Making a PRECISE lead screw nut | CRAIG'S WORKSHOP
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- čas přidán 7. 06. 2024
- It's time to look at the Herless 14x40* lathe again. It's got large amounts of backlash in the compound and crossfeed, so let's pull it apart, do some measuring and find out which parts need remaking.
* I started work on this lathe in the previous video, please see that one for the backstory.
Enjoy!
If you would like to help me to make these videos, here is my patreon link:
/ craigsworkshop
Take a look at my website here:
craigsworkshop.net
Chapters:
0:00 Intro
0:17 Preview
0:32 How big is the problem?
0:51 Tear it down
3:02 Inspect the parts
5:09 Choose some materials
5:48 Machine the blank
8:14 Measure the old part
8:55 Side project #590953
10:42 Surface plate goodness
13:20 Thread cutting tool
14:22 Old school layout
16:14 Screw cutting
19:32 The finished part
19:59 Put it back together
20:14 Is it any better? - Věda a technologie
Striving for precision on all dimensions, a healthy amount of self-deprecating humor AND a side project? You've got yourself a good video here! Also super clever technique working out the thread centerline 😎
Thanks Brandon. I am grateful for the kind comments. In editing, I had to resist adding a side project counter... It even felt like plagiarism calling it a side project, so I settled on calling it a detour. Look out for the detour counter in the next video 🤣
I agree 100%…. particularly the thread bore centreline technique 👍👏
I’m going to steal that idea to find the ‘average’ centreline on a PB casting for a loco cylinder 🧐
Regards
Robert
@@RobertBrown-lf8yq Thanks for the kind words Robert. Good luck with the loco!
I was wondering if you would chime in on the "Detour Count" ;-p
@@CraigsWorkshop Hard to lay claim to naming something we all experience 😂 But I appreciate the regard nonetheless. "Detour tally" has a certain ring to it!
Well done Craig. Lots of great techniques used. I learn a lot from watching every time.
Thanks Rob 👍 You are a very loyal supporter 🙂
Beautiful video Craig! I love the overhead lathe shots; the contrasting colors and shades of the different metals in the soft light together with the smooth bokeh background and perfect perpendicularity of the composition; awesome!
Thank you Monochrom - it's great to have you watching, and thanks for the generous comment. Sorry my mention of you the other day has not resulted in more of a bump in subscribers and viewers to your channel, we'll have to hope that one of the bigger channels finds you soon and promotes you a bit. Thanks again - I love your comment. Cheers, Craig
Nothing to be sorry about! I was super proud of your message and Brandon from Inheritance Machining watched and commented on my videos because of it. A little company from like-minded people like you is most of what I was hoping to get out of this. My name is Stefan by the way.
@@monochromworkshop Thanks, and great to meet you Stefan! Looking forward to more of your videos and more conversations. 🍻👌
Good vid Craig. We've all got our lathes sitting there waiting for banishment of backlash in the feeds and this rekindles the inclination to hit the workshop. More power to you, cheers.
Thank you Allan! Kind words 👍
A thread fit like that is soooo satisfying!
Thanks Russell, I'm glad you agree :)
Very nice job Craig. Thanks for sharing.
Thanks Randy 👍☺️
Your logic is solid. Nice thoughtful procedures, and exposition.
Did you check backlash at multiple points along the leadscrew?
Often there is more wear away from the ends of the travel...
but I guess you'd have a good idea whether there was uneven wear, just from running the screw by hand through the initially tight nut.
Yes - there's a section of screw when the cross slide is moved to the near extreme (towards lathe operator), and that section is about 10mm long or 3/8" and it's a bit tighter than I'd want for comfort, but it's usable. Without recutting the screw or chasing the thread on it, It's about as good as I could hope for.
Considering what I started with, where the nut threads were like blades, and the backlash was out of control, I'm very pleased with it.
your videos are a joy to watch . and quite educational thank you for your time
Thank you - that's great news!
Finally someone i really want to subscribe to. Your presentation superb, well narrated, filming great, explanation top notch & a bit of homour... well done
G'day Steve. Thanks for the great feedback and thanks for the sub!
Nicely executed job and good result. Well done. Like the way you determined the vertical centre line of the thread.
Thanks! Yes with it being so worn there was not a lot to measure, but I think the minor diameter of the threads (which is not meant to be a contact surface) is about as good as I could get, given the circumstances! 👍 thanks again.
Neat, clear, educational, and you keep the action going. Thanks.
Thanks Marcos! Glad you enjoyed 👍
Great repair video, nice work on finding nut center, I learned something I would not have known how to proceed.
Thanks for sharing.
