Settings for Fingernail grinding jig

Very many thanks for taking the trouble to respond

For the sake of completeness, what are the distances from the edge to each of the turned up flanges on the Proset for each of the angles, please?

With best wishes and thanks again.

MC Black

This Forum is full of questions on the subject but not many real answers, so I wish you luck.

Roberty Sorby have produced a very good quality and versatile system but for whatever reason are either unwilling or not bothering to give out the information required and requested by its customers, who like me I am sure when asked express our displeasure at the lack of information.

Tormek have all the answers and reproduce them in a professional way, but as I understand it the two systems are not compatible when it comes to setting up the jigs?

To partially answer the question the figures on the Pro Set are the sharpening angle in degrees, if you look at the Craft Supplies Catalogue from the USA they show a Pro Set with a guide stuck on it indicating what each setting is suitable for, why this is not available on this side of the ditch I do not understand.

Meanwhile we all must wait with bated breath for the ultimate instruction manual.

Richard

I agree Sorby's published help could do with swelling a little but the answers you seek are all published in various posts on this forum. Mostly by Jeff right at the beginning. I'm in France right now. When I get home I'll dig out the relevant post.

This is a (really good) response Jeff gave me some time ago when I was trying to grind a detail gouge on the Proedge for a favourite spindle gouge and specifically I was also coming from the Tormek universe. A detail gouge for those who don't know is a spindle gouge with a bevel ground fingernail style and shallow angle (35 degrees or less) to allow the "point" to access narrow fissures in the wood in other words to turn fine details in spindle projects. Its the sort of thing you might use on a small, intricate finial or similar. I was struggling to recreate what I had on the Tormek on the PE. Jeff's response below gave me the recipe and also a broader explanation about whats happening with the variables of knuckle setting, protrusion setting and jig distance from point of grinding medium. I agree the way to control these variables is not as clear as the published data in the Tormek world but.....I feel certain Sorby will address this over time and in any event the PE, despite less printed data, is a far superior and more flexible tool. Principally it handles both shaping and sharpening with ease. The Tormek's inability to shape used to drive me insane. I hope this helps anyway. What follows is Jeff's post earlier in the forum's life......

Short answer first. As I said in my first reply, use the outmost hole in the three hole version of the boss and you'll get a long wing like an Ellsworth. No adjustment necessary on the protrusion, the jig angle or the collar.


Now, the longer answer.
The original design of the ProEdge aimed at reproducing the factory grinds precisely. If you leave the jig as it is delivered and follow the instructions in the book, you'll produce exactly the profiles found on Robert Sorby Fingernail Gouges when they come out of the package.

That said, like Tormek or Oneway Wolverine or pretty much any elliptical grinding system, three things affect the gouge profile. the amount of tool protruding from the front of the jig, the angle between the tool axis and the rotational axis, and the distance between the point of rotation and the abrasive contact point. A change in any one of those settings will affect the length of the wing and the bevel angle of the grind.

Unfortunately, the adjustment of those three things doesn't affect the profile on the ProEdge in exactly the same way it affects the profile on any other system. On all the rest, the adjustments move the contact point along the arc of a curve (the grindstone). On the ProEdge, the contact point moves along a straight line, rather than a curve. Bottom line, you can't look at the settings in Tormek's book and get the same profile with the same settings on the ProEdge.

With all that as a disclaimer, the knuckle adjustment (which controls the angle between the tool and the rotational axis) has the greatest effect on the wing length. The protrusion and the distance from the contact have the greatest effect on the bevel angle, but also affect the wing length.

If you decide to alter the settings of the fingernail jig from the way it is delivered, make sure you can get it back to the factory settings before you do! Before you move the collar, use a scribe to scratch a line on each side of the collar so you can put it back right where it was. The knuckle adjustment should be at setting number 4, but since the scale is a bit crude, I scribe a tiny line across the parts so I can bring it back accurately and quickly.

I have a spindle gouge ground to a rather long bevel with a fingernail profile. It's what most people would call a detail gouge. It's not exactly the same as the factory standard fingernail grind, so I had to experiment to find the right settings for it. I use a 75mm (3 inch) protrusion, the knuckle is at setting #3, and the back collar is 1-5/16" (34mm) from the end of the shaft.

If you have a favorite profile that you're trying to reproduce on the ProEdge, here's the process I used to arrive at those settings.

1) Take the belt off the ProEdge.
2) In general, if you want a long bevel, work with a long protrusion, short bevel, short protrusion. Use standards you can repeat easily.
3) In general, if you want a short wing, use a lower number on the knuckle scale. If you want a longer wing, use a bigger number.
4) Put the jig in the boss and adjust the back collar until the bevel lays flat on the platen when the tool is at dead center.
5) Roll it from side to side, observing the contact between the bevel and the platen.
6) Adjust as necessary to have contact all the way around the bevel, keeping in mind that an adjustment in one setting will most likely require a slight tweak to at least one other.

Hope this helps rather than complicates.

Here's the Detail gouge recipe Summary for quick ref (will save future readers from having to unpick the long post above.

P=75mm
Knuckle #3
Back of stop collar = 34mm from end of jig shaft

Not true...the detail gouge I just spent hours banging on about above is at 35 degrees from memory. It may be the protrusion setting is different to the pro-set because I've just lazily copied Jeff's recipe and he's fiddled with the knuckle setting too which will have an impact on the P setting. But short of me going in the garage and measuring my detail gouges, I'm pretty sure that recipe delivers a 35 degree bevel.