on a Plymouth work?" "It just does." -Father of Joe Dirt.
True, the Butterfield jaws are symmetrical, but in a less common form: rotationally symmetrical (of order 2). We usually think of symmetry in the mirror-image sense. Just as the tap holder closes at roughly twice the speed of a single screw, so does the turn-buckle shorten or lengthen at twice the speed. The LH-RH threading probably _is_ intended to make it work at all, but the effect is to make it work twice as fast.
Really enjoyed the video I think I like the Greenfield over the Butterflied Thanks for posting the video Mrpete always looking forward to more of them!
I've always been a big fan of the symmetry in Greenfield's handle. I use Starrett wrenches at work and don't like the feel of them because they aren't symmetrical in my hands when using them. About Greenfield vs. Butterfield...let's not overlook the theoretical 3% more holding power of the Butterfield due to it's lead being smaller. For X amount of torque input you will see 3% more force output with the Butterfield. Thanks for the video!
My late father in law worked at GTD for many years. At that time, many years ago, I was not interested in machine tools , only his daughter. I have two brothers living in Greenfield MA. My younger brother worked at Millers Falls Tools until they failed. The employees decided to try their hand at keeping the company going. Well soon after, many tools were being returned and they too failed. My brother is in the process of moving to NV and asked if I wanted a lot of taps and dies. Oh yeah I do, so he put about 65 taps and dies in a 2nd day mailer and sent them off to me in CA. Well, sadly his packaging wasn't so great and the box burst open enroute, due to too much weight and only six taps and three dies arrived here in CA. The post Office is looking into it, yeah. Great video Mr. Pete , I love this stuff. Ken....Marina CA
Interesting. I'm a retired engineer, but not a mechanical one, so take it for what it's worth, but the Butterfield design seems like it would have more surface contact when turning clockwise than the Greenfield, because the longer edges on both jaws would be working together. On the Greenfield, only one long edge on the fixed jaw is applying force at any given time.
Some of the new junk sold in auto parts stores use a compound thread similar to the Butterfield, but of course it's not nearly as durable. The set I have, the moveable jaw will disengage from the thread before it bottoms on the fixed jaw, meaning it's prone to getting lost, or damaged if you try to use it on a really small tap. Nasty pieces of work, they are.
Some older knockout punch sets will used a compound thread. Color case hardening is another service I provide, mainly for firearms. The BIG 5" & 6" conduit size wrench turned KOs used a compound thread set up to avoid too too much movement of the draw stud and to pull the die in faster without stripping the threads off the die or the draw stud. I did not see big wrench driven studs for many years, unless someone brought in an old antique punch.. They were all hydraulic, and now they are back, but only up to 4" conduit, as far as I can tell. The stud drive was a big ugly cast football shaped blob, you turned with a Stilson wrench. You won't see that anymore!
If you play around with wooden planes, Stanley No.62 has a 'Norris type' screw adjuster to advance the blade. In fact, there are many types if this 'Norris Type' screws use on the same sized plane by other manufacturers like Lie Nielsen and Veritas. The threads can be a RH LH configuration or can be both in LH LH configuration.
When I saw your picture of this video, it caught my attention because I made one of these tap handles when I was an apprentice at Buick. Someone in the machine shop had an original and I thought it would be neat to make one for machine shop practice. I saw this gadget in a storage area and found out it is a lathe attachment to round the end of a piece of round stock to a spherical shape (i.e. the rounded end of a handle). My tap handle is 16" long when closed. I used 5/16-18 thread on the movable jaw and 9/16-18 thread on the handle. 18 t.p.i. is .055" per turn, so my jaw moves .111" per turn of the handle. Not sure if you post your email address, I would send you photos of it. Don't know how else to send photos to you. Thanks for the video tubalcain !!!
Shortly after I wrote my last comment, I ran across your Shop Tip #123 Turning A Ball. The gadget I used in the shop did the same thing, but you turned a handle with a worm gear to move the tool around the work.
Thanks so much for this timely video, as I have been lately collecting these fine examples of american tools. I've not been able to find the information that you presented, so I copied your chart on the sizes.
