Compound Rest Casting / Off Center

mcload · Jan 25, 2021

Well, this is from my 1958 9" compound rest and I never noticed this until
reassembly. As you can see, either the hole is machined off-center or the
casting itself was faulty. I know I shouldn't care about this, but it still bugs
the hell outta me. :angry:

I looked on the auction site for a possible replacement, but almost all front corners
(those on the site) are bunged up from chuck strikes, and, all I really need is a decent casting without
all the other assemblies.

Maybe I should just let it go. Sorry for venting.
(I'll have a little whine with that cheese :nopity:

)

PMc

View attachment 311568 View attachment 311567

chipss · Jan 25, 2021

Build it up with bondo and paint it. You'll then forget about it.

texasgeartrain · Jan 25, 2021

The bondo idea is not terrible, less tools and expense to get it symmetrical.

To get the zero mark of bushing centered. Id buy shim packs off ebay, to fit the OD of bushing threads. You can experiment with how many shims to get bushing tight with zero mark at 12 oclock.

Curious, if you assemble rest to compound does small lead screw appear centered and symmetricaly straight ? Or does it appear pulled off center also ?

If off center too, might try a repair. Make a threaded slug you can screw into, and loctite into existing hole. Then re-drill and tap for a centered hole.

Repair might need get slightly more complicated to hold presumed remaining 1/4 moon of slug in place. But pretty doable i think.

mattthemuppet · Jan 25, 2021

my tail stock is like that. Only noticed when measuring it up for an extension. I wouldn't worry about it, it's not going to make the blindest bit of difference to how well it works.

mcload · Jan 25, 2021

texasgunsmith said:
The bondo idea is not terrible, less tools and expense to get it symmetrical.

To get the zero mark of bushing centered. Id buy shim packs off ebay, to fit the OD of bushing threads. You can experiment with how many shims to get bushing tight with zero mark at 12 oclock.

Curious, if you assemble rest to compound does small lead screw appear centered and symmetricaly straight ? Or does it appear pulled off center also ?

If off center too, might try a repair. Make a threaded slug you can screw into, and loctite into existing hole. Then re-drill and tap for a centered hole.

Repair might need get slightly more complicated to hold presumed remaining 1/4 moon of slug in place. But pretty doable i think.

From my classic car restoration days, I'm not too much a fan of bondo, but yes that's an idea for sure.
(I'm a lousy Bondo artist!)
Thanks for the shim tip; I have a package of both brass and SS shim stock and should be able to cut what I need.

I haven't mounted the screw yet to check symmetry and centering with nut. As long as it feeds and feels good, then
it should be accurate. If its a problem, I'd probably just buy another rest.

Looking at that end shot, I would probably rather shape (file) the excess cast iron on the left rather than goop up the right side. Will have to think about that first.

Thanks for responses, greatly appreciated.

PMc

BEFORE Pics

View attachment 311579

jmm03 · Jan 25, 2021

Blending the fat side might be the easiest depending on the amount you have to take off. Jim

SLK001 · Jan 25, 2021

Bore it out, then lightly press in a steel bar (or CI, if you have it), pin it in place, then redrill and rethread the hole in the center.

michiganbuck · Jan 25, 2021

chipss said:
Build it up with bondo and paint it. You'll then forget about it.

Or take it to the bench grinder and eyeball it to an eyeball match.

1yesca · Jan 25, 2021

in the automotive machine shop we call that core shift like on a small block chevy cam bore hole and when you sonic test the cylinder bores it will show up as one side being thicker or thinner . just as the main bearing bore is the bench mark on a block were is the starting point on that casting but one thing is for sure all the machining cuts are were they need to be or it would not work it would not have left south bend lathe with out being right its just that its not all symmetrical well if its that big a deal to you make a mandrel and set it up and make it even but it won't change one bit how it works it will just make you feel better

tommy1010 · Jan 25, 2021

I just looked at a few compounds I have here. They are all drilled off center although not as bad as yours. They all work fine. Leave it alone and start using that lathe to make chips.

SLK001 · Jan 25, 2021

I looked at your photo and it looks like the casting is defective. Maybe not defective, but more "lop sided". In the photo, it doesn't look symmetrical at all. It does look like it was drilled "on center", but the casting is so bad it looks like it is off center.

mcload · Jan 25, 2021

Leave It Alone!

tommy1010 said:
I just looked at a few compounds I have here. They are all drilled off center although not as bad as yours. They all work fine. Leave it alone and start using that lathe to make chips.

Yes, I agree....I'm just gunna leave it alone and keep it as original from factory.
The casting looks to be symmetrical; its just drilled off-center. The feed
of the screw is fine.

Thanks for suggestions and comments.

PMc

kitno455 · Jan 26, 2021

SLK001 said:
Bore it out, then lightly press in a steel bar (or CI, if you have it), pin it in place, then redrill and rethread the hole in the center.

No. The hole is aligned with the nut and the screw is parallel with the direction of travel. if you adjust any of that, you will get binding at one end of travel.

allan

SLK001 · Jan 26, 2021

kitno455 said:
No. The hole is aligned with the nut and the screw is parallel with the direction of travel. if you adjust any of that, you will get binding at one end of travel.

allan

Yeah, on hindsight, that's not a good idea. Looking at the photo of the compound casting, it looks lop-sided, but without additional pics, it's really hard to tell. I'm assuming that the thread of the screw should lie exactly on a line drawn perpendicular from the center of the dovetails. If so, then the boss for the hole is not symmetrical (as the dovetails look properly centered), so this makes the whole casting defective (IMO). Why South Bend would put out defective castings over and over again is beyond me.

mcload · Jan 26, 2021

Just for clarity, here's a pic of the underside with the screw installed.
Seems to be fairly well-centered to me w/o getting out calipers.
Sorry for the soft focus.

Thank you.
PMc

View attachment 311707

1yesca · Jan 26, 2021

treat it like a sore penis don't fornicate with it form fallows function . do you want it to work or do you want it to look good you can keep making it better to the point were its junk life not like burger king all the time sometimes you don't get it your way

mcload · Jan 26, 2021

1yesca said:
treat it like a sore penis don't fornicate with it form fallows function . do you want it to work or do you want it to look good you can keep making it better to the point were its junk life not like burger king all the time sometimes you don't get it your way

Well that certainly added to the conversation.
Get some sleep, dude.

PMc

1yesca · Jan 26, 2021

ya it did and as fred dibner would say as he dropped another chimney [ did you like that ]

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