Thank you Joe. I will be honest, I was just thinking on my feet there. No planning and I had not seen anyone else using that procedure before. Some of the most enjoyable moments for me are when I figure out when to use the stuff I have to do something in a new (to me) way. I find that very satisfying. I just as often get stuck doing something basic and very obvious though, and realise later with a "D'oh!" moment 😂
Very good video! This was satisfying to watch
Thanks Tabriz 👍 More videos soon
Brilliant Craig. Thanks for this. I have exactly the same task to do on my Sealy lathe and have been putting it off since i bought it during COVID.
Outstanding job Craig.
Thanks for sharing the process.
Really a nice upgrade and fix for an old lathe.
Will be working as good as new or better.
Take care, Ed.
Thank you Ed. I am very pleased with it. Thanks for watching and for the comment. Have a good weekend. 👍
Sorry if I made it unclear in the video but the off-white Herless lathe is the one that needs the repair. The grey Premo lathe (while I still have it, it has to go any day now) is being used to make the part, just for convenience.
I thought of a way to make this work on one lathe though, I don't see why someone couldn't remove the crossfeed nut and screw, lock up the gib, and use the compound set at 90 degrees, to advance the cut. And vise versa, for working on the compound nut and/or screw.
Cheers!
Really liked the old ( new to me) trick indicating on the center . Thanks
Thanks Craig! I have a similar project in the queue, so it’s a benefit to walk through it with you. 👍
Thanks. That's great, I hope it is of some help when the time comes 👍
That was a very nice presentation. Thank you.
Thank you Burt. 👍
Hi Craig great video here and excellent final result. I like some of your setup methods they remind me of the way I work just with a bit more precision. Keep up the good work.
Thanks Joe for the kind words! I know of your channel but am not very familiar with it. I will make sure I go and check it out properly. Cheers, Craig
Great job Craig, fantastic end result. This will make a huge difference to the way your lathe behaves. Cheers, Jon
Thanks Jon, I think it will be time well spent. PS: I have been bingeing your channel recently. I think it's very underappreciated, and needs to grow! Your videos are very informative and excellently put together. Anyone reading this, please go and give Jon a sub! Cheers, Craig
@@CraigsWorkshop thanks for the interest, kind feedback, and plug Craig, much appreciated. Cheers, Jon
No problem, I'll be back to watch more as time permits. Best of luck mate. We should do a sticker swap too.
Great result . 👍
Cheers Max. I reckon it will be better than the old shirt-sleeve unit 😂
thank you Craig this was very helpful for me Lots of good information but I happen to need at this time
Thanks Kimber. Glad it was useful to you.
Nicely done. Bookmarked for when I need to rebuild mine. Cheers.
Cheers HM. Good luck with it.
Great video. Your work is so professional. 👍👍
Thank you MASI, very kind of you to say that. I am not a pro, only self taught 👍
New subscriber, thanks for the informative way you produce your videos.Excellent find!
Hi John, Welcome! I'm glad you like the videos. Thanks for commenting. Cheers, Craig
Outstanding brother!!
Thank you!
Nicely done.
Thanks for stopping by and for the comment 👍🙂
Really love the support from other big machining channels here. Great video! new subscriber :)
Thanks Sam. Yep I am grateful to have some excellent creators (and excellent viewers/commenters) looking at my videos 🙂👍
Very well done. This is something I need to do on my lathe too.
Cheers Tompas 👍
really nice improvement !!!!!
Hey Joel :-) Thanks man. I hope it helps the machine feel a bit fresher and work a bit more accurately.
You went nuts on that job!!!!????!!!!! LOL Nicely done there Craig!!! Cheers
I like it! :-) Thanks Yves for your ongoing support, much appreciated. Cheers, Craig
Wow, mad skills man
Thanks mate. Would be great to have a catchup soon
Great build...you have really upped your video game too!
Thanks Craig. I've been working hard on the video game for a couple of years now, seems youtube is only just now deciding to show my channel to new people. Better late than never! Good job I enjoy all this with or without viewers 😂 Cheers for watching and commenting!
Great video Craig 👍 I cut some aluminium bronze for the first time recently and I'll give it a wide berth in future (unless the job really calls for it). It was as tough as old boots! With that in mind, well done on such a nice clean job. I look forward to the next episode.
It's certainly some good material. I didn't do much to it with hand tools, which is when you'd feel it most of course. I could tell when filing it at the end though that it didn't want to be filed! Instead it wanted the file to skate. Thank you for the kind words.