As always, thanks Mr. Pete, very interesting. I will now have to take one of my Starrett wrenches apart to see how they did theirs. I have a Greenfield #7 and wish I had a whole set of their wrenches. I like to looks of that older #5. Perhaps you will do a video on die holders?
Not being a machinist, I would think the handles were threaded on a lathe, vice using a die. The Butterfield handle looked like it was undercut at the end of the threads. Not sure about single pointing an internal left hand thread on the Green field though. I also think the Butterfield has a slight edge in strength, and would better transfer the torque to the tap. In theory anyway.Bob
Since I can't actually measure both here, the appearance shown in the video lead me to believe that an equal amount of tap edge is contacted by both brands. Each side of the greenfield V appears to be (at least close) to the length of the short part of the butterfield L. So equal surface contact. As for which is better, I suspect the butterfield design is, since the entire 1/2 of the tap pressure is on the movable jaw V of the greenfield, and the other half on the 100% contact fixed jaw. Remember, the forces exerted are not solely rotational, since the silly human operators rarely apply pressures in only a single plane at a time, being the defective poorly-programmable meat machines they are. Side thrusts would appear to be more of an issue for the greenfield design. - Wes
It's a form of differential screw, normally used for fine adjustment (one thread moves in opposite direction to the other) but in this case configured for rapid closing while not being back drivable as you say. I think!
Very good video Sir. From years of discussion with tool reps such as Snap-On with their 'Flank Drive", I believe the Greenfield may have a strength advantage given the fact that two adjacent sides are fully captured for turning torque, the movable jaw just holding the driven square of the tap into the fixed jaw. Not an engineer, just looks like it would have similar drive force.
The steady and follow rests for my South Bend use a similar double thread. Its course on the brass bit on the inside and fine for the knurled knob on the outside though.
great video as always ...as for compound thread applications ..not much but ive seen it once inside an old water valve it works on the same fashion this tap does...in order to close and open the valve gate . pretty elaborate if you ask ...now i bet they got rid of this design and used a single thread style
I would suspect the two holding methods work out to be approximately equal, if other factors are equal (like the "depth" of jaws dictating how much of the tool shaft is being held)
Many years ago, late 1950's, I read an article about a German engineer who built a high performance engine using roller bearings on the crankshaft. To get the bearings onto the journals he used hardened tubes as journals and then large screwed pins ti squeeze the webs onto them. The pins were threaded both ends with different pitch right hand threads. The coarse pitch thread traveled faster than the fine pitch thereby drawing the two components together. The effect was that of using a very fine pitch in terms of tightness but with the strength of deeper threads. For example a 2mm and 1mm pitch would give the tightness of a 0.5mm pitch. This is different from your example in as far as the two right hand threads slowed down the travel whereas the right and left combination gave a speeding up. The process is called differential threading.
I have heard but do not know if it's true that Rolls Royce engines used in WW2 Spitfire and Mustang fighter planes had ball bearings in the crank shaft bearings..
The 3 cylinder DKW automobile used roller bearings on the crankshaft. I believe it was a German engineered vehicle.
These are often called "differential" threads. The only application I had heard of before this video was for locking Hirth serrated face couplings together ; If you use a coarse and a very fine thread, it produces a gear reduction which is ideal for producing a lot of torque for a small angular displacement.
I know of no where else that this information could be shared in the fashion that you do. It is like talking to my father who was a machinist by trade but not nearly as patient as you. Thank you once again and keep them coming. BTW I would have to believe the Butterfield would have more surface engagement. Too bad all these good American tools and companies are gone.
WOW.. Your presentation is commensurate with the elegance of these creations.
Thanks
I'm no engineer but I can see why Butterfield made their tap handles the way they did and it's pure genius. The jaws are both the same. Same shape, same thread. This means each handle requires one setup to make the jaws. I wonder if they also initially engineered their handle the way they did, in regards to the compound threading, as a way to avoid any patent infringement with the Greenfield design. Not knowing when each company released their products I can only speculate on that.
Interesting video, I enjoyed it.
Also machining a cylindrical portion on a square block just adds more fuss in the machining of the part. Whereas putting the thread on the already cylindrical handle, just adds another operation to make the handle.
