GlennM
Aluminum
- Joined
- Aug 14, 2004
- Location
- Kingston, WA
This is Chapter 2 of my previous question about jigs. I purchased a sheet of 3/8" A36 for use as the jig base. So far, this is working nicely, except for one little problem:
The piece (18"x32") I cut for my first jig has a slight crown to it, about 1/8" in the middle. The bow appears to be spread evenly across the plate.
I suspect that the source of the distortion is the kerf from the plasma torch, because the large plate from which this smaller piece was cut does not have a bow in it. Or, I may have released residual stresses by cutting off a piece. It doesn't really matter where the distortion came from; the important thing is to reduce it. This piece is too large for me to put into my shop press.
I have often read of flame straightening, and it seems as if it might be the answer to my problem. I have a rosebud tip for my torch, or I could use my propane weed burner (I use it for preheating items for welding), so I think I can put enough heat into the plate. I can easily rig up a spray wand to blow air/water mist on the plate to chill it.
If anyone has hands-on experience with the flame straightening technique, I would appreciate it if you would share a few tips regarding how to approach the task of flattening the jig base.
I don't need perfectly flat, BTW; I'd be happy to halve the 1/8" bow to 1/16" or less. I'm willing to entertain other suggestions for flattening the plate, too. Bring 'em on.
Thanks,
Glenn M.
The piece (18"x32") I cut for my first jig has a slight crown to it, about 1/8" in the middle. The bow appears to be spread evenly across the plate.
I suspect that the source of the distortion is the kerf from the plasma torch, because the large plate from which this smaller piece was cut does not have a bow in it. Or, I may have released residual stresses by cutting off a piece. It doesn't really matter where the distortion came from; the important thing is to reduce it. This piece is too large for me to put into my shop press.
I have often read of flame straightening, and it seems as if it might be the answer to my problem. I have a rosebud tip for my torch, or I could use my propane weed burner (I use it for preheating items for welding), so I think I can put enough heat into the plate. I can easily rig up a spray wand to blow air/water mist on the plate to chill it.
If anyone has hands-on experience with the flame straightening technique, I would appreciate it if you would share a few tips regarding how to approach the task of flattening the jig base.
I don't need perfectly flat, BTW; I'd be happy to halve the 1/8" bow to 1/16" or less. I'm willing to entertain other suggestions for flattening the plate, too. Bring 'em on.
Thanks,
Glenn M.