Tool Grinds - Heligrind

[Mobyturns]

A fellow forumite asked about how I get the Heligrind setup for spindle gouges so this is a shot of my Thompson V10 tools with the grinds I prefer and as PowderPost always says they may not work for you.

All with Kwilia handles with high quality solid brass (not cast rubbish) or copper ferrules. The Copper ferrules are actually one 1/2 of "Yorkshire" plumbing fittings and are getting harder to find.

I like skews with an "obtuse" grind as they are less aggressive for the style of turning I prefer. I use the skew a lot in long point down cutting basically "half beads" and hence the non-standard radiused edge both sides on the Thompson skews (1", 3/4" & 1/2"). Sharpened on the Tormek T7. These have Doug's "standard" grind which I am steadily pulling back to what I prefer hence the two bevels for those who have picked that up.

The detail & spindle gouges are sharpened on the Tormek using the Heligrind spindle jig. I prefer to keep the side wing "straight" as I tend to use it as a "skew" for planing cuts.
The bowl gouges have the relief bevel and are also sharpened using the Tormek T7 and Tormek bowl gouge jig.

Handle is a Woodcut ER25 collett handle with std ER25 collets. I will take some shots and add photos of the Heligrind Jig with spindle gouge over the weekend for you.

Tops on LHS are an unidentified palm with QLD Silver Ash trim, RHS are Northern Silky Oak cut to highlight grain. The three (1l +2R) radiata pine (Porta Pine) and Vic Ash tops have not been sanded at all. All were basically straight of the skew and sanded with #600 to #800, if I'm rough I start at #400 occasionally. Jefferson & Jim Carroll know who showed me how to refine my spindle turning. :U

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[artme]

Good post MT and thanks for the posting!!:2tsup::2tsup::2tsup:

I am the one who asked MT about the Heligrind as he is the only other person with one that I found in a search.

I have had trouble with the grinding of my spindle gouges ever since I got them so I asked for some input from MT. His reply was most helpful and, along with this post, I hope I am on the way to solving the problem.

[Mobyturns]

Artme as promised here are some photos of the Heli-grind jig producing my preferred grind on Hamlet & Thompson spindle & detail gouges.

PDF file of below is attache for any who have a Heli-grind. You may use it for non-commercial purposes only providing the document is kept complete.

The Heli-grind was manufactured by John Crawford, from Blakehurst NSW from about 1999 and was originally designed for use on conventional 200mm (8”) grinders. The helix guide face is an exceptional jig for producing a sweet fingernail grind on spindle gouges and detail gouges. Fortuitously the jig also fits the pivot arm on the Tormek wet stone grinder. The Heli-grind manual explains setting up the vertical support bracket & pivot arm. The original manual can be found at http://members.ozemail.com.au/~kjeeves/heligrind/heligrind.pdf
Mike Darlow covers the Heli-grind in his book “Woodturning Techniques.”

A note on conventional grinder safety – if using a conventional bench grinder you must wear approved eye protection and preferably a face shield too. Do not fit or remove the jig from the pivot arm or make any adjustments to the pivot arm or jig with the grinder running, it must come to a complete stop before doing so. The sharpening of detail gouges requires a very light touch on conventional grinders. (Note the Tormek wheel was set up dry purely for photographic purposes only.)

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The original manual recommends setting the nose extension of the spindle gouge 50mm past the inner sleeve. It is beneficial to experiment a little with the extension distance to suit your turning and the flute profile of your preferred spindle / detail gouge.

Cross sectional profiles do vary across the various manufacturers. Longer extensions produce long & thin bevels which tend to be brittle and “grabby” whereas shorter extensions produce a more robust edge or a transition grind more suited to Australian timbers. My preference for standard Hamlet & Thompson spindle gouges is to reduce the extension distance to approximately 45mm, and a little longer for the detail gouge which has thicker steel & a much shallower flute depth.