On pure aesthetic value, I like the Butterfield. Very pleasing to look at. Thanks for the discourse Mr Pete, very interesting. I would have enjoyed having you as a shop teacher.
+trackdog90 You DO have him as your shop teacher!
Thank you for the video, I have been using a Greenfield no5 that I inherited. I have used it daily at work for the last 27 years. It is a great tool.
I found a nice Greenfield No. 6 today, and was looking for information on it. Thank you for the complete explanation of how it works. I now know I found an excellent tool for my chest.
I was watching this in my shop inspired me to take my tap wrench apart right then and there while watching this thanks love the moivies
Love how you invite folks to "conclude the video right now".
Odd how of all the old tools I've picked up at sales and auctions, you Sir, seem to make a video of them each in turn. By the end of the buying up of crap season (garage sale season)I found myself in the possession of 4 or 5 Greenfield handles. The weight of them and the overall aesthetic drew me in 1st time I picked one up. Great minds I suppose. Excellent video Mr. Pete, thank you.
Would you believe that I just came from an auction this afternoon? I Purchased a tap and die set reasonably priced simply because it had the GreeniField tap wrench. Watch for that video next week.
This "differential screw" system was used for the blade adjustment on the English Norris wood plane, it gives a very precise adjustment, we seem to be abandoning a lot of very good mechanical ideas in our modern world.
I have several of these handles. I never had tried to take one apart before.
All the best!
Mike
ONE MORE TIME YOU SHOWED ME SOMETHING I DIDN,T KNOW. I WOULD SURELY STRIPPED THE THREADS IN AN EFFORT TO DISASSEMBLE IT. THANKS AGAIN MR. PETE
Great video, Mr. Pete!
I picked up a Greenfield No.7 this past weekend at a flea market, and referred to this video to get it apart for cleaning. It's the older pattern design, that of your No. 5. Unfortunately the color from the case hardening is completely gone, and the movable jaw has also been chipped, though making a replacement jaw might make a fun project.
Thanks again for the very informative video, it's much appreciated.
Thanks--you will like the greenfield
I thoroughly enjoyed this video! What brought me here is the recent thrift shop acquisition of a Greenfield No. 00x4 Tap Wrench. The overall length of the tap wrench is: 5-1/4", and its case-hardening is very much in evidence, as the tool shows that it has had very minimal (if any) actual use. Near as I can tell, it is for 1/16" -1/4" taps. It sure is 'a cute little bugger"! You now have another subscriber!
👍👍🙏👍
You da man Mr. Pete!!! Thanks for all that you do, to get a video out. Once again, well done!!!
Enjoyed the video very much. I have Greenfield #0-#7 and some others. For those thinking of taking one apart, mark the orientation of the dynamic jaw. In order to minimize runout the jaws have to fit as they did from the factory. It may take you a while to reposition the static jaw. Ask me how I know. Better yet, don't take one apart if you don't have to. FWIW, in terms of lubricant, I've found that moly grease works best. Thin oil, not so much.
Regarding the wrench that was cited as an older #5, IMO it's newer. I have one of them, as well. Greenfield was bought by TRW in the mid-50s and owned the company until the mid-80s. If ya take a look at a TRW tap wrench, its shape is essentially identical to the #5 in the video. I could be wrong, of course. It would be great if someone knew for sure. I don't have a Butterfield, but hope to one day. It was cool seeing it.
Thank you for the information
Any video with discourse in the title gets a thumbs up from me!
+mc349iii You must be proud
Just rewatched this video. Yes you have done a wonderful job of explaining as usual. I have a Greenfield No. 5 with the old beautiful case Harding. I’m guessing it to be 60+ years old. It still looks like new. I also have taken it apart since they get sluggish with age. Thanks for the refresher.
Thank you for watching, they are awesome tap ranchos
That is wrenches
I am a staying and I am a learning...THANK YOU... for sharing.
You reminded me of a Little Rascals episode when the new schoolmarm asked "What is one and three?" and a kid answered "Oil!"
We've used compound screws to achieve the opposite effect in the high precision coating machines we built. There were just a few differences, however. Both threads were right-handed and one was a single thread pitch different than the other. The net effect was a whole bunch of turns to net a tiny amount of linear motion.
