South Bend 9 Compound Condition & "weld up" fixes?

[Tim9]

Since you have a mill and a welder... maybe get some nickel 99 rods....and do a few light passes ... filling in the missing piece. Make sure to preheat the compound to about 250 degrees F. After each pass...let it cool about 5 minutes. I’d go on the low side of the recommended amperage so that it kind of lays down better and fills in more than heavy penetration which I tend to get when I set my welder to the higher amp settings.

once you’ve fill it where you want it, dunk it in a bucket of sand...dry sand...and let it cool slowly. Sand will work....vermiculite insulation is even better. But the main thing is to let it cool slowly so you don’t get cracks.

Then mill off excess. i was thinking about welding steel on top but cast iron and steel welded together just don’t mix well. Tends to cause cracks as it cools.
Plus, if you add a support piece on top of it.... make sure the added height doesn’t screw up your tooling of your quick change tooling.
Sometimes it’s better to not overthink this stuff in my opinion. Just go the easy route. Weld some nickel 99 and mill off the excess.

I think you could get by with a 13mm or 1/2” end mill. Just do multiple passes and go easy on the cuts. Yeah, a fly cutter would be nice, but I don’t think you absolutely need that. Nickel 99 rod mills fairly easy.

 

[SLK001]

For the top, I like martik777's idea of chucking it up in a 4-jaw and facing off the top, then sanding out the milling marks with some fine emery paper (put the paper on a piece of glass, then polish off the top with the compound face down).

 

[graham-xrf]

Fixture it in a 4 jaw and true up the top with a facing cut.

I love it!
BUT - there is a "Catch 22" !

 

[SLK001]

I love it!
BUT - there is a "Catch 22" !

What's the catch? No 4-jaw chuck?

 

[graham-xrf]

What's the catch? No 4-jaw chuck?

4-Jaw chucks are there, but the lathe that would turn them now has no place to mount it's toolpost!
There are limits to how far one can take the very satisfying route of having a lathe fix up parts of itself!

I am not so afraid of filing something to a good finish. See in post #12, I filed the quite deep dings and corrosion pits out of spheres, using the "rock with two tilts while rotate" filing technique.

 

[ericc]

You could make a plinth to replace the compound and be able to use the lathe for turning. I just watched a YouTube video of someone turning the compound on his mini-lathe. He said, no toolholder, we'll improVISE. This is a pun, by the way.

 

[graham-xrf]

You could make a plinth to replace the compound and be able to use the lathe for turning. I just watched a YouTube video of someone turning the compound on his mini-lathe. He said, no toolholder, we'll improVISE. This is a pun, by the way.

Erik, what you say makes sense! I have noted that Quinn Dunki (of Youtube "Blondihacks") has mentioned that some will make up a block fitting that does away with the compound entirely, in the interests of rigidity, but in a way that it can be put back for the few times it really is essential.
Are we talking of a steel block with a threaded hole in it to mount the toolpost, somehow attached to the cross-slide?

Quite a lot of what I need to make, some parts for the household, some for my machining interests, are depending on that I fix the lathe. Even the XRF project now needs parts made on a lathe.

 

[martik777]

Don't you had a spare lathe?

Anyways, the compound has a round base that can be held by the 3-jaw so no need for a 4 jaw. I just tried this with my 9A's compound. Light cuts recommended.

To operate without a compound you could make a fixture that fits the cross slide hole, preferably with the same angled cylinder as the compound but a straight cylinder should work with light cuts.

You could always reassemble the wounded compound to make these parts.

Edit: The newer SB9's (circa 1950+) have 2 threaded holes on the top of the cross slide just below the hole where the compound fits into. These may be used to secure a fixture to hold a tool bit.

 

[graham-xrf]

Don't you had a spare lathe?

[/QUOTE]
I did! I did!. That was the first one I took to pieces (the 9A).
I was happily restoring bits of it, and the 9C was helping. Then the old belt broke on the 9C, and shortly after, with a partly fixed belt, I got a QCTP - and so discovered the broken compound. I tried to ignore it, and put everything back together. Now hampered by building operations, and having to be moved out to it's new home anyway, I thought to do some repairs, and I bought a brand new serpentine belt to be spliced.

To operate without a compound you could make a fixture that fits the cross slide hole, preferably with the same angled cylinder as the compound but a straight cylinder should work with light cuts.

The shape of it is already forming in the mind - but that would be a future feature, probably one step behind my notion of converting a pair of ex-brake discs into a steady rest..

You could always reassemble the wounded compound to make these parts.

This too, has not escaped my thoughts. What I hope to do is fix the compound broken T-slot, but just put the other parts together with a lick and a promise to re-visit them. Then the 9C can make it's own Acme nut.

I will post pictures of how this goes. I might have to start over if it messes up, but hopefully not.

 

[martik777]

I edited my last reply while you were replying re: cross slide threaded holes.....

BTW: lol, I made a steady from ex-brake rotors - not the best plan