Sunday, July 28, 2013

A Pin Vise Improvement

I brought this over from the garage.

It's quite a nice pin vise, but it has a flaw -- the handle isn't pinned to the chuck's spindle, so the handle will turn on the spindle if it's forced enough. I often use a pin vise as a tap wrench, so that won't do.

Here it is taken apart.

I think I see what happened when my dad was making this.

He'd meant to pin the handle, and began drilling through, but the hardness of the spindle defeated him. (I tried a file on that steel, and the file wouldn't touch it.) He then tried for a shallow, partial pinning, but didn't quite get what he was after.

There's an existing 3/32" hole through the spindle. If I can get that short pin out of the handle's ferrule, there may be a way I can exploit that.

- - -


I got the 'pinlet' out of the ferrule, and here's where I am with the handle/spindle interface now.

The hole in the ferrule is 1/8". The hole through the spindle is 3/32". I can go either of two ways with this.

a) I have cobalt drills. I can risk a costly cobalt drill in that incredibly hard steel, and maybe drill through 1/8", and then install a 1/8" roll pin or equivalent.

b) I can drill through the other side of the ferrule 3/32", install a 3/32" roll pin or equivalent, and then back fill the remaining oversize hole in the ferrule with epoxy.

I think I'll go with 'b)' -- 'b)' will work well enough, and it can't cost me a drill.

- - -

Here's a view of a pin's trial installation.

I got that pin from the shank of a broken 3/32" twist drill. See this post for my method of cutting very hard steel items like that.

Needless to say, I don't have an interference fit here, so I'll install the pin with CA adhesive.

- - -

A Method For Forming An Epoxy Fill

The pin vise's handle has an 11/64" hole through it for hanging it on a nail. Where the drill emerged, there was some splintering out that I 'd like to correct, so I'm going to try something here that I've been meaning to try out. Here's what I've done.

I smeared the shank of an 11/64" twist drill with WD-40, placed the drill in the hole and laid on the epoxy around it. I'm thinking that once the epoxy has fully cured (overninght, even though it's the five-minute stuff), I should be able to knock the drill out fairly easily, leaving behind a fill that exhibits a nice clean hole. We'll see how this works out.

- - -

It worked.

Now I just have to file away the excess epoxy.

- - -

That turned out remarkably well.

At the ferrule, you can see the back-filled, oversize pin hole.

(I sanded the thing in the lathe a little -- that's why it looks so dull. I mean to paint it dark blue.)

The handle is bored all the way through. I'll fill that bore with dowel, and drill a 5/32" hole in the end. That will be the chuck key's parking spot when the tool is idle, hanging on a toolboard.

- - -

All Done

There we are -- always at the ready, and I know where its chuck key is.

I mentioned earlier that I often use a pin vise as a tap wrench for small taps. If the chuck tends to unscrew when I'm doing that, I'll install the chuck with blue thread-locker.

# # #

# # #