Finding the cut - Thompson gouge

[Aaron Craven]

Okay. So here are the pictures. The secondary bevel on the Benjamin's Best gouge was a recent addition, not there when I originally tried to match the grind. In taking these, though, I realized that the Thompson flute definitely doesn't go as deep as the BB flute and the wings are thicker (at least from a head-on perspective):

Top (Thompson gouge on top, Benjamin's Best gouge on bottom):
top.jpg

Profile:
side.jpg

Benjamin's Best head-on (note, it's a little difficult to see, but there's a secondary bevel that makes the tool look a little squatter than it actually is):
bb_front.jpg

Doug Thompson head-on:
dt_front.jpg

[robert baccus]

Are these really V flutes?? Maybe just the pic. Try a bottom feeder on bowl bottoms and your problem may disappear. Good use for the BB gouge.

[Aaron Craven]

Thanks, Dan. This particular bowl was fairly shallow with a relatively smooth curve to it, so I don't think that was the issue here, but it's something to keep in mind.

At this point, I think it was a combination of me needing to "find my groove" so-to-speak with the new gouge along with some possible wood movement due to the bowl drying as I worked it. I checked on it this evening and it has already taken on a good bit of oval shape. I do think I will put a secondary grind on the "heel" of the bevel... both to aid in transitioning on steeper bowls and to make it a little easier to maintain bevel contact.

[Aaron Craven]

Are these really V flutes?? Maybe just the pic. Try a bottom feeder on bowl bottoms and your problem may disappear. Good use for the BB gouge.

The BB gouge only comes in one form, and arrives with what I assume is a traditional grind (wings are not swept back). I of course immediately changed that to the grind you see here. I don't know if the gouge is technically a V flute or not. The Thompson packaging lists the part as a "5/8V Bowl Gouge", so I assume it's a V (though I'm not unwilling to entertain the idea that I'm wrong and it was miss-packaged).

I may eventually do just that with the BB gouge, but I don't want to change the grind I'm used to until I've become completely comfortable with the Thompson gouge. I also have a 5/8" Sorby gouge that is almost used up that needs a new handle. I haven't decided what to do with it yet.

[Prashun Patel]

I have not tried a bottom feeder gouge, but I have never had a problem cutting with a regular bowl gouge.

It may be that with a shallower flute, you need to raise or drop the handle a little vis-a-vis how you worked with the BB gouge.

I would try doing this with the lathe OFF. Present the tool with one hand and spin the bowl with the other. You'll feel when it cuts. Do this at various points along the travel, switching gouges at each position. You have a very valuable learning opportunity to see how (or if) the the depth of the flute affects the required cutting position.

Personally, I am used to a slightly steeper (acute) bevel off the nose. I can't tell you the exact angle, but mine looks steeper. I suspect I need to drop my handle more than you do.

The thicker flute on your Thompson puts the cutting point higher on the nose than your BB. I speculate that this means it requires the tool handle to be RAISED vis-a-vis the BB handle position. If you put a steeper grind, then perhaps your tool handle position could drop down lower to where your comfort zone is.

All this is speculation and I may have it backwards. But certainly don't buy a new tool; analyze your positions and grind angle and I think you'll find your sweet spot.

[Thom Sturgill]

The BB looks to me to be an elliptical flute with gently rounded sides rather than the flat sided V of the Thompson. This will change how it feels when you roll over onto the flute and requires a bit more rounding when viewed from the side (which you appear to have). Biggest difference is the amount of bevel below the flute. Rounding off the heel should help, and I would round off more than you did on the BB.

[Aaron Craven]

I have not tried a bottom feeder gouge, but I have never had a problem cutting with a regular bowl gouge.

It may be that with a shallower flute, you need to raise or drop the handle a little vis-a-vis how you worked with the BB gouge.

I would try doing this with the lathe OFF. Present the tool with one hand and spin the bowl with the other. You'll feel when it cuts. Do this at various points along the travel, switching gouges at each position. You have a very valuable learning opportunity to see how (or if) the the depth of the flute affects the required cutting position.

Personally, I am used to a slightly steeper (acute) bevel off the nose. I can't tell you the exact angle, but mine looks steeper. I suspect I need to drop my handle more than you do.

The thicker flute on your Thompson puts the cutting point higher on the nose than your BB. I speculate that this means it requires the tool handle to be RAISED vis-a-vis the BB handle position. If you put a steeper grind, then perhaps your tool handle position could drop down lower to where your comfort zone is.

All this is speculation and I may have it backwards. But certainly don't buy a new tool; analyze your positions and grind angle and I think you'll find your sweet spot.

Thanks, Prashun. I'll give that a try.

