# Lathe repair advice needed



## thebeebe5 (Jul 2, 2021)

About a year ago I purchased a well used Taiwanese lathe. Here’s a link to the thread posted after my acquisition:








						New to me vintage Taiwan lathe
					

Greetings all.  Yesterday I came home with a vintage "Vico" Vital Corporation lathe.  I've been using a ROMI 13-5 at my pal's engine machine shop almost every weekend for the past 6 years and I'm quite used to it.  This new to me Vico is quite different.  I can find no information on it but was...




					www.hobby-machinist.com
				




I’ve been satisfied enough with it for what I do, but lately have been having an issue with slop in the cross slide causing less than smooth facings, and when machining softer metals like brass or copper the cross slide has enough movement in it that it tilts and digs into my work and damages my project by ripping it partially out of the chuck. I’ve adjusted what I’ve learned is called the gib as far as I can at this point.  When the cross slide is retracted fully towards me the play is almost non existent, but in the middle positions one would use when actually working there’s still considerable movement of the cross slide laterally.    I’m not sure what to do to rectify the problem.   Is it terminal and I should start looking for a more modern replacement, or is this something that can be fixed?
I still consider myself a novice, so if I’m not using correct terms please help me.  I’m willing to learn so I can convey what the issue really is.  All I know is it’s super annoying and I find myself doing most facing operations on the lathe at my friend’s machine shop which works like a dream. 
I’m open to the possibility that this is terminal and I should begin finding a replacement, but honestly if I could repair the issue this lathe is sufficient for my projects.  I use the lathe in the evenings and pretty much all day Saturday and Sunday now, so it’s not just a “once in a while” thing.


----------



## Lo-Fi (Jul 2, 2021)

I think what you're describing is cross slide leadscrew wear, but you might need to be a bit more specific on what movement you're seeing. Is it purely lateral?


----------



## Technical Ted (Jul 2, 2021)

When you say "I’ve adjusted what I’ve learned is called the gib as far as I can at this point" do you mean you have bottomed out the adjusting screw(s)? If so, a shim can be put behind the gib to give you more adjustment. The gib might be too tight when taking the crossfeed to the ends of travel where there's not so much wear, but it will help where you use it the most. 

A lot of us have to learn to live with worn ways on our hobby machines.... either that or have it re-built or buy a different machine.

Good luck,
Ted


----------



## SLK001 (Jul 2, 2021)

I think that Lo-Fi hit the nail on the head - cross-slide leadscrew (or nut) wear.  If the gibs were the problem, the movement would be mostly lateral.


----------



## Lo-Fi (Jul 2, 2021)

It's a classic for "tight where you don't use it" and often overlooked for oiling. Keith Fenner has a good series on redoing his Clausing cross slide screw.


----------



## jwmay (Jul 2, 2021)

You might review toolbit geometry for copper. Using toolbits ground for steel will cause the tool to dig in.


----------



## Richard King 2 (Jul 2, 2021)

Take apart the cross-slide and take some photo's.  If you don't need the lathe for a month take off the saddle and ship it to me.  I will fix it for you.  It would be a great project to show my students in Norway. Jan Sverre Haugjord .  Who has dozens of scraping shows on You Tube.   I suspect the cross-slide ways are worn and as you move it toward the middle it is worn and wiggles.  Take a look at this and check your cross-slide.   Take it apart and lets see what the problem is.  If it is the screw and nut I can help you fix that too.


----------



## jwmay (Jul 2, 2021)

I guess I should say that it's obvious from your description that the nut, screw, and cross slide ways could use some attention. And if I were you, I would take Mr. King up on his most gracious offer. But copper and brass take different toolbit geometry to work, and it seems most prefer to avoid them in job shops. So after you get your parts back, don't be surprised if turning copper and brass are still difficult using standard tools ground for steel. Copper is especially hard on tools. And again, if you aren't busily preparing your cross slide for shipment to Mr King, do that post haste.  It's an amazingly generous offer.


----------



## thebeebe5 (Jul 2, 2021)

Lots of good replies here, gents.  To try to be more specific it’s as if the female dovetail on the cross slide is too big for the male dovetail on the carriage even with the gib screwed in as tight as it can go.  There’s an adjustment or adjustment limit screw on the back of the cross slide to limit gib travel and i’ve backed that out all the way.   I did shim behind the gib with some feeler gauge stock.   No real help noted, and with the gib tight I can’t retract the cross slide all the way.  I took it out this weekend to continue work.    
I understand copper needs different geometry angles.  I don’t have an issue with it on the Bridgeport lathe at the shop.  The bit dug into a brass piece last week and partially extracted it from the chuck.  I was able to re-turn the piece smaller and it was fine.   The work I do at home is 99.9% artistic so it was no real problem for the final product.   

I’ll post up some photos in a few minutes.


