Grinding a HSS Thread Cutting Tool with a CBN Wheel
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- čas přidán 2. 03. 2021
- Building a grinding guide (or jig) to grind a High Speed Steel thread cutting tool using my new CBN wheel and grinder. CBN grinding wheels are used to grind hard materials such as hard ferrous materials, hardened steel, bearing steel and nickel based alloys. CBN is an acronym for “cubic boron nitride” and is the second hardest material known to man, right behind diamond. It grinds HSS fast and with less heat build up than any other material.
Turned out very well. Nice results on your HSS tools.
Thanks - I love it
That is a nice grinding station that you built. HSS sure comes in handy on smaller low rpm lathes. I have a feeling that this grinder is going to see alot of use.
Thanks Andy, and i agree, it will get some use.
Putting a small radius on the tip makes the tool cut smoother than a sharp point. Sharp points tend to to dig in an tear material out as where slightly radiused will cut without tearing. This is particularly true in "gummy" materials.
I agree... and I did this but didn't show it. Thanks
@@WinkysWorkshopIt’s also there because threading is a forming operation and a properly formed thread has a flat that’s 1/4 the pitch wide (more typically a rounded over flat on the tip that starts with a flat 1/8th the pitch wide). A sharp root is a stress riser and makes the minor diameter smaller, reducing strength, especially with coarse threads.
You cost me money, Mark! My wheel is on its way.
@@ikkentonda Haha... I don't feel bad, you will love it.
‘Hope I don’t lose a finger here.’ Priceless
Kept it :o) I made a much better grinder after this one. czcams.com/video/geuMA41ldqQ/video.htmlsi=iKD1fxLmzFFSS4gg
Mark, I was on a job for the Air Force on the base, and we were installing a liner in the concrete drains as the area we were working in had specially treated water, and we installed a metal (stainless?) Strap over the upper edge to anchor the vinyl liner in with. That concrete was so hard that the carbide bits dulled quickly. We finally used the bench grinder to keep them sharp. I don't recommend doing this. Some bits turned blue, so they were junk. We did manage to finish the job, but it sure took its toll on the bits.
CBN is not good for carbide. You need a diamond wheels
@@WinkysWorkshop this was 30 years ago, so we just used aluminum oxide, and a lot of water. A diamond wheel would have been nice, but we used what we had.
@@Farm_fab yeah... that would be a pain.
Very nice grinding tool. Do you make more videos about grinding cutting steels for the lathe?
I might make some. To be honest I've used mostly carbide inserts so this is kind of new to me. One reason I never ground my own tools is that it took forever but the CBN wheel changed that. HSS is sharper and cuts better than the carbide. Thanks
That is so cool. I really the whole build and the end results fantastic. Great thread!
Thank you very much! It worked very well
Great job wink, made one out of aluminum with two set screws it's ok but it don't slide very well on the steel table, I like the wood idea.
Interesting, I never thought about how it would slide. Wood does work well... easy too.
@@WinkysWorkshop It would improve even more if you wax the bottom face of the wooden jig. As the post above says,aluminium has a tendency to gall and stick rather than slide smoothly.
Your voice is like the old 1960's wildlife documentary narrators.
Keep up the great and very inspiring vids, new subscriber here.
Welcome aboard! Intersting... I wonder which documentary.
@@WinkysWorkshop I meant to say documentaries.
@@allenloosescrew8246 Like your name! Ha... I was born in Seattle but have live in KY a long time
Some 30 years ago I lost the tip of a finger in a jointer accident. Your setup cutting slots on the router table scares me. Kickback happens way faster than human reaction time and can pull your hand farther than you would think. I'm not trying to tell you what to do. I'm just urging you to be careful. I still regret my stupid mistake which could have been avoided by taking 5 minutes to come up with a better setup. I do think this is a great project and I thank you for sharing it.
I agree, there is absolutely no way to react to a kickback. I felt safe with my method even if did kick back. But now that you have mentioned it... I just thought of a method I should have used.
Muito bom amigo, parabéns!
