Sanding Belts

[glovejoy]

Looking for a supplier/vender to buy sanding belts.  I use a 2.5 in. X 90 in. belt.

Interested in what type of belt material to use for 440C and hardened runner steel.

Also what grit to use for:

1. touching up dull runners.

2. Changing crown/profile of runner.

3. Openning up entries and ends of runners.

Are you using a progression of grits for the above uses?  Is there a preferred grit or 2 to have compared to having 5 different grits?

Appreciate the input.

Guy Lovejoy

[Geoff Sobering]

We've been using A&H Abrasives for a couple of years: http://www.customsandingbelts.com/

Bob Rast recommends Klinspor: http://www.klingspor.com/

I generally get the (least expensive) closed-coat aluminum oxide belts since I use each section for only a few of passes before shifting up or down on the belt.

I can't remember ever using a belt coarser than 80-grit on 1/4" and 3/16" runners, even for rounding over the ends.
I bought some 50 (or 36?) grit Zirconia Alumina (blue) belts for really bad runners or putting an edge on raw steel, but I don't think I've ever used them. Renegaders (3/8" runners) use coarser belts more often.

I am interested to hear what the real runner experts say about grits and sequencing.

Right now I typically use a 120 belt to touch up a runner and 80 grit (followed by 120) when I want to change the shape (or if there are really bad nicks).

I have some finer belts (400 grit) that I got from Bob Rast with my sharpener that seemed to work nicely the one time I experimented with them. The problem I've had in the past is the splice starts to really affect the sharpening process in most belts when you get finer than 120. The 400 belt runs absolutely smoothly (like it didn't have a splice) and that is a big difference. I think the belt came from a local supplier in Waukesha (WI), but I can't remember the name Bob told me...

[us2360]

I have many belts from 40 to 600 grit. 5$ ea. higher grits will heat runner so lower grits for shaping. Always use belts on cold 440c runners which I keep in freezer before sharping. Better to stone runners for touch up.

[Geoff Sobering]

Pete's comment about stoning reminded me that after belt sharpening there is almost always a small (microscopic) burr on the edge of the runner.

If you use the "fingernail test" for sharpness (drag the flat part of your fingernail across the runner's edge to see if it will slice off a thin curl) the burr will always make the runner appear sharp.
(aside: I was helping a recreational iceboater sharpen some very badly rusted/nicked/dulled runners a couple of years ago. After a couple of passes on the sander I got a nice curl from my thumbnail - I then looked at the runner edge and I could see the "edge" was about 1/2 mm wide flat/rusted/nicked area. What my thumbnail was feeling was the burr on the edge of the newly sharpened part of the runner).

The easiest way to remove the burr is to run your thumbnail along the edge a couple of times. That will almost always break the burr off by bending it back and forth.
A single pass on each side of the edge with a stone will also do the job.

Another way to evaluate the sharpness of a runner (or any cutting edge) is to look for light reflected off the edge. A sharp edge will not reflect any light. If there are any flat sections they will show up as bright regions.

[Rolley]

Ice here in dusty Iowa tends to be dirty so my Sarns runners get sharpened often. I use a 24 grit blue Norton belt start to finish.  They cost about 3X the cheaper aluminum oxide belts but last about 3X as long. I flip the runners in the jig when the fresh shavings catch fire from the sparks.  As Geoff says, you're done when the edge visually disappears.  Maybe should mention that 40 years of belt sander experience has taught me a light touch.

[Rolley]

This simple shop built guide has worked perfectly for me.  Can't beat the price. http://groups.yahoo.com/group/iceflyer/photos/album/376728347/pic/711985984/view?picmode=&mode=tn&order=ordinal&start=1&count=20&dir=asc