Fixing Cross Slide Backlash on my South Bend 11
ฝัง
- เผยแพร่เมื่อ 26 ก.ย. 2024
- Making a new nut for my cross slide to address the excessive backlash. I'll also address the problem with a screw that obstructs the compound angle while cutting internal threads. My South Bend is a 1931 model and I'll be updating the cross slide nut and screw to make it more like newer South Bend lathes.
A great improvement to the cross slide. I learn a lot from your videos. I like the why you explain the problem, how you will fix it, then demonstrate the fix.
Great to hear! Thanks
Gday, this made a great improvement to the lathe, the new bolt doesn’t look out of place at all, definitely worth while doing, great job mate, cheers Matty
Very true! Thanks Matty!
Great job Winky. I replaced the nut,s on my mini mill with sintered bronze, and lengthened the nut 1/4". I sacrificed a little travel, but gained stability. For now there is less than a thou backlash which I discovered is in the thrust bearings.
Nice work! You almost have to have at least .001!
That was fascinating! Excellent analysis and presentation. Thank you.
Glad you enjoyed it!
I made a new cross slide leadscrew nut out of bearing bronze for my lathe. I ended up buying a 30cm bar and just chopped a section off it with a bandsaw. Then machined it on my 4 jaw.
I then just used an M10 x1mm tap.
It feels so much smoother than the stock brass one, and I know bearing bronze will wear a lot slower.
Its worth spending a little time improving your lathes cheaper components, especially when they are easy to make.
Bronze is better, how much is hard to say. The bronze use in bearings is usually not ideal (sintered) but some are solid. I haven't noticed any wear yet and my screw was near perfect.
Hey Winky! A good way to avoid issues while drilling brass and bronze, is to use a oil stone and stone a little negative rake on the face of the cutting edge of the drill bit. It won't take much and sure makes life easier. Use a little cutting fluid while drilling and you can control the drill bit easily. I used to keep a full set of negative rake drills, taps, and counter- bores for bronze, along with a full set of bottoming drill bits and taps. Thanks for the video as always!
Thanks... I definitely should have used oil!
Works a treat for drilling Perspex as well
Excellent video and you have a way of explaining things so that when you're done it all just makes sense. Thank you for that.
Very welcome Thanks for the comment.
Another Winky success. It is great when a plan comes together.
Thanks, yeah, it came together much better than expected. I figured the lead screw was worn.
Had backlash also. So, tapped thread in a 50mm block of propylene. Finished it off to fit, still had a little backlash. Heated it up a little, squeezed it in a vice, now tight. Cheap, easy and as I am 80, won't have problem again. Try it.
Interesting... thanks
Fun to watch you work. Excellent shop project. I need to pay more attention to tuning up my machines. Well done. 😎 -Mark
Thank you sir! This has been bugging me for a while. I can deal with .005 or even .010" but .040 was way too much.
I fell asleep halfway through so I went back and watched it again. Nice job sir!!!!!
I'm not sure that was a positive of negative comment. I'm kidding, Thanks!
@@WinkysWorkshop LOL. I didn't think of it that way. I wasn't bored, I had just eat and you know a person can get a little sleepy after a big meal.... Hopefully they gave you two views !!!
@@dannywilsher4165 No worries... just messing with you.
Absolute genius! Believe it or not, I have actually used my lathe with both of the screws removed, takes a bit of planning but it can be done. Desperation and necessity breed interesting solutions.
Thanks!
Great job ! That is a big improvement in my book , ENJOYED
I agree, Thanks!
Very nice! Unless they watched this video, very few would even know this was not a factory part.
Thanks... I got lucky, everything just worked!
I bought a LH acme thread tap for my lathe cause like you I couldn’t find one on eBay. I may make another one after seeing what you’ve done here! Great job
Go for it
I'd love to have seen these when I was a child... better late than never...
Cheers!
True, thanks
Great upgrade to the South Bend lathe! I did the same operation of my English Smart and Brown SABEL lathe that is clearly a development from the South Bend lathe. Couple of things spring to mind. When machining cast iron it is usually best to cut it dry, the graphite in the cast iron acting as a lubricant. Listening to the milling cutter it sounds as if it was stop/starting in the cut which the lubricant could have made worse.
You can avoid brass grabbing on a drill and pulling it into the cut by grinding a negative rake to the two cutting edges.