Gracious
I have had a CBN 6" wheel on the grinder for 2 years. It walks through tool steel. Mine has a 3" radius cut. I would like to be able to grind flat like Woody. I have bought a couple more CBN wheels from Woodworker Wonders, but have not done the work that Woody did to make his grinder.
Woodworker wonder makes a 6 inch 2-sided CBN disk with 2 different grits. If I was going to make another grinder this is what I would use. The abrasive wraps the end just enough to cut a back rake notch. It's only $59 bucks. It would be perfect to mounting directly to a 3450 motor shaft
The grinder turned out Great Winky. It’s always amazing watching the things you come up with. I plan to incorporate a lot of your ideas into my Shop. Thanks
Thanks! It was a lot of work but I had all the parts so it was very cheap. CBN is amazing for HSS.
Great solution to a nagging problem! Love the simplicity of your design. Solves my problem of multi-facets every time I free hand grind. Don't have the knack and never will. Thanks for sharing.
Glad it helped! Thanks
Great job. Love the way that CBN wheel cuts.
I love it. This is a good deal... two sided disc with two grits woodturnerswonders.com/collections/cbn-wheels/products/cbn-discs-for-work-sharp
Excellent Mark. I like the common sense approach of using wood for the jig. My mind would have been using some metal probably aluminum and doing it in the mill. Your idea is quick easy and functional. A lot can be said for diversity when it comes to creativity. Thanks again for your effort and time.
Thanks 👍 Of course you could still use wood and mill the slots too.
Good Morning from Bonnie Scotland
Thanks!
If I could get a Deal like you did on that wheel I'd build one of those too.
This site sells a new 2-sided disc (two different grits) for $60 buck. Not sure what there shipping rate it but that's not a bad price. The two grits is a huge plus. My 60 grit is a little course. 80 would be better but they sell a 80/180 combo disc. woodturnerswonders.com/collections/cbn-wheels/products/cbn-discs-for-work-sharp
@@WinkysWorkshop Thanks for the info.
Beautiful job
Thank you! 😊
great, idea-where'd you find the clearance angles, please, another way run your wood over the table saw
good man and nice calm voice,\
just tried with the disc on a belt sander with table that tilts
I think I found the clearance in an old lathe manual. wow... the disc cut high speed steel?
Loved it Mark another great video that made sense and establishes a confidence in grinding HSS blank to cut accurate threads.
🏆🏆🏆👍👍👍👍
Glad you enjoyed it
well Mark,i guess you can call this video a rap ,all kidding aside nice video,thanks for sharing my friend....enjoyed it.........stay safe and healthy.....................
You too Ray, Thanks
I always learn something and enjoy watching your videos. Thanks Mr. Winky!!!
Glad to hear it! Thanks
Nothing like getting it perfect 👍 Great job Winky
Hey thanks!
Hi,Mark. This little tool grinder project has turned out exceptionally good. As you would say "I like it".
Cool cutting temp isn't what you would predict from a fine surfaced wheel. You would expect a coarse grit carborundum wheel to produce less heat build up than it does. The specific tip radius geometry is all given in detailed threading nomenclature charts. The main purpose is so the external thread crest and internal thread root have clearance to prevent binding against one another. The contact point should be mainly at the mid point (effective diameter) or PCD.
I am currently building a Worden tool & cutter grinder from a Hemingway kit. It will be a very versatile unit with all the attachments for radius grinding, four facet drill sharpening, slitting saw sharpening etc. I do like your cheap and cheerful version,though.
I'll have to have me one of these CBN wheels.
The CBN wheel is totally amazing. Interesting on the tip radius and it makes sense. It must be a very small radius. It seems like all the insert cutters I use are very sharp.
Neat shop-built grinder!
Thanks. Cleaning up the motor was the hardest part but worth it.
I never thought to do it out of wood. I made mine out of aluminum like Mr Pete did his. mine I made for an acme thread because I needed a 1.5 x 4 threads per inch acme thread. my jig ended up not quite perfect and that created a slight flaw however I did manage to get a functioning acme threaded shaft and nut. 1.5 inch is a big one and so far that is the largest thread I think I can remember cutting so far. I bought some new aluminum stock to make another set for regular threads and a new one for the acme thread. it was a fun project and does help me with grinding HSS which I use HSS a lot more than inserts. enjoyed the video going to check out your video on the build of this CBN grinder now. thanks for sharing the information.
