using a 85 degree bowl gouge

[Michael Ginsberg]

In reading Ellsworth, he suggests a 85 gegree bowl gouge for cutting the end grain in the bottom of a bowl. I recently ground a 5/8 Crown Pm tradional bowl gouge to the 85 degree.
I am having trouble using it and getting it to "bite". At what point do you have the gouge start cutting? Is it partially on the wall towards the lower part near the bottom? Also, should I undercut the bottom of the gouge with a chamfer to allow extra clearence?
I have no problems with using the tradional gouge and the Ellsworth style swept back. This one is tricky for me.
I appreciate any input.

[Reed Gray]

I have 2 gouges ground to about that angle, though probably closer to 75 or 80 degrees. The profile isn't like a traditional grind in the 45 degree angle sweep, but more like a ), so very little sweep. Rub the bevel, and pull the handle towards you. You do want it at a high shear angle, flutes at 3 o clock on the inside, and if you use it on the outside, about 9 o clock.

robo hippy

[Ryan Baker]

+1 to what Reed said.

I have an 85 degree gouge (Thompson U), and it does a great job in the bottom of bowls. There's essentially no sweep to it ... just a traditional grind at a really steep angle. Roll it over to 2:30 or 3 o clock for a shearing cut and ride the bevel. It can take a little practice to get used to, but it really is the same as using any other gouge (just with the handle at a different angle).

[Michael Ginsberg]

Thanks guys.
Do either of you remove any of the metal on the bottom to get better clearence?

[Don Geiger]

Hi Michael:

I have tried the 85° bowl gouge with four different grinds:
1) A traditionally ground gouge
2) Trent Bosh grind with the right wing traditionally ground left wing swept back into a side grind.
3) Both wings swept back
4) Both wings swept back with a 85° primary cutting bevel and a secondary relief bevel. Referred to as a “double-bevel” or “micro-bevel” grind.

So far I like grind # 4 best. I can establish the cut more easily and the micro-bevel is easier to control and maintain bevel contact with. The relief bevel prevents burnishing the grain with the trailing edge, which can happen with singe bevel grinds.

Below is photo of my preferred # 4 “double-bevel” or “micro-bevel” grind.

WARNING: Do not grind an 85° bevel using a jig such as the Wolverine Vari-Grind or the Ellsworth jig on a bench grinder. Due to the extremely steep bevel angle and the downward rotation of the wheels, it will drag the gouge down. When this happens, something has to break. For the same reason, do not place the handle of your gouge in the V-notch of the Wolverine system when producing an 85° grind on a gouge.

I suggest hand grinding the bevel while resting the gouge on a platform tool rest. I did this initially until I got the grind close. Then I switched to my Vertical Solution system for Tormek grinders and an Ellsworth jig (a Vari-Grind would work too). The grinding wheel of the Tormek rotates in the opposite direction of a bench grinder and thus is safer. After grinding the 85° primary bevel, I produce the relief grind by placing a 1-1/4” thick magnetized block in the V-notch of the Vertical Solution moving the stem of the Ellsworth jig forward and presenting just the heel of the bevel to the wheel.

The 85° grind enables maintaining bevel contact in more circumstances than gouges possessing bevels at lesser angles. It also shortens the fulcrum point – minimizing vibration.


Don Geiger

178442
Thanks guys.
Do either of you remove any of the metal on the bottom to get better clearence?

[Ryan Baker]

I'd like to echo Don's comments about the danger of grinding an 85 degree bevel with a jig. That can get real ugly real fast ... i've had it happen. Be careful.

[Reed Gray]

Don has a nice neat second bevel on his gouge. I just free hand roll mine so it is more rounded, and do remove it up to about half way. It does put the bevel edge much closer to where you are cutting when you are on the inside of the bowl.

robo hippy

[Michael Ginsberg]

Thanks guys!!