I made my cross slide nut from phosphor bronze and with no tap to hand, internally screw cut the left hand square section thread. With only the one lathe I had to make a dummy section of male thread to use as a plug gauge when screw cutting the nut. On the SABEL the lead screw nut has a close fitting boss locating in the slide and to clamp uses a slotted head set screw with 45 degree tip that drives out a side pin. The side pin sits in side hole of nut and is radiused one end to match cross slide bore and other end at 45 degrees to bear against conical end of set screw. My set screw slot was worn/damaged so I made a new one. Slot I cut with slitting saw, plunge not traverse cut which is what machined screws usually were before they went to cold headed slots.
Impressive! I'm glad I have two lathes, they have been handy on several occasions. I originally planned to sell one but can't bring myself to do it. The SB is more solid than by Logan but the Logan cuts slightly smoother and the carriage controls are easier to use.
@@WinkysWorkshop Decisions, decisions eh, LOL.
@@TomokosEnterprize The Logan is gone and I miss it now.
@@WinkysWorkshop I bet. We sure love our old iron eh.
You can avoid brass grabbing on a drill and pulling it into the cut by grinding a negative rake to the two cutting edges. That trick also works when drilling plastic.
Nice one , keep them coming always a joy to watch you making somthing usfull
Thanks Richard!
Very nice fix, looks like it has been there from the start and made better than the original.
I think so too. Thanks!
Love watching your process and the presentability of your workspace. Your narration also sounds a note with me, so you have my like and my sub without further ado!
At 11:00, for brass and other soft metals it’s about the cutting edge, not the speed. Grind a wee bit of a land on that edge, at 90 degrees to the work, so that it takes a scraping cut. Of course, that dedicates your bit.
Thank you so much! Somebody else said the same about the cutting edge.
As always, nice job Winky. Glad to see the dial/handle didn't require fussing with like the Logan.
Thanks. I actually made an extension and made a larger dial. I need to put a self locking nut on the handle.
I probably missed the video, and don't know anything about SB to have recognized a
Nice job. I recommend that you drill a hole in a screw that you made and a small hole through the nut that you made so that you can oil that nut and you will get a lot more life out of it. That's the way it's done on a standard cross slide from south Bend.
That's a good idea. Fortunately the south bend cross slide cover comes off easy. I keep it well oiled. Thanks for the idea!
Great project and well devised and explained. Many thanks.
Thank you!
Somehow i missed this video the first time. It seams like a right of passage when we start modifying our machinery to fit our needs.
Another great build.
Backlash is the bane of quality and by extesion ones sanity.
Thanks, Oddly enough, this modification made my lathe like most other South Bend lathes. Apparently this bolt was only used on early South Bend 11" lathes.
hello mr.Wink,another great job done by the master,i like it.......you wink i can not get over the way you get to the core of your work,its almost like deja vue....you and i work as if we were one person,all our conclusions end up the same.great video thanks for sharing,see you next time stay safe.
Thanks Ray, you're too kind!
Nice job. My SB Heavy 10 has a slotted shoulder screw similar to the one you made. This screw is flush with the cross slide. Odd that your SB had a proud screw. I can appreciate the frustration this caused you.
Well done.
Dave.
It is odd. South Bend changed there design after they made mine,
If you want to take up all the backlash in the nut split the nut .250 in perpendicular from the back side and add a couple grub screws just cut it about 3/4 way through so when you tighten them it will spread the threads and take the lash out . Thats the way i did my old Clausing lathe and it worked great
Same design as the adjustable leadscrew nut on my Harrison. The split line is about 1/3rd from the back side with 2 small Allen screws to do the adjusting of backlash with.
My nut was cast iron. It probably would not flex at all. My mill is made like what you describe.
Great Job on the project. Fixed 2 problems at the same time!
Exactly! Thanks!
You keep at this you will have a better than new lathe. I am surprised you chose brass. I thought TQ100 hot plate would have been a beter choice. It is highly machinable with great wear resistance. Brass is slippery enough but I suppose the wear has to happen somewhere eh. Either wear the screw or wear the fitting. You made a better choice my friend. You sure solved the backlash and now time will tell all on your material choice. I am thinking your on the money my friend. Hmm, I was always taught to work cast iron dry with min rake on the tools. Same speeds and feeds as stainless. Great results my friend.
