thompson bottom bowl gouge

[allen thunem]

Have watched doug thompson videos on sharpening this tools.
Maybe i over looked it on his video, but I couldn't see anything that explained how to sharpen his BOTTOM BOWL GOUGE. Can anyone shed some light on how to accomplish this? I did send him an email inquiring and called him as well but no reply to either.

[Brian Kent]

Allen, I don't have an answer t your question, but I do know that you can get in touch with Doug Thompson by calling him. He likes the phone :)

[allen thunem]

thanks brian as stated i did call him but no response he must be traveling

[John Beaver]

Just like a spindle roughing gouge. Set your grinder rest at the angle you like and grind straight to it.

[John Grace]

Check out reed Grey's (aka robots hippy) sharpening video on YouTube. He demonstrates how to sharpen all turning tools

[Brice Rogers]

Just like a spindle roughing gouge. Set your grinder rest at the angle you like and grind straight to it.

Some questions:
1. when rotating the gouge on the rest, do I stop rotating it when the flute is parallel to the grinder rest, 90 degrees from the centerline (which would be beyond being parallel) or would I rotate it 360? Occasionally when I'm turning blind (like inside a hollow form), the top of the flute catches. That's why I'm wondering if I just rotated it 360 that it would take off those flute tips.
2. I've read things about using an 85 degree angle for the bottoming bowl gouge. But I was also told by a fellow turner at the San Diego Wood Turners club that you just blunt the end and then grind off 15 degrees (making the angle 90-15 or 75 degrees). I've been experimenting with 80 degrees and am not sure if that is the best angle.

Advice?

[Scott Hackler]

Doug is on vacation in Las Vegas right now. Give him a call next week and he should help.

For my "bottom feeder" gouge, I sharpen it on the sharpening platform (i.e. RoboRest). I set the angle just like my scrapers and start at the nose. While rotating the tool to each side I rotate the flute slightly away from the wheel to keep the heal recessed from the flute. I use a Thompson spindle gouge for mine because of the super shallow flute.

[Brice Rogers]

I sharpen it on the sharpening platform (i.e. RoboRest). I set the angle just like my scrapers and start at the nose. While rotating the tool to each side I rotate the flute slightly away from the wheel to keep the heal recessed from the flute. I use a Thompson spindle gouge for mine because of the super shallow flute.

Scott, I'm having trouble visualizing your explanation.

If the heal is recessed from the flute, wouldn't that mean that if the tool was introduced flat and flute open that the flutes would contact the wood but the intended cutting edge would not?

Also, for your bottom feeder, what cutting angle are you using?

[Reed Gray]

For my BOB (bottom of bowl) tools, I will use a 60 or 70 degree bevel. The 60 gets me through most transitions and across the bottoms. If the walls are a bit steeper, then I use the 70 degree bevel. Any half circle flute shape can be made into a BOB tool. I do prefer a little bit of sweep on them, so instead of being straight across the top, the nose looks more like ), but not any where near the V shapes. Mostly this is so you can roll it way up on the side, and get a higher shear angle. I do have it in my sharpening video on You Tube. I have a 'new and improved' version coming out soon. I also show pretty much the same thing on my video clip on the fluteless gouge.

It is at about 5:50 where I do a BOB tool. The fluteless gouge is closer to the beginning.

https://www.youtube.com/watch?v=UQ7w6yFhw4c

robo hippy

[John K Jordan]

Doug went to Las Vegas for a week.

JKJ

[Shawn Pachlhofer]

Doug went to Las Vegas for a week.

JKJ
for the SHOT Show?

[allen thunem]

doug gave me a call the other day and gave me the definitive explanation.
two methods
one using the v arm of the wolverine system the other using the wolverine platform
both set at 60 degrees

[Scott Hackler]

Scott, I'm having trouble visualizing your explanation.

If the heal is recessed from the flute, wouldn't that mean that if the tool was introduced flat and flute open that the flutes would contact the wood but the intended cutting edge would not?