Two things:
The compounded threading allows the threads to be self locking when tightened. On the small diameter, a 10TPI would be at a steep enough angle that, when lubricated, it could slip, like back-driving a leadscrew. An extreme example of this is the `spiral' screwdriver. Instead, the threads lock like a two stage screw jack.
My opinion is that the Butterfield is a little stronger used the right way because, as stated by others, both jaws transfer force more directly to the frame. I doubt the difference is significant in service, since the force for both is primarily transferred near the corners of the tap end, and both jaw designs provide a straight line in the force direction (perpendicular to the face applying the force) through the jaw to the frame. Experience tells me that the Butterfield is certainly more resistant to a worn tap end skipping out of the jaws, when used in the correct direction.
A little late to the game here, but another example of compound thread to provide advance speed can be found on the clamp screws of Wild (later Leica) survey instrument tripod legs.
I happened upon this video while searching for an good-quality but inexpensive tap handle that I could trim the arms on so I can use it on my 12" lathe. The Craftsman I was using to tap a 1/2-13 thread today is too big to clear the lathe ways, but I needed all the leverage I could get and my T-handle tap wrench just wasn't big enough. I've had the Craftsman for over 40 years and don't want to chop it, but after watching this video I guess I'm not going to be buying and cutting up a Greenfield, either.
Thank's Lyle...Always look forward to & enjoy your consistently honest levelheaded informative attitude...
An important note about the greenfield model is that, since the fixed jaw is retained with a set screw rather than the handle, you can remove one handle to tap holes in tight spaces without needing a different style of tap wrench, so long as you still have enough room for the tap body. And if I’m not mistaken, the ability to transfer torque should be roughly similar since the contact area is similar, and most importantly, both handles should be able to readily break your tap off while you’re tapping the last hole.
Thank you, I never thought of removing one handle
Even at 76 one learns something new every day. Very interesting how the double threads, LH & RH, are used together, very interesting. Many thanks for taking the time to explain. You make very nice, informative video's. From Missouri
Very interesting video. I have a Craftsman tap handle that looks something like that and I have had it since the 1970's and it has never occurred to me to want to take it apart. I guess I was just glad it stuck together all this time. =(;-) Now I expect that I will not make it all day without taking it apart. Keep on keeping on.
Douglas Corrigan once flew to Ireland after "intending" to fly to Los Angeles (he could not obtain permission for a transatlantic flight). He completed the flight despite the presence of a leaking fuel system.
Mr. Pete, the first time I took one of the apart, as a starting machinist, I was taken aback. The next day I immediately asked my instructor about these threads. Very nice video Sir.
I have a smaller Butterfield tap handle that belonged to my dad. Back in my early childhood of discovering how things went together and worked, I snapped the pin thread off the handle for the fixed jaw, not knowing it was left hand. Mixed up a bit of Epoxy and glued the handle in place and jaw was left loose. Don't know why I didn't glue the jaw in place. Fifty something years later, I still have that little tap handle and it gets used every now and then. Thanks for the video, Mr. Pete. Ken S.
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Hi mrpete222 The thread system shown in the tap wrenches is also found on the Lee Valley adjuster mechanisms for their hand plane blades. Very smooth and positive.
Great video for tool nuts, the time flew by! A few thoughts:
- The contact flats are basically the same in both tools, though with the butterfield it might be stronger in one direction of rotation than the other suggesting you would need to flip it to make sure the wider flats were resting rotation? The Greenfield would be "ambidextrous".
- I'd expect the butterfield to be slightly more resistant to "blackout tendency" since it has the finer thread and the coarser partner thread would be fully pushed in to take up any backlash, suggesting the governor of backout tendency would be the finest thread in the stack.
-I've seen these compound threads used on modern fanlight winders, the type where you use a hooked pole to reach the roof light and twiddle a nut.
Perhaps I'm overthinking it! Love your videos.
+Ian Sanders I agree, I think the Butterfield would be strongest but you would have to pay attention to which direction you put the tap in (similar to the crescent wrench argument). Having the long flats as the driving side would be strongest, although either one would more than likely stronger than most taps
thanks for the revelation, mr. peterson.
never thought of the innards of a tap wrench -- very ingenious.
thanks for the vid,
-toly
Funny, I have a bunch of these wrenches, and I've even had a couple apart, but I never realized what they were doing with the 2 threads. Thanks!