Brass is easier to machine and better than steel for wear plus it's fairly strong. I'm sure some sort of bonze would be better but I'm not sure what type.
@@WinkysWorkshop When I was making silver chopsticks(.925 Sterling)(I have a couple video's on them) It was necessary to toughen up pure silver so the sticks wouldn't bend out of shape when being used. I was originally using copper as the alloy but was having some difficulty with getting the metals mixed so no copper would show. A good friend suggested I use zinc (another soft metal) so I went primarily with zinc and a touch of copper and brass. I had to pour the mix a total of 5 times to get it properly mixed. I am still amazed at how tough the mix was/is. Effort is needed to cut the 1/4 x 3/16 in sticks with a 18 in pair of bolt cutters that if the mix was pure silver a 12 in bolt cutter would easily snip through them. Perhaps a copper/zinc alloy would work for you in this case. It would be easy enough to pour a block of it. Possibly a new project for you when you have nothing else to do, LOL. In the spring I can put a pour of it together for you for fun. It would be great to do a small project together. I would just need an approx. weight and rough casting sizes. I would think an 1/8" on all sides would give you a nice clean piece when finished. I still can't get over how 2 or 3 soft metals will make a really hard one. A while back a pourer called "Backyard Bullion" from England and I did a trade. He did a really nice video on the sticks.
@@TomokosEnterprize - Thanks for the offer. I might take you up on something like that in the future but I'm not sure I want to make the nut again seeing as how it works quite well. I think it will likely last too. Brass might not be idea but compared to steel on steel it's much better... likely better that steel on cast iron too... which is what the original was.
That's a beautiful modification, even looks stock!
Thanks, I'm glad it looks stock, I didn't milling my classic lathe but it added to it's function.
Nice work man, enjoyed the video.
Thanks !
Hi Winky, I've done my share of tapping and also had my share of the dreaded broken tap when tapping small holes. I always use the accepted technique of backing out the tap a half to full turn often to help clear the swarf. I noticed that you also used this technique when you were tapping the Acme Cross Slide Nut. I mention this because I keep coming across TH-cam posts that say never back an Acme Tap up or out. Since I'm going to be Acme tapping too I don't want to make any mistakes. I can say that looking how the Acme tap is tapered I can understand why it should be fed completely through the stock.
Wakodahatchee Chris
Interesting, I never heard this about the acme taps but it might be true. I've had good luck but it takes a lot of torque.
@@WinkysWorkshop Funny, I was just watching, yet another Cross feed video and guess what he says? th-cam.com/video/HbUzO_Ecxic/w-d-xo.html
Very good solution coming from an intelligent mind.
Wow... Thanks!
Good work. Extremely practical!
Thanks Jim
Winky a top fix with excellent video work..Really enjoyed it..greetings from OZ E
Glad you enjoyed it
That was a top-class job. Really good.
Thanks!
Very nice, usefull modification. Thanks for sharing.
My pleasure
I built two nuts for the cross slide of my Boxford CUD lathe (improved copy of South Bend 9").
Mine were a composite, with a steel carrier and brass threaded insert (turned from some big brass bolts I scored for couple of coffees)
I drilled the screw hole through until it was just breaking into the acme thread and tapped it.
Then I stuffed half of a cigarette filter into the hole. I saw this on one of the machining forums.
When I mounted the nut, before I put the grub screw in the top, I filled the hole up with oil.
So my nut contains a wiper and an oil reservoir.
Thats a cool idea!
Well done that man.
Thank You!
Nice video. My South Bend 13, 1978 vintage, is factory made pretty much like your modification.
I noticed that in some pictures - Thanks for the info.
Same with my 1939 SB 11"×4'.
great work as always.
Thanks
Hi outstanding work love the mods, my son restored a 7 or 9 inch southbound, cheers mate
Thanks
Top job. The factory should have done it this way as standard. Great video with none of the high speed footage, which can be annoying. Thanks.
Thanks 👍 I found out later that south bends changed there design later and made it the same as mine. I basically copied there design.
Another job well done, I made one for my pratt&whitney lathe out of cast iron, that what the original was.
Next time it will be brass.
Mine was cast also... I think brass wears about the same or a little better and it is easy to work with
Just subscribed. Great video. I just recently bought an 84-A (1928) this summer. Just had my cross slide apart a few nights ago and cleaned up the ways. Was checking out the cross slide nut and looking at replacing it sometime.