I obtained some old propeller shafts from fishing boats, fairly cheaply from a scrap dealer. They are 30 and 42mm diameter x 1.2m long, aluminium bronze; 11% aluminium, 4% Nickel, 1% iron approximately. I found that it machines beautifully with a carbide insert, without making the tiny chips you often get from brass. It polishes nicely too. I love it!
We live near the coast so a lot of the recycled materials that are available are ex-boat or ex-marine-machine stuff. Aluminium Bronze is very corrosion resistant and used in this environment for that reason, so this is another reason I think this piece I have is Al Bronze. That part of the video was getting lengthy though so I cut my reasoning out. I agree though, it cuts well and is a nice hard (and slippery) material. You did well to get those bits! I will keep my eyes peeled for more.
Hello Craig,
Nice done... you must have been pleased with the outcome... See you on the next one.
Take care.
Paul,,
That is now the best part of the lathe 😂 I need to make some of the other areas catch up to it. Thanks mate. Cheers, Craig
Nice video, and very nice work on that nut, hope it lasts a lifetime plus. Cheers!
Thanks Howder, much appreciated 👍👍
Great job
Thanks Paul - I appreciate you watching the videos and your feedback. Cheers, Craig
Lapping as you go is a great idea. I’ll copy that!
Thank you 👍 Also makes it a little less tedious and gives your thumbs etc a rest 🙂
Nice repair. That will work. For sure.
Thanks Rustinox, I'm pretty happy with the result. We'll see how long it lasts. If it wears out quickly, I can always buy a new piece of bronze. But - if I fix that oiler I think it should last forever. Cheers mate, Craig
The knee bone connected to the ankle bone - a tune covered by the legendary Hong Kong Fuey
Good result Craig. I need to do this for my Milling machine X & Y axis screws. Lots of play but have a DRO system , but needs doing some day.
Regards.
Steve.
Thanks Steve. DROs are fantastic. I actually have one to install on the big lathe some time soon. Can't wait. 👍 Cheers, Craig
Nicely done on setup and process, plus jokes 😂.
Looks like the compound slide has had a rough life?
Great job and thanks for sharing.
Thanks John. Good to hear from you. The lathe certainly has had a rough go! It is a shame, and looks like a student lathe to be honest. Not sure there is much I can do about it, other than give it some TLC for the rest of its days. Thankfully it won't affect its operation 👍
Hi Craigs, nice job on the nut. Always hard to find the centre but your setup looked as though you got it close. Cheers Kevin
Yes it went very well. I did a bunch of measuring of the screw in free space (supported by bearings at dial end) and then the screw's free end while the nut was engaged with the screw and the cross slide wound towards the operator. Any deflection was minimal and the same deflection achievable on the screw with minimal finger pressure when it was sitting free. So I am a happy chap, it is as good as it ever needs to be 👍
Nice tricks for what you have
Thanks Adam 👍
just found your site great content Craig
Thank you very much 👍 Hoping to get back to making more videos soon.
Nice video, thank you for sharing it:)
Thanks for watching Rixtronic, and thanks for the comment 👍🙂
Gday Craig, the new nut turned out great, I didn’t know that you can use magnets to check aluminium bronze, handy to know for sure, great job mate, cheers
Thanks Matty. Appreciate you commenting and watching. I don't remember where I picked up the Al Bronze info, but it makes sense with the iron and nickel content. Hope it helps you out some time. Cheers mate. Craig
@@CraigsWorkshop Alu Bronze is a miracle material. And the only thing which beats it for toughness and reliability is Nickel Alu Bronze.
Many people would assume brass would be ideal for such a nut but the only good thing about it is that it is probably less likely to wear the screw (unless there's grit about, in which case it will embed in the brass and all bets are off). Fixing the lube situation should ensure your screw and nut last a lifetime!
@@Gottenhimfella thanks for that 👍 Yes I have already fixed the lube situation. I found some more of those oilers and fitted a new one the next day. Pumping some oil into there regularly will flush out any muck and hopefully give the nut (and screw) a long life 👍
good job!!
Thanks Graedon!
That oiler will go a LONG way in keeping that lead screw in working order
Very nice! Keep em coming!!!!
Absolutely. I remembered after the video went out that I've actually got a few spare button oilers here that my friend Matty sent me. I'll have to check their size and see if they'll fit. It will make all the difference if the screw and nut is kept clean and lubed. Thanks Hayden!
You'll be pleased to know that I found those oilers, they were 8mm, so I set up the crossslide, drilled and reamed 8H7 and it was a nice snug press fit in place - easy to oil now! 👍
I have .035 and .012 play on my Clausing. Yes, it is time.
