Bowl gouge basic grind profile

[Doug Thompson]

The pictures show the basic profile that needs to be kept to keep the cutting angles on a V and U flute shape bowl gouges. Notice the basic shape of the flute is carried over to the grind, if you look down the flute and straight down on the grind the shape won't be perfect but very close. The wings will be ground to this profile and the gouge will work like a charm, small changes like grinding the wings back won't affect the tool much at all but major changes the tool won't cut. This basic idea can be used on any bowl gouge just find that curve and grind to the shape. I'll be back later tonight.

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[Jon Prouty]

Hi Doug,

Can you post a couple more pics? I think a direct side view of the profile and one of the final grind with wings swept back would help. Also, can you post a pic of bad grinds where the tool won't cut would be awesome for us newer folks.

Thanks!
Jon

[Jon Lanier]

And that angle would be?

[tom martin]

Doug has a page on sharpening on his site, but I don't think I am allowed to post a direct link. Anyway he lists it at 60 degrees. Go to his site and there is a diagram that shows the wolverine setting along with protrusion for bowl gouge , spindle gouge, detail gouge and skew.
Tom
Thanks Ken
http://www.thompsonlathetools.com/images/extra/Sharpening.pdf

[Ken Fitzgerald]

Tom,

You certainly can post a link to the page to which you refer at Doug's website. If Doug posted it, it would become a little sticky as some would complain it was being done for advertisement. In this case since the sharpening page is germane to the subject you could post it.

We post links to commercial websites routinely especially for reference material.

[Tim Thiebaut]

Hi Doug, I am very new to turning, a little over a month now, and have had a heck of a time trying to get my bowl gouges to sharpen properly useing the wolverine vari-grind jig setup. I made sure and kept working on just one of my gouges so as not to damage/ruin any of my others since they are all brand new tools. Long story short, I came across your web site about 4 days ago and printed off YOUR instructions on how to setup the vari-grind jig...it worked FIRST time without any problems for me what so ever following your instructions to the letter, so Thank you very much for your help!!

[bob svoboda]

Doug's info works great!

[Rick Markham]

Thanks Doug! I made sure to keep mine at your original angle of 60 degrees, and they have been a pleasure to use. I did sweep my wings back, but that is the only change I made. Having made my own plane blades, knowing just enough metalurgy to be dangerous, I knew different tool steels perform best at certain angles. (your tools are my first experience with powdered metals) so I kept them the way the "master" made them. Thanks again Doug! I will be calling you again soon ;)

[Don Geiger]

Hi Doug:

When changing a gouge from a traditional grind to a side grind or when I have to make a dramatic change to the profile of any bowl gouge, I actually start by mounting the gouge in a jig and grinding the desired angle on the tip (usually 60 degrees) until the grind meets the bottom of the flute without rotating the gouge. Once this has been done, I remove the gouge from the jig and hand grind the profile just like in your photos. Then I hand grind away the gross amount of metal on either side at approximately the angle I want. Then I place the gouge back into the jig and finish the grind, making a single belvel continuous from one side all the way around to the other side.

Below is a photo of a gouge that was originally supplied with a traditional grind and has had the end bevel angle set to 60 degrees and the top profile hand ground.

The whole task takes about 15 minutes. I use the Vertical Solution with either a Ellsworth jig or a Wolverine Vari-Grind and to refine and maintain the grind and I get really good results.


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[Ryan Baker]

I'd also like to see some pictures of grinds that don't cut. I have tried a lot of different grinds on my gouges. Some were good, others not so much, but I have never found a grind that "wouldn't cut".

I have found that my preferred grind on my Thompson gouges has returned to something very close to Doug's standard grind (with a bit longer wings). It's a good profile right out of the box.

[Doug Thompson]

Below are the same tools ground (well half ground) to show how a grind evolves from the nose bevel to the profile of the wings, then the side wings ground to the profile line.

The basic nose bevel of 60 degrees is a good starting place but it's not written in stone, if your starting out stay in the 58-60 degree nose angle. One reason the 60 degree angle is popular is it works well down in the bottom of a bowl.

The Wolverine grinding jig is setup with a jig (Vari-grind) to hold the tool at a set angle while you grind the tool. The nose bevel is adjusted by moving the "V" shape arm in and out to the angle you want. The Leg angle on the Vari-grind sets the wing angle on a bowl gouge this adjustment is easy to mess up on... a wing to thick won't cut well and a wing to thin won't hold a edge very long. I have a leg setting on my site to get you in the right area. Now spindle gouges don't have wings so leave the leg in the same place when you grind a spindle gouge. The rule to sharpening is keep it simple with basic angles and basic grinds.

How do you find the angle a bowl gouge cuts best... well start with the flute closed (9 o'clock outside and 3 o'clock inside) start cutting then open the flute until it cuts the way you want... that's the angle you need. Rub the bevel only when your close to the finish size and cut other wise don't bother.

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[Neil Strong]

Rub the bevel only when your close to the finish size and cut other wise don't bother.



Thought I had read that right the first time, but let it hang there for a bit expecting to come back and find a heated debate in progress. Not a peep!

The bevel rubbing brigade down our way would have been all over that one with a vengeance... ;-)

Not that I have any issue with it myself, just curious that the Creek doesn't have it fair share of bevel rubbing fundamentalists... :-)
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[Chris Barnett]

Yo Doug, trying to send you a pm but your box is full!!!! Have urgent info.

[John Keeton]

Chris, probably better to just give Doug a call or email him. He may not check this thread again.

[Chris Barnett]

OK, will do that. Bet his website has phone number....might even still have it in cell. Thanks.