Stu Batty 40/40 grind

[boehme]

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?

[AKMike]

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

[Ken S]

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

[SVB]

Hi folks - did this ever land as a 'recipe'?

Thanks

Simon

[Ken S]

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

[RichColvin]

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

[Ken S]

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

[Twisted Trees]

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

[Ken S]

TT,

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

Ken

[Ken S]

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

[SVB]

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

[Twisted Trees]

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.

[Ken S]

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

[RichColvin]

Simon,

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

Kind regards,
Rich

[SVB]

Thanks for the input folks.

To respond to a couple of questions:




• Yes, happy I've got 40 deg nose angle
  
  
• Pretty sure I've set jig right to #5 (btw - do folks use the dips or peaks when setting the jig, provided same each time prob doesn't matter but just minor niggle I have) 
  
  
• I know the wings are far from finished!  I thought I'd stop and ask for help rather than grind all the metal away when I sense it will not be right.

Still trying to get my head round it, experienced turners have told me they've yet to find a grind that can't be done on the tormek so I refuse to be defeated - (but coming close at the moment!)