Next on the list: .875" x 5CLR Die for the Di-Acro No. 4.
0. Make hole pattern for the blank (For those wondering they are 1.06" apart. First hole is a 1" hole and the second is a .75" hole. 1" hole is 2.5" from the back side of the die centered - these are the measurements for a No. 4 bender by the way.):
1. Start each side roughing out the material in a series of steps:
2. This brings me close to the finished radius. It also makes the last two passes on my Bridgeport a bit faster/easier:
3. With both flats pre-machined, onto the rotary table it goes with some custom tooling. Centering the mill's head off the rotary tables center:
4. First step above is to rough out the radius (in this case the center line radius, aka CLR is 5.00") again using that same stepped relief process. I'm using a right angle attachment. Mill is still on center:
5. And then make the final set of passes. Last one I actually bring the spindle speed up a bit so we're humming along for a really nice clean cut:
6. Rough blank with all edges deburred and edge break added by hand & file. There's a bit of hand finish work to be done on the transitions and die faces:
7. Here comes the fun part bringing the part through the steps of emery cloth and then steps of 400 and 600 grit wet dry wrapped on a .75" OD tube to bring it close to .875" OD. This step just takes patience with a lot of stepping back and forth between grits and fine file work and checking with my finger tips. One thing I was taught is that some methods require you to use all your faculties and often your fingers can tell a lot more than what your eyes are "seeing":
8. Finished die with a shallow blind slot for its radius to be stamped:
Close up:
9. Next is the clamp block. Same method:
10. Designations stamped!
11. Complete set up. Just have to make a follower...
3 down. 2 more to go!
