I'm going to look at a used lathe next week.
What is an acceptable level of wear to the bed?
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Jan. 26, 2012 7:21 p.m. Woody SuperDork
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Jan. 26, 2012 7:45 p.m. Streetwiseguy SuperDork
You building nuclear reactor parts or taking a few thou off a shaft so you can beat it into a hole easier?
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Jan. 26, 2012 8:14 p.m. Woody SuperDork
Streetwiseguy wrote:
You building nuclear reactor parts or taking a few thou off a shaft so you can beat it into a hole easier?
I don't know yet.
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Jan. 26, 2012 9:32 p.m. Toyman01 SuperDork
Ideally, none, but you can deal with a little. They usually get worn close to the chuck. It can be adjusted out, but then as you move closer to the tail stock, things get tight. It can become a problem when turning a longer shaft.
The ways can be scrapped to even things up, but that isn't a project I would want to tackle. From everything I've read it's tedious.
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Jan. 26, 2012 9:41 p.m. Woody SuperDork
Toyman01 wrote:
Ideally, none, but you can deal with a little.
What constitutes "a little"?
Suppose I were to bring a straight edge and a set of feeler gauges. At what point do I say, "Thanks anyway..."?
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Jan. 26, 2012 9:59 p.m. Toyman01 SuperDork
Set the carriage close to the chuck and see if it's loose. If the owner will let you, adjust the gibbs on the carriage until the carriage is tight. Then back off the adjustment until the carriage will move freely. Crank the carriage toward the tail stock. If it stops/binds halfway down the bed, the price would have to be pretty reasonable.
Here's a pretty good link on what to look for.
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Jan. 27, 2012 6:47 p.m. Woody SuperDork
That's some great info. Thanks.
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Jan. 27, 2012 7:50 p.m. 914Driver SuperDork
The carriage traverses the bed, rock it left and right for play. Look at the end of the carriage, under the tool post for screws that adjust "gibbs". These are bushings that make up for wear, no adjustments it's a cheapie.
Bring a nice clean towel and a very dependable straight edge with you.
Close tolerance work = no play. If your needs aren't tight, inspect accordingly.
Dan
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Jan. 27, 2012 8:58 p.m. Woody SuperDork
It's a South Bend.
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Jan. 29, 2012 12:18 p.m. motomoron Dork
It's doubtful you have a straight edge that's straight enough - and that's only for checking flat. Twist is an issue as well, as it tailstock height.
This is a straightedge for checking .001" or .0005" stuff:
The very basic version of how to check a lathe is to use a test bar. For larger, more accurate machines one uses a test bar and indicates off it from the carriage. On a smaller machine one would take a series of very thin cuts on a longish bar then mic it at various points over it's length.
Search practical machinist and the home shop machinist and the Chaski machinist boards for info.
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Jan. 29, 2012 2:45 p.m. Woody SuperDork
I appreciate the education. I think I'm going to pass on this particular machine, because I don't think that I'm ready to make a fully informed decision at this point.
For reference, it was a 1966 South Bend Light 10 (aka 10K).
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Jan. 29, 2012 4:11 p.m. motomoron Dork
Light 10 is an ~OK~ machine if your needs are modest and the price is right. A couple things I've learned in a decade of dicking around w/ machines:
You'll almost surely want a bigger one, no matter what you have.
Old is fine, good even, but old, beat up and wore out is a losing proposition.
Bigger is cheaper in general, to a point. South Bends, the 9s to heavy 10s are very popular among the home shop machinist set. If you have the room and the inclination, bigger stuff can be a bargain.
Deals are in funny places. I ended up buying the assets of a shop that was closing to get a very nice Taiwan Bridgeport clone and 13x40 lathe plus pallets of tooling and materials and tools and what not. Once I sell my old machines and all the excess and duplicates I'll have a full shop for next to nothing, but it took years of waiting and the willingness to front the money to pull the deal off.
Use searchtempest.com and look at auctions on dovebid.com. Stuff shows up all the time. Be patient.
