Diamond tool holder.

Edited By John Haine on 30/01/2011 11:01:02

Hi i read all the posts on the tangental tool holder, and because Im'e like a lot of you, I cannot afford to spend much money on tooling, So I make my own. First I cut a piece of 16mm cold rolled square 110mm long, Cut a piece of 10mmX50mm flat steel. Put the flat, length wise in the tilting vice, at 45degrees used an 8mm end mill and cut a groove a little less than half the diagonal measurement, the center of the cut about 6mm from the edge Then cut the oblong into two sections. One of these I ground a 15 degree angle at the rear end of this, so that it was pointing to the left, ie, towards the chuck when it was mounted in the tool holder, then ground a 12 degree angle onto the front edge of the 16mm square, then clamped the flat section so that the groove was at the front and the top of this was flush with top of the 16mm, I also ground a deep chamfer on the edges I was going to weld together. I know this sounds difficult, its not, what is, is doing it by your self without proper clamps, or a second pair of hands, anyway you only need a small tack weld to start with, that way you can bend it into the right position. fully weld it togther when you are happy with the position. Clean up the welds The reason I offset the tool only 15degrees, was that it gave me more clearance. Next I put a spotweld at the rear of the second piece of steel,(to act as a pivot point) I put a 1/4 inch HSS in postion and drilled as close to the HSS to tap for a 6mm round head bolt, and clear drilled the welded one, plus recessed to half cover the head, Bolted it together and with the HSS below the marks, cut and ground off the exess, without weakening the welds.

I made a sharpening jig out of timber and, the same as in the model engineer article, it works OK, I also made one out of 12mm steel, milling a slot upwards 12 degrees and angled about 22 degrees, That work too, The timber jig is good for grinding 1/4 round HSS,

Now the big question is does it work, YES. gives a good finish with both bits, BUT if I made another one, I would use two locking bolts, as when taking very heavy cuts the tool bit gets pushed down and below the the work piece,( I had to use a lot of strength to get it to lock up properly).

I tried various angles of attack for the tool bit, to arrive at a reasonable result. You might do better. because I also added a 3 degree angle, to give clearance, It might not need it ?????.

Good luck.

John Holloway.

Norman Hi, Can you under stand what I did with my tangental tool holder, In the description above, So far it cuts very well with both, the square and round 1/4" HSS. Mine has an offset to the left but if you do one that is straight, you only need to mill, or just do cuts with a hacksaw and file, and not do fiddle welding. Can't send drawings or photo's yet!!!. cause I need my grandson (who is down south in Victoria), to help, trouble is he just started Uni doing Vetinary science. and cannot come up here to help.

By the way. I modified mine, to use two and not one, cap head locking bolt. With one bolt there was a tendency for the tool bit to drop down below the center line, when taking heavy cuts of 3mm or more. Now it does not move at all. Also on the square bit, Hone a small radius at the front, it will give an even better finish.

PS. I was turning something using the round tool bit, and did not move the saddle back far enough, turned the chuck round by hand, ouch!!! drove the razor sharp bit, 1/4" into the back of my thumb.

John Holloway.

Edited By Les Jones 1 on 25/04/2011 12:39:42