# A close look on dull/sharp rotary cutter blades and their effects on cutting bands (Lots of pictures)



## Gardengroove (Feb 13, 2012)

Hello my fellow slingshot enthusiasts!

I thought this could be helpful and interesting for some of you guys. I have had a Fiskars rotary cutter in use with its original blade for 1 year now. At some point I noticed that my bands don't last as long as they did in the beginning when the blade was still very sharp. So I thought it would be cool to have a closer look at the wear of blades, compare new ones to worn out ones and try to sharpen them.

If one of the following points applies for you, you might consider to buy a replacement blade or think about resharpening them:


You can't cut your latex/rubber sheet within one pass
You need to put a lot of pressure on the cutter in order to cut a sheet
Your cutter cuts fine a few inches but there are small sections showing up on the cutting track within certain increments where your material wasn't cut

Let's have a look at my old rotary cutter blade:















From a quick look you couldn't tell the blade was already in very bad shape. With a 10 MP camera you already can see some small nicks and dents on the blade's cutting bevel.

I have a small cheap pocket microscope with 100x magnification. A look through reveals why my blade wasn't cutting smooth any more.





















I could determine several characteristics:


Saw tooth like shape caused by very fine dents all over the bevel (1st picture)
"Big dents" - approximately 0,1 mm deep (equals 0,004") (2nd picture)
Areas where the edge was bent or folded over (3rd picture)

The "big" dents are the main problem, because the metal has to be removed until the notch disappers. Most likely those notches are responsible for the 3rd point mentioned above.

Before we talk about sharpening, let's have a look at a brand new 45 mm blade...





















Those carbide coated blades come razor sharp, but are also very costly (9 € a piece). It's hard to see on the pictures, but it seems that there is some kind of micro-bevel (3rd picture). The general shape is flawless, compared to my old blade. With the width of the primary bevel and the thickness of the blade, you can easily determine the sharpening angle. It is 10° on the new blade.

Back to sharpening:

I haven't found too much information about sharpening rotary cutter blades with tools you have at home. There a two commercial sharpeners I have found on the web so far:















The sharpener on the left is pretty elementary built. The second one uses the system which we already now from some knife sharpeners on the market. I think this is junk. Problem on both is, you can only resharpen the cutting edge but not get rid of dents and nicks.

I also want to point out to a video Dgui made some time ago. He does free hand sharpening on a diamond honing stone

http://www.youtube.com/watch?v=Sposzsfw5Qk)

This is what I came up with. I took a dremel tool I had never used before and clamped my blade in with the help of a small washer.









This was the only way I could get rid of the notches. If you try this, be VERY careful!!! I cannot be held responsible if some cuts his fingers... I used a hard but fine grinding wheel and with very light pressure (just touches) and could get rid of the notches. I know this isn't ideal as the dremel spins way to fast even on the lowest setting. Furthermore it's a pain in the *** to get the blade perfectly centered (which is crucial).

After the grind I had to restore the primary bevel. I used my 1000/6000 jap. waterstone for that job. It turned out, that the washer was just about the right height to get the cutting angle near 10 degrees.















On the second picture you can see the sharpening motion. A straight movement combined with rotating the jig. This was done several times on both sides on 1000 grit / 6000 grit and on a leather strop.

Here is the result after the stropping.









Not too bad, right? 

Let's look at the differences, what a dull and worn out blade does to rubber vs. a brand new / resharpened blade does:















I think there is nothing to say, as the pictures tell everything. I have to say it took me 1 hour to restore the dull blade, but I think it was worth the effort. Of course you could just buy a replacement, but that's up to everyone. If anyone has one of the two commercial sharpeners, I would encourage you to make a small review about it. I guess this would be much appreciated by a lot of folks here...

What's left to say: Always keep your blades sharp and have fun with longer lasting bandsets.

Cheers, Simon


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## All Buns Glazing (Apr 22, 2012)

Excellent - I can't figure out what's going on in the latex cut photo, though. Is there a comparison between the old and new cutters results on latex?


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## Aussie Allan In Thailand (Jan 28, 2013)

Excellent work, and explaination, thanks.

Cheers Allan


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## ash (Apr 23, 2013)

Well done and well documented.


