Paper cutter blade?

[grepper]

I was asked if I could sharpen a paper cutter blade.

Can I?  Anyone ever do it?  Any tips?

The problem I have with the Tormek is how to hold long blade steady.

I have a belt grinder with grits from 80 to 1200.  Maybe that is the way to go.

Thanks for any assistance!

[MakerUnknown]

I have but it's been awhile.
If I remember right I clamped the blade in a vise and used  the diamond plates handheld.  Sometimes doing things by hand is quicker than trying to jig something up.

[Rob]

if its wide enough the planar knife jig might do it...what are its dimensions?

[mike40]

Doesn't the knife jig work for paper cutter blades? What jig is used for lawnmower blades?

[Rob]

I would freehand lawnmower blades personally

[Rhino]

I wouldn't do it.  It is big and complicated and the risks outweigh the benefits especially if the cutter is really dull and you have to take off a lot of metal.

On the other hand, if it is not really dull, maybe a little honing will help.  All cutting edges come to a point and eventual this thin bit of metal gets bent over. Honing the blade, by what ever method, knocks off the burr and the cutter becomes sharper.

I suggest a circular trimmer for low capacity or a bulk paper cutter for high capacity cutting - I have both.  They can both be sharpened.

[grepper]

Thanks Rhino.  I may very well heed you advice.   When this person said paper cutter, I was thinking of your basic long straight arm blade type of cutter.  I don't think I'd want to get into a guillotine type paper cutter and definitely not a circular paper cutter. 

After a little searching around, I see that the blades for these things can get pretty costy too.   You may very right on when you say, "the risks outweigh the benefits".

I have not ruined anybody's stuff yet, and I don't think that would be a good place to start!

It sounds like maybe you have sharpened one?

[Rhino]

Just sharing my thoughts.  It would really depend on your customers or friend who made the request. Sharpening for an elementary school or a regular office is maybe forgiving but sharpening for a business require much precision.

On a lot of cheap paperbacks, you can see marks from a dull bulk cutter blade.  This would be unacceptable in a medium to high end business.  Even if you buy a $5 magazine, when you look at the edge, they should all be cut in a perfect straight line with no tears.

If you are sharpening for a Christmas or other card maker, a photographer, a graphic design house, etc, they are expecting perfect blades.  People sometimes pay $3 or more for a Christmas card or they are making layouts for magazines.  They don't want to see a nick in the middle of a cut or a small tear anywhere.

Take a look at this site.  http://www.comemachines.com/html/parts.html
The commercial paper cutter blades are about $100 to $200 or more each when you figure in shipping.  The machines are more expensive.
This is a site for one of the more reasonably priced machines.  Other machines/parts are more expensive.

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See, this on the same site:

"For paper cutters equipped with metal cutting bases, a common problem is that there may be a gap between the bottom of the back support arm and the metal cutting base. This is due to the fact that metal may expand/shrink slightly due to temperature changes. Consequently, sheets on the bottom of the paper stack may slip through the gap."

This means any uneveness in the blade is not acceptable in a regular machine.
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See also this:

" In addition to the features of the COME®-2700, the COME®-2770EZ is equipped with a High Speed Steel blade that can be replaced in just a few minutes.  All you need to do to change the blade is to remove five screws - that's it."

This means that on a machine not equipped with these features, taking the blade out and putting it back in can take some times - especially if you have no experience and involves more than 5 screws. 
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Rotary blades are $10 new, so I do not recommend trying to sharpen them.

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I think the blade on a bulk cutter is about 10 to 20 pounds.  The machines are 30 to 100 pounds.

Be careful.  You have a guillotine, with a 20 pound very sharp blade 18 inches long, and a big gap for 500 sheets, a fine heavy solid steel handle for leveraging, a mechanism designed to allow a weak person to cut with gravity without electricity reams and reams of paper in one stroke all day long, and a safety you have to remove to get at the blade.  Be careful removing a 10-20 pound razor blade which does not have a handle and which is all greased up inside the machine.  I am paranoid, of course.

So why do they need their bulk cutter sharpened - possibly because some intern nicked the blade cutting through a staple.  So sometimes, the work involve quite a bit of grinding.  Make sure to charge more for a nicked blade.  And, the customer may be expecting the blade to come back perfect.

So that's my experience that I am sharing. 

[Ken S]

I would agree with Rhino.  I have an old Rotatrim cutter from my darkroom days.  It cost almost $150 thirty five years ago. (17" length) The factory grinder who sharpened the rotary blade signed it.

The commonly used guillotine trimmers back then were the Dahle trimmers.  They cost at least as much.

I generally cut my overmats "floating", which meant the print edge cuts were highly visible.  I would only trust a very reputable specialty firm to sharpen my Rotatrim cutter, probably the factory.

The problem with paper cutter blades is that they are a combination of a specialized item and low volume.  if someone had a contract to regularly sharpen fifty trimmers at say fifty dollars per blade, it would be worthwhile to develop the jigs.  If the local church or grade school wants its paper cutter blade sharpened for low cost, it might be worth spending a quarter hour massaging the edge with a diamond hone. That should make a noticeable difference.

For what it's worth, I picked up an old Pootatuck miter trimmer fifteen years ago.  I gladly spent thirty five dollars back then to have the blades sharpened.  (Since I have the planer jig and Tormek now, I would do it myself.  Those blades fit the jig well and are small enough to be easily handled.)

ken

[grepper]

Thanks Rhino and Ken.  I appreciate your responses.

I guess I'll have to see what I'm dealing with, but because of everybody's input, at this point I have reservations.  I don't want to get stuck replacing an expensive blade.

[Ken S]

You're welcome, grepper.  Keep us posted.

[Herman Trivilino]

My local sharpening service does them.  I forget how much they charge.