My Hardinge has adjustable nuts to take backlash out. Worth looking at to copy. 👍
Thanks Chris. My PAL mill has a cartridge with two large opposing bronze nuts with lots of engagement on the screw, and they have a fine thread separating them allowing some axial displacement, to take the backlash out. Works well, but takes up a fist-sized space in the table. This lathe has a much smaller space, and this lathe will not get industrial use again, only hobbyist, so what I've done will be great. I can add the original adjustment feature back in, in about half an hour, when needed, so that's on the "someday maybe" list, depending on how fast it wears. With a brand new oiler feeding that nut and screw, and with my light usage, I think it'll last a while. Thanks for the idea!
That was the nuttiest video you’ve made to date. I liked it!
Even nuttier than the t-nuts video? (there were six nuts in that one!) :-) Cheers, Craig
Well now I’m embarrassed, somehow I missed that video. No worries I watched it and now I can profess: this video is pretty nuts and the other is the nuttiest!
😂 sorry if I embarrassed you. Thank you for the comments and support Ed. 👍👍
I just replaced a number of oilers on my Voust. They were all blind holes since I didn’t want to disassemble. The oilers were 8 mm. After cleaning out the balls and springs I found a 5/16 tap wound grab the shell and let me spin them out. I may need to create a new nut for the cross feed as well so this video is right on time.
That's a great idea thanks, and I might just give that a go. Good luck with your own rebuild.
Nice job, very nutty 😝
Cheers Tom. Yes it was nutty and crunchy, now it's nutty and smooth.
Great job Craig! I also like to machine harder/hardened steel. The chips just seem to pull the heat, are very distinct, and it just seems easier to get a great finish! Tool wear aside of course.
I’m glad we got to see the height gauge in use. I think the last time we saw that was in one of your update videos
Thanks Dan. Yes - it was quite satisfying watching the carbide produce the tidy little pile of chips! And most importantly the DTI arm is now usable whenever I need it. So that's a bit of a win. Cheers! Craig
Never heard of Herless but your lathe have the same handwheel at the right side as my Shenwai SW-350 and that is very rare I believe. but very practical. no hot swarfs on your hands during turning., great job making the nut.
Thanks Jozefa. I did not realise that this option was rare, but thank you for letting me know. I prefer the handwheel on the right too. No burnt hands 😁
Great work and love the nod to Monty Python's Parrot skit...
😁 Nice to have a Monty Python Connoisseur in the audience!
When i remade my cross feed leadscrew nut of my hungarian E1N lathe i used i different method than yours of marking the center of the leadscrew threaded hole on the nut. I made a transfer punch that fits perfectly in the carriage's leadscrew hole and hit the semi-finished nut with it that i previously installed into its place. After that i disassembled the nut and clamped it on the 4jaw chuck and dialed it in using the center mark as a reference. I think it is a quicker and maybe more precise method than measuring a worn-out thread. I would like to make it clear that, i am not criticizing your method, i am just trying to help others.
By the way i have just found your channel, i really enjoy your videos, moreover i learn a lot from them.
I hope i was understandable english is not my first language.
Te olyan aranyos vagy
Thanks Buresz, that is a great idea, and a very accurate method. I wish I had thought of it before I started! Next time. Thanks for sharing your idea, and thanks for the kind comments. See you in the next video.
PS: Your English is perfect.
"This is an ex-nut, nailed to the perch".
Only those familiar with Monty Python would catch that one.
I'm glad you noticed that bit. I sometimes sprinkle these in, and wonder if anyone notices, it's great when people do :-)
When lapping we were taught to go in a figure 8 motion so as not to round an edge.
Yes that's the correct way to do it. 👍
It's possible also to lap in a straight line, to get rid of machine marks and keep it flat within a certain tolerance.
Prick punch? Sounds like someone needs to make themselves an optical punch! I had a ton of fun making mine. Turned out non critical dimensions were so accurate, I could not measure them! Very satisfying, but also took a month to make 😮
I may well be picking your brain about this topic in the future! For best accuracy here in the workshop my main method is to use the DRO directly, but for this particular setup, for some reason I wanted to do it the old fashioned way. Those punch marks did come out exactly where I wanted them, but they don't always! An optical centre punch would make it spot-on every time.
Just found you. I thought that was excellent. I did exactly the same as you in that I used an old threading tool (mine was brazed carbide so used slow speed green wheel) to make a tool to cut a 5tpi acme nut for my Harrison Mill restoration. Unfortunately my tool was too flimsy and I ended up using a solid carbide 5 acme tool instead. Look forward to watching your back catalogue.