Sir, I am going to have to accuse you of thinking like a machinist... (compliment)... indeed, you sir, are an intellectual (no offense meant)... you put a great deal of contemplation and effort into these videos... so much detail on the complexity of what until today I was sure was a simple device... I turn it... it tightens... but NO, like almost everything in life; nothing is ever as simple as it first appears! Thanks.
+bentontool Your comment means a lot to me!!!
I am a Registered Professional Engineer, but I have never designed tools. Many thanks again, Lyle.
Thank you once again for the detailed information, we all use tools like these regularly, but one does not often stop and think how much thought actually went into the design of a everyday used tool! Never too old to learn and look at something from a different aspect!
Thanks for the simple and clear tutorial. It explains why our El Cheapo tap holder at work, without a compound thread, comes loose while tapping.
The Butterfield is the stronger one because of the larger clamping area on both jaws, but notice that it also cut 5+ operations (not counting the threaded holes), when making the Greenfield jaws, down to two operations for the Butterfield because both jaws have the same design. That's a real costsaver...
I disagree, the Butterfield design is directional, and only has more contact area when operating in one direction of torsion, in the other direction it has much less contact area in reference to the force direction.
On the Greenfield jaws there is one full surface contact for each torque direction on one jaw, and the small surface contact areas on the second jaw are just for inward linear force instead of torque resistance.
the mechanical principle to use the advancement of two screws with a single rotating part is called "differential screw": en.wikipedia.org/wiki/Differential_screw In the majority of its applications the two advancements work against each other (hence the word differential) such as in microscopes to achieve minute advancements per turn. E.g one thread has a lead of 50 thou forward and the other 48 thou backward resulting in only 2 thou advancement per turn. In your example in the video the two advancements are added to achieve an extra long advancement. The same happens in turn buckles.
+rol eic Thank you ever so much.--I added that to the video at 10:15.
+mrpete222 You are very welcome. The differential screw is not very widely known and deserves more publicity. The differential pulley en.wikipedia.org/wiki/Differential_pulley is already better known. And the differential gear is the star. en.wikipedia.org/wiki/Differential_%28mechanical_device%29. All three are governed by the same principle: two opposed, slightly different movements. Considering your talent to visualize and explain technical principles this might be worthy material for a new video. I think you have covered the differential pulley and gear before. (BTW the car differential does not lend itself to easily explain that principle since the two opposed movements are equal. An ordinary planetary gear, which is also a differential gear, is easier to explain.)
I have used this type of tap handle , but never new how they came apart , now I do thanks mrpete.
Now eyeing my tap wrench with bad intent...thanks Mr. Pete! Great video.
Snap-on sells a tap wrench that looks very similar to the Butterfield. It appears to be about the same size as that #10. It sells for $91.00 on the site. It is tough to tell but it looks as though it is cast instead of machined. I have a T & E tap and die set. Both of the dismally inferior die cast wrenches from that set have been replaced by Greenfields.
Yes-the die cast wrenches are pathetic
Great video Mr Pete. I feel I paid too much @ $10.00. Try to buy one of this quality at the Big Box Stores.
Very good Mr. pete, never had one apart really did' not know how they worked now I know.
I enjoyed it, and now understand why I have been outbid several times on E Bay. Maybe someday! I must keep using my "cheap," but workable imitations; but, there's nothing like the "real thing!"
Very interesting, never occurred to me there was that much engineering in something so simple
I like the style of that last Greenfield No 5 .
Thank you, I love learning how and why tools work. The Butterfield is brilliant thinking, too bad they aren't made anymore. Love the videos
Many thanks Mr. Pete, I enjoyed it very much.
Thanks for watching
Engineers are so ingenious. I really enjoyed this video.
Watched with great interest and equally great enjoyment. Could be included in your "What makes it work" series which I love too. Thanks Mr. Pete!
Very interesting video Mr. Peterson. I think it is great that technology so old is still genius in it's concept.
