The first two frames I built were truly done by hand, meaning outside of a bench grinder used to rough in miters on the tube ends everything else was done with hand files and a hacksaw. This past winter after starting out this way I remembered I had a Dremel tool from about 20 years ago. Serious labor saver. Unfortunately, the thing died this week. Got it running again, but it died once more. Time to move on.
Went to the local hardware and found the Rotozip tool. Much more substantial tool, 5.5 amps vs. 1.8 for the old Dremel. Wasn't sure I could slot stays for drop outs with it figuring it was a beast of a tool, however it has proven to be better than the Dremel. I use the Dremel cut-off discs from the old tool. So happy I found this thing. Had two stays slotted and fitted in about an hour. With a hacksaw and hand file it would have taken many more hours than that.

My name it tihabanero and I approve this tool!