Jig for Sharpening Bowl Gouges

[Brett Bobo]

I'm new to turning and sharpening turning tools but I'm in the process of making a homemade version shown on the UK Workshop's website (see link below) of the Vari-Grind jig for sharpening bowl gouges. Even with commercially available jigs, much is made about the 23 degree angle between the gouge and the jig, the projection of the gouge from the jig, distance from the grinder to the v-groove stop, distance from the v-groove stop to the centerline of the grinder, and distance from the end of the dowel bearing into the v-groove stop to the centerline of the gouge. Which of these is critical or are these just individual preferences? Also, with the homemade version, is the length of the dowel from the v-groove stop to the gougle holder block critical? Any help would be very much appreciated.

http:// www. ukworkshop.co.uk/forums/viewtopic.php?t=20682&highlight=sharpening+jig
(copy address to your browser and then remove spaces before activating link)

http://www2.woodcraft.com/PDF/77B61.pdf

Thanks,
Brett

[David E Keller]

Not sure I know enough to be useful, but my guess is that none of the items are critical. What you really want is something simple that allows for reproducible results. If you make the varying parts adjustable, then it's just a matter of dialing it in(then LOCKING IT DOWN). I'd love to see your finished product. Good luck.

[Richard Madison]

Brett, a big Welcome to the forum.

Ditto exactly what David said. I built my first sharpening jig from plans online and there was no way it would produce a proper fingernail grind/sharpening. It took some experimentation and "adjustments" to get it to sharpen the desired shape. Suggest you follow the plans as closely as feasible, and/but be prepared to do a bit of tweaking of your jig to get exactly the results you want. Once there, as mentioned, leave everything set where it is.

[Steve Harder]

Brett - this is a link to a sharpening jig I built when I first started turning and still use. Not much expense involved and it works just as well as the factory jigs.

http://aroundthewoods.com/sharp.shtml (look for the diagram on the right side of the page half way down to get the big picture)

I have a number of these jig blocks, each sized for a different tool, most of them at 45 degrees.

[Jake Helmboldt]

Brett, look online for an article called "Sharpening Demystified" by Kirk DeHeer. I found it at some point as a PDF from American Woodturner. DeHeer has a DVD by the same title. The article speaks to the specific question of the leg angle and set up of the jigs. And it is interesting cuz he goes into what actually creates the wing/sweep angles.

You hit it on the head; these are individual preferences and all of the different jigs use different settings. David Elsworth has his jig with a fixed leg and the distances to the wheel are different than what Oneway calls for. Same with all the others out there. The key is finding the setting that works for what you want and the repeatability. Heck, for that matter I have been getting by with approximate settings because I haven't gotten around to making my complete setup. I'm close each time, but may be off a bit on the nose angle or sweep. Doesn't make that much of a difference, but I do need to get off my duff and get my jig complete.

That is my 2 cents anyway. I just found the article:

http://www.donleman.com/cows/2009_1-13/DeHeerSharpening.pdf

Jake

[larry cronkite]

I was thinking about a VS grinder to sharpen my lathe gouges when I realized I already have a variable speed motor - my lathe.
I have the WorkSharp 3000 but even with the see-thru wheel it is not easy to sharpen gouges and if I try to sharpen them on top of the wheel I still can't see where the gouge meets the wheel.
I have seen most of the jigs for sharpening gouges and they all look like "Rube Goldberg" contraptions to me.
I screwed a 3/4" oak board on the lathe face plate, band sawed and sanded it round and applied self-stick 120 grit sandpaper to the wheel and it's right up there where I can see what's going on.
A little touch up with a diamond sharpening hone and it's sharp again.

[Brett Bobo]

Thanks for the input thus far. Comparing the angle setup for the homemade jig from "Around the Woods" and the Vari-Gring jig, the "Around the Woods" angle setting is 45 degrees from vertical (or horizontal); however, the Vari-Grind angle setting is 23 degrees from horizontal. If I'm understanding this correctly, there's a 22 degree difference for the bevel angle at the nose of the bowl gouge. If so, why is there such a large difference and does this just show that virtually angle bevel angle, within reason, is acceptable?

I completed my version of the grinding jig in my original post last night and tried it out. Initially, I spent too much time grinding the bevel at the nose of the bowl gouge and found that I got a concave shape of the nose to the wings in plan view. So, I switched to grinding out to in with the wings getting most of the abuse. I think it worked fairly well but I noticed the nose was not exactly concave and slightly rough. It cut well but maybe I'm still missing something. I'll try to post photos of the jig and the shape of the gouge tonight, which may help make sense of my explanation.

