There was a recent thread about that

Ugliest frame repair EVER!



Ok, so can you post a photo of the frame you're working on? Go to the Advanced editor, and click on the paper clip "Attachments" icon, then upload.

Anything is possible. I suppose the first question is WHY? If it is a quality frame, then there must be better alternatives, and if it is a cheap frame, then they're a dime a dozen.

If you wish to take a horizontal top tube and make a sloping top tube, then you'd have to be mighty lucky with length as the angles should make the tubes longer, although perhaps the angled seat tube will compensate slightly. Still, if you're cutting miters into the tubes, you still may have a length problem.

I've also found it difficult to do precision cuts around welded joints.

One thing to also consider is that a smaller frame isn't just shorter in height, but is usually also shorter in length as the short rider's arms aren't quite as long as the tall rider's arms. And many of the angles are typically changed slightly. So just cutting a frame shorter in height could create an unwieldy frame size that isn't built proportional to the rider.

Smaller frames tend to have a steeper seat tube, and a greater angle for the head tube. Larger frames are the opposite with more of an angle for the seat tube, and a steeper head tube.

Are your tubes "double butted", or "straight"?

The Double Butted tubes are thicker at the ends, and thin in the middle. One end often has a little longer but than the other, but you might not know until you cut it open. Away from the butted end, the frame tubing is mighty thin.

TIG welding is the preferred welding method due to working with the thinwall tubing.

One other note, many of the vintage frames (60's to early 80's) were brazed, so technically the frame should be able to be completely disassembled, cut down, then reassembled (and aligned).