Help with Ellsworth type grind

[Tiger]

After seeing and the quality of his gouge grinding with his jig I thought I would try a jig to see how it compared with my usual freehand method. I knocked up a crude jig based on King Heiple's Fine Woodworking jig and while the shape of the bevel is ok the wings of the gouge are concave with a point rather than the convex shape which is what I'm aiming for. I cannot work out why the grind comes out this way. Can anybody help. I am. aiming for a swept back grind or lady's finger style grind

[Sawdust Maker]

Tiger

this may sound silly, but is it upside down in the jig?
other then that I've no idea and will no doubt look extremely silly when the expert answers come in

[jefferson]

Tiger,

it's a shame you missed the sharpening weekend - or were you there?

From what I know, almost no-one can do the Ellsworth grind freehand.

The beak you have means that you are not cutting enough from the sides. You might have to start again from the snout and work back to rescue it. (For my mind, the swept-back Irish grind has but one advantage - with sheer scraping. But you cannot do that cut with such a beak!)

Ellsworth himself suggests more time on either side and less time in the middle.

If you use the gouge with that profile - DANGER.

Talk with the experts here. What breed of gouge is it? Some are not suited to the E. grind apparently because of the flute design.

Hope this helps, no doubt the troops will arrive in due course.

Jeff

[RETIRED]

Jeff is nearly right. Take more off the sides and work on them first.. Some jigs will not allow an Irish grind and some tools will not allow it either.

You have to lay the tool over so that the shaft of the tool is nearly or at right angles to the wheel.

Try that and see how you go.

[Skew ChiDAMN!!]

As took some pains to point out at the sharpfest, the flute profile of some gouges don't work well with some grinds.

[jefferson]

Tiger,

I forgot to say that I found the Irish grind very difficult to use (as a novice) with my 5/8 Kryo, but I did play with 's 1/2 inch Kryo last week and it was a bit more user friendly. Less aggressive cuts. (I've ordered one). So I apologise to Ellsworth for saying that I didn't like the grind....

I had one gouge down at the SharpFest that gave me some problems on the Tormek. Same "beaking" problems. fixed it by re-grinding on the white wheel free-hand, getting the right profile then back to the Tormek for super-sharp.

Just remember, convex is fine, concave a definite NO NO. I've learnt that one from experience. The tool (I think) cuts at the beak, then nothing in the furrow, then potentially digs in when the wood re-engages at the end of the concave curve.

Technical isn't it?

is working up a duo system for me - using the Tormek jigs and bar on the white wheel first to get the right grind, then touch up again and again with mimimum steel loss on the Tormek.

I'll post when we () gets it right.

And also, talk with Ern, as he likes the E. grind. Some gouge flutes eg. Hamlet don't seem well suited for it.

Jeff

[Texian]

Which flute shape are you saying does not do well with the E. grind? Deep V, shallow U??

[tea lady]

The inner flute profile of the gouge dictates what the outer grind can be. Unless you've got the Robert Sorby parabolic flue chisel the grind won't be right. Kinda looks like you might have a "u" shaped flute so you gotta have a U shaped outside grind too. (To quote from the weekend- The cutting edge is the intersection of two angles, the inside flute and the ground angle. ) grind the bottom of the "U like a spindle gouge then do the sides with the gouge layed nearly all the way over on its side, blending the front and sides together a little at the transition. (or the sides first and then the front.

You can do a "kinda Elsworth grind on both "u" and "v" flutes. You just gotta follow the inner profile.

[Skew ChiDAMN!!]

Which flute shape are you saying does not do well with the E. grind? Deep V, shallow U??

I'm pretty sure that mentioned Hamlets as being one brand that's not particularly suitable.

I've an unhandled generic bowl gouge (could be McJing?) that's sort of a compromise shape between a U and a deep V. A pregnant V, if you like. It's thick-walled at the tip & and at the the tips of the wings, but fairly thin-walled just to either side of the tip.

