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motomoron
01-14-2007, 09:40 PM
My new shop is finally finished (finished! ha!) so before I waded into the abyss of a backlog of work, I had a little "me" time. I made a nice sliding fence for the Walker-Turner bandsaw (Thanks, Nitearc) which with it's newly installed Carter ball bearing guides, some urethane tires properly crowned, and drive belt newer than the Coolidge sdministration , is cutting beautifully.

Then I addressed something which I've been working around for several years now. No matter how carefully I fit and adjust the gibs, the Smithy 1324 Granite is not a really rigid machine, and the bulk of the problem, near as I can tell is the compound rest. There are many turning operations where I don't need to use it, so I set to making a toolpost support block to take the place of the compound.

I had a 2' length of 4" mild steel bar; mystery metal, but it machines about like 1018, so I'll say that's what it is. I sawed a 3" chunk on with the horizontal bandsaw, faced and shouldered it, center drilled it and tapped it 1/2-20. I measured this part, and in SolidWorks modeled it and added the reliefs for the hold-downs.

I laid out the slots on the bottom, clamped it on it's side in the vise, and cut the slot with a 3/8" ball end mill. I hogged out the cavity with a rougher, and finished with the ball end. Flipped it and repeated the other side.

Whole thing took a couple hours. With the toolpost fitted it weighs about
15 pounds. Much, much more solid than the compound.

http://img.photobucket.com/albums/v341/motomoron/DSC02912.jpg

IOWOLF
01-15-2007, 05:34 AM
Nice, But pretty tall,How heavy of a cut can you make?

kap pullen
01-15-2007, 06:08 AM
Yep,

That's a nice looking job!

I can see that you work "outside the box".

Did you machine it on the Smithy.

If so, they must not be as bad as some claim.

Kap

-----------------------------------

"A poor mechanic blames his tools."

motomoron
01-15-2007, 12:12 PM
I did it on the Smithy in question. For what it's worth, the Granite 1324 and 1340 are *worlds* more substantial than the little Smithies. D1-4 headstock, R8 quill.

You have to keep the gibs on the snug side, use heavy way oil, (Vactra #4) rigid setups, and appropriate sized tooling. Roughing out the reliefs I was using a 1/2" cobalt rougher and I was just wailing on it. Shop vac sucking up fistfuls of blue chips. The finish cuts were a 3/8" HSS ball end mill with thin cuts with a spritz of cutting fluid.

I tried it this morning on a scrap of 1" 304 SS, and I could take a .125 DOC without chatter.

surface finish looks a lot better as well.

As for it's height, it has essentially zero flex, so the lower the tool holder is on the post, the better.

It's orders of magnatude stiffer than the compound, and that's what matters.