work holding question

[dilligaf]

i have to make 10 parts that need 3 milled places on them the problem is they are 38 inches long and a foot wide. How is the best way to put them on my mill table to cut them one at a time of course. the material is 1/4 inch thick aluminum it has a cut out in the middle and a larger hole on one side and a small hole on the other side. i have a bridgeport clone with a 9x42 table. I was thinking 1.2.3 blocks under the center and ends and use the steps on the ends to hold it down is this correct? or better ideas?

thanks
Jason

[squirrel]

Jason, just keep in mind that it will vibrate and chatter if you have more than a few inches unclamped. If you are just drilling holes don't worry too much but if you are milling it needs a rigid set up. If you can push on it and see deflection you will have an issue with milling finish and possible tool breakage or launching the part.

[krutch]

Or you could use a piece of al. wider and longer as scrap to mill into instead of the mill table. I had a job which required a slot through and for most of its' length. I bolted an al. scrap plate to the mill table to take the cutter and to support the work. I fit dowel pins to locate the work for repeat pieces. All came out fine.