Need help with rotary table project

[praetor]

I have a small 4" sherline rotary table that i have never used (came with the milling machine package) but I now have a project that requires a concave arc within a 1.530 -1.535 radius on .375 thick x 1.750 wide x 6" long aluminum bar to be fastened to a 1.530 O.D. aluminum collar. Can anyone possibly instruct me on how to do this, or guide me to a website tha covers this, please? It's my first commssioned piece and I thought it'd be easy enough, only I don't know how to set this particular job on the rotary table to cut said arc.

[awerby]

You could do it it vertical mode, I suppose, but you'll need to make a fixture that holds onto that aluminum bar under the centerline of the rotary table faceplate while spacing it far enough away that the head of the mill can reach it without banging into anything.

You don't say how much of that arc you need, but if the stock has to remain 6" long it seems like you're not going to get to too much of it before the end of the aluminum bar hits the edge of your mill table.

A better way would be to use the rotary table in horizontal mode, held down to the table and facing up. You'll still need to provide some fixturing, but you'd minimize the clearance issues. Cut an arc-shaped slot inboard of your final dimension, and then creep up on it slowly...

Andrew Werby
www.computersculpture.com

[praetor]

Sorry, I have the measurements wrong, the correct measurement are 2.280 collar dia. and the width of the bar is 1.750, Well the arc is going to sit on the OD of a 2.280 aluminum collar, so I thought I could use the OD of the collar onto the aluminum [flat] bar using this measurement (2.280 collar OD) as a reference point to get an inner radius on the bar to mate with said collar OD. thanks for the reply, i relly appreciate it.