Thanks to you, the mysteries unfold a bit more quickly. A great help
Mr Pete, you used up all the dry ice, could have used it on those jaws. great video as always. Thanks
That was one of my first projects... I loved how the right and left hand threads worked together..
Yes MrPete the color case hardening is beautiful ....BUT alas I'am sure that the process probably involved chemicals the EPA has banned for some reason .... great video as always
Nice video. The slanted jaws have 100% contact on the drive side of the tap.
Thanks Mr. Pete! Interesting to many I'm sure. Glad you added the care and feeding of these fine old tools...with it they will last many life times. You inspired some great conversations below. I agree that the Butterfield is easier to manufacture, more simplistic in design and possibly stronger of the 2. The body design seems more substantial too. As for the right vs left hand tap strength on the Butterfield it may be stronger because of the overall capture length of the tap is possibly greater than the Greenfields...but without mic'ing them out and knowing the tap range for each it's only an earball thought. Would also like to know what % of thread engagement they have? Always appreciative of your gifts to education and us!! ~PJ
Hi Tublicain, I too have a No 7 & No. 5 GREEBFIELD Die's straight handles. Used White Vinegar to clean up. It's magic stuff.It Dose the job quit well. Thanks for the advice. Will keep watching RSA. Rob Schofield I will keep watching.
+Rob Schofield Hi Tublicain, I too have a No 7 & No. 6 GREEBFIELD Die's straight handles. Used White Vinegar to clean up. It's magic stuff.It Dose the job quit well. Thanks for the advice. Will keep watching RSA. Rob Schofield I will keep watching. Sorry about the above in error 5 should read 6. thanks
Great video Mr. Pete! Another one of those seemingly simple, but ingenious designs.
Something not so ingenious, I got a Harbor Freight tap and die set many years ago. The taps and dies actually aren't that bad, they still do the job to this day, although admittedly I don't make a lot of threads here at home.
But the tap wrench was the most abysmal piece of junk! It had no jaws at all, just a V cast in the opening on one side and the handle was a threaded rod on the other that would push the tap into the V. It never worked and it went in the garbage.
The jaw design on the Butterfield seems the superior one to me because the load is transferred to the frame as the tap end is clamped. In the Greenfield, the load is transferred to the screw alone.
Very good demo for a rookie tool restorer! Thank you for sharing!
Mr. Rucker is going to like this one!
It was interesting to see how the Butterfield did the compound threads versus the Greenfield. I have had my Greenfield apart to see how they did that. I see on the #4 that it looks like there is a small screw that holds the movable jaw on the shaft?
It looks like the Greenfield would hold left and right hand taps equally, but the Butterfield would hold right hand taps better than left hand taps the way the V's in the jaws are shaped.
Thanks for the vid. One of these days I'm going to make a tap handle as a fun project. Figuring how I would want to mill/turn the center part for looks is going to be an interesting thing to figure out.
I really enjoyed this presentation. Thank you! Keep up the fine work.
also, since having seen your videos on threading: the "compound threading" seems to offer TWO mechanical advantages... travel *and* torque... over a double-cut thread (travel only)?
GREAT STUFF - thank you!!!
The commonest place where a combination of RH and LH threads move something twice as fast is the simple turnbuckle.
I like the design of the Butterfield a bit better. I think (no engineering; just a guess) the asymmetrical jaws will give a better grip in one direction (flip it to get a better grip in the other direction). But the really cool thing is that left hand thread in the fixed jaw. That (combined with the asymmetrical jaws) _makes the two jaws identical_. The company only needs to make and stock one part to cover both jaws.
=======and here I digress (as usual)========
I was faced with making safety grilles for some low windows and wanted something with a stronger pull-out strength than a simple press fit for the cross bars and the uprights at each side. (This let me use very thin rods to avoid obscuring too much of the view, and still get the strength required by the building code.) I got a set of left-hand tap and die in 5/16-24 (from our old friends at McMaster-Carr) and fitted the left ends and side rail with left hand threads and the right side with right hand threads. Then it was just a matter of assembling both ends of 9 rods simultaneously. (It can be done. I did four of those grilles.)
