Bevel prep the inside bore of the mount so that you have a 45 degree bevel
3/32 nds deep. Make up a dummy flange/disc to mimic the wheel and the disc.
Bolt them to the mounts in order to hold the mounts flat during welding.
With the preparation you only need to put in enough weld to come out a
sixteenth of an inch maximum beyond the mount surface. You will have almost
full penetration with the bevel prep. The more weld you locate further
away from the centreline of the mount the more distortion you will have.
I am guessing the mounts are just small flanges with bolt holes. Can
you modify your CNC program to create several ribs on the open face of the
mount. It would add fancy detail and create a more rigid disc mount.
Randy

"Terry" wrote in message
oups.com...
I am building a new hub for a 8" rim I use on my mini chopper. I
turned down a tube to about 3/16" thick, and bored each end to fit a
new bearing. I then CNC machined 2 mounts out of 1/8" thick steel, one
for my rim and one for a disc brake. They each have four mounting
holes on them.

I then attempted to weld the two mounts onto the tube. The mounts fit
very snug on the tube so I was able to get them perfectly square before
I started welding. Though for the hub to work properly, I can only
weld on one side of each mount becuase the other side needs to sit
flush against the rim and the disc brake. This is how the original hub
was designed.

I began by making small tacks 180 deg from eachother. Then I stitch
welded small portion 90 deg apart until I had a bead all around the
tube. But both mounts ended up warping up towards the welded side. So
now my mounts are not perfectly square to the tube, and I have about
..030" run out on my disc brake and rim when spinning on the axle.

So basically I have to start all over again, but I really don't know
how to avoid this warpage while welding on one side of a part. I
could use less heat, but I really want to make sure I penetrate the
1/8" steel. This is a wheel hub which has a lot of weight on it, 100's
of pounds.

Any suggestions in preventing this type of warpage would be greatly
appreciated.

Thanks.