Is there a part missing from this 11" lathe tailstock?

garyrice · Mar 6, 2020

I'm working on an 11" tailstock that I just bought. Comparing it to my existing lathe, the new tailstock MAY be missing a quill wedge lock. But since the tailstock is split, the wedge may not be necessary. The hole (and the other lathe that has such a wedge) suggests that there should be one in the new tailstock as well.

What do you think?

Gary

Dumpster_diving · Mar 6, 2020

I think you really need to figure out 'how' that quill locks.

Is it by squeezing the casting together on the split-line (I say unlikely).

Or is it via a split wedge that fits above and below the quill in that open bore (my guess).

But I'm unfamiliar with a tailstock casting being split longitudally along the quill.

What holds the top of the casting to the lower casting? What's inside the hole (and below the quill)?

garyrice · Mar 6, 2020

Answers to your questions:

Inside the hole is a threaded hole (1/2-13). I removed the threaded rod it contained for cleaning.

You asked:
What holds the top of the casting to the lower casting?

I'm not sure what you are asking. But the slit ends at the edge of the photo. So the casting itself holds the "pieces" together.

The hole has room for only 1/2 of a 2-sided wedge. The hole is only deep enough to expose the upper 3rd of the quill.

The handle just barely covers the hole (see new photo).

Gary

APD · Mar 6, 2020

You are definitely missing a part: The part where you tell us if it actually locks when you turn the handle.

...and the part where you say what lathe model it is.

Also, it seems to me that with a split in the casting, any type of wedge mechanism would force the casting halves apart, resulting in less locking force.

I could be wrong, but I think any tailstock with a split is going to pinch to lock, and any with cam or wedge are going to have a solid (not split) casting.

DDoug · Mar 6, 2020

It's missing a nice coat of paint..... :ack2:

garyrice · Mar 7, 2020

digger doug said:
It's missing a nice coat of paint.....

I always paint things last. You can see that I've started with the handles.

Gary

garyrice · Mar 7, 2020

APD said:
You are definitely missing a part: The part where you tell us if it actually locks when you turn the handle.

...and the part where you say what lathe model it is.

Well, the quill locks but I have to exert considerable force on the handle to make that happen. That is the reason I began to suspect a missing part.

As for the lathe model, I haven't a clue. I only have the tailstock. It has no markings except for a number (CE 91) that is cast into the base. I've looked at hundreds of photos but only a South Bend comes close. And by "close" I mean only about a 70% match.

Also, I hastily said it was an 11". It actually is a 10" swing.

Gary

Clive603 · Mar 7, 2020

Could it have been modified from a simple close the slit system to a sort of wedge style by opening out the original locking screw hole?

Consider a short cylinder nicely fitting in the hole, bored for the locking screw with a flat top for the handle to seat on. Let the bottom end be made a part circle of the same radius as the quill. When the cylinder is pulled into the hole by the locking screw and handle it will force the quill down and slightly sideways into the base of the tailstock bore. Which should lock it more than well enough and be kinder to the casting than closing a slit.

I have seen a similar concept in a rather different application.

Clive

crossthread · Mar 7, 2020

If it is an SB then the lever pinches the split casting around the quill. Pretty much simple as that. The only thing that I can think of that would cause your problem is crud (unlikely) in the slot , or the quill is worn so badly that you are fighting the casting before it clamps. Make sure your clamping lever is really clamping. By that I mean make sure there isn't a thrust washer missing where the threaded part of the lever meets the casting. Could be you are running out of threads or something.

garyrice · Mar 7, 2020

Clive603 said:
Could it have been modified from a simple close the slit system to a sort of wedge style by opening out the original locking screw hole?

It's possible. The hole is nicely reamed to 1.125" although the bottom is a typical 118 degree taper from a twist drill.

Clive603 said:
Consider a short cylinder nicely fitting in the hole, bored for the locking screw with a flat top for the handle to seat on. Let the bottom end be made a part circle of the same radius as the quill. When the cylinder is pulled into the hole by the locking screw and handle it will force the quill down and slightly sideways into the base of the tailstock bore. Which should lock it more than well enough and be kinder to the casting than closing a slit.

That's what I've already started.

Gary

Rob F. · Mar 7, 2020

If the handle was meant to just pinch the casting closed I see no reason for the top half to be drilled much larger. The other thing is the handle is almost the same size as the hole. If the handle was meant to pinch the casting shut it would have a smaller 1/2" hole so the handle would have some real material to bear on.

john.k · Mar 7, 2020

From what you say ,there may have been a bushing with one end profiled to fit the quill,forced in by tightening the screw.....I havent seen this used on a tailstock ,but its a fairly common mechanical device to lock a spindle.

JST · Mar 8, 2020

It has been modified. The question is which part.

A split cotter (or half of one) would have adequately locked the ram, and would not require the split. And there is no other adjustment location to suggest that the split is for adjusting the ram slop.

So either the split cotter system is original, and the cut through the casting was added, or else the split is original, and the hole was only a clearance hole to begin with, that was later bored out.

It is so similar to a Southbend as to make me think that is is one that had the split cotter system added. Possibly the person who did it realized that was a bad idea, and set the tailstock aside in favor of a new one, which is why you have that by itself.

Of course, the "save" would have been to make a top-hat piece to fit, which would have restored the original system

Rob F. · Mar 8, 2020

JST said:
It is so similar to a Southbend as to make me think that is is one that had the split cotter system added. Possibly the person who did it realized that was a bad idea, and set the tailstock aside in favor of a new one, which is why you have that by itself.

Maybe a foreign company making copies of southbends, official or unofficial.
Sanches Blane in Brazil or any number of others:
\South Bend 9-inch Lathe Clones

kitno455 · Mar 8, 2020

Lots of SBs used the split cotter.

JST · Mar 8, 2020

The tailstock just does not look like any SB I can find a pic of. It's close, but different in detail. Could still be SB.

The way the bracing curves up on the side of the barrel looks a bit like some Sidney lathes. Don't think they made a 10", though.

iwananew10K · Mar 9, 2020

any chance thats a 10" CENTER or 20" SWING?

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