homemade carbide tool questions

[Jesse Tutterrow]

A friend made me a set of carbide cutters without handles (like Easy Wood Tools). I have a couple of questions:

1. He did not know what angle to grind the tip under the carbide cutter (is clearance angle the correct term?). So what angle should I grind this?

2. He made them out of 1/2 inch bar stock about 12 inches long. What is the best way of installing a turned handle on them?

a. I thought of trying to use two pieces of wood, route a channel, and glue them together. But I am concerned about glue squeeze out into the channel where I will put the steel.
b. A local turner told me to drill a big enough hole and use lots of epoxy.​

3. How much steel should I have hanging out (in front of) the handle and should the rest be berried into the handle or should I trim it? And how much to trim.

 

[Marshall Sadler]

I have made some homemade carbide tools for a small hollow form. They were alright as I am not a machinist.

1. I believe the term clearance angle is correct. Clearance is just so the carbide and not the bar contacts the wood. The exact angle is not so important, it just needs to get the tool out of its own way.

2. Method A. I would use this for something with a square tang, though it will work in this situation. I am not sure how you would "combat" the squeeze out although it may not matter at all.
Method B. is what I used when making my carbide tools. In either method it would be wise to add a ferrule of some kind.

3. Stuart Batty is the only person I have heard that has a ratio for tool length to handle; for scrapers (carbide) it's 1:7. For every inch you hang over the tool rest, you need 7 inches of tool handle. You can keep this ratio in mind as you make your handle. My Carter gouges have a 3 inch tang so that is what I would recommend.

 

[hockenbery]

Tool handles should have a Ferrel. Brass or copper pipe or pipe fittings work well
Tightly wound cord will make a Ferrel too.

I need something to keep the square steel fro turning
Routing a groove will work.
Also drilling tight hole and epoxy will work

 

[Bill Boehme]

Twelve inches is a bit longer than necessary. I think that I would cut off a couple inches. You can put about 2 to 2½" in the handle. If you leave the tool shank square, drill a 11/16" hole and fill the gaps with epoxy. If you round the corners then you can drill a smaller hole. I have a bunch of brass nipples that I use to make ferrules.

 

[Gerald Lawrence]

Look at Thompson Tools site, he has a article about how to turn and fit handle for round or flat bars.

 

[RichColvin]

1. He did not know what angle to grind the tip under the carbide cutter (is clearance angle the correct term?). So what angle should I grind this?

I just picked up 6 scrapers from a fellow at my club last month. They are various shapes, but basically ¼ inch thick (shown below in green) with a cutout for a ⅛ inch piece of carbide (shown below in blue). I sharpened them to be negative rake scrapers.


The angles I used are 22.5 degrees top & bottom, yielding a 45 degree included angle (picture angles aren’t perfect). You can notice that the bottom is ground more so that the 45 degree angle basically comes at the middle of the carbide.

This is working extremely well.

Kind regards,
Rich