Two more bowl gouge flute profiles

[Gordon Seto]

In addition to those I posted earlier, these are the side by side comparison of the Thompson 5/8†“V†and “U†bowl gouges.
The pictures of the other gouges can be found here:
http://www.aawforum.org/vbforum/showthread.php?t=4901

Gary Guenther (GaryG in MD) has approached me and suggested he would write an article summing up the collective wisdom from posts regarding the effects on flute profiles. We hope this will generate a lot of subjective comments so we can all benefit from the findings.
Gary has two PSI Benjamin’s Best LX230 5/8†bowl gouges; he is going to loan them to me at the Richmond Symposium. I am going to include them after I return from Symposium.

When I posted the pictures, a keen turner noticed the flute on the Mastercut gouges was not symmetrical and asked whether the mold got deformed when I remove the gouge. So I did another casting. It confirmed that it is slightly lopsided. I didn’t buy this gouge brand new. I bought it from a member who moved to a retirement community. I don’t know whether he bought it as seconds or not. I had the gouge for several years; I never noticed any irregularity in its flute until in the cast. This proves my point that casting the molds helps us to see the difference better.

 

[KEW]

Cool! This is exciting. I know that the Ellsworth is pretty specific about his grind. I cannot accept that flute shape isn't just as important and suspect he also has a specific flute shape required.
I can't wait to read some good discussion/analysis of flute shape!

 

[KEW]

Gary has two PSI Benjamin’s Best LX230 5/8†bowl gouges; he is going to loan them to me at the Richmond Symposium. I am going to include them after I return from Symposium.

Is this a typo? Why two of the same gouge?
Are they suspected to be different?

 

[Mark Mandell]

Is this a typo? Why two of the same gouge?
Are they suspected to be different?

I think he's comparing the Oneway with the two Thompson gauges with different flutes.

 

[Gordon Seto]

Is this a typo? Why two of the same gouge?
Are they suspected to be different?

Yes, that is what observation that Gary had. He was frustrated about getting another BB LX230 with the same model number, but the shapes of the second flute were obviously different.

I haven't seen the gouges yet. My suspicion is the difference would be more profound in cross section.

Gary posted about that in here:
http://www.woodcentral.com/cgi-bin/turning3.pl?frames;read=185915#185915

 

[Richard Baker]

Thanks Gordon and Gary. Sounds like it will be a very interesting article.

My original interest in the BB tool was not so much that it was low priced, but the fact that mine has a rather deep V flute shape, unlike most other gouges I have seen. I used it mostly for sharpening practice, as it's more difficult for me to control than an Ellsworth or other U flute tool. Still use the little one (10 mm) a lot, with a straight conical grind.

 

[Gordon Seto]

I have a question and a theory

My experience with smaller diameter bowl gouges is they can’t extend over the tool rest much. They are likely to chatter. Doug Thompson has been recommending turners, who don’t know what to get, to get a 3/8†or ½†bowl gouge if they have a mini lathe. He uses 3/8†and ½†bowl gouges to turn his full size cowboy hat at his demo.
I already have enough bowl gouges of various sizes; I don’t have a lot of Thompson bowl gouges. (Doug loaned me the 5/8†U & V for making the molds) My chattering experience was based on other brands of smaller bowl gouges.
After carefully examining the flute profiles, I come up with a theory. I want to see whether my theory makes sense. If the smaller gouges are the scaled back version of the 5/8†gouges. The Thompson U & V bowl gouges have thicker steel under the flutes. Of course Doug is making his size recommendation based on his Thompson gouges. Do we need to use a bigger bowl gouge to compensate for gouges with less steel? What is the advantage of having thinner steel?
I have been wondering about this for some time. I didn’t post this in the original post, because I want more diversified discussion.

 

[Malcolm Smith]

My experience with smaller diameter bowl gouges is they can’t extend over the tool rest much. They are likely to chatter. Doug Thompson has been recommending turners, who don’t know what to get, to get a 3/8†or ½†bowl gouge if they have a mini lathe. He uses 3/8†and ½†bowl gouges to turn his full size cowboy hat at his demo.
I already have enough bowl gouges of various sizes; I don’t have a lot of Thompson bowl gouges. (Doug loaned me the 5/8†U & V for making the molds) My chattering experience was based on other brands of smaller bowl gouges.
After carefully examining the flute profiles, I come up with a theory. I want to see whether my theory makes sense. If the smaller gouges are the scaled back version of the 5/8†gouges. The Thompson U & V bowl gouges have thicker steel under the flutes. Of course Doug is making his size recommendation based on his Thompson gouges. Do we need to use a bigger bowl gouge to compensate for gouges with less steel? What is the advantage of having thinner steel?
I have been wondering about this for some time. I didn’t post this in the original post, because I want more diversified discussion.

Most of us go to a heavier gouge when we encounter chatter inside a bowl. It's a good idea to consider what is happening. Very slightly raising the tool handle of a small gouge quickly increases the depth of the cut to the point where the chatter begins. The slightly larger tool is more forgiving in this respect. I'm not suggesting that one shouldn't use a heavier tool but it helps to understand what is happening. Key to this is the above referred to thicker steel under the flute. The angle at which this is ground is another factor. Still another factor is how successfully one follows the curve toward the bottom of the bowl.

Malcolm Smith.

 

[Doug Thompson]

This is a very good topic because we all learn, there is no perfect tool but who says we can't keep trying. I've tried many and still make a one of a kind to try a different idea.

That's why we need to continue to talk... what works/what doesn't and bring up new ideas.

Gordon does a lot of testing of different ideas, the question why... or what if... is enough for him to start a test to find out.

 

[Malcolm Smith]

Yes, try different tools and different grinds but keep in mind that when one changes to a different manufacturer's tool one will attempt to use it the way one uses the tools one is accustomed to. All of the gouges I use are Glaser. If someone handed me a different tool and said 'try this', I would, on doing so, tend to conclude that the Glaser works better. There is a learning curve even though the tools might seem similar. This is really an argument for using gouges from one manufacturer. I refer to gouges because the flutes are often different in those from different manufacturers. Also, in the above example, the tool will have been sharpened by the other turner.

Malcolm Smith.