Your welcome! I need to try Acme threads again. I didn't have very good luck my first time.
Does a nice job...enjoyed.
Yeah... I'm impressed with CBN - Thanks
Great machine, what RPM is it running at?
About 3000 RPM. Woodworkers Wonder sells 8 inch CBN wheels and they recommend 1750 RPM on there 8 inch wheel. My wheel is a little under 5 inch. I calculated the surface speed and installed the pulleys to make it run the right speed. It's not super critical. The same web site says you can run there wheel on a 3450 grinder also but they recommend the slower speed.
I read somewhere that there should be zero top rake.
Something to do with it changing the geometry ?
I think as the top rake increases the actual angle of the cutting edges relative to the workpiece changes.
The 60° has to be measured at the workpiece centreline and top rake lowers the cutting edge.
I am probably quoting some purist ultra precision reference book.
Actually you're correct, the top rake does change the angle. I don't think its enough to worry about but it might be good to minimize the top rake. It would work without any but I do think it cuts better with a little top rake. I need to experiment. Thanks!
@@WinkysWorkshop I was going to mention this but you've already covered the subject. The deviation caused by introducing top rake can be compensated for with small angular corrections on the flank grinding. Again,these calculations can all be found in the Machinery's Handbook etc.
I think you have the largest Table Saw Sled I've ever seen! lol
Ha... Yeah, I used to make cabinets and need to be able to cut sheets of plywood. I could never go back to a smaller sled. It also have a 4 x 6 foot outfeed table. You may have noticed the sled (and outfeed table) also doubles as a work bench. It still works well but I'm thinking I need a clean start. Thanks for the comment!
That is an excellent threading tool grind, I like it! I have a spare bench grinder from an auction, now I need to find a CBN wheel for it, lol!
Check out Woodturners Wonder. They have some 8 inch wheels that should run 1750 but work okay at 3450. They are a little high priced but they also sell a 6 inch disc that is 1/4" think. One side is 80 grit and the other is 180. You might need to bore the hole and build a side rest for your grinder but it's very cheap and the smaller diameter makes it more suitable to a 3450 grinder.
I would've expected much lower RPM with CBN wheels, I need to get me one of those.
To determine the speed I went to Woodworkers Wonder web site. They sell 8-inch CBN wheels and recommend 1750 RPM. I calculated the surface speed and applied it to a smaller wheel (4.8 inch) and made it go the needed RPM. Actually the web site said you can run the 8-inch wheel up to 3450. So my grinder is on the lower end of the speed range. What amazes me the most is almost no heat build up. Thanks for watching.
I purchased an 8 inch cbn wheel recently and in absolute aww with it running at 3000 rpm.
Its a great tool
Thanks for sharing.
You bet - Thanks
Hello Mark,
A good video and I like the wooden jig... a simple design and not over engineered. It seem to work great, thanks for sharing...
Take care.
Paul,,
Thanks 👍
Even better when the plan comes together. I wonder what you’re up to next. 👍👍😎👍👍
You and me both! Thanks
fantastic Mark.....
Glad you enjoyed it. I'm currently building another CBN grinder. Part 2 will be posted tomorrow *Friday
Good Job there man!!!! . I am definately gonna build one . Thanx for sharin .
No problem 👍 Thanks
Great video Winky. I guess I am going to have to order a CBN wheel.
Get one of these two sided discs. I think they would be the best. woodturnerswonders.com/collections/cbn-wheels/products/cbn-discs-for-work-sharp
Like #92
Thanks for the video!
Thank you too
i really like it.
Thanks Ray!
CBN wheel? That is new for me.
I' ll look for that here in Brazil. Thanks for trick
Apparently it's been around a few years but it's new to me also. It's great!
I’m gonna need to build me one of them.
Just what I need. Another project. 😁
Thanks Wink.
