How to Avoid Belt Sander Rounding the Tip

[pelotonjon]

How do you avoid rounding the tip of a knife when using a belt sander to sharpen it? Are there any specific tips I should try?

 

[Komitadjie]

Try to never take the tip farther than halfway across the belt. Also, remember that as you get near the tip you should lighten up the pressure you're using, since instead of grinding with the whole width of the belt, you're grinding with just a small bit since you're on an arc that's getting smaller as you get closer to the tip. Watch the heat, too, it builds easiest near the tip since the metal is thinner and has less thermal mass to suck the heat away.

 

[crunky]

What Komitadjie said. When I am sharpening on the sander, as I get near the tip I start to pull the handle back towards me and up a little bit and match the arcing motion I am making to the sweep of the tip... If that makes any sense to you.
There are some youtube videos that demonstrate this technique, might want to check some of those out.

 

[Komitadjie]

Hmm, something else that I thought of a second ago that I just kind of took for granted: Make sure that the edge you are grinding is always parallel to the floor! That means that as the tip sweeps up, the handle of the knife moves upwards and slightly outwards as well so that the angle the belt sees stays the same. If you don't do that, the angle changes as you get toward the tip, and you start taking off large amounts of metal fast!