An evening with Doug Thompson

[Ken S]

Forum Member, Rich Colvin, and I recently recently attended a meeting of the Central Ohio Woodturners. Doug Thompson was the featured speaker. Doug makes top of the line quality turning tools. Although Doug does not sharpen with a Tormek, I still learned a lot.

Doug´s clientele includes several well known professional turners. He made the comment that most pros actually use basic grinds.

Doug uses only one steel for all of his turning tools, top of the line CPM 10V. This steel alloy has ten percent vanadium, noted for adding long wearability. He manufactures no ¨second linë, only first line steel tools. He explained the difference between various high speed steel alloys.

M2 steel has 2% vanadium.

M4 has 4% vanadium.

2030 has 5% vanadium.

2060 has 7% vanadium.

CPM10V has 10% vanadium, and is not considered ¨high speed¨ steel.

CPM15V actually has 15% vanadium, however, it is very difficult to grind and is not commonly used in turning tools.

Cyrogenics are done after hardening to create smaller carbides in the steel.

All Thompson tools are hardened their entire length.

For those of you who use a dry grinder with the BGM 100, Doug uses 46 and 80 grit Norton 3X wheels in the harder K grade. He also uses a 60 grit CBN wheel for a consistent eight inch diameter.

Here is a link to Thompon Lathe Tools.

http://thompsonlathetools.com/

Enjoy!

Ken

[AKMike]

I would love to hear Doug Thompson speak, I have many of his tools.

Out of curiosity, did he say if he would be producing any bowl gouges with a parabolic flute? Both Glenn Lucas and Nick Agar claim that the Tormek and SVD-185/6 combination work best with parabolic flutes.

The pros that I have had the privilege of taking classes with do seem to use basic, but slightly varying, grinds. I've seen 3-65-A, 4-65-A, and 5-65-A for general use bowl gouges.

Mike

[RichColvin]

Mike,

What I recorded for "V vs U" shape is that the "U" has no wing, but a larger cutting edge at the bottom.  I don't remember him talking about parabolic shapes though.  But send him an email and ask.

Kind regards,
Rich

[Jan]

Ken, thanks for the report from the interesting wood turners meeting.

High speed and low speed grinding are two different worlds. I am wondering if the tools made of CPM10 steel can be effectively sharpened using Tormek SG or SG stone. The vanadium carbides are significantly harder than alumina abrasive in the SG stone and even slightly harder than the silicon carbide abrasive in the SB stone.

Vanadium carbides of the CPM10 steel are no problem for diamond wheel of course.

Jan

[Ken S]

Good question, Jan. I am not certain how close these two steels are, however, I have heard from a very knowledgeable source that Veritas PM-V11 works very well with the Tormek and SG grinding wheel.

http://www.pm-v11.com/Story.aspx

Ken

[Jan]

Yes, Ken. Stig recently reported about good grindability of PMV-11 with SG stone. But the composition PMV-11 steel is not known. Good grindability of PMV-11 steel with SG stone may indicate that only limited amount of hard vanadium carbides is present.

On the contrary there is high abundance of vanadium carbides in CPM10 steel.

Jan

[Ken S]

Jan,

This gets far beyond my limited knowledge of metallurgy. Maybe Mike will post. He uses both a Tormek and Thompson tools.

Ken

[John_B]

I am feeling the need to update my metallurgy knowledge. There have been so many advances since my college classes and early mechanical engineering work and my knowledge is I am afraid severely dated. I think I will start with a trip to the library and possibly take a refresher college class.

It appears that some of the steels and their heat treatment is proprietary but we do get enough information to make wise choices when sharpening.

[AKMike]

When I'm turning, I have an SB stone mounted, and it works fine for the Doug Thompson tools. I haven't tried the SG stone, sorry.

Mike

[Ken S]

Thanks, Mike. I was hoping you would post.

Ken

[RichColvin]

I am feeling the need to update my metallurgy knowledge. There have been so many advances since my college classes and early mechanical engineering work and my knowledge is I am afraid severely dated. I think I will start with a trip to the library and possibly take a refresher college class.

It appears that some of the steels and their heat treatment is proprietary but we do get enough information to make wise choices when sharpening.

John,

Check out your local university.  Many allow seniors to audit courses for free.  I'm not yet 60, but when I am, I'll certainly take advantage of this!

Kind regards,
Rich

[Jan]

Guys, metallurgy is really exciting discipline. Last year I build small electric kiln of my own design. I got excellent guidance from two advisors from the BESSEX forum, Mr. Scott and Mr. Reich.

The installed power is only 1500 W but because the chamber is small and well insulated the max. temperature is 2300⁰F. On the first view the wiring looks complicated, but in fact it is not. Quenching the first knife was an unforgettable experience.

Jan

[Ken S]

Jan,

You remind me of two of the professors I knew from my college days. After graduating, I lived most of my adult life near my college and had the opportunity to know several of my professors as an adult. These two professors stood out. They were both PhDs from Yale University. One taught geology; one taught physics. They both retained their enthusiastic curiosity. Both followed me and were fascinated when I repaired their telephone service, even though their education and life experience equipped them for much more complicated things.

I hope your enthusiasm effects and benefits other forum members as much as it has inspired and benefitted me.

Ken

[Jan]

Thank you, Ken! 

Jan