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## Gardengroove (Feb 13, 2012)

All Buns Glazing said:


> Excellent - I can't figure out what's going on in the latex cut photo, though. Is there a comparison between the old and new cutters results on latex?


Hi Buns. You're right. The strip above was cut with the new blade and the one beneath was more ripped than cut with the old blade. It is hard to get the pics focussed right when photographing through that tiny lens.


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## Tom Kretschmer (Apr 4, 2013)

Thanks for taking the time to post this, very informative :thumbsup:


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## Btoon84 (Nov 22, 2011)

Nice write up Simon. It was really cool to see the old blade close up!! I wonder if mine look like that... (going to get my magnification on)


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## Charles (Aug 26, 2010)

Good work!

Cheers ..... Charles


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## Rayshot (Feb 1, 2010)

Really good write up especially the photos. Not a complaint but I was so interested to see the close ups of each latex edge, one cut with dull and one cut with sharp.


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## Gardengroove (Feb 13, 2012)

Thanks guys, much appreciated.

@Ray: I will try to make better photos on the weekend. Problem is I don't have a dull blade anymore, but some old bandsets instead, which I lately have cut with the dull blade. By the way the Latex in the last picture is Hygienic 0.04", if someone wondered.

Something I forgot to mention: With a razor sharp new blade the cut survace has a certain glance, I noticed that especially on natural latex. I tried but couldn't get it on camera.

Cheers, Simon


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## mattardel (May 27, 2011)

Has anyone tried the folded aluminum foil method of sharpening? It involves running the rotary blade over a piece of folded aluminum foil a few times until the blade is back to good working order. I've tried it on a cheap rotary cutter and it seems to work relatively well.


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## Gardengroove (Feb 13, 2012)

Thanks Mattardel. This is new to me, will have a look at it. If you guys know better methods or different ones to get your blades back sharp feel free to tell us. We are all here to learn something.


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## mattardel (May 27, 2011)

Here's a link to the page I found which detailed the aluminum foil method, in car anyone wants to take a look: http://pennyshands.blogspot.com/2011/03/how-to-sharpen-your-rotary-cutter-blade.html?m=1


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## mattardel (May 27, 2011)

.


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## Gardengroove (Feb 13, 2012)

Thx for the link. I will try this when one of the blades is losing sharpness again.


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## flipgun (Nov 14, 2012)

mattardel said:


> Here's a link to the page I found which detailed the aluminum foil method, in car anyone wants to take a look: http://pennyshands.blogspot.com/2011/03/how-to-sharpen-your-rotary-cutter-blade.html?m=1


Thanx! I have a couple that need work. I'll try it and get back.


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## treefork (Feb 1, 2010)

I use a method that is easy ,fast and effective. I have discussed it in numerous other posts. It involves a knife sharpening system utilizing two cardboard wheels mounted on a bench grinder. One has 220 grit and the other uses a white buffing compound. For a rotary cutting wheel the buffing process is used only to bring the edge back straight in a similar fashion as " stropping".I have been using the same blade for years and the whole process takes minutes. If the blade is already severely neglected this may not work. My blade is always razor sharp as well as all my knifes. Just another option.


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## treefork (Feb 1, 2010)

Here is a video of it used on regular knife blades


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## leon13 (Oct 4, 2012)

thanks a lot to show us how to do so ! it`s a Pain in the ***** to do that !!

it tuck me a lot of effort to find out how to sharpen those blades.

i will show u soon how i solved that with the help from the People of the Tormek Company.

have a slinging weak end every body

cheers


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## ruthiexxxx (Sep 15, 2012)

leon13 said:


> thanks a lot to show us how to do so ! it`s a Pain in the ***** to do that !!
> it tuck me a lot of effort to find out how to sharpen those blades.
> i will show u soon how i solved that with the help from the People of the Tormek Company.
> have a slinging weak end every body
> cheers


WOW...have you got a Tormek ? A wonderful system !


