Tormek Community Forum

In the Shop => Wood Turning => Topic started by: boehme on October 25, 2017, 11:46:46 PM

Title: Stu Batty 40/40 grind
Post by: boehme on October 25, 2017, 11:46:46 PM
I was wondering if anybody has tried replicating the Stuart Batty 40/40 grind using the Tormek.  If anybody has successfully accomplished this what are the jig settings used?
Title: Re: Stu Batty 40/40 grind
Post by: AKMike on November 03, 2017, 07:08:56 AM
I'm sure that you know that you can do that grind freehand using the SVD-110 tool rest and following any of the many videos that are out there, so I guess you're asking about using the SVD-186/185. I've never had a gouge with that particular grind, and I don't have a spare gouge to practice on, so I can't help you too much. However, jig setting 5 with the SVD-186/185 will get you the 40 degree angle from horizontal that you need. The numbers on the jig are units of ten degrees from parallel with the jig axis of rotation. You want 40 degrees from perpendicular or 50 degrees from parallel, so jig setting 5. Then it is just a matter of picking the one of an  infinite number of combinations of protrusion and USB setting that give a 40 degree nose angle that results in the grind that you want. Protrusion 55mm and hole B on the TTS-100 comes close, but results in a nose angle of about 45 degrees, instead of the desired 40.

Not much help, I know, but if you find the right combination, please share.

Mike
Title: Re: Stu Batty 40/40 grind
Post by: Ken S on August 04, 2018, 05:01:12 AM
Good post, Mike. You saved a lot of trial and error with the jig setting.

Setting the bevel angle with the TTS-100 setting tool should just be a matter of using the 65mm slot. Place a piece of masking tape in the 65mm slot with a pencil mark at half depth. Grind the bevel and measure the angle. This should get you closer. Keep guesstimating. Your next guess should be very close.

Ken
Title: Re: Stu Batty 40/40 grind
Post by: SVB on June 26, 2019, 10:12:48 AM
Hi folks - did this ever land as a 'recipe'?

Thanks

Simon
Title: Re: Stu Batty 40/40 grind
Post by: Ken S on June 26, 2019, 03:50:56 PM
Welcome to the forum, Simon.

To the best of my knowledge, there is no published Tormek recipe for the Batty 40-40 grind. It and the Alan Lacer grind were unfortunately not included in the Tormek TNT-300 Woodturner's Instruction Box book and DVD. The TNT-300 is generally very done. I consider the DVD the most outstanding video Tormek has ever produced. However, it does have a few deficiencies. Part of the problem may be due to when it was made. I don't know the exact date, however, the Tormek used in it was a SuperGrind. There is nothing wrong with the SuperGrind and SG-250, however, the DVD predates the SB, SJ and diamond wheels as well as more recent jig designs. I suspect the DVD and book also predate the popularity of the Batty and Lacer grinds. Jeff Farris, who was instrumental in the project is an accomplished turner. He is also partial to Sorby turning tools. Neither the Batty nor the Lacer grinds are available through Sorby.

I hope Tormek will produce an updated version of the book and DVD. Until that happens, I suggest following Mike's advice and making controlled test grinds. Mike's jig setting5; protrusion 55; and
hole B will get you close. Assuming you want to get closer, try lengthening or shortening the protrusion by 5mm. My math is not quite awake this morning. I think shortening the projection will produce a slightly higher angle. If a change of 5mm gets you closer, try increasing the variation slightly. By the second variation attempt you should be close enough.

Keep us posted.

Ken
Title: Re: Stu Batty 40/40 grind
Post by: RichColvin on June 27, 2019, 03:11:14 PM
I think it is doable with the SVD-186.   I don't use that grind, but I know a 40° nose bevel is doable, and the 40° wing angle is about the grind depth on the side swings. 

I've detailed this in my Sharpening Handbook on this page :  https://www.sharpeninghandbook.info/WW-BowlGouge.html.

I really recommend the SVD-186 based approach.  It is very repeatable.

Kind regards,
Rich
Title: Re: Stu Batty 40/40 grind
Post by: Ken S on June 27, 2019, 03:51:44 PM
Rich,
I agree about the repeatability benefits of the SVD-186. The first skew I worked on was close to a Tormek profile, but not exactly so. I was surprised with the extra amount of grinding necessary. The next sharpening was considerably quicker and easier on both the tool and the sharpener.

