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Advice needed - Repair to a Rotary Table

Jersey John

Stainless
Joined
May 29, 2015
Location
Beccles / Suffolk, United Kingdom
Hi folk

I'm looking for some advice about repairing a Rotary Table.

I'm potentially looking to purchase a really nice Swiss 12" rotary table that has a broken corner (See picture) ... andI don't have the broken lug!

I admit to know nothing about welding charistics but I'm wondering if a new piece of Cast Iron can be welded or braised on the corner so I can machine it back into something like its original profile. On the outset it looks simple - "weld a bit on and then machine", BUT is it really that SIMPLE?

Swiss 12" Quality Rotary Table

There are a lot of Rotary Tables out there but this one really appeals "IF" I can get it back to near it's original state.

All comments and thoughts sincerely welcomed.

John :typing:
 
It seems to me that the goal of the bolt at that point is to clamp the table down to ensure a positive friction-based clamp of the bottom of the rotab to the mill table. To that end, you could use a hold-down, with a spacer slightly taller than the broken ear was thick, and you'd be good using this as is. In short: you don't need to fix this, you have an easy work-around. I wouldn't trust a CI weld at that high-stress point anyway. At least I wouldn't trust MY CI weld at that point - there may be welding wizards out there that could get better than original strength.
 
Not a welder, but i hear you need to heat cast iron significantly before welding.
Brazing might be a better option if you have the original piece, as capillary action would draw the braze through.

a good washer under the bolt may preclude the need to repair at all.
 
If it were mine, and the rest of the table was in good order id leave it and use a clamp. Start messing with it and you just might make it worse.
Ive used tables that had broken stud castings and I just used a clamp.
 
Don't get me wrong. There's not a guy on this site who would look at that picture and not think "Boy, that would be great if you could repair that". So your initial impulse is completely appreciated.
 
.... yes "BUT" ???? ... I feel there are implications ???

I wouldn't fusion weld it myself. Braze, maybe, but you need to define your goal here.

Is it to return the RT to as close as possible to original?

Or is it to have a functional RT?

If the latter, ignore the break and just use it as-is. That's what I'd do myself.

PDW
 
I'd look in to the possibility of cutting off and tarting up the damaged lug and redrilling n slotting the bolting hole, .........or m/c up a new corner piece of steel and do the best I could to bolt and dowel it to the original casting - which could be machined to take the corner etc etc etc.

Think ''If you can't hide the repair make it obvious and look nice,''

I WOULD NOT GO ANYWERE NEAR THAT WITH HEAT OF ANY SORT!
 
Treat that like a sore dick...Don't f*ck with it! You stand a lot better chance of making it worse than better. Use a toe clamp to hold it down and each time you use it just wish some dumbass hadn't broken it. And wonder why some engineer who should have known better designed it that way.
 
I generally agree with the "just clean it up and use it" crowd, but i think i could probably (80+percent?) fix that. scarf it out so that the filler is at least an inch long, bit of oxy-fuel preheat, use 99 Ni TIG rod, slightly oversized mild steel lug held in place, peen lightly while at red heat intermittently as you go, grind sand machine to finish.

as said, not that it really needs it, but it would be an interesting challenge to me. but that's just me!
 
It is readily weldable (probably is not really oil soaked, just oily) but I don't think it is worthwhile. It appears to have been nothing but a little finger sticking out, and it was just ASKING "Break me off". Bad design not worth restoring to original. Would that slot actually line up with a T slot on your mill table anyways? Looks kind of offset a bit much.
 
Welding, brazing, and silver-soldering sound like really bad ideas to me. My inclination would be to mill or file the broken surface to clean it up, add a bit of chamfer around the edges, and call it good.

John

Thanks John ... The thoughts of just cleaning up the damaged area was a thought I'd considered ... sounds like everyone is avoiding a re-weld / braze etc etc ...

Appreciate you input!

John :typing:
 
I wouldn't fusion weld it myself. Braze, maybe, but you need to define your goal here.

Is it to return the RT to as close as possible to original?

Or is it to have a functional RT?

If the latter, ignore the break and just use it as-is. That's what I'd do myself.

PDW


Well what "IF" I said I'd like "BOTH" ... I find it sad / criminal that such a wonderful precision RT has been damaged! Sounds though like most feel the repair is not a go'er.

So it maybe accept you look elsewhere!

John :typing::cheers:
 
I'd look in to the possibility of cutting off and tarting up the damaged lug and redrilling n slotting the bolting hole, .........or m/c up a new corner piece of steel and do the best I could to bolt and dowel it to the original casting - which could be machined to take the corner etc etc etc.

Think ''If you can't hide the repair make it obvious and look nice,''

I WOULD NOT GO ANYWERE NEAR THAT WITH HEAT OF ANY SORT!

Hi Sami ... may give you a call on this one! ... thanks for the thoughts ;)

John :cheers:
 
I generally agree with the "just clean it up and use it" crowd, but i think i could probably (80+percent?) fix that. scarf it out so that the filler is at least an inch long, bit of oxy-fuel preheat, use 99 Ni TIG rod, slightly oversized mild steel lug held in place, peen lightly while at red heat intermittently as you go, grind sand machine to finish.

as said, not that it really needs it, but it would be an interesting challenge to me. but that's just me!

It's been my experience that 99% Ni rods aren't all that shit hot for welding cast iron: they burn too slow and take forever to deposit enough metal to get the job done. So you're standing there pouring heat into the thing waiting for a few drops of metal to transfer. Pure nickel has the property of being 'hot short' which makes it pretty absurd to weld with (not a critique of you, but of the welding rod industry in general) because you don't want something that is going to crack when hot, and I'm afraid metal beneath an arc is a tad hot.

I use ferro-nickel rods now (every welding rod supplier makes an equivalent) and have very good success with them: they still burn at a low heat, and go on nice and fast. So you can actually lay a decent bead, and then get right on it with the peen and relax it. None of this 'barely get 'er hot', BS for me. I always preheat and then get in there and get it done (with maybe 3/4" long beads at a time). Peening has to be done only in the very hot stage (get about 5 seconds worth) as the weld temporarily cools.

This job at hand is quite similar to welding a broken lug on an electric motor base, which I've done plenty of. No harm in welding a chunk of steel onto the cast iron, no need to go to pains to scrounge up a piece of cast iron.
 








 
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