Ellsworth Crown Pro-PM gouge jig settings

[gctree]

I have a new 1/2" Crown Ellsworth Pro-PM gouge and was trying to set up the SVD-186 following the Tormek instructions for the Ellsworth grind (75 mm projection, #6, and hole A).

The jig settings get the middle of the gouge bang on, but would make the wings quite a bit higher angle than the factory grind.  In the pictures you can see the gap when the the gouge is on its side, and also you can see where the marker has been worn away in each image - on the sides there's just the smallest sliver near the cutting edge.  I would have to grind a lot of steel away at this setting.


Since I got the gouge mostly as a reference to the Ellsworth grind dimensions for trying techniques in his book, and have two other "non-Ellsworth" P&N bowl gouges already that I've set up with an Irish grind following the "Ellsworth" jig settings in the Tormek book, I would prefer to hone the new one without changing the factory grind dimensions.  My other reason for getting the new gouge was to compare how the Ellsworth factory grind profile compares to my other two in use...  I would prefer to be able to hone to that profile on the Tormek, to prolong the life of the gouge and get a sharper edge. 

It doesn't look like the SVG-186 can be set beyond #6, but maybe that's what would be needed to match the grind?

-Has anyone been able to successfully replicate the grind on the Tormek without freehanding?

Thanks, Jason

[RichColvin]

Jason,

I've not advanced to the level where the difference in the tool's edge shape you noted would impair my abilities. 

But, I have very much come to appreciate that using my Tormek gives me a consistent grind each time.  And that has made me a far better woodturner !

One question that does come to mind though:  are you sure the factory grind is correct ?

Good luck & kind regards,
Rich

[gctree]

Hi Rich,

That is a good question.  I would hope that the factory grind is correct, given that Crown charges a very large premium on that gouge just for the grind, compared to their non-Ellsworth 1/2 Pro PM gouge.  As I mentioned, I do have two other bowl gouges that I have sharpened with the Ellsworth jig settings in the Tormek book. I spent the premium on this gouge just to gauge how that geometry cuts compared to the other two - it would be a shame to spend an hour or two grinding away steel to make it the same as the other two before even using it  

Just for the time savings, given the amount of steel removal needed for those settings, I would probably just freehand it to the factory grind instead. But would much prefer a jig setting that got at least closer to it...

[Ken S]

Welcome to the forum, Jason.

You piqued my curiosity. The predecessor to the SVD-186, the SVD-185, originally only went to number 5, although it actually could be set beyond five, which we called six. The 186 introduced a series of sawtooth ridges to hold the jig setting, which is a major improvement.

I disassembled my 186 to see if the range could be extended to "seven". The sawtooth pattern becomes elevated on both surfaces to provide a stop at number 6. I think you could carefully file or grind down the last elevated sawtooth on both surfaces. Try filing just one sawtooth on each surface and sharpen your gouge. Does this get you closer to the shape you want?  If it gets you closer, but not quite where you want, try filing one more sawtooth on each surface.

All you need to do is unscrew the plastic jig setting knob. Be careful not to lose the washer and spring. I was able to disassemble and reassemble my jig several times easily.Look at the jig parts carefully before you decide if you want to try this. I have not actually refiled my jig. (My 1930s lathe is really designed for spindle and very limited faceplate turning, and I am a beginning turner.)

My grandson would call this a "hack". Tormek intentionally put the stop at jig setting 6. I have no idea if this limitation was placed for advanced turning reasons or just as a general precaution. I do not believe there are any active turners presently on the Tormek full time staff.

I leave the decision to you.

Ken

[Twisted Trees]

I don't use the Elsworth grind, so this is pure speculation....

From your pictures it appears that the grind you have on that tool is a blend, at a pure guess I would say the sides are an 80mm projection while the tip is a 75mm and number 6 setting gives you the swing to get the blend points to merge. once the side sharpening projection is found it would be simple to make a jig to make it repeatable.

This would be easy to test using the marker method, and would explain the extra cost as it would need more fiddling with any sharpening system.

[RichColvin]

I heard that Spinal Tap found a way to take it to 11 !

https://youtu.be/4xgx4k83zzc

Rich

[gctree]

Ken - that's where I was thinking of going next...  but I just remembered I'd read somewhere that the dry grinder jig Ellsworth makes to replicate the grind has a 45 degree pivot arm.  As long as the SVD 186 detents go close to 45 degrees, making another stop beyond 6 might not help.

I figure the only jig variables can be:
1) the angle of the pivot arm
2) the distance from the pivot point to the grindstone
3) the projection of the tool, and
4) the length of the pivot arm

#1, 2, and 3 are easy to adjust with the SVD-186, but I can't think of a way to adjust #4... Adjusting the stop ring is really just another way of adjusting #2.  I think with the Tormek jig #4 is the distance from the centre of the sleeve to where the tool sits in the holder, and to increase it I think you would need to lengthen the tool holder component.  I wonder if that is the adjustment that would be required to match the factory grind?

