The Chopper Compendium

While anticipating a moment of shear horror, I decided to take a break by making another pot of coffee. Procrastinating has always been one of my strengths. While waiting on the coffee, I discovered I could kill some more time by posting what I've done this weekend. I told you I was good. I decided to build a weldment for the die that's stalled my build. It should provide up to 70* of bend. More than what I need. In any weldment, you need to have enough material to account for mis-alignment. Didn't do that. I trust on the grace of God, shear luck, and an assortment of hammers. The web came in @0.002" off center. I'll call that good (luck/grace).

Any slack beyond that point will be machined to the hub so the profile will be centered to the hub's thru-hole. I turned a groove into the hub to center it to the block. The f-up on the right is a problem with brain-print coordination. Everything is programed using radius. For some reason I printed the CLR as 9" dia. For an entirely different reason, I programmed a 9" rad.

Looking at the pic below. How many of you can tell what I did wrong. I cut the profile 0.025" over to allow for a cleanup pass on the lathe. See the flat spot? That should be there! Right? These are the parts prior to final weld. One c-clamp and it was pretty easy. No matter how lucky you are, or how much you account for error, something always goes pair shaped. After cleaning the OD (center-line-radius), it came in @4.475". I forgot to account for clean-up when machining the hub c-line. It does look good though.

Oh, yeh! This was suppose to be a horror story. I've moved my tool as far back as I could. There's about 0.025" clearance between the insert and the part. I was hoping to do this with cutter compensation so I could squeak the profile to my sample. Oh, well! I'll just have to modify the program itself. The moral to procrastination is that while you dread the tough stuff, the easy stuff comes to light. Round insert + round profile = 3 lines of code. And I'm not even done with my coffee, yet.

OK! That wasn't so bad. This is the rough pass to check my dia. As expected it was small. Should have checked my insert. One side was toast. Several cleanup passes to squeak the dia to my sample and this is about as good as it's gonna get. I still have one last pass to put the tube c-line even with the die OD. I may go a little farther also. But, I'm already into my jaws. It's a sweet sound, and I'm not using that part anyway. I may just go for it.

Hard for me to tell, but it looks like you have used layers of steel plate to build the die.
I see a weld on the flat outer face of the body, is that joining two of the layers?

good on you rudy. keep on keepin on.

Thanx Krymis.

Bob, the weldment is a 2x2 block, 5/8 web and 2" hub. The layering that you see is actually chip wiping from the insert. I'm not good with one-off pieces. It would take several more peices to get the speed/feed for a good surface finish. Interupted cuts on such an imballanced piece is tough.