Having Trouble Sharpening w/ Belt Sander

[me2]

I noticed on a chef's knife I sharpened for a neighbor, and on a few of my own knives, that sometimes I leave a small divot right in front of the choil/plunge grind. Its 1/4" to 1/2" in front, and, now that I've noticed, seems to be on most blades I've sharpened more than 2 times. I had a Kershaw Vapor that I sharpened on the sander most of the times it needed sharpening, but it was recurved anyway, so I didnt notice it there. Does anyone else have this problem, and does anyone know how to fix it? I'm using a Harbor Freight 1x30 with a 180 to 320 grit belt (which ever is cheapest and most available; its happened on all the grits) from either Klingspor or Fastenall. It happens sharpening edge trailing, leading, w/ or w/o the platen as a backing.

 

[tgt3]

If you look at the belt on the sander it does not sit flat, due to the shape of the wheels it rides on. This bothered me enough that I bought a delta belt sander that the belt sits even on.

 

[siguy]

that happens to me sometimes if i'm not careful about my timing...

what i mean is that i pause when i'm lining up the angle at the heel of the blade...so the belt contacts for a half a second longer than the rest of the edge.

i have solved this by using a very light touch, especially on thin bladed kitchen knives and similar, as well as not pausing when i put the blade on the belt...just one long smooth stroke. i line up the angle off of the belt and just move the edge down the belt without any pauses.

 

[Grampa]

that happens to me sometimes if i'm not careful about my timing...

what i mean is that i pause when i'm lining up the angle at the heel of the blade...so the belt contacts for a half a second longer than the rest of the edge.

i have solved this by using a very light touch, especially on thin bladed kitchen knives and similar, as well as not pausing when i put the blade on the belt...just one long smooth stroke. i line up the angle off of the belt and just move the edge down the belt without any pauses.

siguy has nailed it! :thumbup:


You could also try (first on some throw away blades) starting your grind at the tip instead of the heel.

 

[popcornpicker]

I would also move higher on the belt. If you work just below the top wheel or on it the results are dramatically different. Be very careful though.

 

[me2]

Thanks. I'll try again tomorrow night. I've got 2 10 degree guides I made that I'm dying to try out. One is for edge leading, the other for edge trailing. Should be interesting.

 

[Andrew Colglazier]

You might also try a finer grit. It doesn't take much to sharpen.

Andy

 

[IUKE12]

You might benefit greatly be going here and watching the belt sander videos. Brian did a great job with them and it really explains a lot.