sharpening rotary cutters

D

dscheidt

Joined
Nov 24, 2007
Messages
28
My mother asked if I could sharpen her rotary cutter blades. I figured I can make a mandrel to hold the blade, chuck it in the drill press, and then lower it at slow speed onto a stone held in some sort of fixture at the correct angle. Make sense?

Anyone know what angle these things are ground at? I don't have one. I know they're fiendishly sharp when new -- they have to be to push cut fabric.
 
The issue with doing what you propose is that the grooves produced by abrasion will run parallel to the edge, instead of perpendicular to it (which is generally the preferred method). May work, and it's worth a shot, but I think that you would be much better trying to use a moving abrasive (belt sander) and a slowly rotating mandrel at the right angle to get the right effect.
 
i have sharpened many of thoes cutters but you dont want to use a stone. i can sharpen it if you want to ship it to me. it would only take me less than a minute and it would be scarry sharp when i'm done. all i ask is you pay shipping both ways.
 
Attach a circle of wet/dry sandpaper to a stiff rubber sanding disk mounted in a hand-held drill. Turn the drill press with blade at a very low rpm and sneak up on the bottom of the blade with the sandpaper turning at a slow/moderate rpm. Make sure the cutting direction is OFF the edge, not into the edge. Increasing grits will give you smooth shaving sharp. WARNING: It's easy to get carried away and hone toooooo much.:) You can strop the blade with a circle of stiff clay-coated paper (like the cover of a phone book). Sharper yet.:)
 
richard j said:
i have sharpened many of thoes cutters but you dont want to use a stone. i can sharpen it if you want to ship it to me. it would only take me less than a minute and it would be scarry sharp when i'm done. all i ask is you pay shipping both ways.
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Thanks for the offer. I think I'll try it myself. It's the sort of thing I should be able to figure out. Why do you say not to use a stone, and what do you suggest instead? Sandpaper? CrO charged softwood?
 
i use my cardboard buffing wheel to hone the cutter which wont take off any metal at all which will make them last a whole lot longer. the only time i use sandpaper on them is if there is a nick that needs removed. i sharpen quite a few each year for friends here in town and they cut just as good if not better than new ones when i'm done.
 
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