Welding Tips and Tricks

Hello all,
I just had to drive hours to get a crankshaft from a 16 ton punch press ground. I make the split bearings so the new smaller size doesn't matter too much.
At some point I'd like to resize the journals to factory spec. What would be the correct way to do this?
Spray welding? Hard chrome? some shops do submerged arc but I don't know much about that.
They're about 3 feet long and may have helped win one of the World Wars.
Thanks!

Regrind and make undersized bearings.

I’d go with spray welding for a build-up if you have the equipment.

I’m too cautious to grind down crank journals on units that size fearing the stress they’re put under. But that’s me…

You can always MIG it while it’s on the lathe (assuming you have the capacity?) and build it up directly. Make a decent scratch for better adhesion. Turn the lathe manually and you have a built-in orbital. Watch the heat input and weld only one section at a time until it cools. Turn it down to spec afterwards.

Yes BugH that's what I did. UCF in Carlisle PA is the shop I took it to. They did it in 2.5 hours while I waited. Very nice slow RPM grinding lathe for cranks. Picture a 4 jaw chuck on head and tailstock with a 16 inch grinding wheel to get in there.

CJ, yeah, I guess they're not 16 ton presses anymore! The journals started at 2.25 inches. Now the worst one is 2.18 inches. It's a continuous cutting operation, not what punch presses are normally used for. (Cutting rubber) I actually cut one on a 9 inch lathe but the journal ate a bearing in 6 months of 12 hours a day running. Has to be ground and polished.

Refrigeration compressors have cranks that typically can be reground 2 times and then use oversized bearings.

nelson wrote: ↑Wed Aug 18, 2021 11:52 am Yes BugH that's what I did. UCF in Carlisle PA is the shop I took it to. They did it in 2.5 hours while I waited. Very nice slow RPM grinding lathe for cranks. Picture a 4 jaw chuck on head and tailstock with a 16 inch grinding wheel to get in there.

I've done a little crank grinding here, though something your size might have been too big for the machines I have. I don't have the correct machines, but of course, in a pinch I can make a lathe with a tool-post-grinder 'kinda-sorta' handle it. Not for long term service though.

The slow speed is for the massive amount of weight slinging around, so it doesn't throw the machine off or make it walk across the floor.

I was in Carlisle over the weekend for the car show (2nd day off in 2021, lol).

CJ, yeah, I guess they're not 16 ton presses anymore! The journals started at 2.25 inches. Now the worst one is 2.18 inches. It's a continuous cutting operation, not what punch presses are normally used for. (Cutting rubber) I actually cut one on a 9 inch lathe but the journal ate a bearing in 6 months of 12 hours a day running. Has to be ground and polished.

I'm surprised they're so small.

If you ever tried it again, you can sand/polish it after you machine the part and get away with a lot of surface finish sins. I made a new main-shaft for a machine here and it runs every single day. I don't know how many strokes, don't even recall when I did it but it was a couple years back. On a typical day it makes about 25-30k strokes. I used oil-impregnated bronze bushings from McMaster Carr, just off the shelf parts. I can't detect any wear at all. I did put those little flip-open oiler-caps on them so they get oiled regularly. I cut the tubes into halves in order to install them, and drilled holes for anti-rotation pins to keep them from turning. Machined with a boring bar (used as an external turning tool), and then polished with sandpaper (down to crocus cloth) and let her rip!

Thanks for the info. You local?
What do you process on that press? I've never seen PP's used the way we do.

If Lock Haven area is "Local", then yea. About 2 hours north of Carlisle. Nice drive however. Right up 322 and/or 15, either to 80 or 880.

Mine isn't a press actually, it's a loom. But, a machine's a machine. Seen one you've seen em all! As built new, it had steel on cast steel as the "Bearings", and it lasted from just after WW2 until about 2 or 3 years ago. Now let me tell ya, it was SHOT. And I do mean hoofed. But, the base machine was great and it just needed new journals bored and reamed, then bushings in bronze added and it's as good as new. With a totally new main shaft that is. 2" square stock with ~ 2.5" journals on it turned round in the lathe and then polished. Biggest pain there was the 2" square stock wouldn't fit through the lathe without having the "Very" edges of the square cut down. So it needed milled to fit in the 2.75" through-hole in the lathe. Shaft is around 80" long, so that was a serious pain. But otherwise, a fairly easy job.

I'd love to build one from scratch someday. (yes, I have a need to).