----------



## thebeebe5 (Jul 2, 2021)

Richard King 2 said:


> Take apart the cross-slide and take some photo's.  If you don't need the lathe for a month take off the saddle and ship it to me.  I will fix it for you.  It would be a great project to show my students in Norway. Jan Sverre Haugjord .  Who has dozens of scraping shows on You Tube.   I suspect the cross-slide ways are worn and as you move it toward the middle it is worn and wiggles.  Take a look at this and check your cross-slide.   Take it apart and lets see what the problem is.  If it is the screw and nut I can help you fix that too.


Thank you very much!   I will review this video this morning after I’m fully conscious and I’ll post up some images!


----------



## Richard King 2 (Jul 2, 2021)

I you have a good Bridgeport take the saddle off and indicate the top of saddle cross-slide ways.  Flats co-planor then indicate the dove- tails.  then do the same to the bottom of the cross-slide ways.  I suspect you will figure it out then.  It sounds as if your sharp and can do it your-self.  I can teach you how on here I think.   If you have a dovetail cutter or a good fly cutter we can do it.


----------



## thebeebe5 (Jul 2, 2021)

Richard King 2 said:


> I you have a good Bridgeport take the saddle off and indicate the top of saddle cross-slide ways.  Flats co-planor then indicate the dove- tails.  then do the same to the bottom of the cross-slide ways.  I suspect you will figure it out then.  It sounds as if your sharp and can do it your-self.  I can teach you how on here I think.   If you have a dovetail cutter or a good fly cutter we can do it.


Sounds really scary...  
The measurements you mention are foreign to me. I’m not sure I can get Brian’s permission to take his lathe apart. Maybe when he’s not looking! 
But i’ve dived into worse I suppose.  I did watch the video.  I don’t have any precision pins, but I could make a pair at the shop tomorrow and then I can make some measurements.  
Here are some photos for what good they are.  I always feel a bit lost when looking at lathe parts photos.  Lack of familiarity I suppose.  The gib looks a bit beat up.
The worn screw also makes sense and I’m wondering if that can be replaced on this machine.


----------



## markba633csi (Jul 2, 2021)

So who's Brian? Aren't you the owner of this lathe? I'm a bit confused
Anyhow, it does sound like the cross slide is badly worn and if Rich can re-scrape it for you for a reasonable price I would do that rather than trying to fix it yourself and making it worse
-Mark


----------



## SLK001 (Jul 2, 2021)

The cross slide doesn't look all that worn at all.  You can still see the original scraping marks on it.  I suspect that your bronze nut is worn.  Your nut does have an anti-backlash adjuster built in to it.  Just reassemble the slide and tighten the screw a bit.


----------



## Richard King 2 (Jul 2, 2021)

I was using the video as an example on "how to do it".  A easy way to check it is in a Bridgeport.  It might not be Jig Bore precision, but should get you in the ball park.  If it wiggles .010 or what ever. You can figure it out with-out a lot of rebuilding experience.  It would be real handy if your milling machine vise swiveled.  It would be be easy to indicate the flats co-planer and tap the vise around while indicating the dovetails.  do one side and move the indicator to the other side and it should indicate .001" or less.  middle 1/3 low.  If it is more then that it needs to be machined or scrapped.   I don't do you tube shows but my students do.  This shows some examples.
Check it out and lets figure it out.  Here is another couple showing how to.


----------



## jwmay (Jul 3, 2021)

Probably neither here nor there, whats with this perfectly straight line across the saddle ways? Looks like an almost perfect joint between two pieces of metal. It's NOT a crack, right? I also noticed what could be a crack in the gib. Idk... it's what it looks like from here.


----------



## Richard King 2 (Jul 3, 2021)

That looks like a crack, clean up the inside and get a flash light and look in there and under the dovetail.  It could be something the builder scribed on to show you the slide travel limit....hard to say.  A quick way to check backlash in the screw and nut is to assemble it and push and pull the slide at different sections of the screw.  You can put a dial indicator against the slide and push and pull with your hands.  Or just read the lost motion of the feed crank.  The scraping looks pretty dismal.   What brand lathe is it? Made in China I suspect.  No oil groves either.   Use a stiff paint brush and clean the screw.  Look at it all along the the screw and see if the pitch or threads all look the same thiickness.   Look at the gib screw too and see how the head fits in the slot.   The cross side is probably high in the middle and rocks like a rocking chair because there are no wipers, no lube holes and grooves.  The scratch looks bad too on the top slide is a sure sign chips got drug under there with no wipers.  Also lack of lube can cause scratches.   .   Measure it up like Keith Rucker does in his show, dowel pins, etc.


----------



## Richard King 2 (Jul 3, 2021)

For the crack, buy some brake cleaner in a spray can, wear safety goggle... and see if it penetrates into the crack..


----------



## SLK001 (Jul 3, 2021)

And, can you post pictures with a little less detail?  Those ultra sharp photos just make things too easy.