+Peter W. Meek I thought about the holding of the Butterfield (actually it is symmetrical) and read until I found your comment. I agree, it will hold better in one direction. My logic is that with the Greenfield (and all the others I've seen), you get full contact on one side and a smaller amount of contact on the other; this is not going to hold as well as for example, full contact on both sides. Therefore, full contact along the side with the most pressure, duplicated on the other side, will logically work better or allow more force to be applied. And I like your two jaws identical conclusion.
I have to say though, you mentioned that "The commonest place where.a combination of RH and LH threads move something twice as fast is the simple turnbuckle." Hold on, it doesn't speed up the action of the threads, just allows the thing to work while turning in one direction. Either both sides come together or both sides move away. The combination of RH and LH on the tapping tools "gears it up" in the right arrangement. If they are the same direction, the design changes like you pointed out enabling both jaws to be the same, just a different screw arrangement, both same handed. Interesting to see both tools use a different approach with the same end result.
It's a good video. Reminds me of: "How exactly does a posi-traction on a Plymouth work?" "It just does." -Father of Joe Dirt.
True, the Butterfield jaws are symmetrical, but in a less common form: rotationally symmetrical (of order 2). We usually think of symmetry in the mirror-image sense.
Just as the tap holder closes at roughly twice the speed of a single screw, so does the turn-buckle shorten or lengthen at twice the speed. The LH-RH threading probably _is_ intended to make it work at all, but the effect is to make it work twice as fast.
I enjoyed this video very much. Good information. Thanks
I think Greenfield also made these for others, including Sears Craftsman.
Really enjoyed the video I think I like the Greenfield over the Butterflied Thanks for posting the video Mrpete always looking forward to more of them!
I've always been a big fan of the symmetry in Greenfield's handle. I use Starrett wrenches at work and don't like the feel of them because they aren't symmetrical in my hands when using them. About Greenfield vs. Butterfield...let's not overlook the theoretical 3% more holding power of the Butterfield due to it's lead being smaller. For X amount of torque input you will see 3% more force output with the Butterfield. Thanks for the video!
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My late father in law worked at GTD for many years. At that time, many years ago, I was not interested in machine tools , only his daughter. I have two brothers living in Greenfield MA. My younger brother worked at Millers Falls Tools until they failed. The employees decided to try their hand at keeping the company going. Well soon after, many tools were being returned and they too failed. My brother is in the process of moving to NV and asked if I wanted a lot of taps and dies. Oh yeah I do, so he put about 65 taps and dies in a 2nd day mailer and sent them off to me in CA. Well, sadly his packaging wasn't so great and the box burst open enroute, due to too much weight and only six taps and three dies arrived here in CA. The post Office is looking into it, yeah. Great video Mr. Pete , I love this stuff. Ken....Marina CA
great video Mr. Pete, thanks for you service
Interesting. I'm a retired engineer, but not a mechanical one, so take it for what it's worth, but the Butterfield design seems like it would have more surface contact when turning clockwise than the Greenfield, because the longer edges on both jaws would be working together. On the Greenfield, only one long edge on the fixed jaw is applying force at any given time.
Great observation and analysis
Some of the new junk sold in auto parts stores use a compound thread similar to the Butterfield, but of course it's not nearly as durable. The set I have, the moveable jaw will disengage from the thread before it bottoms on the fixed jaw, meaning it's prone to getting lost, or damaged if you try to use it on a really small tap. Nasty pieces of work, they are.
Some older knockout punch sets will used a compound thread. Color case hardening is another service I provide, mainly for firearms. The BIG 5" & 6" conduit size wrench turned KOs used a compound thread set up to avoid too too much movement of the draw stud and to pull the die in faster without stripping the threads off the die or the draw stud. I did not see big wrench driven studs for many years, unless someone brought in an old antique punch.. They were all hydraulic, and now they are back, but only up to 4" conduit, as far as I can tell. The stud drive was a big ugly cast football shaped blob, you turned with a Stilson wrench. You won't see that anymore!
The big name in KO cutters is "Greenlee" who started out making mortise chisel & drill bit sets, for woodworking.
If you play around with wooden planes, Stanley No.62 has a 'Norris type' screw adjuster to advance the blade. In fact, there are many types if this 'Norris Type' screws use on the same sized plane by other manufacturers like Lie Nielsen and Veritas. The threads can be a RH LH configuration or can be both in LH LH configuration.