I like this lathe, was the bolt holding your nut sticking up ?
@@WinkysWorkshop Yes, it does have the bolt that restricts the rotation of the compound.
@@RAYAR54 Thanks, the only reason I asked is that after posting this video I had several tell me that mine was not original. I suspected it was and you just confirmed my suspicion.
Beyond excellent!
Thank you sir
I have a 1937 Pedestal style South Bend 11 inch and my cross slide isn't made like yours. Mine doesn't have the protruding bolt, but my lathe also has the taper attachment and I think that's the difference. It's nice to finally see someone else that has one of South Bend's "orphan" lathes!
I like the 11 inch lathe. Yes I was looking at a lot of pictures and most are made different. Mines a 1931.
@@WinkysWorkshop I could see that yours was older than mine from the apron controls, but many things do look identical. You wouldn't have an extra follower rest you're not using, would you? I have a steady rest, but no follower. Also, I am curious to see if your spindle threads are the same size as mine. Mine are 1 5/8 X 8 tpi.
@@cleophusA - Yes that's the size of my spindle too. I don't have a follow rest of steady rest although I plan on making both at some point.
@@WinkysWorkshop Oh, good! I'll look forward to seeing that. There's really only a couple of things I would like to get for my lathe that I don't have yet. One, as I said is a follower rest, and the other is a 3 or 4 jaw Buck or Bernard scrolling chuck. Do you have a supplier for cast iron backing plate blanks?
@@cleophusA - I prefer steel and make my own back plates. It's a big job but still worth while.
OH boy, a new video from Winky!!! Now I will watch it...
Hello Danny! thanks for watching!
A job well done !!! I have to do the same on my lathe pretty soon since the backlash in the cross slide is now becoming a real pain . I will have to cut the threads on the nut on the lathe though . Thank you for sharing this .
This old Tony did a video where he tapped inside acme threads. The tap is way easier and only cost me $22 on ebay. Thanks!
I wonder if that protruding bolt head is the result of some previous owner's effort to "fix" a broken or missing part?
I'm no expert at all on Southbend lathes, but I'd bet dollars to doughnuts that it left the factory looking a lot more like your 'modification' than it looked before you started. I simply can't believe that SB - or any other manufacturer of industrial machinery during that period - would produce a product with such a glaringly obvious (and easily avoided) design flaw.
...I have an 11" Logan (model 955) lathe that came to me with a couple of similarly bone-headed "repairs" that I've had to re-repair in ways that made more sense.
Thank you sir for another excellent video! 👍
I don't know, it looked original but you are right... a silly thing to overlook. Thanks.
Nice job! Thanks for sharing and keep up your great work!
Thanks for the visit
Amazing job winky and.great job on the fix
Thank you !
The Boxford Lathe, UK version of Southbend The Cross Slide Nut has a Long What you call an extension, it is fixed to the Cross Slide by a Grub Screw Which has a point Which pushes a small plunger in a hole @ 90deg to the "extension" . the extension is a good fit in the cross slide so no real movement of centreline.
I was just going to mention the grub/pinch screw tightened onto the leadnut extension boss. It is a good method of securing the lead nut.
Thanks for the show, great job
Thanks for watching!
Thanks... enjoy it very much..!!
Your welcome, thanks for watching!
Nice job Wink, a little bluing and it will match the rest of those screws. Nice job on the brass, cheers!
Thanks you sir!
Excellent work. Enjoyed it.
Thank you sir
Play/ backlash is inherent in any normal thread. With a conventional lathe, the play is always moved to one side so it's never a problem. CNC is a whole different ball game although the same principles apply. A really useful feature is a locking mechanism on any slide not in use for the operation at hand. If you don't have it invest time there. We have a Colchester Triumph 2000 lathe at work which I found has a very nicely executed locking mechanism for the compound, also the saddle can be locked. I have yet to locate the cross slide lock.
Yeah, I should have titled the video, "Reducing backlash". You're right about a slide lock. I sometimes use a gib adjustment screw to do this but a separate lock would be great!
@@WinkysWorkshop If you need tips on execution I could send some info on how Colchester did it - simple and effective.
@@bigbattenberg I'm not sure if could be applied to my south bend but feel free to send pics. winkysworkshop@GMX.com THANKS
@@WinkysWorkshop Hmm I just realized I will have to disassemble it again to take a picture. I'll look and see if we have a parts book at the shop or if I can find some image online.
