Setup question; a flange too tall

[jwmelvin]

I made a flanged adapter for my air-compressor inlet and I wanted to machine the flange flat after welding it. But the flange was only 0.188” thick and the overall piece was a couple inches. I’ll show how I ended up holding it for the fly cutter to take some light cuts. But I’m interested in any advice you may have for next time.

Thanks

 

[AmericanMachinist]

Does the final alignment of the flat face to any of the tubing matter (i.e. does it just accept a rubber hose, etc.)? I'm likewise interested to hear others' input and am formulating thoughts of my own. Thanks for sharing.

 

[markba633csi]

Not much choice there unless next time you drilled the two holes undersized, tapped them, and ran bolts thru from the underside to secure it somehow
then mill the flange. Afterwards, you drill the holes to size.
You could also make a split collar block from wood to clamp the tubing- that wouldn't be too difficult
-Mark

 

[AmericanMachinist]

Its messy but you could also weld on nuts below to do what Mark said. And grind or mill them off after fly cutting.

 

[darkzero]

If the only thing that mattered was the flange mating surface being flat, I would have just flattened it with a belt or disc sander. For it's purpose, doesn't sound like it needs to be machined flat like if it were say a cylinder head & I assume there's going to be some sort of gasket which should take care of any minor variances.

 

[MrWhoopee]

Looks like your setup worked. Other options: lathe, belt sander.

 

[jwmelvin]

Thanks all, I like the additional ideas.

It’s true there was no need to machine it rather than use the belt/disc sander; I did it more as a learning experience than anything. And it was nice to have a really flat flange.

The pipe coupling at the other end of the adapter isn’t particularly straight so didn’t make a good reference; also, not much of it is round as it transitions to an oval.

 

[DeanB]

Are the round sections straight sided or tapered? if straight and the flange is perpendicular maybe clamp in V blocks?

 

[jwmelvin]

Are the round sections straight sided or tapered? if straight and the flange is perpendicular maybe clamp in V blocks?

It’s a transition from the rectangular inlet on my compressor to a 3/4” pipe thread for a filter silencer. While the 3/4” coupling started straight, I heated and pounded one end of it into an oval, welded it to another, larger piece of pipe that had been ovaled, and then welded that to the flange. So in the final form, nearly nothing was straight. I did consider a v-block but the pipe wasn’t straight enough.

Had I considered my desire to machine the flange surface, I might have done things a little differently; it was ad hoc design for sure.