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Assemble the jig and set the spindle/detail gouge in the jig and just firm up the star bolt on the guide tube. It is important to centre the gouge well to obtain a symmetrical sharpening profile & once centred correctly lock the star bolt. Mark the face of the bevel with a marker pen so you can see what part of the steel is actually contacting the grinding wheel. With the grinder off slide the head onto the pivot arm and adjust the arm position so the face of the bevel fully contacts the wheel.

If the tool has a poor grind that you do not wish to replicate then set the extension to 45mm or perhaps even 40mm and approximate the angle of the tool to the grinding wheel as illustrated. Shorter extensions are more forgiving and allow for regrinding the profile without wasting the length of the tool if you choose latter to lengthen the bevel.

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Slide the tool sideways across the wheel surface to remove the marker pen and check if full contact is being made with the grinding wheel, adjust the pivot arm to correct. Repeat as necessary and when satisfied lock the pivot arm position. This method is faster and far safer than turning the grinder on and off.

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Ensure the tool is not contacting the grinding wheel then turn on the grinder and with a very light touch start from the centre, i.e. with the star bolt vertical, then roll the handle of the tool left, then right so the star bolt is not quite horizontal. The side wings require more attention than the centre. The nose shape in the RH photo is the goal.

It is important to maintain light downward pressure on the tool to the grindstone but also a slight upward pressure on the underside of the rear of the tool handle to keep the bearing, or guide pin with older models, in contact with the helix guide face of the jig. This action totally controls the shape of the “fingernail grind”. The bearing or pin must remain in contact with the helix face for the entire motion.

Too much grinding attention to the nose distorts the profile usually producing a distinct flat on the nose or an “angle” or kink at the transition from circular to straight on the side wing. Too much attention to the sides produces a scalloped or concave side “wing.” Rolling past horizontal produces a convex face to the wing. These conditions will produce a grind that will not perform well and will grab as a cut transitions along the bevel edge.

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Start in Centre

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Roll Left

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Roll right

Note the alignment of the tool shaft to the jig sleeve notch and the removal of the blackening on the bevel face in the LH image above. The pivot arm needs to come in slightly for full bevel face contact to the wheel. The jig with a 45 - 50mm extension produces a 30° nose bevel.

Bowl Gouges The flat rotation guide face produces a very good “bottom feeder” profile on bowl gouges. Darlow covers a process similar to that for the spindle gouge for bowl gouge swept back profiles, however I much prefer the Tormek jigs for them.

[Brett57]

Hi mobyturns,
I am just getting back into some turning and become pretty obsessed.
I have just returned from a garage sale where the older guy who had died was obviously also obsessive..
He had bought ever turning chisel in the Sorby catalog, I do mean every most never used.
I did buy some at $40 each and have some nice tools now.
I also picked up an older mk1 Heligrind the same as you have shown in this post.

I have both the skew and spindle gouge fittings, however there is a flat plate with a slot in it that I cannot work out what it is used for.
I have attached a photo hoping you may shed some light on it.

cheers

[hughie]

I have always liked the way the Heligrind operates/preforms and have been meaning to get one myself.
Thanks for the post

[NeilS]

there is a flat plate with a slot in it that I cannot work out what it is used for.
I have attached a photo hoping you may shed some light on it.

cheers

Hi Brett

That is the sharpening platform (mentioned in my post above) that came with the Heli-Grind. It worked OK, but the platform uses the same bracket as the gouge jig component, so you can only use one or the other at the same time.

[Mobyturns]

Hi mobyturns,
I am just getting back into some turning and become pretty obsessed.
I have just returned from a garage sale where the older guy who had died was obviously also obsessive..
He had bought ever turning chisel in the Sorby catalog, I do mean every most never used.
I did buy some at $40 each and have some nice tools now.
I also picked up an older mk1 Heligrind the same as you have shown in this post.

I have both the skew and spindle gouge fittings, however there is a flat plate with a slot in it that I cannot work out what it is used for.
I have attached a photo hoping you may shed some light on it.

cheers

My apologies I missed this one. I use the platform for scrapers, garden mulcher blades etc. The slot can be used somewhat like a miter slot on a TS to align jigs. I have one somewhere that I fashioned up to do electric hand planer blades. Haven't used it in a long time now.