@@bigbattenberg Don't go to too much trouble.
Really love that tap handle! My next project...
Yes the tap handle is simple and super nice. Thank!
thanks for the video great job. time to buy a broaching tool for the lathe
Thanks
Where there's a will, there's a way. Nice job.
Thanks
You made that look easy. And neat
Thanks... I'll admit, it went smoother than expected.
NICE JOB, WELL WORTH IT. REGARDS R.
I'm pleased with the results for sure! Thanks!
Good job! I notice your "other" lathe is a Logan. I had a Logan 10" for a long time, I liked it. I also had access to and used a South Bend Heavy 10. I really liked the SB taper attachment set up-it was like a larger lathe. I didn't care for the South Bend's spindle sleeve bearings. The machine was old, but the spindle didn't have excessive run out, the Logan just seemed to run smoother and cut easier.
I think my south bend if more solid but the logan cuts smoother. I like them both.
very good job
Thanks
⭐⭐⭐⭐⭐ You earned five stars! Nice work.
Yay! Thank you!
Good video. Plus love the Cornet music. 😎
Thanks 👍Yeah, Old time sounding, I like it too!
must be the fall for backlash removal
👍👍😎👍👍 - very nice result.
Thanks Joel!
Looks factory! Great job!
Thanks!
Hard to tell it wasn't done that way stock. Which is a high compliment indeed. Very nice. It's silly how some try to keep their machines totally factory stock. Valuing a blue ribbon from a contest that does not exist. ;-)
Yeah... I like to make sure a modification is worthwhile before I alter a machine but if it's worthwhile I do it. Thanks for the compliment!
Now you have a better attachment with the nut, drill a small hole through to the crosslide, to allow oil to get into where it is needed.
I thought about that too but I've been giving the lead screw a shot of oil. I'm sure it is adequate. Thanks
Wink, you need to come live with me for a month. Teach me stuff and help me with all my projects.
I have an extra room. House on the cliffs, cougar, black bear, deer, bobcats, foxes, squirrels and ravens in my backyard. You would like it.
I’ll leave a candle burning in the window.
"Lions and tigers and bears? Oh my!" Hahaha... sounds very interesting actually. Morning coffee with the view might be nice. Thanks for the offer and I watch for the candle. ;o)
Nice work..
Thank you! Cheers!
Ok, A question. Did I miss you explaining the tap? I have been worried a standard Acme tap would have to much clearance and you'd end up with a lot of backlash. I've purchased a couple but not used them yet. You however ended up with good backlash which is encouraging. Did you use s special tight tolerance or standard tap?
No you didn't miss it. I thought I bought the tap on ebay but apparently I bought it on Amazon. Either way the G spec was not specified. I was actually kind of shocked that it was tight. This is the name of the tap if you need one. "MPI Tools Acme TAP High Speed Cobalt Steel 1/2" 10 TPI Left Hand Threads"
@@WinkysWorkshop I bought the same size tap on ebay for $13.70 to make crosslide nut for 1936 atlas 10d and had nearly no backlash! can't believe how well that cheap tap worked good vid thanx!
@@bowlweevil4161 Thanks! Yeah it worked great for me as well. I was worried about lead screw wear but apparently I didn't have much. Most of my remaining backlash is the adjustment near the dial. Thrust bearings would be a big plus.
Good creative fix!
Thank you! Cheers!
Well done sir!!
Thanks!
Very well planned out, now looks as though it's always been like that.
Thanks, yes and that is a good thing. I hated to drill the casting but the original design was limiting.
Please refer to Brown & Sharp 2g universal grinder cross nut design.Its SPRING loaded split nut.Zero backlash from END TO END.
GOOD JOB ,BEST OF LUCK.
Thanks, I'll look at that although space is an issue I think.
Nice Job!!
Thanks for the visit
Given the lead screw nut is keyed to the Cross-slide with the boss, did you really need a shoulder bolt?
Wouldn't a standard Allen bolt have been sufficient?
You might be right although I just copied a more modern South Bend. Either way I'd have to counter bore and sink and the bolt was east to make.
Nice ,I think I might have learned something.
Glad to hear it!
For internal threading, why not swing the compound in the opposite direction, so it is pointing toward the chuck, as seen from the operators view?