On this tool I've found that any swept back grind tends to leave a "beak" on the tool and what Jefferson is referring to as a concave edge... but that could be partly due to my own ineptitude.

(I'm fairly conservative in my grinds, preferring a rolled-over straight grind or at best only a minor sweep back. Then again, I don't do many bowls and have more continental spindle gouges than any other gouge type. )

[Texian]

Thanks Skew. Not familiar with the Hamlets but maybe can find one online. Have a Sorby that is a moderate or mild V (as opposed to deep or sharp V) that works well with a straight conical grind but swept back just a little at the corners. Have a deep/sharp V that I cannot control very well with any grind (cheap tool, good for grinding practice). Have a Thompson V with modest fingernail grind that am liking better everry day.

As a novice, one may not realize that with any given jig and settings, a considerable variety of grinds is possible (without changing any of the settings). Even my "straight conical grind" is not straight, because I grind the sides back a bit extra. Supposedly the Ellsworth grind is a fingernail shape with a 60 degree included angle all around the edge. As TL said, if you do a 60 degree included edge all around, the resulting shape is a function of the flute shape.

Tiger's chisel looks like a shallow spindle gouge. As mentioned, needs to take more off the corners and round the nose a bit more (less pointy). Hope some of that made sense.

Edit: Found the Hamlets; standard looks like my deep V which is useless to me; super-flute looks liike my Sorby which is excellent.

[RETIRED]

As has been said, some tools are easier to get an Irish grind than others.

Some jigs also will not allow you to obtain it without a little mucking about.

The hardest ones to get an Irish grind on are shallow V shaped flutes as there is a lot of metal under the base of the flute at the nose and it is hard to get a good transition from the nose to the sides.

Parabolic flutes generally have less metal under the nose of the flute and lend themselves to the Ellsworth or Irish grind.

There is a trick to get started on shaping it and it takes practise.Attachment 108900See page 11.

Tony. If you want to take a run down here with the grinder and jig I will see what I can do.

I am here all weekend.

[KenW]

Tony, if you can't take up on his offer, show us a picture of your grinding jig.
The length of the side wings is usualy controled by the angle that the jig is set at.
The concave grind might be a result of not having enough tool protruding out of the jig.

[KenW]

, it sounds like the Grasshoper is learning.

[Tiger]

Thanks guys. I should clarify my post by saying that the point is on the wing rather than at the nose of the gouge. I am satisfied with the grind at the nose. Upon reflection maybe this gouge is not suited to an "Ellsworth" type grind and Texian is right in identifying the gouge as a shallow spindle gouge. I will now try and put a lady's finger grind on it but does the same sort of advice apply ie do I need to work on the sides first?

, same sort of family commitments would make it hard for me to come down this weekend, but I appreciate the offer and see what I can do.

[Alastair]

FWIW, a summary of my findings, which coincide with most said above.

Some flute profiles are more challenging: The parabolic flute is easier. The P&N has a more "U" shape, and care is needed. The more U shaped, the bigger the problem. Beyond some point it will become impossible.

Grind: The more extreme the grind, ie more swept back, the harder it is to avoid the problem.

Jigs: If the jig does not have the clearance to grind right up onto the wing, you may not succeed.

The single most important though, is to remember that the jig, (applies to all the offset angle types, eg Unijig Trugrind etc) DO NOT give you an automatic perfect grind and profile.


ALL THEY DO is define the bevel angle at the tip, and at the wing, and the transition of that bevel from one to other.

The PROFILE of the finished grind is determined by the bloke at the grindstone, and the amount of steel he takes off and where.

For example, I can put my trusty P&N into my jig, and grind away , getting (as I frequently did in early days) a "beak" very like Tigers' above. I can then, with no changes to the jig or setting, but at the cost of some steel, regrind it to the following, or further:


Further, a similar philosophy applies to the fingernail grind on a detail gouge: bevel angles=jig, profile=you

regards