I definitely won't be buying a new tool. Despite some initial difficulties, it didn't take me long to realize that I'm going to love this tool. I just need to figure out how to use it.

[Aaron Craven]

The BB looks to me to be an elliptical flute with gently rounded sides rather than the flat sided V of the Thompson. This will change how it feels when you roll over onto the flute and requires a bit more rounding when viewed from the side (which you appear to have). Biggest difference is the amount of bevel below the flute. Rounding off the heel should help, and I would round off more than you did on the BB.

Thanks, Thom. I almost certainly will, though I'm hesitant to make any major changes until after I fully understand what's wrong with my tool presentation (I just need to get out to the shop and do some practicing).

[Steve Schlumpf]

Aaron - just my opinion - but based on your photos, I would say that the nose angle is OK but that you would find it a lot easier to use if you removed 1/2 of the bevel. Using a bevel that wide is going to cause issues when hollowing a bowl. Think of it as trying to force a straight line around the inside of a circle. It can be done but not without a lot of force because the leading edge and the lagging edge will both be digging in.

[Aaron Craven]

To all who have offered their advice, a very heartfelt thank you. I'm itching to get out and try some of your suggestions.

By thinking through all this (especially Prashun's suggestion of dropping the tool handle), I had a sudden "Eureka!" thought that probably would probably have been obvious to all of you... I kept varying my presentation, but I set my tool rest at roughly the same height I usually do and left it there. I can only drop the handle as far as the tool rest will let me... as I near the center of the bowl, the handle is very nearly horizontal. So I'm thinking I need to drop the tool rest a little.

The suggestions regarding removing the heel of the bevel are also good, and I'm almost certainly going to do this. For the bowl in question, I don't think this was an issue simply because the transition was gradual enough. That said, it may be making it harder for me to find the cut simply because I'm used to something a bit more shortened.

[Aaron Craven]

Aaron - just my opinion - but based on your photos, I would say that the nose angle is OK but that you would find it a lot easier to use if you removed 1/2 of the bevel. Using a bevel that wide is going to cause issues when hollowing a bowl. Think of it as trying to force a straight line around the inside of a circle. It can be done but not without a lot of force because the leading edge and the lagging edge will both be digging in.

Thanks Steve. I'll give it a try, but probably not quite 1/2 to begin with. Actually, I'll probably make that change first on the BB gouge and if it works well for me there, I'll do it on the Thompson gouge. The BB gouge is cheap enough that I don't mind grinding away lots of steel to experiment with different grinds.

[Steve Schlumpf]

Aaron, there are a number of threads on this forum that deal with gouges and the various grinds. Everyone has their favorite based on what works for them. Here is a link to an old thread about how I had my go-to gouge at the time (Thompson 5/8" V) set up. Grind

My go-to gouge is now a D-way 5/8" and while I still use swept back wings, they are not quite as long as shown in the old thread.

[Aaron Craven]

Aaron, there are a number of threads on this forum that deal with gouges and the various grinds. Everyone has their favorite based on what works for them. Here is a link to an old thread about how I had my go-to gouge at the time (Thompson 5/8" V) set up. Grind

My go-to gouge is now a D-way 5/8" and while I still use swept back wings, they are not quite as long as shown in the old thread.

Those were some seriously long wings! Can your gouge fly?

Thanks for the link. Definitely helpful.

[John K Jordan]

I actually just did that to try out on my older gouge. For the bowl in question, it wasn't a problem, because it had a fairly even slope, but I think this is something I will eventually be doing on my new gouge as well. It does seem to help -- especially if I do a somewhat more abrupt transition.

Chris Ramsey from Kentucky, visited our club and turned a couple of cowboy hats. I always grind away the heel of the bevel on both spindle and bowl gouges, rounding the heel and sometimes polishing it to keep it from contacting and burnishing a mark in the wood. Chris, however, takes that a step further, he rounds nearly all of the bevel leaving only about a thin 1/16" wide "cutting" bevel along the edge.

I took a photo with my phone and although it is a horrible photo, I think you can see the grind:

Ramsey_gouge.jpg

I tried this with one of my bowl gouges and sure enough, it worked very well. With a bevel angle like this you can cut nicely in the very bottom of the bowl.

Chris sharpened entirely by hand with no jig. He probably has more experience at this than most of us. I have no idea how many hats he has turned but it is hundreds.

JKJ

[robert baccus]

You can fight it or smile while cutting in the bottom. Take a cheap BB 1/2" bowl gouge (or whatever) and grind a 70 deg. bevel on it and call it a bottom feeder. Been using one for 20 years and its also good for other cuts. Great finishing tool and unbeatable for platters. It simply allows you to ride the whole bevel for control while cutting long curls. Allows the handle to be held at almost 90 deg. to the cut surface.