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Inspecting a Used Lathe

J

ja762

Aluminum
Joined
Dec 12, 2017
Searching the forums, I've noticed a lot of newbies (myself included), who go out and buy a used South Bend without having the information/knowledge they really need to make an informed buying decision. Before buying, I searched the forums and got a pretty good idea of what I was looking for, but had much less of an idea about what I was looking to avoid. I couldn't find any threads about inspecting a used lathe.
I did the best I could giving it the once-over, and seem to have purchased a pretty good machine, but I could have just as easily been taken.
As it turns out, I've come across another SB lathe which I'm trying to make arrangements to go see. I'm putting together an inspection checklist based on what I've learned so far, and I was hoping some of you more experienced guys might chime in. This would be greatly appreciated by me and, no doubt, all of the prospective South Bend owners who read this thread in the future.
 
It would help a lot if we knew what lathe you're going to look at. SB has made a whole lot of different models and while some characteristics apply to all of them, individual models have their own specific issues you should be know about.
 
I'm going to look at another 13", and I would certainly appreciate any advice specific to that model, but I was referring more to the general things that someone would look for in any lathe from say the '30s up. Considering many of them are the same basic design just on a different scale, there are certainly many commonalities. Checking for bed wear, spindle bearing play, etc. is going to be the same on pretty much any of them, no?
I garnered enough knowledge in the last few weeks since I bought mine that I have a pretty good idea of what to look for, but not everything, and certainly not enough to be giving anyone else advice. I wish I had a checklist to take with me the first time, and to that end I started this thread, more for the next guy than for myself.
 
DanMc77 said:
Let the masters start to chime in.
Click to expand...

"Victims", rather! DAMHIKT!!!

Long and short of it is that used manual machine tools actually available WILL have issues.

The trick - if there even IS one?

Try to find one with only the issues one has a high probability of being able to deal with successfully.

Very different paradigms for (s)he who has, or has access to, a functioning machine shop with which to make repairs to a NON-functioning new acquisition, (s)he who has the economic horsepower to hire even rather costly things done by third-party professionals, and (s)he who has neither.

First sanity check, then, is not WHETHER repairs will be needed. They near-as-dammit WILL ALWAYS be.

It is rather HOW will those needs be managed and funded?

Got no teeth? Better a safe brand of ready-made tinned beef stew, fresh - than hard-dried beef jerky, stale.
 
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I'm going to be the dick and say that "klunkers" document sucks...unless of course it's a klunker you want.

I'll try to add more as the days goes...but I can tell you if I'm spending good money you can bet your ass im taking a bar of steel(for cutting test),mag base and indicator and a micrometer with me...the key is knowing what you're going to do with it.

And that goofy tighten the carriage lock thing needs to go...especially on a SB...as if one can expEct a rough cast/machined lock in a sloppy clearance hole held in with a coarse thread bolt riding on a non precision surface to be any decent indicator of anything.
 
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A 16" pry bar and a block of wood would be useful on the drive section. Motor shaft. Looking for slop in shafts. Excessive gear wear can be an indication of a bad bearings. Not to pry on gears but shafts. The visible inspection is easy but Knowing what wears the most is important. Look at the oilers and see if they look like they were used on a regular basis. No oil stains around the oilers on old paint is bad news. Fresh paint blows that all away
I know the worm gear wears in the carriage and gets worn at the thrust bearing surfaces.
As Iwananew10k says a steel bar a magnetic base with an indicator and a micrometer.
For a new guy some suggestions on where to pry, where to place the mag. base and what is acceptical. Facing the lathe I have a general idea but I'm not an expert on a lathe.
I would think a good 12 and 24 inch strait edge wouldn't hurt for the ways. Being un-level that may not help but air under a short span is bad.
Make sure the back gear all works and the drive pulleys aren't stuck to the spindle.

Thomas went through his 16". He may have some input to give on other things too check.
Then there is the feed screws. Everyone can check those.
I forgot the half nuts.

The things listed here are what I would look at. That doesn't make them right.
 
"I'll try to add more as the days goes...but I can tell you if I'm spending good money you can bet your ass im taking a bar of steel(for cutting test),mag base and indicator and a micrometer with me...the key is knowing what you're going to do with it."

I always thought dave ficken's blurb was pretty good.