Thanks again,
Brett

[Joshua Dinerstein]

Thanks for the input thus far. Comparing the angle setup for the homemade jig from "Around the Woods" and the Vari-Gring jig, the "Around the Woods" angle setting is 45 degrees from vertical (or horizontal); however, the Vari-Grind angle setting is 23 degrees from horizontal. If I'm understanding this correctly, there's a 22 degree difference for the bevel angle at the nose of the bowl gouge. If so, why is there such a large difference and does this just show that virtually angle bevel angle, within reason, is acceptable?
That angle from the stem down to the base of the slider arm and the shaft of the tool IS NOT what you sent the bevel angle on the tool with. That is control instead by the closeness of the pocket on the arm to the front surface of the wheel. I have found that changing that relationship and where exactly on the wheel you are grinding controls that.

Rather what this arm angle sets is the length of the wings on the side grind of the gouge. The closer to parallel these bars are, the tool shaft and the "leg" on the jig, the smaller the wings will be (if there are any) and the closer the bevel shape will be to the older style traditional grind. The more these are apart in that angle the longer the wing is on the tool. I have seen a few turners sharpen was feels like the entire tool shaft. Bill Grumbine is one of them. His comment in his video is that he like to "sharpen the handle". I.e. not really but he goes for some massive long side grinds. Another english turner uses quite effectively a bowl gouge that has no side grind at all.

What you like will fit somewhere in the midst of what everyone else suggests.

Joshua

[Richard Madison]

does this just show that virtually angle bevel angle, within reason, is acceptable?

No, but there is considerable variation in bevel angle depending upon the individual turner and purpose of the specific tool. For starters try for a nose included angle in the range of 50 to 60 degrees.

Many turners tend to sharpen the nose too much as you did. Always sharpen the wings first and then just make a light pass or two around the nose. Remember you are "sharpening" (once the right shape is extablished), not "grinding".

Reread my previous post. Some experimentation may be required, but you can get there.

[Steve Harder]

Thanks for the input thus far. Comparing the angle setup for the homemade jig from "Around the Woods" and the Vari-Gring jig, the "Around the Woods" angle setting is 45 degrees from vertical (or horizontal); however, the Vari-Grind angle setting is 23 degrees from horizontal.

Thanks again,
Brett

Brett - as other posters have mentioned, the angle setting will control what you end up grinding.

Here is a link to ThompsonTools diagram of a Varigrind tool, with angles listed for various grinds. His instructions tell Varigrind users to set their tool to the angle shown in the actual size image of the Varigrind.

http://www.thompsonlathetools.com/images/extra/Sharpening.pdf

When I build my wooden jigs I construct them so their dimensions exactly match the Varigrind pictured here. And several of my turner friends who do own Varigrinds never change the angle of the leg, leaving at the pictured angle for all their bowl gouges.

[Richard Madison]

Good link Steve. Need to build a slightly more rigid jig and will give this a try.

[Brett Bobo]

With everyone's help, I think I'm understanding the settings. I'd like feedback from the photos I've attached to be sure I'm on the right track. The angle between the leg of the jig and the gouge is set to 45 degrees and the bevel angle at the nose of the gouge is set to 60 degrees. Question-is the bevel angle supposed to be measured tangent to where the tool touches the grinding wheel? That's how I measured the 60 degrees so maybe that's not quite right. I look forward to your criticism-thanks!

[Richard Madison]

Brett, The 60 degree angle should be the included angle of the tool at the cutting edge of the nose. Said another way it's the angle between the bevel (at the nose) and the axis of the tool. Yours look about 70 degrees but can't really tell from small picture. If you reduce the 45 degree leg angle (like, make it more straight) a little you should get a slightly sharper bevel angle and longer wings. May have to move the pivot point back a little. Keep experimenting. If you have a gouge with the grind you like just use it as a gage, with out grinding. Just try it with the grinder off and match the shape of your gouge.

[Brett Bobo]

[QUOTE=Richard Madison;1411531] but can't really tell from small picture. QUOTE]

Actually, how do I create a "slideshow" with the photos, like I've seen with other posts? I had to downsize the photos a lot due to the file size requirements for uploads.

[Patrick Doody]

not sure how you create a slide show, but if you save the file as a JPG, you should be able to upload larger pictures, BMP files don't have a good compression level (to the best of my knowledge).

[Brett Bobo]

Thanks, Patrick. I didn't realize they were resized and saved as .bmp files. Let's try this again and hopefully, it's alot easier to view...

[Richard Madison]

Much better. Your jig looks fine Brett. Just grind/sharpen the wings first and then make a couple light passes across the nose. Angle looks pretty good from new pictures. Note that you can change the shape of the wings by how much or how little you grind them without any changes in your jig settings.