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What size inserted bits?

I found some 7/16 round steel rods lost in a corner of my shop and am cobbling up some small inserted bit hollowing tools. I wouldn't sully his memory by calling my messies, "Oland Tools". :)

I have some 3/16 round hss bits, but they seem a bit too aggressive. Could be my technique since I have used square 3/16 bits without making too many funnels. :)

What size bits do you all suggest for these small tools? Also what length of exposed shaft do you suggest and what reasonable depth should I expect to hollow to, say in cherry or mahogany, with a 7/16 crs shaft?

Turn to Safety, Arch Fortiter

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Arch
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Hi Arch

7/16=11mm, not very thick rod, you surely know that the depth you can go "depends" dry, green/wet, endgrain, sidegrain, curly, knotty, etc., but I would expect not to go much deeper than 4 to 5 inches, maybe 6 before they would start to chatter. 3/16 inserts should be OK, I've used those, I leave them sticking out very little and sometimes turn them so that they are working like a shear scraper, like at 45 degrees, with a rounded end, not straight across, (clear as mud I guess). However is it not easier to use just some drill rod for those small tools (swan neck) ?? the amount of wood to be removed is getting pretty small, almost any decent steel rod would do, but I digress.

Have fun and take care Leo Van Der Loo

Reply to
l.vanderloo

Hello Arch,

I agree with Leo on the extension over the tool rest 4 to 6 inches should be about maximum for a 7/16" cold steel rod. The 3/16" round rods should work just fine, but I would recommend grinding about 1/2 way down and then grinding a gouge shape on the end. This has always given me better cutting with round rod; i.e., this makes a flat on the top of the cutting edge which is then similar to what you have with the 3/16" square tools.

I would also recommend the minimum extension you can get away with and still cut ok.

Fred Holder

Reply to
Fred Holder

Arch I use 3/16" square bits in a 1/2" shaft with no problem and I suspect that it would be fine in a 7/16" steel rod. When you say hollow I assume you mean to use this as a scraper. Seldom would I use greater than a 3/16" bit in a hollowing tool. Even 1/4" tends ot be too wide for other than smoothing use and 1/8" can be too aggressive a cutter, at least for me. I would say that you have the right combination for about 5" depth and maybe a little more. If you get chatter, reduce the cut.

Reply to
Darrell Feltmate

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