Thank you Carl. Great to have you on board. Solid Carbide sounds like it would make a very nice rigid (and accurate) threading tool. 👍 Don't go too far back into my back catalogue, I had no idea how to make a reasonably good video for the first couple of years! Anything from the last year or 18 months should be watchable though. 👍
@@CraigsWorkshop No problem. I've been making films for just over a year now and I try to be myself and just show people what I am doing. The solid carbide tool was pricey but did the job. I still have a long way to go with my mill Resto but it is a case of one bite at a time.
Hi Carl, I did not realise that you were making videos. Just went to check out your threading video and after a few mins watching, it's great. Love the channel so far by the way - very clear descriptions and good video. I'll be watching more! Thanks for the heads up.
@@CraigsWorkshop Thank you that is extremely kind of you to say. I work away so I don't post regularly. When I do I try to make it the best quality I can in terms of content and clarity.
Great work! I did a couple of those but I found the tool hard to grind
Thanks Dermot! You're right, it's a bit tricky. I got the tool "finished" as in it seemed like I was up to the lines, but after checking with the protractor again, I was back to the grinder to tweak it further. It's a bit of a knack, but if you're patient it usually goes ok. Thanks for the comment. Cheers, Craig
@@CraigsWorkshop I finished the tool off with a hand stone because I was too scared to go undersize. It took ages lol
I know that feeling! I ground the sides, got the angles right and locked in, honed them, and only then did I think about the tip width (which I also did with a stone), this gives me a relatively decent amount of leeway on the sides.
G'day Craig. Excellent video, & showing what can be done in a Meticulous Endeavour. The Lead Screw Nut worked out really well.
Just wondering what would happen if the Nut was 50 to 100% longer. Would it give more stability over a longer term
Thanks Ted, that's kind of you to say. I think a longer nut would wear better, yes. But threading it would become more of a challenge because of the aspect ratio of the tool. Perhaps with a boring bar style threading tool, which can more closely fill the 12.5mm minor diameter? Or - perhaps a solid carbide bar.
I need to change some oilers on my lathe. I’d appreciate if you did a video on their removal and installation, especially if one doesn’t have access to the far side. Thanks!
Thanks JW. Next time I do this, I will do a video 👍
@@CraigsWorkshopthank you Craig! Enjoying your content!
"And the T Slot's connected to the knee bone." Me: GOT OUT OF MY HEAD! I think I've just happened upon another machining channel to watch, along with This Old Tony (who doesn't upload very often anymore...he's a busy guy) and Cutting Edge Engineering.
Thanks Matthew 😁👍
@13:37 what tool was that, which you used to determine the 30deg angle?
That was a vernier protractor (sorry don't recall the brand) that I have had for a couple of years. It's quite useful for this kind of thing.
I realised half way through making the tool that I have a D-bit grinder and a lathe tool attachment, I could/should have given that a go. But the way I did it worked well too.
The prick punch had me. Subbed.
🥲 Thanks
Комментарий в поддержку канала и ролика, а также труда мастера.
Hi very informative video what is the thread I can't find a 15 mm trapezoidal tap
Sorry I can't recall 100%, but I think from memory it is 15mm X 2.5mm trapezoidal.
Loved the Monty Python pet store skit reference.
🦜
Good work there Craig.
That'll last a good while.
Not really sure why you didn't cut the adjuster slot while it was apart..
But, hay, the bronze will out last brass anyways.
Thanks Carl! Good to hear from you! I just thought it would be interesting to see how long the nut can maintain "acceptable" backlash before I feel the need to adjust it out. A bit of an experiment. On my emco, which is decades old, the "ear" that provides the adjustment on the cross feed nut is actually missing, broken off. It has excellent, tiny amounts of backlash, so I thought I would try it here. Whipping the nut out of the slide, cutting a slot, and drilling and tapping that hole will only take half an hour. 👍
And yes, half an hour in my imagination is probably 2h+ in reality 😂
What material did you use to make the bushing?
Aluminium bronze
Woa i didn't even know there's a variety of bronze that got some parts pf iron so it can be magnetic. One recommendation i would give by experience is using liquid metal (epoxy) for making the lead screw, you just make the thread using the screw itself as mold so you got a perfect fit thread, and you believe or not the screw is very resistant, you can even add brass dust to the mix for better result
Thank you for the idea. I have heard some folks use delrin and mold it around the screw too.
@@CraigsWorkshop yeah, i even used liquid metal to hold bearings, of course you need to cover with a metal sheet to avoid cracks, but is the best way when you don't have a way to machine parts
Very nice work overall. And a great video for doing an internal Acme thread. One thing though.... At 17:45 you mention the need to leave the thread lever engaged due to cutting a metric thread on an Imperial lathe. That suggests to me that your lead screw is actually 2.54mm or 10 TPI for pitch rather than 2.5mm. A small error since the nut is fitting well. But it does mean that perhaps the ends of the nut will be doing more of the work until it wears in by that last 0.04mm.
