Thread: Aluminium Oxide, silicon carbide or what wheel - for sharpening lathe tools

I know what you are going through Larks!!

When my Blue Max Is done with I am looking at either a a pink alox wheel - the wider the better - in the "soft"
range or going to a CBN wheel.

Yes, Silicon Carbide wheels are made for sharpening tool steel but so are alox wheels

I found that reading the references above after talking to the local saw sharpener was very helpful.

I suggest that your retailer may not know much as I have found the same with the retailers I have talked to.

The retailers do not necessarily keep abreast of advancing technology and tend to stick with what they know.

Choosing grinding wheels can certainly be a confusing & complex subject, and I think that for marketing reasons, the manufacturers make it more complex than it needs to be, in order to try to differentiate their product from the opposition manufacturers' products.

The first thing that I found when I wanted to buy new Aluminum Oxide wheels for my grinder was that the colour of the wheel is just that - a colour. One sales person at a specialist supplier in Brisbane advised me that the colour is just a dye added to the mix by the manufacturer. In that manufacturer's product range, a colour (for example white) is allocated to a particular product in their range, that will be suitable for a particular use, for example grinding High Speed Steel. That does not mean that a white aluminum oxide wheel made by another manufacturer is suitable for the same purpose. So, when you say that "I have been warned off the white ones... though I don't know why...and was told to go for the blue aluminium oxide wheel", you would have to ask - white wheels made by which manufacturer and blue wheels made by which manufacturer.

Factors such as; the size of the grains that make up the wheel, the type of material used to bond the grains together to make the wheel, the rate at which the wheel abrades to expose fresh grains, and lots of other technical specifications, mean that grinding wheels can be tailored to all sorts of uses by mixing and matching the specifications. The following article provides much more background to grinding wheel design and specs, but unfortunately, may just add to the confusion as it doesn't simply say "buy this specific wheel for HSS grinding". http://www.mmsonline.com/articles/ch...grinding-wheel

Along with a small group of local woodworkers, about a year ago I visited a specialist grinding materials supplier in Brisbane. They only supply to industry, but were very helpful in helping explain grinding wheel selection to us. One thing that they showed us was three different wheels, all Aluminum Oxide 80 grit suitable for High Speed Steel grinding, but made by three different manufacturers. The three wheels were three different colours. When you looked at the specifications, it was clear that all three wheels were 99% the same specification. They also explained how to read the series of letter and number codes on some of the brands of wheels. I won't explain those codes here, as it gets too involved - a Google search will give you lots of articles, but if you can learn the basics of these codes, it will help if you want to buy grinding wheels from your local hardware store.

They advised that most industrial buyers find a brand they like, and then stick with that one brand of grinding wheel, so that they have a consistent colour code on their wheels. That way their staff know that if they want a wheel for HSS they choose this colour, and if they want a wheel for tool steel, they choose that colour, and so on - it lessens the possibility of someone using the wrong wheel on a job in the factory.

The final recommendation by the people at the specialist grinding materials supplier, was that for High Speed Steel woodworking and woodturning tools, an Aluminum Oxide 80 grit wheel was suitable for use with a typical high speed grinder running at 2800 RPM. A 120 grit wheel would also be suitable and will produce a finer ground surface, but cuts quite a bit slower.

Hope that info helps...

Regards,

Roy

Good info Roy!!

I , like many others I suppose, tend to think Norton and their colours when the subject of grinding wheels comes up.

Several suppliers have informed me that the pink alox tends to run cooler than the white for the same grit.

The Blue Max is the coolest running of all. It breaks away more easily as you sharpen thereby exposing new sharp grit. For this reason it removes metal very quickly and also runs cooler. Unfortunately I don't like the rough finish it gives.

A CBN wheel seems to be the answer for those who cannot afford a Tormek.