Holding Question For Stock On Rotary Table

[Pmedic828]

I was wondering how to hold a cylinder on a rotary table so you can mill the top and bottom. I cut some mystery metal that is about 4 inches in diameter. I wanted to make some fly wheels by surface milling both sides, then drilling 5 or more holes around the diameter of the steel. I thought about drilling a hole in the metal and bolting it down holding it from the hub but cannot face mill this because the bolt is sticking out the top. I cannot clamp the cylinder as anything that is placed on top prevents flatting out the sides. I also attempted to turn my lathe jaws around to hold and face this piece off but my lathe only opens up to 2 inches in diameter even with the outside jaws. I am not sure if you could hold it by the sides because the shear force pushing on the diameter would lift the blank. Please guide me on how to hold this piece. After surfacing I wanted to cut about 0.300 from each side leaving about .250 rim. After drilling, I could hold it thru the drilled holes but cannot figure out how to get started.

 

[Wreck™Wreck]

If a hole in the back of the part is allowed then drill and tap it and mount it to a piece of scrap material, clamp the mounted stock on the rotary table and have at it. If no holes are permitted then you will have to make a fixture that will be clamped to the table and hold the part much like a split collar.

http://us.misumi-ec.com/material/mech/MSM1/PHOTO/10300009220.jpg

 

[brino]

Hey, if you will be drilling multiple holes eventually anyway, how about doing them counterbored now so that you can bolt them down with the bolt head below your face cuts. Use socket-head cap screws into your mill/rotary table t-nuts. Perhaps a couple recessed holes from each side allowing you to flip it and do it again.....afterwards you can drill thru with the larger counter bore diameter.

-brino

 

[David VanNorman]

Stand it up set a big Vee block up to it and clamp it to the vee block. You can then use hold downs on the vee block/