That is a option although it what you have in your chuck is large it will hit the back of the compound. You can lengthen the reach of the boring bar/ threading tool but that's not ideal. For me it is way easier from the back side. You hand is also clear of a moving chuck.
Great project, nicely done! Taking out the backlash is a great result. I don’t see why you had to hide the top of the bolt, though. Is it because the compound would not swing even 120 degrees? How did Southbend never realize that folks would be threading things internally?
I've looked at all kinds of pictures of south bends and they all have a recessed bolt. Apparently they corrected this on later models.
Not being able to swing a compound 360 degrees is odd, but you don't need to swing it so far to thread internally. For normal, right hand threads cut by moving the tool toward the check, swing the compound 30 degrees to the right. Advance the tool with right hand turns of the crank, pushing it into the work (I know you know how to do this, just setting the stage for step 2.)
For internal, right hand threads, swing the compound 30 degrees to the left. Advance the tool with left hand turns of the crank, "pulling" it into the work.
As an added bonus, it keeps all of the controls on the front of the apron. Reaching over the ways to dial in a cut for threading seems silly to me.
Nice job. I need to do this also. How did that brass nut hold up?
It's holding up very well. Most the backlash is at the dial. Ideally a set of thrust bearings would be helpful but space is an issue
I'm curious as to why you swing your compound towards the back. Why not just rotate the compound to the left of the cross-slide? Then your handwheel for the compound would still be towards the front of your lathe when cutting internal threads. With the compound rotated towards the back, the tailstock is going the be in the way and you have to put your hand behind the work piece. Maybe I'm missing something, but I think that you create an issue as a consequence of a bad technique.
To the left works great in some cases but the chuck jaws run into the compound if you try to thread near the chuck. This is only for internal threads so the tail stock is not an issue at all.
@@WinkysWorkshop A longer boring bar might be another option.
@@EDesigns_FL - The last thing I threaded was a 6-inch back plate. I would have had to hang the boring bar out another 2 inches. You are correct however, in most cases slightly longer would work.
Detailed video that I will have to do soon too to remove my Cross Slide Backlash.
Just a thought: with a countersunk hex screw instead of the shoulderbold less material would have been lost from the carriage?
This seems like a good solution and it would have worked but the hole was fairly large from the original shoulder bolt. The material loss would probably be about the same but I was mostly worried about changing the location of the hole with the countersink.
@@WinkysWorkshop OK, lot's of good tips and ideas 😊
@@MLCprojects It helped the backlash on mine a lot but it still has about .010 to .015
Hi, i noticed you've used a parting blade for normal turning, is that recommended? Or is that some special tool that i'm not aware of? Thanks for the video.
It's called a grooving tool. You can part with it but it also cuts side to side. They are great for cutting a square shoulder.
obviously it sounds like you never did much brass work, Use a back rake drilling brass, You never have to worry about it grabing
as it also makes a much better surface.
Yep... not much. If I did I'd have a set of drills just for brass!
The only issue I see, would be the shoulder on the nut, if you were using a taper attachment. The nut would get released so the attachment would pull the slide back and forth to follow the taper. Still a great solution.
I've never used a tapering attachment although I do know they are fairly simple. I'll find a work around if I ever get one. Thanks!
Think of this. Use a tap Drill to drill 2 holes across above the acme thread on either side of the 3/8-16. Counter bore the holes for button head Allen's. Use tiny belville springs or high compression rate springs only 1/4" or 5/16" tall. Cut an angled slot from the top beside the stub sticking up into the upper acme hole. Now by varying the button head tension you can vary the grip on the cross slide screw automatically. You may end up boring a little out of the acme hole to allow it to contract on the acme thread angle instead of bottoming out in the root on the screw.
It's just a thought depending on how worn your lead screw is. You could also slip some wick felt into the slot to oil the lead screw. Drill and shallow tap a hole in you cross slide for an removable set screw to oil the felt once In a while. Again. Only a thought.
Thanks for the input. I'm not sure there is enough room to do this although I might try if the nut starts to wear. Currently the amount of backlash is very slight and even slightly tight on one end of the travel. Also, when I ran the tap through the nut again it opened a small hole between the mounting bolt threads and the acme. I think I might drill a small oil port in the mounting bolt.
@@WinkysWorkshop if you drill a hole thru the mounting bolt.. put a piece of felt at the bottom of the 3/8-16 hole in the brass part..
