Author Topic: Simple way to increase Tormek RPM by 40%  (Read 5841 times)

Offline wootz

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Simple way to increase Tormek RPM by 40%
« on: October 17, 2019, 01:12:29 am »




You've heard that CBN and diamond wheels grind better than stone wheels, but that is given the pressure on the blade is the same.  Since pressure on CBN and diamond wheels is to be less than on the stone wheel, to see their grinding advantage we need higher RPM.

Generally speaking, with the evolution from stone toCBN and diamond wheels that dissipate heat from grinding very well, the Tormek RPM could be increased to 250 RPM. You will not want that much speed in precision grinding of delicate blades, but for grinding bevels on grossly dull knives and tools or reprofiling you'd love it. So if this ever is going to happen, it better be done with a removable RPM-increasing insert that the user can put on the motor spindle when he needs more intensive grinding.
« Last Edit: July 23, 2020, 09:00:12 am by wootz »

Offline Ken S

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Re: Simple way to increase Tormek RPM by 40%
« Reply #1 on: October 17, 2019, 02:46:09 am »
Clever, Wootz!!!

For those of us who don't happen to live in metricland, a one inch length of plastic water pipe, 5/8” Outside Diameter; 7/16” Inside Diameter also works. If you don't happen to have an odd piece at home, any hardware store will carry it. Some stores may even have it in shorter lengths.

Ken

Offline Elden

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Re: Simple way to increase Tormek RPM by 40%
« Reply #2 on: October 17, 2019, 02:51:25 am »
 Neat idea. Do you have any slippage occur between the tube and the shaft?
Elden

Offline Ken S

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Re: Simple way to increase Tormek RPM by 40%
« Reply #3 on: October 17, 2019, 02:58:38 am »
Elden, my piece of plastic water pipe doesn't seem to slip.

Ken

Offline wootz

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Re: Simple way to increase Tormek RPM by 40%
« Reply #4 on: October 17, 2019, 03:10:45 am »
Last week a professional sharpener from Europe, who already has several Tormeks, wrote to me that he is looking at a clone only because it runs at 125 RPM, to speed up his sharpening. I must have been thinking about this till the last night I saw this solution in my night dream, actually :)

No slippage of the insert, and no spillage of the water at this speed. In the T7 I could insert a 2.5 mm bushing that increases RPM to near 150, but the T8 takes maximum a 2mm insert.

CORRECTION - there is slippage when the blade is pressed against the wheel. The insert must be fixed on the motor spindle to work. Not as simple as it seemed initially.
« Last Edit: October 19, 2019, 09:57:58 am by wootz »

Offline Sharpco

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Re: Simple way to increase Tormek RPM by 40%
« Reply #5 on: October 17, 2019, 03:18:24 am »
Very clever!

In South Korea, Tormek T8 runs at 112 RPM.

https://youtu.be/LoaWuhudtis

So if I do it, T8 will run at 156 RPM.

Offline ega

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Re: Simple way to increase Tormek RPM by 40%
« Reply #6 on: October 18, 2019, 12:24:54 pm »
Oddly enough, I was wondering about this idea just the other day prompted, I think by the 150 RPM limit on the standard 250mm wheel.
Apart from the danger of unacceptable water spillage and spray, is bearing wear likely to be accelerated? so far as I know, the nylon bushes are not available from Tormek on their own (they can, of course, be shop-made if a lathe is available).

Offline wootz

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Re: Simple way to increase Tormek RPM by 40%
« Reply #7 on: November 18, 2019, 03:44:58 am »
The working prototype:



Sleeve 1.5mm thick

Inner diameter 11mm
Outer diameter 14mm

Length:
Tormek-7  28mm
Tormek-8  32mm

One Threaded hole M4
Socket set screw M4
Set screw length: Totmek-8 max 4mm; Tormek-7 - any.

Allen key 2mm

My coarse wheel Tormek now runs overclocked to 130 RPM.

... before you ask, we are too busy at the moment to make them for others, maybe in January next year. Check with your local steelworks shop if they can make one for you.
« Last Edit: November 18, 2019, 04:05:21 am by wootz »

Offline Ken S

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Re: Simple way to increase Tormek RPM by 40%
« Reply #8 on: November 18, 2019, 04:38:37 am »
Oddly enough, I was wondering about this idea just the other day prompted, I think by the 150 RPM limit on the standard 250mm wheel.
Apart from the danger of unacceptable water spillage and spray, is bearing wear likely to be accelerated? so far as I know, the nylon bushes are not available from Tormek on their own (they can, of course, be shop-made if a lathe is available).

Ega,
Here is a link to Advanced Machinery, the primary source of Tormek parts in the US. The part number should be the same with any Tormek dealer which handles parts. Remember that you need two of them.

https://advanced-machinery.myshopify.com/products/16-nylon-bearing

Depending on your work volume, the possible extra bushing wear with higher speed might be made up in higher productivity.

Ken

Offline ega

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Re: Simple way to increase Tormek RPM by 40%
« Reply #9 on: November 18, 2019, 12:07:33 pm »
Ken S
Thank you for the useful link to the parts breakdown.
I should have said that, so far as I am aware, the nylon bushes are not available on their own in the UK
Because, no doubt, of the size of the US market I sense that Tormek users are better served there than here. The existence of this forum must also help in that direction.
I should be glad to be corrected on this: where do UK users get their individual spare parts?

Offline Ken S

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Re: Simple way to increase Tormek RPM by 40%
« Reply #10 on: November 18, 2019, 02:51:20 pm »
I would suggest either contacting support (support@tormek.se). You might also ask your local reseller or the UK agent. Here is the link:

https://www.tormek.com/uk/en/resellers/

Ken
« Last Edit: November 18, 2019, 02:56:09 pm by Ken S »

Offline ega

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Re: Simple way to increase Tormek RPM by 40%
« Reply #11 on: November 18, 2019, 03:46:43 pm »
Ken S:
Thanks again.
The UK importer/reseller is part of a group which includes my local tool store; I will ask them next time I am there.

Offline Ken S

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Re: Simple way to increase Tormek RPM by 40%
« Reply #12 on: November 19, 2019, 05:50:19 pm »
Stig and I discussed the speed increase. Stig has reservations about the higher speed. Many years ago, Tormek made a specialized machine, the model 4000. (This was the ancestor machine of the T2, and the original machine to use the US-400, which evolved into the US-430).) Tormek used a larger sleeve on the motor shaft. Then and now, the idea is appealing in theory. Tormek abandoned the larger sleeve because increasing the pressure of the SG-250 grinding wheel proved more effective.

Tormek found that 90 to 100 rpm was the most effective. Beyond that there was trouble with the machine throwing water.

I think we should explore the speed increase carefully.

Ken


 

Offline cbwx34

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Re: Simple way to increase Tormek RPM by 40%
« Reply #13 on: November 19, 2019, 07:37:14 pm »
...
Tormek abandoned the larger sleeve because increasing the pressure of the SG-250 grinding wheel proved more effective.
...
Ken

Hmmm.... what has changed.....  ???

...

You've heard that CBN and diamond wheels grind better than stone wheels, but that is given the pressure on the blade is the same.  Since pressure on CBN and diamond wheels is to be less than on the stone wheel, to see their grinding advantage we need higher RPM.
...

 ::)
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Offline Josu V

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Re: Simple way to increase Tormek RPM by 40%
« Reply #14 on: November 19, 2019, 08:06:52 pm »
Actually, my SG-250 is in 222mm (diameter). I have lost about 6meter/min of grinding distance respect original size of 250mm.

Would be interesting a little increase of speed from now on... dont you think?
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