Following my Irwin chisel idea, I think we should also have comparable learning turning tools.
Ken
Title: Re: Stu Batty 40/40 grind
Post by: Twisted Trees on June 27, 2019, 05:35:12 PM
I also agree, I don't use the 40/40 grind but the thing with woodturning is you need to sharpen often so quick repeatable and accurate are the watchwords. plus you really wouldn't know the difference between a 40/40 and a 39.5/42 when in use anyway, so get the basic profile that works both for you and for your jigs, then you won't be tempted to continue with a blunt tool rather than fussing around with jigs!

Those experienced with freehand sharpening may get an almost perfect angle on sharpening but it is only ever almost ;)
Title: Re: Stu Batty 40/40 grind
Post by: Ken S on June 28, 2019, 03:51:56 AM
TT,

Step into your nearby forest and ask one of your local bodgers. I believe they generally prefer 39.3/42.1    :)

Ken
Title: Re: Stu Batty 40/40 grind
Post by: Ken S on June 28, 2019, 03:57:59 AM
On a more serious note, I think uniformity of settings is important to minimize both the amount of metal removed from the tool and the amount of remaining time subtracted from the turner's lifetime. However, we must not lose sight of sharpening being done for centuries under all different freehand conditions by individual workmen. The old craftsmen did some "pretty fair" work.

Ken
Title: Re: Stu Batty 40/40 grind
Post by: SVB on August 17, 2019, 03:53:43 PM
Struggling with this.  Trying JS5 / B / 55mm.  Got tip shape / angle etc but wings seem to be coming very steep and if I finish grinding to cutting edge will be very thin / weak. 

I'm not doing something right - any one offer any help / suggestions please?

Thanks

Simon
Title: Re: Stu Batty 40/40 grind
Post by: Twisted Trees on August 17, 2019, 06:46:13 PM
Hard to say, but from the pictures that front edge looks closer to 60° plus you have a lot of metal to remove before it comes sharp!

Since my post above where I said I don't use the 40/40 I have worn out a bowl gouge below the tormek jig required flute. so have played with the 40 40 as a manual grind.

Simply set the table to 40° then set a pencil line from each edge of the wheel at 40° as your start and finish lines. Put the gouge upside down on the table and flatten it off on the wheel if starting from scratch that will give the profile. Then sharpen it in 3 sections the twist action is very different on the front to the wings, so it's very hard to sharpen as one action. finally blend the 3 faces together with quick light grinds.

I have to say I have not found a good setting on a jig for this grind, but have found it very easy to achieve from the table.
Title: Re: Stu Batty 40/40 grind
Post by: Ken S on August 17, 2019, 07:22:31 PM
Simon,

I know this is frustrating for you. Here is my suggestion:

Grind your gouge to what you have found to be close.
Assuming you are using 55mm projection, reset the projection to 50mm. Use your black marker to blacken the bevels. Grade your wheel fine. Grind with very light pressure only enough to remove the blacking.
Does this change look like it will improve your wing shape or make it worse? If it looks improved, try making small changes, such as 45mm, until you get the result you want. If 50 is going the wrong direction, try 60.
If this does not get your desired result, I suggest you return to "neutral", in this case 55mm and raise the universal support bar by two revolutions. Use the same black marker and observation method.

This is not a no brainer magic bullet method, but it should get you close.

Unfortunately, I do not know of anyone presently with Tormek who has both the Tormek expertise and the turning expertise needed to answer your question. The 40-40 grind was not included in the original guide.

Ken
Title: Re: Stu Batty 40/40 grind
Post by: RichColvin on August 18, 2019, 01:52:23 AM
Simon,

The SVD doesn't seem to be set on 5.

Kind regards,
Rich
Title: Re: Stu Batty 40/40 grind
Post by: SVB on August 18, 2019, 01:14:43 PM
Title: Re: Stu Batty 40/40 grind
Post by: Twisted Trees 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.
Title: Re: Stu Batty 40/40 grind
Post by: RichColvin 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:

QuoteGuidelines 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
Title: Re: Stu Batty 40/40 grind
Post by: Ken S 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
Title: Re: Stu Batty 40/40 grind
Post by: RichColvin 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