I have no machine vise, but my project called for one. These pulleys come with a pilot hole. This way you can decide for yourself what kind and size of hole you want in them. I want them tight, 4 mm wide and perfectly perpendicular.
So what is a guy with a jig saw and a drill press to do? Right. This.
It's a piece of ply with a hole in it. The second piece is a lever to grip the teeth of the pulley. However, the lever pushes it askew. The pulley no longer sits perfectly flat and as a result, the hole is crooked and damaged. This is the left pulley in the top photo. You can see it does not sit on the 4mm shaft very tightly. It wobbles too. Shoot! I've got ten of these. Can't hold them in my fingers. The ply-vise even was not strong enough to hold the wheel still. When the drill bit reaches the other side, it "bites" into the aluminium and the wheel starts spinning with the bit.
Keep It Simple Rik! Superglue to the rescue!
On a piece of nice flat mdf. Which I can hold safely in my left hand, while operating the drill press with the right hand. But will they ever come loose? Turns out, that is not a problem. The top layer of the mdf will come loose when you pull hard enough. The wheel is not hurt by the abuse, that’s why it’s called a pulley.
Mind you, superglue on this combination of material is not so super. You need to let is sit in the open air for a little while until the glue becomes sticky. Just like any contact glue. Then push in place and apply pressure.
A bit of extra lube never hurt any drilling.
After pulling them of with plyers, sand off the mdf that's still attached. If you care about that sort of thing. I do, so I did.
And thusly the chemical vise was invented.