Also, for your bottom feeder, what cutting angle are you using?

Brian,

Just like a scraper, the "sides" of the gouge are ground so that the bottom of the tool is narrower that the flute, but only slightly. I found that because of the lack of a strong flute on the spindle gouge, rotating the tool around on the rest and sharpening like a scraper, wasn't quite enough for my style, so I started clearing a little more metal on the sides of the flute. Understand that this angle is NOT a swept back design and more like a round nose scraper with a very slight flute. It's not a very strong of an angle, but since I don't won a protractor I couldn't tell you the angle I set my grinding platform to. I can tell you that it is a #7 on my RoboRest! It is the exact same angle that all my scrapers and hollowing tools are set. I will try to take a photo of it in the next day or so and show you what I am talking about.

[Bob Bouis]

I got one of these, but I haven't made a handle for it yet because I'm not quite sure how to use it. Never had a tool like it before.

Just grasping the bare tool in my hands, I haven't had a lot of luck figuring out the technique. It's still got the straight across grind it came with, which I assumed is the one you're supposed to use -- but now from reading this thread, I'm not so sure. Intuitively I think I would rather have a bit more of a "D" shape, but I just don't know.

Any thoughts on the handle length and the pros and cons of the competing grinds would be appreciated.

[ron david]

doug gave me a call the other day and gave me the definitive explanation.
two methods
one using the v arm of the wolverine system the other using the wolverine platform
both set at 60 degrees

3rd method is just to do it on the grinder tool rest
ron

[John Grace]

Check out Carl Jacobson's recent video on making tool handles...he makes it very explainable to the person making their own first handles.

[Joe Kaufman]

Check d-waytools.com I believe Dave shows how to sharpen his bottom feeder or whatever it's called on Bowl Gouge Sharpening. I haven't seen Doug's gouge and grind. I do have 2 of dave's but presume they are very similar.

[Bob Bouis]

John, I guess I should have been more clear: I know how to make the handle; I just don't know how long I should make it, and that depends on how it's used. If it has to be held at an angle a long handle could get in the way, whereas if it's held level with the centers it might provide better balance or support.

Joe, the Thompson version seems to be different for the D-way; it's wider with a shallower flute like a spindle roughing gouge. The Thompson version came to me ground straight across. I originally thought that was the way it was intended to be used, but after reading this thread I suspect it may just be to preserve the end-user's option as to how he wants it ground.

[robert baccus]

A straight across grin is fine--so is a 75 deg, bevel. To use it just ride the bevel, even on a flat platter surface. This same grind on a 1' roughing gouge is a favorite of mine for vases and bowls-exterior only of course. I have spindle and deep bowl bottom feeders and prefere the deep bowl version.

[Reed Gray]

I don't care for the straight across grain, and always put 10 or so degrees of sweep into the front. I like to roll it up on its side and cut for a slightly higher shear angle. 70 degrees is what I use for most of them, and grind away most of the bevel, leaving at most 1/8 inch or less, and really round back the heel too.

robo hippy

[Pat Scott]

... since I don't own a protractor I couldn't tell you the angle I set my grinding platform to. I can tell you that it is a #7 on my RoboRest!

My understanding is #7 on the Robo Rest means 70 degrees. 6 means 60 degrees, 5 means 50 degrees, etc.

[Reed Gray]

Correct. There isn't enough room to write all the numbers in any size that could be seen. Upper row is the 5's, so in between 4 and 5 is 45, or close to it. Can't make them to fit every grinder perfectly...

robo hippy

[Bob Bouis]

I tried grinding a slight "D" shape to the Thompson bottom gouge. The result was a tool that handled much better, or at least more intuitively, but the quality of the cut was just fair, not nearly as good as a regular bowl gouge when I can get in there with it. I guess that'd be because no matter how I rotate the tool, I'm still cutting with no shear angle. Any thoughts?