I have a Thompson 1/2" bowl gouge with a U flute. I don't like it much. All my other gouges cut better. Can I regrind this U flute into a detail spindle gouge?
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Regrinding a Thompson 1/2" Bowl Gouge to Spindle Gouge
- Thread starter Kent Reisdorph
- Start date
You won’t know till you try it. Only will cost you some time and a little steel.
Detail gouges are made with a shallow flute milled in the top of the full diameter bar, leaving about 2/3 of the steel below the bottom of the flute for greater stiffness than a standard spindle gouge. Bowl gouges have much less steel below the bottom of the deeper flute. You can grind away the vertical wings of your bowl gouge but you will be left with something more like a standard spindle gouge, probably with a smaller radius curve than normal.
I've never used a U-flute bowl gouge. What don't you like about yours? How do you shape the nose?
My go-to gouge is a Thompson V ground to a swept-back shape.
I've never used a U-flute bowl gouge. What don't you like about yours? How do you shape the nose?
My go-to gouge is a Thompson V ground to a swept-back shape.
I was thinking along the lines of Kevin. A more useful tool might be had by grinding a more traditional bowl profile on it and use for final cuts or bottom of bowls with a steeper grind.
Or put it up for sale, and put that money towards a gouge you really want.
Or put it up for sale, and put that money towards a gouge you really want.
Hmmm, the flute would be rather deep, might have to grind away a lot on the top to get a profile useful for some spindle operations. How about I put up a donation box at my next spindle demo: "Donations to buy Kent a Thompson spindle gouge" and see if anyone falls for it.
But what don't you like about the tool as a bowl gouge? Any particular cuts it doesn't make well - outside, inside, bottom transition? Try different angles and wing shapes? I've been pretty happy with those I have, although I don't turn many bowls and when I do they are almost always from dry wood.
I could trade you for a good 3/8" spindle gouge - I know someone with poor tools and few resources looking for a bowl gouge.
(But Doug sells "normal" spindle gouges, shallow spindle gouges, and shallow detail spindle gouges. Which to use depends on the use.)
JKJ
Thanks all for the responses.
John, I have Crown and Hurricane gouges with Ellsworth grinds, and one 3/8" Crown with what I assume is a fingernail grind. The best way to describe it is to say the Thompson never gets used because all my other gouges work better. In particular, that 3/8" Crown moves material faster than anything else. I'd like to regrind that Thompson to a grind that cuts on par with the others. I don't have a 40/40 gouge, so maybe that's an option.
John, I have Crown and Hurricane gouges with Ellsworth grinds, and one 3/8" Crown with what I assume is a fingernail grind. The best way to describe it is to say the Thompson never gets used because all my other gouges work better. In particular, that 3/8" Crown moves material faster than anything else. I'd like to regrind that Thompson to a grind that cuts on par with the others. I don't have a 40/40 gouge, so maybe that's an option.
Never had a U flute gouge. From research over the years, the best use is as a bottoming gouge, with a 65-70* bevel and a traditional wing grind, wings 0 to ~10* back angle.
I have seen some folks use them with longer wings and sharper bevel angles - they kinda worked but very inferior to a parabolic flute for that type grind.
I have seen some folks use them with longer wings and sharper bevel angles - they kinda worked but very inferior to a parabolic flute for that type grind.
Thanks, Doug. I do have a 5/8" parabolic flute ground as a micro bevel/bottom feeder. I could grind the Thompson to that and then repurpose the other one.
I bought the same gouge a while back and I didn't like how it cut for me. I reground it to be a bottom feeder and it works great for that. I have a very steep bevel of around 75-80 degrees with very little back angle. For me it leaves a near perfect cut on the bottom of a bowl (when I remember or need to use it).
I don't think a 40/40 grind is compatible with a U shaped flute. Another option is to turn it into a spindle roughing gouge. Mark St Leger uses a very small SRG and works wonders with it.
john lucas
AAW Forum Expert
I ground my u shaped thompson gouge to roughly 40/40. Didn't like it. I left the nose at 40 and ground the wings back into more of an elksworth grind. Now I like it. Not as much as I like his V bowl gouge which is my go to topl.
I was never successful in putting wings on a Thompson U gouge. Because the insides of the U go straight down, when the wing meets it you would have to cut with the U facing the cut and that is going to be a scrape. My main reason for not using the U is that I feel it self feeds and I have a lot less control. Best regrind I have come up with is the bottom feeder, it does great in the transition area of a bowl where you sometimes get a lot of tear out.
Kent-I have the same issue with my 5/8" Thompson Lyle Jameison gouge. I loved it when I first got it a few years ago with its original grind; it was my 1st big gouge and helped me learn all the basic cuts very well. It was and is advertised as being parabolic, but the wings have slightly less recurve compared alongside my Crown PM Ellsworth gouges. I vaguely recall some debate about whether that grind was/is truly parabolic. Anyway, for reasons I still haven't figured out, I have been unable to recreate the Jameison grind with either an Ellsworth jig or the Vari-Grind to my satisfaction (and my freehand grinding skills are definitely a work in progress!), so I find myself reaching for it less and less, which is a shame because it's an expensive, well-made tool that I would like to put back in the rotation. I should probably just contact Lyle himself.