The lathe doing the screwcutting is natively an imperial lathe yes, but it's using metric translation gears to provide a true metric lead. The lathe that is shown in the start is the one that needs the part, and that one is all-metric. Sorry for any confusion. Cheers!
@@CraigsWorkshop You had me going there! All is well. Cheers!
I'm not going to lie Bruce, the whole thing had me going for a while too. :)
Great video. I need to make / have made (I don’t have a mill) a new split nut for my ENCO 14x40 as I have about as much play in my cross slide as you did. Is this my excuse for buying a mill?!? ;)
It could be the excuse you were looking for, yes.. :)
Regarding hardened parts, i have found that they machine perfectly if you have a tool that can cut them... The harder the piece - the better the finish... I took some cbn inserts aswell, and even on my minilathe, a precision lathe from the early 70`s, not a new import - file hard steel pins machine perfectly with a mirror finish... Not really optical mirror finish, but a mirror like finish with rainbow reflection of the light...
And if you do machine hard parts, treat the operation as if you were using abrasive media... The chips that come from hard parts are machine killers if the machine isnt properly covered and thoroughly cleaned after taking the covers off - just to get rid of any potential crap that fell off the covers onto the ways...
Also, for checking the threads on the internal diameter, dont, just take a scrap piece and make an outer pass... Check that, and if that is right, well, the lathe will cut the same cut as long as you dont mess with the gear ratios, be it internal or external cuts...
Those are some very good points. I do try to be very wary of chips from cast iron or hardened stuff, as you say - it's the ideal material for ruining those lovely precision ways!
Great idea about doing the internal thread checking, it seems obvious now that you mention it, but - I hadn't found the solution so far! Thank you for the idea.
@@CraigsWorkshop
You are most welcome... I thought it stupid to even write down, but i know that i was taught dozens of tricks that once you look back seem like such an obvious thing, yet without being shown, they take ages to precipitate in the mind...
All the best!
I kept losing track of which lathe you were doing the work on - when you were cutting the thread, you actually had the compound screw in your hand for testing?! Or have you still got both lathes (which would help tremendously...)
Apologies Paul. The pale coloured lathe shown on the start is the lathe being repaired. I am using the grey lathe to make the parts, while I still have access to it.
PS. I did consider how to do this on a single lathe though. I would remove the cross feed screw, lock the cross feed gib and use the compound feed square to the lathes axis, to advance the cut. If you need to make a compound nut you could do the same using the other way around, with a locked compound gib. Hard to explain without making it confusing.
Can this threading be done with a tap too?
This replacement of the nut is what is needed even on my new chinese lathe with a lot of backlash. Thanks for the instruction video.
Thanks for your comment. Yes in principle this can be done with a tap. There were a couple of reasons I went the way I did though. First is I can (in theory) make the nut a better fit to the screw than the tap would, especially when you take the wear on the screw into account, and secondly I don't have that tap. It was a good excuse to dust off my single point threading skills 🙂
@@CraigsWorkshop Oh man, I really didn't take into account "the wear" of the screw, good one!
Don't forget to grind the single point threading tool some more several years later when you want to make a new one.
You made a little adjustment screw for reducing backlash. The backlash will accumulate in time. But than you have to disassemble the carriage everytime.
I thought on replacing mine for CNC-purposes with two nuts and a spring in between design. Any thoughts of advise?
I think the spring would have to be strong enough to resist cutting forces in both directions (turning and boring) but not be so strong as to cause premature wear on both threaded halves of the nut. I don't know how you can balance this except without a spring, only with a threaded clamp adjustment.
Thanks for the good tips.
Why are all nuts for compound /cross slides basically made of bronze?
It has very good wear properties when used with steel 👍
👍
Thanks Avijit 👍
If you end up with a narrow tool for threading you can pitch off on the compound plus then minus
I was taught this method in the tool room I started in 1977.
Thanks, that is a good idea 👍 If I remember correctly that is what I did for the final 1 thou pass.
@@CraigsWorkshop It is usful also on roughing out big wide threads as you can use a narrower tool (for square profile)
As then you have less full profile which on a long run less chance of chatter...
