How to sharpen profile inserts

[Chris Fite]

I have an profile insert head for my shaper. One of the pairs of knives is obviously dull. It is similar to this: http://www.lagunatools.com/index.asp?PageAction=VIEWPROD&ProdID=49
How do I sharpen the inserts (knives)? Is this the same as lapping the back of a chisel?

[Norman Hitt]

I have an profile insert head for my shaper. One of the pairs of knives is obviously dull.

How do I sharpen the inserts (knives)? Is this the same as lapping the back of a chisel?

Chris, on any flat insert, lay the "front face" of the insert flat on a (600 grit diamond stone if it is carbide), or, (if it is HSS), lay it on fine grit sandpaper wetted and laying on glass, and stroke it back and forth lengthwise.

Note: [Be sure to count the strokes and repeat the same number of strokes for "Each" insert that mounts to the cutterhead as a set.]

Hold each insert up and twist it back and forth to see if there is any shiny spots from reflected light anywhere along the cutting edge. When there is no reflected light along that edge, the insert is sharpened.

[Jay T. Marlin]

Chris, Norman's advice is good. I use a 1000 grit waterstone instead of a sandpaper but either will work. Worst case, get a new set of knives.

O.T. - I can't believe Laguna is charging $400 for that set. Looks like the other European machine companies are charging the same. Can't be worth more than $150. CTSaw has an aluminum cutterhead version that's only $113!!! Replacement knives are $14-20 from CTSaw rather than $40. Talk about price gouging your patrons. :(

[Charles McCracken]

I recommend that you avoid trying to sharpen them yourself unless you have a surface grinder. It doesn't take much to make the cutters different thicknesses at which point only one knife will be cutting. This increases the load on that knife and affects the cut quality. Your sharpener should be able to do this for very little expense.

Charles M
Freud America, Inc.

[Steve Clardy]

I send mine out to be sharpened.
But in a pinch, I do the sandpaper method also. I just lay the paper flat on my table saw, and work the back side of the cutter around till it feels sharp.