The real question is, you show up to buy a lathe, do the visual inspection, and then do your rain dance with the inspection tools.

Then what?

It cuts some taper. The bed has some wear. The indicator does this, or that.

Seller: " this is the price. take it or leave it, somebody else is arriving soon to buy."

I'd rather tell a seller 'no thanks' based on visual inspection (after finding major problems) and walk away,
rather than try to convince him that the machine needs to be lowered in price by 25 percent based on
the rain dance.

Nothing you find with a dial indicator will be a 'walk away' problem for a used lathe.
 
I thought the "klunkers" article was spot on. I see it more and more with noobs that seem to think any wear on a machine makes it scrap, even though all they want to do is make non-precision parts. The idea of shopping for a USED lathe and finding one only used for 15 minutes on Sundays by a little old lady is a joke. Sure there is a rare find of a used machine that never got used, but I have not found one yet.

As for selling a lathe, if you show up with a prybar and want to jack around with it on my machine you will be asked to leave. Bring a test bar and a dial indicator and convince me you know what you are doing and I might let you run the machine, but I would also want to see the cash on the table and if you crash the machine you just bought it.
 
The old instructors in college used to say: A blacksmith can make precision parts on a new lathe, it takes a machinist to produce accurate parts on an old lathe.
I figure that I am somewhere between a blacksmith and a machinist. :rolleyes5:
 
What I would do with a pry bar wouldn't be anything different than putting a bar in the spindle and checking for wear. Just looking at it doesn't tell you
anything.
Who are these people a that have Nubie affliction. Grow up
I have 40 years working with worn production machinery and have had to work with slop in machinery. You want to buy something that's workable. I know how to deal with slop when it's workable. Before my work history I grew up on a farm. Who is the Nubie

The man that started this thread is not a Nubie either. He asked a civil lagit question. What to check. Because someone doesn't have lathe experience and branding them a Nubie is making assumptions. Swelled head.
I would like to start over and be a Nubie. :)
Especially with all the slop in my joints. Non repairable
When I buy I don't try to knock down price. I take it or leave it.i don't check machines to knock it down. I don't want to buy junk. Sometimes I still get junk. You can't see it all.

Mutual Respect
 
1-visual the article does cover that well
2-function- this is where it can get tricky..if you have power all good,take a cut on a bar unsupported and mKe your decision (not between center like the article says..I have yet to see a machine that wasn't dragging its asaddle not be able to do decent work between centers)
But sometimes maybe no power,maybe no chuck,tool post,etc....this is where the tools come into play...and it still shouldn't take more than 15 min- no one
Ike a tire kicker(or crank turner)
 
I can see that putting the load on between centers would put the load on and give running time to listen and look at everything. I mis read. Cut unsupported!!
Iwananew10k
In a previous post you spoke ok tightening down the carriage not being a good test. I missed the point. What does the carriage do as far as showing wear when it's under load UNSUPPORTED. Was that a test that will show way wear?
 
By unsupported I mean chuck up a good size(at least 1.25" diameter) with about 4-5x the diameter stick out of the chuck...no tailstock support,very sharp tool and light cut.

the reason I hate the tighten the carriage test is it was demonstrated to me on a perfect condition machine it can still bind....just like when you don't release your tailstock clamp enough and it catches.

I always took a mag base and indicator so if something was questionAble or no power,etc I could just stick it to the carriage wing and indicate the tailstock flat...not a perfect test by any means but can give a good clue...takes only a minute to do and is a way better indicator than tightening the carriage lock IMO.

The worst thing to do is nitpick, this is also where the article is good.

Backlash doesn't matter.
Tailstock alignment largely doesn't matter, only ever bought one SB that didn't need work there...as long as it isn't beat to hell you can work with it.
 
Thanks Iwananew10k
i never tell the seller what I see wrong or expect perfection. If I walk away it's not because of small problems. My hobby is repairing machines with my machines. Cast iron bearings in the spindle are a concern. Quick change gearbox shafts can be made and bronze bushings installed Compensating for imperfection will always be there You learn your machine and make it work. Or loose your job. I think that Ja762 that started the thread knows that also. Tips from people in a trade are always good. I'll stop learning the day I die.
I thought there was a sticky on this subject.
Your tips are helpful
 
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