@@theessexhunter1305 Ah yes - I see what you mean. Great idea especially for deeper internal threads or threads in harder material, or larger pitch. Thank you for the comment 👍
Nice one Craig👍... Meanwhile poor old Emco is thinking " I'll punch you ya prick for not giving me a cameo part" 🤣
Glad someone got that joke ☺️ Yes the emco is going to feature in a few videos soon. Just need to get the daily driver fully running, and the premo to its new home. I have a bunch of upgrades for the bigger one. Parts are arriving faster than I can make videos... Thanks mate. Chat soon. 🙏🍻
24 thou, pretty terrible, lol, if only my old early 50's Macson was that good, times that by 3 or 4.
Good video, be plenty of people needing to do this job, thanks for sharing.
Hey Woz. Good to hear from you. What I should have added is that there is only 30 thou to play with (before it becomes a knife edge thread) on these relatively fine pitch screws. On a bigger coarser screw, you can get away with a lot more.
@@CraigsWorkshop i use a mag base dial indicator on mine so i don't have to trust the dials, easy to see if it moves too
@@warrenwise8127 Absolutely - I do too, for stuff where I have to be careful and definitely get something right. I have a DRO to go on the new lathe, which will be great. Like a big multidimensional digital dial indicator with great resolution and always set up. Easier to zero too. I hope to do a future video on it.
Lapping should be done in a figure 8 motion, or an Infiniti symbol to allow for all movements to cancel without rocking due to rapid change of motion
You're absolutely right and for critical faces that is the best idea 👍 on these non critical faces I wanted them to have that familiar straight line brushed look. Thanks for your comment!
He is a youtuber, not a machinist
Hi @chipmaster7738 isn't it possible to be a bit of both?
The broken gib 'ear' seems to be a common finding in second-(third? seventh?)hand lathes and machinery. They're cast iron, so not great in tension, and if they've been greased rather than oiled and then aggressively torqued on the adjuster, that combination is often enough to snap the poor thing off.
Yes it's an unfortunate thing. I've considered a different options. 1) new gib from cast iron 2) shim the non sliding side of this gib with brass sheet, soldered on which could give me enough extension to cut a new slot or 3) braze on a piece of steel, and shape it to suit. What are your thoughts on the best way forward? Perhaps there's a better option that I haven't thought of. Cheers, Craig
@@CraigsWorkshop when I was faced with this problem on the compound of a similar lathe, I made a copy of the adjuster screw, and then modified the body of the slide to accept that screw on the back side as well, so that the gib is completely adjustable with the two screws which will always be pushing against the gib rather than pulling. This approach may not be possible in all compounds, however.
@@StripeyType Thanks for that. I had not considered pinching it between two screws, even though that's how the cross slide is set up. I'll have a closer look in the morning and see what's possible.
@@CraigsWorkshop glad to have been able to help even a little bit. :D
Old school layout rather than using the traditional edge finder?
I just fancied trying the recently acquired height gauge out with its scriber feature. I do generally use a DRO and edge finder.
3d print or cast plastic then graphite then electroform to titanium
Maybe. But I don't think it would work quite as well as one made from bearing bronze. Bronze has been used for lathe nuts since the beginning of lathes, and is still used today by the world's best manufacturers.
so close... so close.
theres been a proponderence of "differential threads" lately.
i did this years ago to my little lathe...
a concentric, coaxial leadscrew nut of two pitches.
the "socket" emerges at the rear of the saddle and can be locked. it screws inside the nut bolted to the slide. it is 0.25mm steeper than the original screw.
the leadscrew acts as normal, threading inside the socket, and as long as the socket is locked, its normal. 2.5mm on this lathe iirc. yep, its a rare metric one.
turning the socket makes for 0.25mm/turn resolution.
i was doing a lot of toolpost grinding. couldnt use the compound trick as i was using the compound!
Thanks, yes, differential threads can be very handy. I haven't had cause to use them in an engineering setup as yet, but I've known about them for a decade or two, and it would be very fun to put them into practise. I can see how having to grind a taper would stop you using the compound trick :-)
Hi Craig, I cheated on my Lathe changing the cross slide nut, purchased a LH Trapezoidal tap and made the nut 15mm longer, not restricted by boring bar length and hopefully increasing the life of the nut.
Don't agree with the split nut adjustment, only works for a short time preventing backlash as the short section wears quickly.
My trusty DSG had 2 nuts, one of them adjustable, the old girl never suffered from backlash.
Thanks Willem. That's not cheating, that's the sensible way :-) I've cheated before on an older lathe I had (Hercus 9A, same lathe as the Southbend 9A) by just buying a new nut.
Lengthening the nut crossed my mind, and if I had made the boring bar style threading tool it would make more sense. As it is, I was a little limited by tool length/rigidity.
