It is about the size of a 3/8 bolt. How do I cut that on a milling machine, I have no index machine, but have a small 4" rotary table w/o any accessories to turn the piece, and have them right with 4 corners. Maybe there is an article one of you wonderful people here can send me.....The whole project is 2-3 inches long, and the flat piece is at the most 1/2 inch and the rest is 3/8 or so round..
I use 5C collets in square or hex blocks to cut wrench flats on shafts.
Otherwise you could support the part in the milling vise on parallels that will raise the cut above the vise. Cut one flat, turn it 90, insert a piece of stock thicker than the depth of cut into the cut and tighten. The inserted piece and the vise jaw will ensure that the next cut is square to the first. You'll need two inserts for the last cut.
================ assuming your table is similar to the one shown below
suggest you get 2 pieces of steel or aluminum 3/4 to 1 inch square and about 4 inches long. Square as required.
Drill one piece so you can bolt it to the table using slots that are 90 degrees apart and so that the edge of the #1 block goes over the center of the table. The second piece is drilled so the two pieces can be bolted together to pinch the 3/8 rod, and the first piece drilled and tapped to take the "squeeze" bolts. 1/4 X
20 SHCS should be adequate. Bolt the blocks together with a .005 [or so shim] between them. Very carefully center the rotary table under the mill spindle. Bolt the block assembly to your rotary table and drill/ream the 3/8 hole for the part. Leave the first piece bolted to the table but unbolt the #2 block from the first. remove the shims. Insert the 3/8 part and re bolt blocks
1 and 2, offset the table the required amount, and machine away. The shim is used to generate a .005 "crush" when it is removed. Put a punch mark on the ends of the blocks so they will be reassembled the same way every time.
This is also good when you need to clamp on threads without damage. Just drill and tap the center hole as required with the shim between the blocks, and then clamp the part w/o the shim.
Bigger shim when drilling the hole = more "crush" when it is removed. You can also mill off the block after machining for the crush but this is more/extra work.
As in most machining, the less overhang or amount of material you have sticking out of the clamp the more rigid the setup will be.
If you are a real cheap screw [ like me ] reverse the blocks and you can drill another hole for a different size on the other edge. It can be helpful to etch or stamp the exact size of the holes on the blocks.
Let us know how everything works out.
Unka' George [George McDuffee] ============ Merchants have no country. The mere spot they stand on does not constitute so strong an attachment as that from which they draw their gains.
Thomas Jefferson (1743-1826), U.S. president. Letter, 17 March 1814.
Tom got to be a cool guy, he is funny alright, and now you have been de-throned. I'm dumber then you Tom. Anyway, I will do the job tonight, I'm with the grandkids for 2 days, and back home tonight. I think all the answers are appealing to me, but I think I will read all the answers again, and then decide. Some of the gray matter is appearing again. I have a milling machine, a lathe a Shaper and a surface grinder. However, not too much knowledge in using any of them. I promise I will try hard to use my head, and report the results. No question shall be left unanswered. You guys are great.......Peter