Thompson bowl gouge - first impressions

[rsser]

5/8 V flute, mildly swept back grind. Doug Thompson says this profile is v. similar to the Ellsworth Sig. gouge and it is, only a little tighter at the flute bottom.

The selling point of this gouge is the 10% Vanadium content which is said to increase its abrasion resistance. Doug uses Crucible steel cryo treated.

First use was to take the epoxy out of the bottom of Thumbsucker's bowl.

Then, resharpened, to start to true a dense and dry bowl blank of dunno wood. Prob euc of some sort. With this it soon started to produce dust rather than shavings. At this stage I was wondering about the value of the selling point.

Not much liking the bevel geometry I then reshaped it as a straight-across grind, ie. the bevel line around the shaft outside is all about 90 degrees to the shaft axis if that makes sense.

This worked better with the pounding the blank served up.

With this grind, the flute wings are pretty straight. Compared eg. to the HT Superflute which is my first reach-for bowl gouge, whose flute shape conforms to the intended parabolic curve.

I can't really comment on the abrasion resistance of this kind of tool steel since this wasn't a comparative test. But after the regrind and some more pounding the tool still felt it had a fairly keen edge as measured by that most scientific of gauges, the thumb.

As posted elsewhere the finish of the flute is good. Little in the way of milling marks. The flute depth is comparatively shallow and that makes for a shaft with good heft for overhanging the tool rest as far as you feel game.

I'd intended this tool to be one for hogging out. On reflection, a U profile flute may be better for this.

As for value for money, when our buck was worth something this unhandled tool came in at under a hundred posted IIRC and with some more testing I expect to conclude that this was pretty good value.

Just a note on gouge measurements btw. The Yanks' measure is the diameter of the rod. The Brits usually the max flute width. So eg. a 3/8 HT Superflute would be rated as 1/2" by the Yanks.

[bobsreturn2003]

would be interested in some comparisons . against say sorby or p&n . have a pair of hamlet 2060 . that i bought when i got some abrasive qld walnut , that cut around 4inches,with p&n gouge hamlet did almost the whole platter around 450mm dia . so worth the money for the abrasive timbers . also got really sharp . . happy new year to all bob

[Sawdust Maker]

Ern
do you have a piccy of each grind? Just for us whom aren't caught up with the jargon yet :) (gees that was beaut english - please don't tell my auntie english teacher!)

[rsser]

Bob, when you take into account all the variables and control all but the one of interest, a comparo is a major undertaking. You stuck with one timber but were the bevel geometries the same, the speed of the workpiece, the sharpening method (inc burr, or honed edge) etc.

That's why I'm just offering an impression.

Sawdust Maker: ah, what a tangled web we weave when we practice to, er, describe. Lots of good stuff on grinds here: http://www.woodworkforums.ubeaut.com.au/showthread.php?t=78578&highlight=ellsworth

[Sawdust Maker]

Ern
thanks
so there is the swept back grind (ellsworth?) as per Stu's video and the straight-across grind would be what the P&N come sold as? did that make sense?

[Pat]

Ern
thanks
so there is the swept back grind (ellsworth?) as per Stu's video and the straight-across grind would be what the P&N come sold as? did that make sense?

No :q

[rsser]

Haven't looked at Stu's vid, and am no longer sure of what my P&N's came with, but unlike Pat (with one qual'n) I'd say yes.

One use of straight-across as a term (not mine) is of a grind on a U flute gouge with even wall thickness such that the bevel length all round is the same. My meaning FWIW is as described above.

Then there is 'fingernail' grind in which the wings are ground back somewhat so that the gouge tip, seen in plan, resembles a lady's finger tip. In the event, my 'straight across' grind produces something like this with a Superflute gouge.

Then beyond that you can grind the wings right back to produce a wing edge of an inch or more.

Tangled web.

PM me if you'd like a scan of some diags.

[Sawdust Maker]

No :q

bvgger!

[wheelinround]

bvgger!


Nick here's the web site (http://www.thompsonlathetools.com/) :2tsup:

[Pat]

Ray, you are an evil man! Nick's credit card will cop a hammering now :U

[Texian]

Ern, I got the 5/8 U Thompson, believing the U is more versatile and easier to control than the V. It came with a moderate fingernail grind, somewhat coarsely ground. Have not made a sharpening jig for it yet. My go-to gouge for years has been a 5/8 U Sorby with a straight conical grind. Sometimes I knock the corners down just a tad.

For a look at some different grinds, go to www.woodcentral.com/newforum/grinds.shtml (http://www.woodcentral.com/newforum/grinds.shtml).

[rsser]

Yeah Richard, I spoke with Doug by email and went for the V which as noted he said was close to the Ellsworth Sig, which I like.

But what I like more is the parabolic curve in the HT Superflutes.

Partly, or even mainly I guess, it's a matter of what you've learned to use, and mixing flute shapes and bevel grinds in your kit is just a matter of learning more and that can't be bad.

Added: FWIW, if I can only have one bowl gouge, IMO the HT Superflute, say in 3/8 or 1/2" (UK measurement) with a 45 degree bevel, is the best.

