Author Topic: Stu Batty 40/40 grind  (Read 3124 times)

Offline Twisted Trees

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Re: Stu Batty 40/40 grind
« Reply #15 on: August 18, 2019, 01:56:35 pm »
As I said it was hard to see the angle in the original photo.

The second 40 refers to the swing on the wing, you could measure 40° and put a bit of tape on the bar to show you the extent of the swing in each direction. I would still recommend that the 3 facets should be approached separately then blended together.

Offline RichColvin

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Re: Stu Batty 40/40 grind
« Reply #16 on: October 26, 2019, 04:40:56 pm »
Stuart Batty presented at our woodturning club this past week.  He graciously reviewed what I’d put on the Sharpening Handbook regarding bowl gouges. 

         http://sharpeninghandbook.info/WW-BowlGouge.html

One really key insight he provided is in the intro on that page:

Quote
Guidelines below can be taken with two approaches :
  • Sharpening for a workflow which uses a single bowl gouge - consider the shape used by artists whose work you admire (e.g., the "Ellsworth grind" if you wish to pursue work like David Ellsworth).
  • Sharpening for a workflow which uses multiple bowl gouges - consider the 40/40 grind for one, and a much higher α for the other (i.e., for using the second bowl gouge for the inside bottom of the bowl).

And I think that is a huge point for what angle you choose. 

I’d love feedback.

Kind regards,
Rich
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Rich Colvin
www.SharpeningHandbook.info - a reference guide for sharpening
www.OTBoK.info - help those getting started in ornamental turning -- to make that journey easier.

You are born weak & frail, and you die weak & frail.  What you do between those is up to you.

Offline Ken S

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Re: Stu Batty 40/40 grind
« Reply #17 on: October 26, 2019, 05:46:53 pm »
Good post, Rich.

Are you recommending js2;75mm projection; and hole A on the Tormek to approximate Stuart's 40-40 grind? Unfortunately, this popular grind was not included in the Tormek listing.

I have always thought highly of Alan Holtham and his videos.

I disagree with the second reviewer when he asks if the 186 is worth another hundred dollars for 185 users. I stated clearly in my initial review of the 186 that I thought it was worth the cost for 185 users to upgrade. I still feel that way. The improvements are substantial and several.

I wish Tormek would add an addendum to the turning handbook to include the 40-40 grind (or a close approximation) which could be printed and taped into the turning handbook.

Good work, Rich!

Ken

Offline RichColvin

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Re: Stu Batty 40/40 grind
« Reply #18 on: October 26, 2019, 06:57:02 pm »
I’ve used the Ellsworth grind for years, and have seen limitations for the type of turning I do.  Especially as I make basic shapes on my traditional lathe so that I can finish the work on my rose engine lathe. 

So, I’m going to regrind one of my bowl gouges to be a 40/40 grind and try it.

One of the arguments Stuart made that helped me decide this way is that 40° requires less pressure to cut.


And, I agree :  the SVD-186 is definitely worth the money, even if you already have the SVD-185!

Kind regards,
Yes
« Last Edit: October 26, 2019, 07:00:15 pm by RichColvin »
---------------------------
Rich Colvin
www.SharpeningHandbook.info - a reference guide for sharpening
www.OTBoK.info - help those getting started in ornamental turning -- to make that journey easier.

You are born weak & frail, and you die weak & frail.  What you do between those is up to you.