----------



## Richard King 2 (Jul 3, 2021)

As SL said, I usually download them at 10%  pixel as the higher setting take for ever for me to download and come across as a close up sometimes.  It's a learning curve figuring out al the things on these sites.


----------



## thebeebe5 (Jul 3, 2021)

The “crack” is some kind of casting flashing it looks like.   There are oiling holes all over these slides.  They’re all patent and i’ve kept it all oiled since I acquired it a year ago.  Who knows how it was treated in the past. It’s not a fancy lathe.   In my first post I included a link with some info about it.  It’a a 1980 year model lathe made in Taiwan.    I don’t see any visible cracks in the saddle or cross slide or gib.  I don’t know how to remove the top of the carriage or I’d take it to the shop with me today and magnaflux all the parts. I can do the cross slide and gib today though. The brass nut is messy enough I can’t appreciate its condition.  I’ll wash that in the parts washer at the shop today.  Not sure how that set screw is useful for any kind of adjustment....   it’s tightened in the back of the nut already.  The screw looks good.  It’s clean and straight.  No crazy wear noted at all, but the brass nut might be well worn inside.  

I posted images with measurements.   Sorry they’re not a good resolution, but I have no way of reducing it without getting on the computer and figuring out a way to do that.   I’ll kwep practicing.  

Also, I’m not sure how valid my measurements are under the cross slide. It’s tapered so that seems useless. The larger numbers on the left of that image are without the gib in place.  With the gib it place it’s certainly not straight either.  

Mr. King, I’ll do some additional measurements with the dial indicator that you mentioned either this evening or tomorrow.  It’s about time I got to the shop and got busy for the day.


----------



## Richard King 2 (Jul 3, 2021)

The slot in the nut is an adjustment where you tighten it or push apart to take up backlash.  Are the theads inside thin and sharp ?  The one test of the tapered side is meaningless.  .005 to .006" smaller at back explains why it gets tight with the gib tight and cranked toward you.  You may only need a new nut and screw.  You can buy lengths of  Acme screws and brass nuts you machine to fit from http://www.greenbaymfgco.com/

You need room for oil on the ways. .001 per side.  You can also assemble the slide  and slide in the gib with your cut shim the length of it and then leave it loose and put a mag base on the top of cross-slide and dial indicator on the other side or saddle and push and pull left and right to check the slop.  Say at .002"  and then move the indicator to the operator side and do the slop test again.  Don't move the gib.  You need it loose.  The slop should be about the same on frt and back side.   This is hard to explain.   I will see if I can find some pictures.   Rich


----------



## thebeebe5 (Jul 3, 2021)

The inside of the nut doesn’t look like the threads are thin and pointy.  They’re square on top. I’ll look at the link you sent this evening.  Thank you!


----------



## Richard King 2 (Jul 3, 2021)

Screw the nut onto the screw and there should not be any movement.  The photo looks like the threads are worn more the 1/2 out.  The thread pitch should be the same width bottom and top of threads.  They maybe square .. but worn in 1/2.


----------



## thebeebe5 (Jul 4, 2021)

Richard King 2 said:


> Screw the nut onto the screw and there should not be any movement.  The photo looks like the threads are worn more the 1/2 out.  The thread pitch should be the same width bottom and top of threads.  They maybe square .. but worn in 1/2.


Ok. Good to know.  I’ll check that first thing in the morning.


----------



## thebeebe5 (Jul 4, 2021)

Richard, there was definitely some play in the nut/screw fitment.  After getting both clean and gaining a bit of an understanding of how the adjustmwnt screw works I gave it a 1/8 turn and the slop was gone. I have a full array of Starrett feeler gauge stock and had tried a portion of a 0.004” about the midway point between the gib and cross slide.  After measurements I moved that same piece all the way to the back of the slide and reassembled.  
I’m surprised, but there’s no perceptible shifing or movement currently.  It also isn’t sticking horribly if I try to back thr slide all the way out. Far more even feeling than when id shimmed before.  I need to go set a dial indicator on it and try, but this might do the trick while I either save up for a new/newer machine or find a nice (brand name US made) vintage machine that is in good shape.


----------



## Richard King 2 (Jul 4, 2021)

You should leave the brass nut cap screw loose that holds it to the cross-slide, snug it but loose.  Then screw the cross-slide toward the operator as far as it will go.  Then tighten the screw so the alignment of the nut is gained there as it has less deflection.  The reason it may get tight on the far end is because the screw is not as worn there.  You could leave the back lash screw loose and screw it back there and tighten the screw or if you seldom use it there split the difference.   I would think you could face the back-lash cap screw toward the back, so you can reach in there with a long Allen wrench and adjust it when it's on.  Remember you need a thin film of oil on the ways.  minimum of .001".  It sounds like you figured it out.


----------

