Keyway Bushing

[aametalmaster]

Nope no mill here at that time. I have a small arbor mill but its still in pcs on the floor...Bob

[Highpower]

OK... This is something you don't want to do:

Here we are, set up in the press - ready to cut a key slot.



Getting late, tired, and in a hurry to get done. I didn't put the hub back far enough in the press, and then failed to check the underside to make sure the broach would clear the hole on exit.



Needless to say, I am going to cut out more of my benchtop for more clearance. My fault though for not checking the path.

[aametalmaster]

Thats good.
I bent my cutter about 15* one night in a hurry but it flattened right out. I thought i was out 50 bucks...Bob

[Highpower]

Bob,

This is the price I paid. Original hub on the left - the replacement hub I made on the right. Notice that after my little faux-pax, I filled in the key slot with stainless steel infused epoxy. Why???



Because... when the broach hit the edge of the hole it kicked it out at an angle and proceeded to cut right through the side of one end of the hub.




After the epoxy had cured, I re-cut the keyway (straight this time...) leaving the upper portion as filler material in the tapered end. Luckily the "key" only contacts a short area in the back end of the hub where the slot was still straight with solid metal walls.




So if this little warning helps to prevent one other person from making the same mistake I did - it will have been worth it.

[aametalmaster]

I have one just like that. And people say you can't cut tapered keyways with a broach LOL. I used to borrow my cousins press and all he had was wooden blocks and i didn't notice the pulley sinking in on one side until it was done. Then i finished my press...Bob