Rubber wheel

[SHARPCO]

Why use a rubber wheel for sharpening?  What are the advantages / disadvantages?

I was just curious. I will continue to use the Tormek and Viel S-5 mainly.

[Mark Reich]

Well, from experience i know that the combination of diamond paste & oil on Paper Wheels can work very well.
Have never tried to put diamond paste on a Rubber Wheel, but my guess would be that the paste would not stick too well to the surface.
Glued diamond grit on a Rubber Wheel however works very well and with good longevity, but the grit has to be used with a layer of wax on top of it, to protect both your knife edges as well as the diamond particles themselves from overheating.

We are fortunate to have your experience. Please elaborate. Where do you get diamond grit and what grit are you using? You must have a killer setup to be able to afford a diamond encrusted wheel. All you need now is a VFD, and you probably wouldn't have to worry about heat so much.

Personally, I can't imagine sharpening in a way that gets a blade warm, yet you're concerned about overheating the diamonds? What sort of wax and glue work at that temperature?

[Kwakster]

My current supply of diamond grit comes from here: http://www.techdiamondtools.com/ and is actually quite affordable.
So far i have good experiences with 230 grit and 170 grit.
No worries about heat build-up here, as i have found that covering the diamond grit layer with the same wax that is also used on a gritted Paper Wheel keeps the temperature at the apex well below critical values, and the edges sharpened this way also perform very well, both at initial sharpness & longevity.

Combining diamond grit and wax makes use of certain specific properties of both.
Any frictional heat from sharpening is quickly and efficiently "wicked away" by the diamond grit itself due to diamond's extremely high thermal conductivity (even higher than CBN), but if just left there the diamond particles would quickly deteriorate from overheating.
Covering the diamond grit with wax however makes that the diamond particles can transfer the heat directly to the wax, which in turn neutralizes it by beginning to melt (and immediately solidify again while the Wheel spins)
To glue the diamond particles on the rim of a Rubber Wheel i use a good quality waterproof wood glue.
My current Rubber Wheel coated this way with 170 grit mono-diamond is in use for about two years, and still works as intended (which i keep track of through detailed customer feedback)

I've also been using a combination of various diamond pastes & specialty oils for years on Paper Wheels, which also works quite well.
See this thread on the Australian Bladeforums:

https://www.australianbladeforums.com/vb...edges.html

[Mark Reich]

Thanks a bunch Kwakster, very interesting and the TechDiamond site looks like a fabulous resource. I use a lot of diamond compounds, but I haven't seen anything like this, so I have plenty of questions, if you'd care to indulge me.

Could you explain "gluing to the rim" of a rubber wheel, as opposed to the face? Are you using Cratex, or rubber contact wheels? What size? What machine? This is intriguing to me.

I've been using wood glue forever, but only for wood. It joins wood very well, but it just pops right off the surface of wood (on glue-ups) and anything else. That has always seemed like a great property of wood glue. I would not have guessed it sticks to high speed (I assume) rubber wheels.

Thanks again for sharing.

[Kwakster]

The Rubber Wheels i have are heavy cast rubber discs filled with abrasive particles throughout, in my case silicon carbide. (they were also available with aluminium oxide)
These discs can be used on a standard bench grinder to deburr & polish various kinds of metal, and also to sharpen knives.
I have 4 different ones, each one measuring 8" in diameter, and they were manufactured by a small Dutch company.
My current bench grinder is a Creusen DS7500TS which runs between 1400-1700 r.p.m.

As an experiment i glued +/- 230 grit diamond particles on the rim of one of them with the same waterproof wood glue i use to attach SiC grit to a Paper Wheel, and then covered it with wax, also the same as on a Paper Wheel with SiC grit.
Since i liked the results i got with this Wheel (have been using it since early 2015) i later did another one, this time with +/- 170 grit diamond powder.
Fairly recently i converted my oldest Paper SiC grit Wheel into one that also uses 170 grit diamond powder.

For gluing SiC or diamond grit to either Paper Wheels or Rubber Wheels i use 3 layers of glue which provides for a much stronger bond of the grit to the Wheel surface compared to just one layer of glue: a base layer, a second layer on which the grit is applied, and then a third thin layer over the grit. (yes, i know it sounds strange)
Allow each layer of glue to dry at least overnight and don't forget to apply the layer of wax before you start using the Wheel.