Thread: Belt speeds for sharpening

Artme,

The Sorby Pro edge sharpening system belt speed is 700 ft (220m) per minute so the slower would be better. However Derek Cohen made a sharpening system using belt sanders about 9 years ago without any problems.

Here are the links from the Forums "Best of the best "about the posts. https://www.woodworkforums.com/14908-...blade-grinder/ and https://www.woodworkforums.com/16156-...de-grinder-mk/ which may be of interest to you.


Peter.

Thanks Peter!!

I did see that the Sorby tool was 700fpm and also looked up Derek's system.

The Multitool runs at about 4,000 fpm from what I remember.

Maybe the belt sander I have will be OK, just a matter of not leaving the tool on the belt for too long.

I have a table on the sander so setting angles will be fine. I can probably make a jig for lathe tools
along the lines of the one made by Eddie Castelin. Eddie has some great and inexpensive ideas.

My belt grinder runs from 1300 fpm to 2600. I have been using it for years like that and I can't say I have ever needed it slower or faster.... But you have me thinking now!

Faster does = heat but you can get around that somewhat by doing most of your work with sharp, coarse grit belts. If I'm re grinding badly worn axes or slasher blades, I start with a big 36g zirconia belt. It cuts very fast and generates little ribbons of steel rather than dust. It looks a bit like the shavings you get from a sharp file.

Dull belts generate a lot of heat and the finer you go down the grit scale, the faster the heat build up.

Just about every belt grinder set up I have seen will run a 40grit belt but a few did not have the space or grunt to run the 36grit belts. There is a big difference in the grit size when you compare them to a 40grit belt.

I'm not convinced that the surface speed of the belts is the most important factor when using them for sharpening. You can adjust so many other factors to suit how you want to use them.

Zirconia belts is a great place to start. The standard brown belts dull way to fast for sharpening but i started out using them and I got around that issue for a while.

For me, the real bonus to belt grinders is the ability to swap belts very quickly.

I mentioned this before in another thread but I keep a lot of my worn out belts. The dull abrasive acts more like a polishing belt for parts that are not heat sensitive.

Just be mindful of the friction heating and take your time. Some claim that cold water dipping is critical to success, I think it's superfluous.

I squared off a good 12mm skew on a 3750 bench grinder.
Then to the stationary disk/belt sander to establish the 10 degree bevel each face.
Didn't cook it at all. Didn't care if it took me 20-30 minutes as we all know that the job only needs to be done once = don't screw up.
Back in my own shop, I finished the refinement of the bevels freehand.
Excellent carver's stop chisel, about a 1/12 in size.

There are still a few almighty deep scratches from the belt sander but it's the edge that interests me not pretty.