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South Bend lathe cracked headstock casting

Jayhawk

Plastic
Joined
Jul 29, 2015
IMG_1564[1].jpgIMG_1564[1].jpgFirst time posting on PM as I've always been able to search and find the info I need, plus I'm a rookie machinist. I recently acquired a South Bend lathe model CL370ZD made in 1985 thru an online auction with no description of the condition it was in. When I got it home is when I noticed that the headstock casting is cracked across the spindle adjustment screws. Not sure how to remedy this, south bend does not have the part (p/n PT2575K1). There is one on ebay but I'm not ready to spend that much. The lathe came from a high school and the story I got was that it sat in storage for the last 15 yrs. The ways are in great shape as is everything else. I suspect it got tipped over at some. Any suggestions on a fix or parts would be great! Thanks all, I really appreciate being a part of this site!

BTW It's a 10k light
 

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The lathe serial is on the ways near the lead-screw attachment at the tail-stock end. CL370ZD is the gearbox model. There is an online method to determine model/age from the serial no.

I would not try to fix that break. Its a weak point and that bore needs to be perfect, maybe caused by someone trying to adjust spindle bearings without the shim pack installed, IDK. A tip-over usually breaks tumblers and feed handles. I would figure out what model and wait on a deal for a good replacement casting to appear online.

It will be nice when its cleaned up.
 
That is unfortunate, puts a knot in your stomach to see something like that. But that is a weak point on these machines. It's rare that it happens but it does happen. Unfortunately the best way to fix this problem is to replace the headstock. There is not a good way to fix something like this unless you are really skilled at welding and you're a good machinist as well. Any misalignment will show up in your work. And if you have it fixed, The fix may cost you more than the headstock. It might be better to part out the machine, and use the money you get from the parts to buy another machine. Or by a second machine, use the best parts from each to make a good machine, And sell the rest is parts.

Sorry if this is not what you want to hear, but it is what it is.

Stay safe and have fun.

Joe.
 
I figured the headstock would need replaced, but had to ask if someone else had ever come up with a solution not involving replacement.
 
I figured the headstock would need replaced, but had to ask if someone else had ever come up with a solution not involving replacement.

It is possible to braze or weld it, but there's a lot that can go wrong. That crack is right where the casting holds the spindle, possibly the worst place for that to happen.

You might be able to get another headstock casting without getting another headstock, if you can find one.

Check these two out on ebay:

VERY NICE ORIGINAL SOUTH BEND 1K HORIZONTAL DRIVE LATHE HEADSTOCK HOUSING CAST | eBay

ORIGINAL SOUTH BEND LATHE 1K HEADSTOCK BARE CASTING | eBay
 
need to take the headstock off and then machine away that broken section, machine it down to either the level of the shimstack (so you can reuse the same shim stack, or machine it flush with the front of the headstock and replace the shim stack after cutting the slot), replace it with a block of cast iron with 2 or 3 or 4 bolts to hold the block to the headstock where the break is now. These bolts should never be removed again: glue them in place permanently.

Then bore the hole out. since you only have half a circle of metal to cut away, probably best to do this on a milling machine with an end mill, get close to a circular hole then bore it out. Alignment isn't super critical unless you don't want to rescrape the headstock for alignment.

after boring the hole to the diameter needed, cut the slot in the front, where the single bolt is now, replace it with a shim pack the same thickness as the slot you cut, clamp down on the shim pack. then either rebore the head to the alignment you want, or just get the spindle running if you can and remove shims later to get the bearing clearance you want, and you'll need to scrape the headstock for alignment. i would imagine it should not be that difficult to get the true position of the center of the bored hole to with .001" if you have the tools. if not, you'll have to rescrape the headstock if .002" taper per 10 inches isn't good enough. anyhow, the spindle doesn't ride in the center of the bored hole, the fluid film bearing (if turning clockwise) runs in an elliptical path around the 4-5 o'clock position if i'm not drinking. (when the load is pulling the spindle directly downwards)

better to have to wedge the slot open with .001" worth of shims more than you need to fit the spindle, my guess is you'll have .0005" worn off your newly bored cast iron headstock bearing before the bearing is run in, so undersize and prying open the shim stack is better than oversize and clamping it shut.


what the hell is the purpose of those two bolts anyways? initially i figured they held bronze bearing inserts in but that does not appear to be the case.
 
I see some headstock castings on Ebay that are reasonable but they are for a Horizontal drive. Have people ground out the bottoms of them to fit them on an UMD model or is there more to it?

Jo, I think you missed the part where he said he is a rookie machinist.
 








 
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