Base grinding methods?

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stormyclouds
Posts: 45
Joined: Mon Jun 04, 2012 1:24 pm

Base grinding methods?

Post by stormyclouds » Sat May 06, 2017 3:30 pm

I just acquired a grindrite st600 with autofeed and I am looking for advice on feed speeds vs. Belt grit vs pressure. Would anyone mind sharing their methods or can you point me to some links? Thanks!

pmg
Posts: 435
Joined: Sat Dec 01, 2012 8:59 am
Location: Sonthofen

Post by pmg » Sun May 07, 2017 6:53 am

Hi,

1) you will never get the base perfectly flat with a belt grinder (only possible with a stone grinder), but you can achieve very good results nevertheless.

2) The more pressure you apply, the more uneven your base will get. So I am a supporter of little pressure. Of course some pressure is needed to have the autofeed work correctly.

3) With normal belts you will make your base very flat - so the base lacks a structure to transport the water when skiing. There are special cork based belts which put some structure on your base - try to get one of these for finishing.

4) grit and dull vs. sharp belts is something you need to experiment a bit. My skis are quite flat after pressing, and after about 10-15 passes on a relatively sharp grit 100 belt the whole surface is grinded. Then I go on with a dull 120 grit belt to take away the deeper "cuts" the sharp belt produces before I do the finishing on a stone grinder. Here one of these special cork based finishing belts would be your friend.

If I would have to buy new belts, I would go for:
- 1 sharp 120 grit belt to start with until the whole surface is grinded
- 1 relatively dull 120 (or even higher like 150...) grit belt to remove the deeper "cuts" the sharp belt produces
- 1 finishing belt (they usually have grit 400 or higher) to get structure in the base and to further smoothen the grind.

One thing you will definitely need is some kind of "stone" to make the belts dull, even if the should remain relatively sharp. A completely undulled belt will be much too aggressive and produce a lot of hairs on your base and maybe kick the ski out despite the autofeed.

Before you take your skis on the autofeed, just put them on by hand the get a feeling for the belt (how sharp/dull it is).

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