John
Woodworkers Wonder CBN (run a search). They sell a two sided disc with two grits. My wheel is 60 grit but 80 would be better. They sell a 6 inch disk with 80 on one side and 180 on the other. You could mount it direct drive on a 3450 motor!
@@WinkysWorkshop
Thanks,
John
muy buena explicacion , saludos desde argentina
Gracias
Yes,it works well,Mark.Thank you.
Thank you for watching
That is nice!
Thanks... CBN is amazing.
Can you grind HSS tool bits with a diamond wheel
Yes but this works twice as fast with half the heat.
What grit is your wheel?
It's 60 grit which is actually fairly smooth but 80 grit would be better.
Winky, what grit is the CBN that you are using?
This wheel is 60 grit. However I built another grinder with 2 wheels and it is 80 and 180. I think the 180 would be better if it was more like 300 grit but it does well anyway. czcams.com/video/q-lZwf3Se54/video.htmlsi=P9QO6wJefVuB9DO9
Thank you, Sir. I enjoy watching your work! As a machinist apprentice, your clips are helping me tremendously.
@@saulcardenas1268 Your welcome
Hello....What grit rating is your wheel?
It's 60 grit which is okay but 80 would be better.
Not being a machinist i was wondering how do you determine how deep to cut a thread?
The shape of the crest gives you a good indication, once you go beyond the ideal depth then you'll start cutting into threads. Eyeballing is good enough if you do this often and you don't need a perfect fit. You can always using a DRO and the metric / imperial charts to cut to the depth required but best approach is to get close and then test against the nut or whatever you're using.
There are ways to measure the thread depth but if you are cutting 1/2" threads and you start with a 1/2" bar the depth will be very close when the threads are sharp.
The quick and dirty methods described above work adequately for most home shop depth of thread measurements. If the threads need to be a specific to drawing design then measuring the vee's over thread wires with a micrometer is the method used. Winky did an earlier video on measuring cut threads with the 3 wire method. Look up on google measuring screw threads with wires,there are loads of diagram explanations how its done.
Hey Winky the price of those wheels just went up on eBay great job
Ooops...Sorry! must be my video! I never thought about driving the prices up. Anyway, here's a fairly good alternative. It's a two sides disc with 80 grit on one side and 180 on the other. Good price I think. woodturnerswonders.com/collections/cbn-wheels/products/cbn-discs-for-work-sharp
ΚΑΛΗΜΕΡΑΑΑΑΑ
Thanks
Is that a Z belt on A pulleys?
The number is 3L140 and it .38" wide. The L stands for light duty fractional HP
@@WinkysWorkshop More to this belting lark than you might think...
www.mibelting.com/v-belts.html
There's stuff here that I've never encountered in my 50 year career - GULP!
Very nice jig and cheap for the home gamer
Thanks
jeez , brought back some memories, the rake..imagine a plough in the field... little less rake and angle to right slightly, makes the chips curl out like the oll plough in the field,, best way i can discribe it. the bluntning of the tip? weld we need a bit off free angle to bottom of cutterm, so stone the top a wee bit more than the bottom, the the tip cuts a bit wider (less rubbing in the corners) = smooth cut. We did this by hand and an home made 60 degree gauge (hand filed) for tradetest ! those were the days , 1 inch cube must fit in a inch sqaure plate, no light to shine through, man we got grey ..hehe
Thanks... I'll grind a little more off the bottom.
@@WinkysWorkshop dont make it weak Winky just anormal tiny carefull touch, i , dont blunten the tip , never done it :) was tought different, a slight flattening is ok to open up the thread inner V (but with V threads no nead.) tks for the vids i enjoy it.
30° plus 30° = 60° included angle
yes
tip flat should be 1/8th of pitch
Interesting... I'm guessing it's not critical but good to have a guideline. Thanks!
Very nice and cheap jig for the home gamer
Thanks
Take about the next new techniques sir
Ok. Thanks
@@WinkysWorkshop thanks for your responding sir 🙏
Buen trabajo amigo haber cuando haces una makina de afilar brocas
Podría hacer una guía para esto en el futuro. Gracias por ver.