Machining warped flange on pipe end

That's pretty ugly.

The flat end could probably just be pressed against a belt grinder to even it, but the other end with the pipe protruding wouldn't work that way.

My thought is that the Bridgeport is the way to go, trying to get that thing in a lathe would be a nightmare. I'd think support it from underneath the flange with step blocks, 123 blocks, shims, etc. and held down with clamp bars.

Support and clamp at four points so you can remove one clamp, mill that area, put the clamp back, remove the next one and mill that area, etc.

Pete C.

I considered the belt linisher for the square end, what about grinding out the pipe stub at the other end (it's not a continuous extension of the pipe itself, it is actually either a turned part of the oval flange, or a short separate piece welded in), belt linishing that flat, then TIG in another short stub? Thanks for the reply and suggestions, keep `em coming! :)

The grinding out and TIGing back sounds like more work than setting it up in the mill. If it's using gaskets some slight mill marks shouldn't be a problem as long as it's flat.

Pete C.

Just how bad is the warpage? If not too great the protruding end can be done on the lathe if you are careful. Here's how: Put a disc of aluminum, or whatever you have around that's easiest, and face it. Then bore it to accept the protruding pipe with perhaps .005" clearance. Then use either sanding discs or sand paper glued to the disc. The center can be cut out with a utility knife. Use some kind of cutting lube on the paper. Use a coarse grit to begin with. But I was just thinking that these flanges are probably warped down at the ears. So the ears have been pulled toward the mating surface. If this is so then either a file can be used or the ears can be grasped in a vise and the flange bent back. In any event you should probably use the faced and bored disc to check the flatness after trying to flatten things. If you are careful these ears can be bent back. I've even done it with cast aluminum parts. Just be patient and move small amounts at a time. If you have a 1 inch travel indicator this can help. Clamp the part in the vise and then run the indicator up to it till it touches the part somewhere. Zero it. Pull on the part a little and notice the indicator deflection. Release the part and see if it moved. Pull more and more until things start to move. But always just a little more each time. The metal won't move until deflected a certain amount. Then it will move fast. You may need to pull the pipe back .125" before things start to move. Then pulling it back .130" may get you a .003" movement. This all depends on where the indicator is mounted and how the metal behaves. It really takes longer to read than to do it. But if you are careful it's possible to get things real straight and flat. Or you could just use thicker gaskets. ERS

Someone skilled with a file could probably fix that. Someone not skilled with a file could probably ruin it.

I would make a flat gage as Eric Snow suggests. I'd then blue the gage, mark the flange, file off the blue spots with a large flat sharp first-cut mill bastard file. A good new file cuts surprisingly fast. ( If you're tempted to grab the angle grinder, cut the cord off it. You can later repair the cord more easily than you can repair the damage it'd do to your flange.) Re-blue with the gage, file off the blue spots, and so on. It goes faster than you might think if the warpage is slight as you say and you have a good file.