@@waynep343 - Sounds like a plan.
Great job!
Thanks!
That was cool.
Thanks!
Still needs an oiler hole. You could split the nut and add a take up screw to adjust backlash even more.
Maybe if I need to. Right now it works great. I'll keep the threads lubricated, the cover just drops on. Thanks
Where on earth did you get a left hand Acme tap (in 1/2"?). Not many machine shops would have one of those!
Apparently amazon has everything amzn.to/34tf4kQ
why did you choose to use brass instead of steal? I need to do the same repair on my Montgomery Ward (Logan) lathe
Brass wears a better than steel although bronze would have been ideal but the main reason was that it was very easy to machine. Using an Acme tap in steel is doable but very slow going.
Nice fix on the new nut Winky. You have to like going from. .040 play to under .005 play. The modification that you did on the cross slide looks like it came from the factory that way, especially with the flat slotted bolt. It is hard to believe that it was originally designed where you couldn't cut a ID tread.
Well you can cut thread with the compound to the left front but the chuck tends to get in the way. It looks like South bend corrected this problem after my lathe. Mine if a 31 model and a guy commented that is 1937 lathe was not made like mind. Thanks for the comment Andy.
are you using straight brass or some sort of aluminum bronze ?
360 brass, bronze would have been better but brass is a bit stronger and wears better than steel.
Winky, you really did not need to make a new shoulder bolt, as the nut was now located inside the original 1/2 " hole in the cross slide. All that was needed was to retain the nut from dropping out when you removed the cross slide in the future. You could have just countersunk the cross slide 1/2 " hole and fitted a standard countersunk Allen screw or even just a slotted soft screw. The Manufactures only used a shoulder bolt to take the load on the nut, you now have no load on the new nut as it is now located in the 1/2" hole. Tip for drilling brass / Perspex ect. to stop the drill grabbing, is to "back off" the cutting edge with a few rubs with an oilstone. This is to make the drill a NEGATIVE rake tool. As an accomplished woodturner, you should know this with your negative rake scraper, and found out that a standard tool will grab. Another great project and video under your belt, well done. Thought, should you want to reduce the backlash you have, make a thin nut say 1/4 inch thick and fit a compression spring in between it and the original nut. That will keep a tension between the leadscrew and the nut at all times. You may need to add a tiny anti rotation pin between the original nut and the "washer nut" otherwise it could rotate slightly and jam in the saddle. If you have a 3 d printer, you can see the idea on the Z axis . Stay Safe and Well.
I thought about that too. I should have made a longer extension on the nut. Still I feel a little better with the steel thread going into the brass and nut. There is a lot of force on the brass, if nothing else I think it would get loose over time. Also the way I did this is just like the later model South Bend lathes. I wonder if lower RPM would have helped the drill and the mill grabbing. I'd hate to blut the edge of my drill for one hole.
Great video. Great work. Thanks for sharing it. I have an old SB heavy 10 and I have the same issue. What’s the tap size for you used to tap fir the cross feed nut please? I’m an ammeter, I need all the help I can get. Thanks again
It was a 1/2"-10 LH Acme tap. I got it on ebay for about $24. I still have some backlash but it's much better.
Thank you for the information. I measured mine, it is a 7/16"-10 ACME
LH thread. After watching your video, I disassembled mine and found a
couple loose bolts that had contributed to the issue. I cleaned and
reassembled the unit. I was surprised and glad that the backlash is
much, much better now. .007” vs .018” of backlash. I wish I can
completely eliminate it.
What do you think about making an anti-backlash nut by using maybe one
third of the old cross slide nut (I call it the tension nut) and
bolting it to the new one with a spring in between them? In my case I
would use a 1/2" dia X 3/4" spring outside the lead screw and two #10
bolts (in the area above it) to bolt the tension nut to the cross
slide feed nut
@@TinhNguyen-mb7gx - Honestly .007 is fantastic. Without ball screws and some kind of thrust bearing at the dial you can't expect much better than that. I think a anti-backlash nut of some type would help but I'm guessing you will always have .004" or more. I'm not sure it is worth the effort. I've seen people modify the nut by cutting part way through (as if you were separating the nut it into two nuts) and adding a small set screw that separates them at the cut. The uncut section flexes a little and removes the backlash when you tighten the set screw.