Guidelines shown below are for use with the Tormek SVD-186 Gouge Jig or SVD-185 Gouge Jig.
Guidelines below can be taken with two approaches :
|40°||50°||10°||Primary bowl gouge - the 40°/40° is good.|
|55°||10°||10°||Used for the inside bottom of the bowl|
A relief ground into the bottom part of the gouge helps reduce bruising the wood as the turner comes around the inside curve of the bowl. The Tormek handbook, Water Cooled Sharpening of Edge Tools, refers to this as "Rounding Off the Heel".
|40°||50°||5° - 10°||2||75 mm||A||
The "40/40" grind is advocated by Stuart Batty (Allan's son), and is used by his protégé Ashley Harwood. They both advocate hand grinding on a platform set for 40° (a number of companies make such platforms).
My experience is that this shape is very useful for the really hard woods used in ornamental turning. Examples include African Blackwood and Desert Ironwood (both with Janka hardness measures > 13,000 N).
As shown in the diagram to the left, the wings are not swept back as far as the diagram below on the right, but the α remains the same. Also, the wings (on the rake) are recommended to be flat, not convex. This is because the wings are not a key element of the style Stuart uses for his work (unlike that advocated by David Ellsworth). I have found it difficult to produce truly flat wings; mine are more convex. This has not decreased the usage of the tool's grind shape for me.
|40°||60° - 75°||5° - 10°||2||75 mm||A||
The profile shown to the right with long swept back wings can be achieved by adding more side-to-side swing of the tool when sharpening it (i.e., grinding the wings further back for a higher rake angle -- more information about this is in the comments below).
The Tormek handbook, Water Cooled Sharpening of Edge Tools, advises that this grind shape is not recommended for starter-level turners as it can be somewhat aggressive, but many others feel that 40° is the optimal grind angle (except for bowl bottom gouges, where 60° is recommended).
|45°||5° - 15°||5° - 10°||2||65 mm||A||
Others feel that 40° is a far better grind angle (except for bowl bottom gouges), especially if pursuing a multiple bowl gouge workflow.
|45°||45° - 60°||5° - 10°||2||65 mm||A||
The "Irish" profile with swept back wings was pioneered by Liam O’Neil, and can be achieved by adding more side-to-side swing of the tool when sharpening it (i.e., grinding the wings back further).
Allan Batty recommended this angle, though Stuart Batty noted that his father's recommendation for this angle was based on his production work being made easier (vs. using a second bowl gouge for bowl bottom work).
Stuart's stories of working for his father are worth the price of admission to his classes (oh, and the instruction is good too).
|50°||5° - 15°||5° - 10°||n/a||n/a||n/a||
This is a good grind for bottoms of shallow bowls.
|55°||5° - 15°||5° - 10°||4||65 mm||A||
The larger edge angle is beneficial when turning deeper within bowls.
|60°||5° - 15°||5° - 10°||6||75 mm||A||
This is a good cutting angle for bottoms of the bowl, especially a deep bowl.
|60°||60° - 75°||5° - 10°||6||75 mm||A||
David turns a lot of wet wood for the objects he makes, and I have found that this shape works well for such turning. I have also found that this shape is not as usable for really hard woods (i.e., Desert Ironwood or African Blackwood).
These wings are a key element of the style David uses for his work (unlike that advocated by Stuart Batty).
Notes & Comments
Tormek Sharpening Classes: Part 5 - Woodturning Tools
Want to learn how you get your woodturning tools razor-sharp? In this week's sharpening class we take a closer look at the tools for the woodturner; Gouges, skews, parting tools, scrapers, cutters and more. Sebastien and Wolfgang will show you the methods for sharpening all these turning tools and how you achieve repeatable edges every time. Stay tuned and hit us with your questions during the stream!
How to sharpen bowl and spindle gouges – Tormek SVD-186 Gouge Jig – with Nick Agar
In this episode Nick Agar shows how you create a fingernail grind on your woodturning gouge and to replicate this grind every time. Nick goes through the procedure step by step using Tormek’s TTS-100 Turning Tool Setter, the SVD-186 Gouge Jig, the SB-250 Blackstone Silicon and the LA-120 Profiled Leather Honing Wheel.
|Allan Holtham - Tormek SVD-186 Gouge Jig|
David Peters - Tormek SVD-186 Gouge Jig Review
and Comparison to the SVD-185
|Sharpen gouges with the Tormek Gouge Jig SVD-185|
|Jeff Farris - Sharpening with the Tormek SVD-185 Gouge Jig|
|Sharpen short edge tools with the Tormek Short Tool Jig SVS-32|
|Fundamental #3; Video 1 - Sharp Tools|
|Fundamental #3; Video 2 - Importance of Sharpening, Part 1|
|Fundamental #3; Video 3 - Importance of Sharpening, Part 2|
|Grinding a gouge into a beading tool|
Make a Point Tool for Woodturning
I particularly like the triangular jig he makes to help ensure a good grind.
The late Bill Jones has a really good description of how to use this tool in his 1997 book, Further Notes from the Turning Shop.
|Tormek Turning Tool Setter TTS-100|
|Tormek AngleMaster WM-200|
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