What (blade work) do you use your disk grinder for? +1 unrelated question.

[richard j]

i'm getting ready to send the vids out to everybody. there is a trick to grinding with a disk. if you go too low or too high from center you can change the angle and mess up a blade. in the vids you will notice i put a circle with a magic marker. you keep the blade inside that circle and you are ok. that disk is 9" and i made it myself. it has a 1° taper and i also have one that i put a slight convex along the edge. i'm playing around with that one to see what all i can do with it.

 

[richard j]

My Powermatic 6x48 has a 12" disc on the side. It's single speed, meaning fast, and non reversible so it's not as easy to use as the variable speed reversible types Stacy mentioned must be, but I have been able to use it some, mainly for achieving flat surfaces like the others mentioned,

Mine is to big for sheets of wet or dry paper so I've been using the PSA cloth backed Zirconia discs from Supergrit:

http://www.supergrit.com/products/products_discs-cloth.asp#psazarc

These discs last a lot longer than silicone carbide wet or dry paper.

i like this
Supergrit® Cloth Backed Ceramic PSA Discs

If you need more cutting power than the blue zirconia discs listed above, try our ceramic discs with cryolite surface treatment. These will cut the toughest steel.

the steel i make my knives from starts out at 56 rc. i usually get 4 blades per disk before they are trashed. i use 24 grit martin senour fiber disks used in autobody shops. in the vids you will see a hole in the center about the size of a quarter.

 

[richard j]

Wow, okay... For flat grinding? I'm gonna try that as soon as I can get some more psa papers.

Question.

Assuming the disk spins clockwise and you're coming from the right side, do you use the top (abrasive spinning toward you) or at the bottom (spinning away from you), or does it not really matter?

Mine is just a small humble machine, but we have a big, very heavy 24" (30"?) at work that runs off of a reversible vfd. Only problem with that one is that the maintenance crew tend to use the hell out of the sheet of abrasive and never replace it. I guess I can look into buying some psa's for it if mine seems useful for flat grinding, but as Xander pointed out, I'd almost certainly never use up one disk. They'd trash it pretty quickly, but if it's less than $10 it might be worthwhile if I took a couple of blades.

Let's see that video Richard!

you want to make sure the grinder is spinning counter clockwise with the motor on the left. when you watch the vid, you will see why. it is also easier to keep the knife in position grinding with the disk going counter clockwise.

i would suggest everyone get a face shield. i know i'm going to when i get the chance.