View Full Version : Grinding HSS tools with training wheels

02-08-2010, 10:42 PM
When I start to rough out HSS tool bits, the first thing that I do is set the table inclination to 7 with my little Starrett magnetic based incline indicator. This establishes the side clearance as we grind the side.

If I want to grind the tool free hand I mark the line with a fine marks a lot and get after it resting the bottom surface on the table but holding the bit with the line parallel to the belt. Most of the time I resort to using a simple plastic guide that is like learning to ride a bicycle with training wheels.
This guide has a tab that rides the bottom edge of the table and a side cut to the appropriate angle. For side one of a right hand turning tool.


Next I use another guide with the second side angle.

Another real utility of the belt sander is that you can change grit size in about 30 seconds. You can go from course to fine in larger steps and produce a very smooth surface.

For the Baldor type tool grinder I made similar guides with a center tab that rides in the slot on the grinder table. The inclination of this table can be set with the same tool used on the belt sander. With the exact duplication of angles the surfaces can be dressed with just a light touch to the grinder wheel.

Grinding the top of the tool to establish the back and side rake is done free hand. I use a Dremel tool with a small cut-off to add chip breaker grooves.

I dress the edges with a fine stone running the stone over the edge in the same direction the chip will move. I use my magnifiers and look for a small polished zone along the cutting edge.

02-09-2010, 01:59 AM
Ever considered running your belt sander.. backwards?

That way the rounding over of the cutting edge part is (more or less) solved.

My biggest beef with bench grinders is the piss slow change over of wheels. Amen to belt changes. Someday i'll make that QC bench grinder..

Gary Gill
02-09-2010, 06:11 AM
I like your guides. Thanks for sharing.

02-09-2010, 06:45 AM
That's good stuff. Especially the Baldor guide.

Ed P
02-09-2010, 09:05 AM
What material did you use for your guides?

Ed P

02-09-2010, 11:05 AM
I know that freehand grinding of cutters is very effective once you have the touch. I admit to setting the table to the correct angle and sometimes setting a bevel gauge up to help eyeball the cuts. Guys that just head up to the stone are well beyond me.

This being said I really like the look of a cutter that is cleanly ground with no bobbles or nicks etc. Your system ensures this outcome as much as possible. Your cutters will last longer too as you don't remove excess material by grinding at a slightly different angle each time - efficient use of time and materials.

In the sincerest form of flattery I am going to make a few jigs like yours. If I get ambitious I may just colour code them for each cutter.

Thanks for the tip!

02-09-2010, 11:45 AM
[QUOTE=Black_Moons]Ever considered running your belt sander.. backwards?

That way the rounding over of the cutting edge part is (more or less) solved.

Now why didn't I think of that. I really appreciate your input. The only thing I can say is I guess that I have my head so far up my *ss that I can't see daylight.

The guides shown are 3/8" HDPE

02-09-2010, 11:55 AM
What material did you use for your guides?

Ed P

I could be wrong but it appears that he used HDPE (High Density PolyEthylene)



It is the same stuff the white plastic kitchen cutting boards are made out of. I have some and it is very handy to have a small sheet or two in the shop for making jigs and soft fixtures. It has a similar weight and feel to that of hard jeweler's wax. It is also quite slippery when used as a bearing surface.

02-09-2010, 09:00 PM
Make you up a pair of thes for your sanders ,then you can change the angle if need be.

02-09-2010, 11:11 PM
I just mark-out and cut the guides/angles from a bit of sheet metal that is about and grind my tools on the face of the pedestal grinder. Metal from tin cans from the kitchen work just fine.

If I am grinding on the belt sander, I use the front of the roller. That way I get a good "hollow grind" which is easier to stone and hone the cutting edge either free-hand off the machine (lathe or mill) or while it is still on the machine.

On the pedestal grinder I have the cutting edge "up" so that I minimise any "feather" (burr). In the sander I have the cutting edge "down" to eliminate the "roll-over" the cutting edge and to eliminate the "feather".

I never use the sanding disk or the angle guides on my sander and can't see the need to put one my grinder.




I prefer to grind to a protractor or angle guage if the cutting edge/s needs to be straight and/or at a specific angle.


















And a really unusual but excellent protractor (the design originated in Russia but was "acquired"/"copied"/pinched by the Chinese):