That said, I have been looking into a larger BOB gouge, though 5/8" seems like a big gouge for finishing cuts around to the bottom, at least at my current skill level. My current D-Way BOB gouge is 3/8" IIRC, which is controllable when I'm doing everything right. I'm still refining those final light sweeping passes, and finding that the fundamentals (a freshly-sharpened edge, gouge locked against my side, pressure down on the tool rest, watching the nose/wing position while observing the horizon, and letting the tool feed into the cut without pushing) are making a huge difference. If I overcome my inertia to reach out to Lyle, I'll try what he suggests. But I am intrigued by the concept of it as a bottom feeder, so I may just try that. I often start a reprofile on my tools with a 50-grit belt on my 2x72" grinder before refining it on the wheels, so it shouldn't be too hard.
That said, I have been looking into a larger BOB gouge, though 5/8" seems like a big gouge for finishing cuts around to the bottom, at least at my current skill level. My current D-Way BOB gouge is 3/8" IIRC, which is controllable when I'm doing everything right. I'm still refining those final light sweeping passes, and finding that the fundamentals (a freshly-sharpened edge, gouge locked against my side, pressure down on the tool rest, watching the nose/wing position while observing the horizon, and letting the tool feed into the cut without pushing) are making a huge difference. If I overcome my inertia to reach out to Lyle, I'll try what he suggests. But I am intrigued by the concept of it as a bottom feeder, so I may just try that. I often start a reprofile on my tools with a 50-grit belt on my 2x72" grinder before refining it on the wheels, so it shouldn't be too hard.
Figure out an angle to grind it flat, so you can flip it over and be a giant bead scraper. 
john lucas
AAW Forum Expert
Here is my Thomson U flute bowl gouge ground with a 49 degree nose and wings using the Wolverine jig with the arm set at the #3 notch of about 45 degrees. The wing edge is very acute and cuts super clean on pull cuts. The wings are probably too fragile for serious deep cutting. I may go to my Mickelson jig which rounds over tge wings slightly making them less likely to chip. I had to do that on my Robust gouge and it works great. Guess I forgot the photo. Here it is.
Attachments
It isn't parabolic. Doug told me and JKH at TAW Symposium that he had a parabolic in the works.
A new Richard Raffan video showing another option for grind profile and use of a U flute bowl gouge. IMO a U flute is better used as a bottoming gouge. I find a long wing grind on a 5/8" parabolic gouge works very well for the pull cut he demonstrates (which he also shows in the video). Raffan uses scrapers to complete hollowing of the middle of a bowl (which he and others have proven to work just fine - so much for "optimum technique"):
View: https://youtu.be/MkSJ2aTT9e8?si=CUAt_uZGpSYJ9H1D
Richard is doing a series of videos on his tools. His scrapers have evolved to be in the 45 degree bevel area, but he commented that he will be taking them back to closer to 50 degrees. Mine came at 65 degrees, and have stayed there. I have watched both Tomislav and Richard get finish cuts with their scrapers to define the final shape of their bowls. It just baffles me. I had wondered if it was just a thing about green vs dry wood, and when asked, Tomislav said he got nearly the same surface regardless. I am now suspecting that there are 2 things going on. One is the type of wood as in, some woods just cut cleaner than others. The other is how feather light the cuts are. I am not sure if it is a sharpness thing or not. though the tools HAVE to be sharp to get a clean surface. I do use a NRS as the final tool cut on the bottoms of my bowls, but not up the sides. When sanding, I can some times start at 120, and some times I have to start at 100 grit, but most of the time I can avoid the 80 grit. These guys start sanding at 180. This takes me back to Mike and Stuart doing their 2 ways to turn a bowl, which are almost identical to me, and Mike commented that he would spend less time sanding than Stuart because Stuart started at a higher grit where Mike started at 80. Not sure about that one, in part because some times 80 grit scratches seem to be deeper than the tear out....
robo hippy
robo hippy
Hmmm. I must be working differently from these guys or using different wood or tools. I seldom start with coarser than 220, often finer. I turn as cleanly as I can manage at fairly high speed,, remove gouge marks with curved NRS inside and out to smooth (not to shape), and then further smooth with hand scrapers with the lathe off before sanding by hand, also with the lathe off. Never use rotating sanding disks on a drill since I don't like the dust or what it can do to some wood.
I turn dry wood, usually not big things, maybe those are factors - tearout with most dry wood is rare with sharp tools. We all work in different ways.
I do use 80 grit - to clean brake drums, prep surfaces for paint!
JKJ