[Ken S]

Jason, I have several constraints with the Ellsworth grind and perhaps an advantage or two. On the minus side, I am not an experienced turner. My limited turning is spindle turning. I have never actually seen or used an Ellsworth grind bowl gouge. My two bowl gouges are more conservative fingernail grind. My high school math is also a constraint. I contacted support hoping for more information about how the SVD-186 and TTS-100 are calibrated without success. I would guess these were designed by Torgny Johansson, who unfortunately passed away almost ten years ago.

On the plus side, I have been working with the TTS-100 for almost ten years. Before Dutchman's tables and the kenjig, I used the TTS-100 for repeatably setting chisels and planes. Dutchman's tables were a hyper leap forward in understanding setting angles. I have worked with this stuff enough that it has become second nature.

I have often stated that I consider the TTS-100 and the SVD-186 to be Tormek's most advanced setting tool and jig combination. The Tormek presets are really quite clever, allowing inexperienced users to choose from a variety of proven grinding combinations. Among the directions is the statement that one can also use custom grinding settings outside of the presets. I think this is what you will have to do.

Using one (better with two) of your non Ellsworth gouges, after getting it close to the shape, I would start changing the projection distance P from 75mm five or ten mm in either direction. Hopefully one of these changes will get you closer. If you start to get closer, keep fine tuning. The bowl gouges all seem to use hole A. The Projection seems to be the easiest to change.

Plan B would be to try increasing the jig setting. If you happen to also have an SVD-185, take them both apart. (My 185 is presently packed away.) One of the two designs may be easier to modify.

Please post your progress. In his personal turning, Jeff Farris used the number four jig setting. He also did not use the Alan Lacer skew. I suspect that these two grinds were not included in the original design parameters.

Please post your progress and any further questions.

Ken

[gctree]

Thanks Ken. 

I tried a bunch of different projections - going shorter got me closer but still quite far off.  I also played with moving the universal support distance, using different jig settings, as well as flipping the sleeve around to increase the length of the arm.  One of the permutations got quite close to matching the grind, but it wouldn't allow the tool to swing far enough over so missed about 1/4" of the ends of the wings.

I took out my old Wolverine Vari-Grind jig, and very quickly was able to adjust the projection and angle to get the grind to match precisely, removing all of the marker moving my dry grinder by hand (For what it's worth, the Vari-Grind setting that worked was about the same angle as #4 on the SVD-186, but I suppose the reason the SVD didn't match at that setting had to do with the extension of the tool holder beyond the plane of the shaft of the gouge, and the length of the pivot arm).

Then I cobbled together a socket for the Vari-Grind for the Tormek and could easily replicate it.  I would prefer a way to get the SVD 186 to replicate the grind, if anyone has found a setting or hack that can do that, but I think I'll use the Vari-Grind on the Tormek for now for the Crown Ellsworth gouge (I'll still keep honing my other bowl gouges on the SVD 186).

Has anyone come up with a better way of making a socket fixture that extends farther than the universal support?  The only easy solution I could think of was fixing the extension to the SVD 110 tool rest as it locks onto the universal support to keep it from pivoting (picture below).  I first tried drilling a hole in the wooden extension, but because the wolverine jig is angled, the force would rotate the extension on the universal support.  It would be nice to have a universal support with a longer extension to rig something, but making one would be too big a project for me right now...

I'd love to hear any other ideas for that...

[Ken S]

Jason,

I am not quite clear on your meaning for a universal support with a longer extension. Check this out:

https://forum.tormek.com/index.php?topic=3399.0

I have one and like it. Partway down there is a link to Robin to order one. (Robin is a forum member.)

The other idea which comes to mind is the Sharp Fast. This is a similar jig to the Wolverine. I know the designer, Dave Hout. He is a very experienced turner and sharpener. It might suit your requirements better.

Keep us posted.

Ken

[gctree]

That looks like it might just be long enough - I think it would need to extend about twice as far from the machine as the standard universal support to allow the jig socket to rest on the universal support instead of extending beyond it like the one I jury-rigged.

Looks like it would be pretty pricey to have shipped to Canada, so I'll put that on the long-term wish list for now...  I could see that coming in handy for other things and it looks really well made.

The wolverine does work perfectly for this application, but it would be nice to have a slicker system for resting the jig on.  Would still be interested to see if anyone has come up with a different way of doing that.

[gctree]

Here's my quick and dirty solution I came up with today.  While not elegant, I just sharpened the gouge and it worked great.  Slides onto the side of the tool rest, and the tool rest locks it in position and keeps it from rotating in the same plane as the grindstone.  Slides off the toolrest easily for storage.  I'll try to make another out of less humidity-sensitive materials, as I imagine it will swell and jam once things get less dry in the spring, or at least give it a couple coats of epoxy to seal the wood.

[Ken S]

Jason,

In more polite circles, your "quick and dirty solution" might be called "a working prototype". 

It sounds promising; keep us posted. Your work supports my belief that the Tormek can be a much more versatile machine with skilled hands and an innovative mind.

Keep up the good work.

Ken

[Chris 007]

Hi Jason
Thanks for the heads up on the Ellsworth grind. I will try and get a normal grind but all very interesting
Cheers Chris