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## leon13 (Oct 4, 2012)

ruthiexxxx said:


> leon13 said:
> 
> 
> > thanks a lot to show us how to do so ! it`s a Pain in the ***** to do that !!
> ...


jip after we you se like every weak a bunch of rollerblades i had to decide to buy new blades ore sharpening them by myself,long story short i contacted Tormek and they ask t for a sample of blades and 6 weeks later he send back the sharp blade and gave me a coal and teatsht me how to do that on a Machine its a really cool machine i have the money oalredy back in no time i sharpen the first 30 blades in close to 3 ours and i get faster every time i do it again,and for knifes !!! HA ! its so nice i sharpen even my cutter blades with that its so easy

dont start to think i have any connection wit this company and i don`t get money from them but this thing,is for me " the Machine " i still use my Japany`s wet stones to sharpen my throat cutter to loose my face fur. so if any one is wonting that i sharpen his rollerblades ,sign/mark them and ship them over with a return letter with stamps on it and i will sharpen them and send them back. have a beautiful weak end

cheers


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## jazz (May 15, 2012)

Very relevant, excelent post, thank you very much!

cheers,

jazz


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## ZorroSlinger (Dec 12, 2012)

For those that regularly cut rubber latex, theraband & similar - I wonder if you use same blade to also cut leather or other materials? The other materials perhaps can accelerate blade wear? Maybe one dedicated cutter for rubber and another cutter for other materials. I don't know, as I am not a blade edging/sharperner expert and just a random thought


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## Gardengroove (Feb 13, 2012)

@ZorroSlinger: That's a good point you are asking. I am still figuring out where I got that one specific "big" dent from. I was cutting rubber, latex and leather only. Such a breakout does often occur when rolling over a pin for example. I read this a lot in terms of quilting forums. Next time I get to my buddy who has a lathe, I'll try to make something similar to those round sharpening thingies I posted in the main thread.

I am also by no means an sharpening expert, but since I managed to sharpen my blades on waterstones it is also a goal for me now to keep the rotary blades in their best condition. It would be really cool if we could manage to construct a relatively simple device, everybody can make with limited tools, in order to keep your blades in perfect condition. I know that those "jigs" and devices out on the market aren't that expensive, but that's not my point here. I always like it when you can achieve something by yourself without buying an industrial made product.

Off to the beergarden now, have a nice weekend everyone


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## leon13 (Oct 4, 2012)

Gardengroove said:


> @ZorroSlinger: That's a good point you are asking. I am still figuring out where I got that one specific "big" dent from. I was cutting rubber, latex and leather only. Such a breakout does often occur when rolling over a pin for example. I read this a lot in terms of quilting forums. Next time I get to my buddy who has a lathe, I'll try to make something similar to those round sharpening thingies I posted in the main thread.
> 
> I am also by no means an sharpening expert, but since I managed to sharpen my blades on waterstones it is also a goal for me now to keep the rotary blades in their best condition. It would be really cool if we could manage to construct a relatively simple device, everybody can make with limited tools, in order to keep your blades in perfect condition. I know that those "jigs" and devices out on the market aren't that expensive, but that's not my point here. I always like it when you can achieve something by yourself without buying an industrial made product.
> 
> Off to the beergarden now, have a nice weekend everyone


have a "Mass" for me 2 ;-)


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## flipgun (Nov 14, 2012)

ZorroSlinger said:


> For those that regularly cut rubber latex, theraband & similar - I wonder if you use same blade to also cut leather or other materials? The other materials perhaps can accelerate blade wear? Maybe one dedicated cutter for rubber and another cutter for other materials. I don't know, as I am not a blade edging/sharperner expert and just a random thought


That is exactly what I do. Too dull for rubber is plenty sharp for leather.

"I am still figuring out where I got that one specific "big" dent from.

Very likely from running up the edge of your ruler.


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## leon13 (Oct 4, 2012)

flipgun said:


> ZorroSlinger said:
> 
> 
> > For those that regularly cut rubber latex, theraband & similar - I wonder if you use same blade to also cut leather or other materials? The other materials perhaps can accelerate blade wear? Maybe one dedicated cutter for rubber and another cutter for other materials. I don't know, as I am not a blade edging/sharperner expert and just a random thought
> ...


jip thats the way to go and @ the end its time for pizza cutter ;-) i did it and it works perfect


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## e~shot (Jun 3, 2010)

Wonderful work!


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## Gardengroove (Feb 13, 2012)

@flipgun: You reminded me, i was cutting some plastic scraps of some triangles...


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