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

[SLK001]

A little detail.. Is this stuff done by welding on it while it is over a gas grill?

I had thought to keep it heated between weld passes using a propane torch, and then transfer it into the box of wood ash, or even put it into the woodburner, covered in wood ash, and let it take all night to cool down. I would have a thermocouple on it to keep an eye on temperature, just because I do have one,

Yes.

A propane torch will allow the temp to fluctuate too much. A TC is probably just a waste of time. Also, your part is relatively small, so any time taken to move it somewhere else to cool would drop the temp too much. Better to just leave it in the grill and to slowly lower the heat.

 

[graham-xrf]

Yes.

A propane torch will allow the temp to fluctuate too much. A TC is probably just a waste of time. Also, your part is relatively small, so any time taken to move it somewhere else to cool would drop the temp too much. Better to just leave it in the grill and to slowly lower the heat.

OK - you all have got me onto this in a deeper way.
Despite the impression one can get from those cheerful guys on YT making it look like 10 minutes fun with a welder, and plugging either the welder or the rods, getting this right involves some planning.

Pretty much, every move is choreographed. The preparation of all the resources, and hot things. The sequence of what gets done when, right down to thinking through the weld lay plan. I will get it hot, and keep it hot, right through the whole thing.

The Handle
I had a go at the corroded handle. I used a 5mm wide little file to take out the pits, using the "rock it around the curve" filing technique, but this time, in two directions at once, while rotating the part. Apparently, this ensures what is filed off comes off a sphere. It seems to have worked OK.

I followed with some abrasive paper grades to take out the file marks, and get it somewhat shiny. I plan to give it a dose of vinegar nickel, but here is what we have so far. Its a "before 'n after" thing




Sure - I was messing with the bit I knew how to fix while thinking about the novel weld fun yet to come!

 

[finsruskw]

Your cross slide nut looks nothing the one in my 9A

 

[erikmannie]

If you were paranoid (like I am), you could bolt down & AND weld (and/or braze) the broken off part of the compound.

I would mill it down to where it was missing a rectangular prism, machine the missing rectangular prism with 2 countersinks on top, tap original compound, bolt down your new machined piece, do a plug weld over the countersunk washers & bolts, and then probably braze the existing seams (.001” is good for brazing). The mechanical connection should be enough for the job, & the brazing serves to fill the gaps & serve as insurance.

Welding the bottom seam would be tough because it is hard to get to; that is why I would choose brazing there. You know that if you are going to both braze and weld, you need to do all the welding first.

Be wary of prexisting oil in the original compound. Another reason to opt for fasteners.

 

[brino]

would just find one on ebay and buy it. Probably not a lot of $$$

They are available from eBay.co.uk from local sellers.
........... a Tempilstik or two adds up to a reasonable fraction of the whole instrument with free postage!

I thought @gonzo was talking about buying a new top-slide............not just a temperature crayon.........now I'm not sure!


As to the business at hand. I would definitely braze NOT weld, as @Ulma Doctor recommends.
Just considering the possibility of temperature induced issues, the brazing temperature is much lower.
Pre-heat and slow cool still recommended, but likely not as critical due to the lower temps involved.

.....of course I have the oxy-acetylene rig and have had a few successes with brazing myself.

I wish you all the best success and please let us know how it goes!

-brino

 

[erikmannie]

Brazing is always nice because it doesn’t threaten the base material.

 

[graham-xrf]

Be wary of prexisting oil in the original compound. Another reason to opt for fasteners.

Erik - In the "belt 'n braces" theme, I had thought about what would make a stronger thing. Sure, I could figure up a design, freely helping myself to all sorts of smarts from the internet, but I wanted it just to look like what it is, work a whole lot better, have a large dials upgrade (when it becomes capable of turning it's own stuff), and a better paint job.

Re: Oil in the weld. I plan to grind the torn metal surface away back to clean, and likely give it a last minute go-over with a Dremel burr when it's hot. There cannot be oil left inside the metal - can there?

 

[graham-xrf]

Your cross slide nut looks nothing the one in my 9A

Do tell!
As it happens, this is the only one I have ever seen. I don't know what a proper one is supposed to look like.
Now you got me looking for old catalog PDFs, and paging through "A Guide to Renovating the South Bend Lathe 9" Model A, B & C Plus Model 10K".

 

[graham-xrf]

.....of course I have the oxy-acetylene rig and have had a few successes with brazing myself.
I wish you all the best success and please let us know how it goes!

-brino

I don't have oxy-acetylene. I once helped a pal get an acetylene cylinder to his place, and then I got to watch him light it, and make the smoky yellow flame turn blue.

I principle, I could persuade the Sherman welder into "lift-TIG braze mode". I have definitely considered all the braze options.We had those amazing pics from Ulma Doctor where he went to what looked like brazing fine art sculpture on a compound that had been chewed by a crash with a chuck!

This Old Tony has explored TIG brazing, taking it to a high skill..
Here ->

WeldingTipsandTricks explains aluminum bronze TIG braze, as opposed to silicon bronze braze for a vise repair, saying the braze is stronger provided the part is not going to be temperature cycled, like an exhaust.
Here - >

I will check the thermal expansion coefficient of the 45/55% ferro-nickel alloy, but we already know it has to be close enough to cool without too much stress, because that is what the alloy was developed for in the first place. I get it that getting the weld to "take" is the key thing. This is where brazing can easily "wet" on the join, and from then on, easily joins to itself. Pure nickel famously wets to iron, which is why it was traditionally used for repairs to higher carbon cast iron. I know that once non-ferrous braze metal is in there, you can never weld again short of cutting it all the way back to iron. If I try the weld first, and it turns out to be a fiasco, I can maybe try the braze as the alternative.

In the way folk are at HM, nobody is going to come onto me bad if I get it totally screwed up (other than a few laughs), so I don't mind having you see all see what happens. I just have to figure out some sensible heat treat arrangements, because kitchen grill is verboten!

 

[SLK001]

Your cross slide nut looks nothing the one in my 9A

That's not the cross slide nut - it's the compound slide nut. It looks as it should.