It's strange that, no matter how many tools you have, you still never seem to have the right ones.
For this project I'd already modified a collet, and when it came time to run the part, I needed to be able to chamfer an inner passage. The tool block didn't already have a cutter that could do the job, and I didn't want to have to set up and prove a whole new toolset.
What I did have was a 60-degree diamond (shape) profiling cutter...
But it's too "thick". It's not meant to fit into small-diameter holes, and so the back of the toolholder hits and 'smears' the metal.
I'd started making a tool for exactly this a while ago, but I'd made it from undersized material. I either needed to whip up an adapter bushing, or just remake the tool. The latter was only moderately easier, so I sawed off a chunk of 5/8" O-1 (oil-hardening) tool steel, and turned a 60 degree point on it.
Set up in the mill, I cut a flat along the top...
And then milled half the point off.
After that, I got out the seldom-used gas-axe, and by lucky chance (and a little laziness
) I had a can of some of the old ****** fluid left lying about. I heated the cutter to cherry red and quenched 'er in the oil- no pics, hard to juggle a lit torch, a bar of red-hot steel
and a camera without either melting my face off or, y'know, burning the shop down.
Now, as anyone who has heat-treated O-1 will tell you, it tends to "grow" slightly in the process- in my case, the treated end grew almost exactly .001", and since it was already a snug fit into the tool holder, I had to turn that thou back off, very carefully.
In that pic, the cutter is moving away from the chuck- the thin darker band at the far left is the starting point. The lighter colored dull band is untreated steel, and the shiny band is the heat-treated portion.
With a little strategic sanding and polishing here and there, it fit nice and snugly. Took a little trial-and-error to get it adjusted, but she works.
Interesting tidbit there: That tool is a one-off, basically meant just for this one part. Therefore I didn't bother assigning a tool number to it. I'd used the threading tool directly below it ("T15") to very lightly chamfer the outer corners, so I simply sent it down and to the left 'til the new tool went where I wanted it.
And she worked perfectly- which is more than I can say for the camera.
Hard to tell with the overexposure, but that burred, rolled corner from the original tool is gone, with a smooth, proper chamfer in it's place.
After that, I just had to chew my way through the rest of the parts.
Still a few steps left, but with luck, I hope to have these off to the anodizers by Saturday or Monday.
Doc.