If you can have more, then add to the kit a larger gouge with a 60 degree bevel at the tip and swept back wings. For hollowing, a steeper bevel works well for deeper pieces and/or lathes with a modest swing, and it transfers more of the force to the toolrest rather than the hands.

[NeilS]

Courtesy of Ern's generous efforts on the bulk buy/import of Thompson tools I now have two Thompson-V-gouges, a 3/8"V and a 5/8"V.

After adding handles I gave the smaller 3/8"V a quick test spin. Edge seemed to hold up quite well, but I'm yet to fully test it out on some of our really hard/abrasive woods before giving a final verdict on edge retention compared to HT, Sorby and P&N.

First impressions on cut and feel are that the Thom-V-gouge flute profile (not the grind) feels perceptibly different to my HT Ellsworth sig gouges. Will alternate between the HT 5/8"V and T 5/8"V on next chunk of wood to see if I can understand the difference between the two gouges.

Neil

[Texian]

Ern et. al.,
Since my earlier post have learned that my go-to Sorby is actually a moderate V, not a U. Also Doug's 5/8 U is more of a C, I did not care for the 5/8 U and it languished in the rack, virtually unused. Months later Doug graciously agreed (at my request) to trade me for a 5/8 V, which I like better and seems much more versatile than the U. Have since also purchased the 1/2" V. The nominal fingernail grind that Doug supplies works well for me, and am not inclined to experiment much with valuable steel.

Realize that my experience with various grinds is negligible compared to yours, and/but just discovered my earlier post and wanted to correct it. I have learned a lot since January.

[NeilS]

First impressions on cut and feel are that the Thom-V-gouge flute profile (not the grind) feels perceptibly different to my HT Ellsworth sig gouges. Will alternate between the HT 5/8"V and T 5/8"V on next chunk of wood to see if I can understand the difference between the two gouges.



Gave the HT 5/8"V and T 5/8"V gouges a comparative 'test run' this morning.

Looking at the two flute profiles, there is an obvious difference between the two. As Ern described it, the Thompson (on left in first pic) has a "tighter"/more acute apex in its parabolic curve, and thus straighter sides. In comparison, the HT has a much fuller curve throughout its parabola. The Thompson is also thicker resulting in a wider bevel. These characteristics account for the different feel and cutting action of the two gouges.

The Thompson was used as received and the HT Ellsworth was sharpened before starting. For the test run I alternated between the two gouges on some almost dry silver birch that I had to rough down.

There wasn't much difference between the two gouges on the outside of the bowls. If anything, the T-gouge produces more 'chip' and dust on the push cut than the HT. On the pull cut the T-gouge could become (suddenly) quite aggressive producing banana skin shavings (wide without much twist).

The differences became more obvious on the inside of the bowls. As expected from the different flute profiles, the T-gouge handled the plunge cut down the insides of the bowls best, but was not as good as the HT on the transition and bottom where the 'fuller' HT behaves more like a standard bowl gouge.

Of less significance is the extra distance the T-gouge 'squirts' the shavings beyond the HT. About 2.5m compared to about 1.5m (Pic 2). All good fun when entertaining people, but a just extra work when you have to clean up after yourself. The tighter parabolic flute must compress then project the shavings further.

Lastly, and more importantly, the HT had to be resharpened half way through whereas the T-gouge (which I also used more) was still holding a cutting edge after doing four bowls (Pic 3). For reference the largest of the four bowls was about 17" diam.

So, which gouge would I go for and when. Having both I will probably reach for the T-gouge on deeper bowls and the HT on platters, and perhaps also back to the HT for a finishing cut in the bottom of deeper bowls.

Neil

[INVENTOR]

I have been using Doug's tools for many months (probably over a year) I have the 1/2" and 5/8" V's and after using comparable P&N, Glaser 15V and Glaser A11. I have found them exactly as I imagined, (after using the Glaser's for many years.)

On our Aussie hardwoods, dry collabah etc, the list goes like --

P&N , then the Thompson and/or Glaser A11, and then the Glaser V15 , for abiltiy to hold an edge. ( No surprises there)
The P&N just collects dust, on the shelf.

So for value for money etc I don't think you can go past the Thompson tools.

[rsser]

Good data. Thanks gents.

[tea lady]

I've got the 3/8th and 1/2 V shaped bowl gouges. Taking me a while to get the bevel right. Did one on 's jig the other day, but it doesn't work as well as the one I fiddled with free hand. :shrug: I think my other b-gouge is a v shaped 3/8 p&n. Must be just subtly different. I'm sure they'll ride up with wear.:cool:

[Skew ChiDAMN!!]

I rather like the grind that came with my 3/8" V. I may grind the wings back a little more, because I'm using it primarily in enclosed spaces.

But then again, I'm used to the old "square ended grind" (aka "conical grind") so it doesn't take much at all in the way of a wing for me to feel a difference. :rolleyes:

[Texian]

Skew, am similarly used to a "straight conical" grind on my trusty 5/8" Sorby V, which looks a lot like Neil's HT V. Maybe bring the corners back a very little bit. Also like the Thompson "as delivered" shape with a clean-up on a finer wheel. Wish I could afford the 3/8" V also, but must get by with an old Ben's Best 3/8" V, as the tool budget is shot for this decade. Good report by Neil.