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Ring Master Cutting Angles

Posted: Sun Jan 06, 2008 1:22 am
by paulmcohen
The instructions that come with the Ring Master have a very complicated way to calculate the cutting angle when they could have just included a table.

I used Excel to calculate these so it anyone wants the template just send me private mail. There is a 1/2 degree discrepancy from the manual at 3/8" that I can't explain.

Thickness - Angle
3/8 - 40.0
7/16 - 35.5
1/2 - 32.0
9/16 - 29.0
5/8 - 26.5
11/16 - 24.5
3/4 - 22.5
13/16 - 21.0
7/8 - 19.5

Posted: Sun Jan 06, 2008 1:50 pm
by charlese
Paul, Excellent Point. Sometimes inventors/engineers/manufacturers ignore the more practical applications of their products such as considering - "What would I want if I were to purchase, then try to use the product."

Could the 1/2 degree difference be due to rounding error? Maybe only trial and error will tell!

Posted: Sun Jan 06, 2008 3:52 pm
by Nick
To be as kind as possible to the mindless hack who pasted together Ringmaster’s dismal excuse for an Owner’s Manual, it really does suck dead toads. The business that you have pointed out concerning angles is just one of the many, many boats this clueless cretin missed.

Not so with the tool. Drew and I have been exploring the Ringmaster for these last few weeks, getting ready for the January 12 Sawdust Session, and we’ve found that it is delightfully versatile and capable. I fully expected to find that it was a moderately useful gizmo the capacity of which could be demonstrated in 15 to 20 minutes. Not so. Drew and I are now considering that it will take 3 or 4 sessions just to explain the major uses of the Ringmaster, and we can already see possibilities for more.

Those two things being established – the tool is great; the manual is horse puckey – let me say one more thing. There is no reason in the world why the user should be restricted to using a single angle for a given thickness of stock. In fact, if you reject this premise, begin exploring what you can do with a range of angles, and navigate this new territory using a little trigonometry, the possibilities begin to multiply quickly.

This coming weekend, I’m going to address how to create bowls with straight sides from a single piece of wood. Select the thickness of your stock (up to 1”) and the slope of the bowl wall (up to 45 degrees), then calculate the “ring spacing” needed to achieve it. You can also figure the wall thickness, if you want. The illustration below hints at the process. If you plane your stock to 3/4” thick and want to create a bowl with walls sloped at 30 degrees (not the suggested 22-1/2 degrees), cut rings every 7/16”. (3/4 x tan30 = 7/16) They will match up perfectly.


By the way, Drew and I have also developed an Excel calculator for the mathematically challenged who would rather not deal with sines, cosines, and tangents. Think of it as a GPS for exploring Ringmasterland.

With all good wishes,

Posted: Sun Jan 06, 2008 8:05 pm
by paulmcohen
I just found that the Shopsmith version of the Ring Master came with a CD with a new manual. I almost threw out the box without noticing it. The CD has a lot of information but not a simple and clear as what Nick posted. There is also a commercial application called ProtoShaper I am not sure how it is different than the Excel sheets Nick has created.

Re: Ring Master Cutting Angles

Posted: Wed Feb 27, 2019 6:22 pm
by twobachs
I have a used ringmaster and I sure could use your excel program. How can I get a copy?


Re: Ring Master Cutting Angles

Posted: Wed Feb 27, 2019 11:03 pm
by rpd
twobachs wrote:I have a used ringmaster and I sure could use your excel program. How can I get a copy?

. .
Welcome aboard, but I suspect you won't get an answer, This thread is 11 years old. Also, I just checked Paul's profile and it has been almost two years since he was last active on this forum.

Re: Ring Master Cutting Angles

Posted: Thu Feb 28, 2019 5:31 pm
by bach939
Bummer. Thanks for getting back to me.

Re: Ring Master Cutting Angles

Posted: Thu Feb 28, 2019 7:43 pm
by rpd
bach939 wrote:Bummer. Thanks for getting back to me.
I should have read the thread a bit more. :o

The spreadsheet was actually mentioned by Nick.

It is part of Sawdust Session 14. The link is below. you have to scroll down the window on the right to get to the spreadsheet. ... _Bowls.htm