Thanks
When I saw your picture of this video, it caught my attention because I made one of these tap handles when I was an apprentice at Buick. Someone in the machine shop had an original and I thought it would be neat to make one for machine shop practice. I saw this gadget in a storage area and found out it is a lathe attachment to round the end of a piece of round stock to a spherical shape (i.e. the rounded end of a handle). My tap handle is 16" long when closed. I used 5/16-18 thread on the movable jaw and 9/16-18 thread on the handle. 18 t.p.i. is .055" per turn, so my jaw moves .111" per turn of the handle. Not sure if you post your email address, I would send you photos of it. Don't know how else to send photos to you. Thanks for the video tubalcain !!!
Shortly after I wrote my last comment, I ran across your Shop Tip #123 Turning A Ball. The gadget I used in the shop did the same thing, but you turned a handle with a worm gear to move the tool around the work.
Thanks so much for this timely video, as I have been lately collecting these fine examples of american tools. I've not been able to find the information that you presented, so I copied your chart on the sizes.
Also I have a couple that appears to be gtd but branded as trw. But the number sizes are different.
The double thread system is also used in South Bend's telescoping steady rest fingers as well.
As always, thanks Mr. Pete, very interesting. I will now have to take one of my Starrett wrenches apart to see how they did theirs. I have a Greenfield #7 and wish I had a whole set of their wrenches. I like to looks of that older #5. Perhaps you will do a video on die holders?
I just used my #8 today to cut threads on a wobble box for an IH mower.
Very interesting video! You're like the grandpa I never had!
Thanks
Not being a machinist, I would think the handles were threaded on a lathe, vice using a die. The Butterfield handle looked like it was undercut at the end of the threads. Not sure about single pointing an internal left hand thread on the Green field though. I also think the Butterfield has a slight edge in strength, and would better transfer the torque to the tap. In theory anyway.Bob
Since I can't actually measure both here, the appearance shown in the video lead me to believe that an equal amount of tap edge is contacted by both brands. Each side of the greenfield V appears to be (at least close) to the length of the short part of the butterfield L. So equal surface contact.
As for which is better, I suspect the butterfield design is, since the entire 1/2 of the tap pressure is on the movable jaw V of the greenfield, and the other half on the 100% contact fixed jaw. Remember, the forces exerted are not solely rotational, since the silly human operators rarely apply pressures in only a single plane at a time, being the defective poorly-programmable meat machines they are. Side thrusts would appear to be more of an issue for the greenfield design.
- Wes
excellent mr pete
It's a form of differential screw, normally used for fine adjustment (one thread moves in opposite direction to the other) but in this case configured for rapid closing while not being back drivable as you say. I think!
Turnbuckles used to tension wire ropes utilise left and right hand threads.
Very good video Sir. From years of discussion with tool reps such as Snap-On with their 'Flank Drive", I believe the Greenfield may have a strength advantage given the fact that two adjacent sides are fully captured for turning torque, the movable jaw just holding the driven square of the tap into the fixed jaw. Not an engineer, just looks like it would have similar drive force.
thanks Mr Pete, great video
Steady Rest screws like the South Bend have that same two thread system.
I made a tap wrench of that design as a first year apprentice in 1969.
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I currently have greenfield 4 & 5 and I'm trying to find 6.
Nice job
The steady and follow rests for my South Bend use a similar double thread. Its course on the brass bit on the inside and fine for the knurled knob on the outside though.
great video as always
...as for compound thread applications ..not much but ive seen it once inside an old water valve
it works on the same fashion this tap does...in order to close and open the valve gate .
pretty elaborate if you ask ...now i bet they got rid of this design and used a single thread style
Wow, $57.15 for a number 24 in 1958. That would be $473 in today's money. What is the oldest McMaster catalog you have in print?
thats it
A quick scan of ebay shows that butterfield used the same jaw system as greenfield at one time. Maybe made by greenfield once?
I would suspect the two holding methods work out to be approximately equal, if other factors are equal (like the "depth" of jaws dictating how much of the tool shaft is being held)