I'll give the nut some use for a while without the adjuster, it'll surely work well to start with, and it'll be a very quick job to incorporate the adjuster when needed. The layout is all set up ready for it, so it'll be perhaps a half hour job when the time comes.
Thanks for the advice and info! Cheers, Craig
Gave my Hercus 9A to my Brother in Perth, still going strong, nice lathe.
Gave my Hercus 9A to my Brother in Perth, still going strong, nice lathe.
Looks like you had the same lathes I had, gave my Emco V 10 Maximat to my other brother, not as robust as the Hercus, not a fan of the fibre gears in the Headstock but easy to make if needed.
@@willemvantsant5105 agreed. I am not a fan of the fibre gears but I am a big fan of the lathe overall. This one was filthy but in excellent minimal-wear condition otherwise. I may remake the headstock gears yet. The other weak area is the electrics and motor, so I have sourced a 1hp 3ph motor and VFD to replace the lot. That will be the subject of a future video. It is not a hogging machine, I have the 14x40 for that. The two lathes will complement each other nicely I think. One for fine work and precision and one that has a bit more beef, coolant, etc.
I find that backlash is often an exaggerated issue, considering that when using the handwheel dial one can get to measure correctly anyway, or if you need precision just set a dial indicator as needed. Or install a DRO, these come pretty cheap nowadays.
If no backlash is absolutely needed, e.g. as in CNC, then adapt a nut-spring-counternut system, which unlike the split nut and adjuster will not add any significant wear and friction.
Regarding the tightening of the nut to the slide, these two should never be rigidly attached, as with the leadscrew supporteded only at handwheel one can't expect that it will stay centered while being operated. If you tighten the nut to the slide, no matter how precisely you try to align it, that will add strain and wear the nut faster. Use a shouldered bolt instead so you can tighten the bolt only to the nut, while keeping some play between nut and slide.
Thanks for the idea of using the shoulder bolt. You're right about backlash being an exaggerated issue. But you can see the nut was completely worn out to begin with. When it came to replacing it, I thought I'd try to do as good a job as possible. Cheers, Craig
@@CraigsWorkshop Absolutely, one should always aim to replace or repair worn parts, even if with experience and ingenuity sometime one can work around defects. Good work all the way and sorry for not having said that before.
@@jdm2651 Thanks JDM. Fingers crossed it will give me a good few years of service now.
well i thought i may gain some thing out of watching you make things until i seen the carnage on your compound and cross slides so i seed no thanks and have gone to greener pastures Cheers
The lathe is new to me. That carnage was by a previous owner.
@@CraigsWorkshop oh bugger sorry then he would have known he crashed that lot of Carnegie there needs clean up on mill sorry Cheers
I made a new cross slide screw nut for my Chinese Mini lathe. I am a non precision hacker. But it worked out well. I made a video of it which I posted on my channel. I wish I could do work like you. But alas I have to settle for being a bubba.
Thanks Hans - your comment gave me a chuckle :-) I'll go and look for your video. Cheers, Craig
You can always check your thread pitch before chucking the job by running a scratch pass with an external threading tool on a round piece of scrap, diameter. Is unimportant.
Yes that is a good point but I had already jumped the gun and chucked up the block. So this ended up being quicker all things considered but yes checking on a bit of scrap is the best way 👍
Could have been worse? One good nut and one bad nut but still two good screws sounds like a positive scenario to me ;)
😉😂
Its pining for the fields
😁
Fjords - It's a Norwegian Blue.😀
😁 indeed
ஒரு முறை மட்டுமே. எனவே இந்த விவகாரத்தில் . ...
Hi Mkn Gani. Is that Tamil language? When I translate it, it reads "Only once. So in this case. ..." and I'm not sure what that means. Thanks, Craig
Never would I ever machine an unknown bronze or copper alloy, brass however sure.
I spent a long time in the video showing how I identified it as more likely aluminium bronze than anything else. It came from a much larger piece that I have in stock which I don't want to waste. Once I've machined it once, I have a much better idea of how it cuts, and more confidence when deciding to use it on future projects.
If it wears out in 5-10 years instead of 30 this time around, I'm happy to make another. Cheers, Craig
@@CraigsWorkshop well magnetic test pretty much disqualifies the presence of beryllium but not 100% sure,... flies off to the practicalmachinist forum to ask... :)
You should have bought an anti backlash nut and just made a mount for it. Maybe next time.
I don't think they are available in this size. Also clicking buy-now on a shop listing wouldn't have made as good a video, or taught me as much, or been as much fun, or saved me as much money, or reduced my stockpile of materials 🙂
True but if that's your goal you should make one! @@CraigsWorkshop