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Tips & Techniques > Rotary Blade Sharpener - an easy fix [so it works again]

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Posted by: SewVeryTall

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Member since: 3/2/04
Reviews: 161 (tips: 68)
Skill level:Advanced
Favored by: 63 people
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Posted on: 8/29/07 6:46 AM
Review Rating: Helpful by 1 people   Very Helpful by 39 people   
Web site/URL: photo
Many of us have purchased the Tri-Sharp Rotary Blade Sharpener [see photo link above]. It works well on the first few blades sharpened, but then it wears out and doesn't seem to do the job anymore.

First, let me point out that this tool is ingeniously designed. The part of the tool that grinds the blade to sharpen it has the correct pitch or angle, so the blade is sharpened correctly. The handle that holds the blade is a wonderful design too, making it so the task can be done safely.

The problem is, in order for the manufacturer to make this tool inexpensively, they used sandpaper instead of a 'wet stone' for grinding the blade. A wet stone would last almost forever, but given the design and pitch needed for a circular blade, it would have made the tool way more expensive. Also, a tool that lasts forever doesn't make for repeat sales.

By using a wet/dry sandpaper, the tool can be made very very cheaply. Unfortunately, sandpaper of any type wears out quickly. This makes most people think this tool is a piece of junk. It's not! We just need to replace the sandpaper.

At first I thought we'd need self-adhesive aluminum oxide sandpaper, but I haven't found it in a sticky-backed. Here are the 3 things you need to fix this tool:

Wet or dry sandpaper, 400 grit [3M Imperial aluminum oxide is the best]. This is better than what the tool had originally. I found the package shown in the link above, at Walmart in the automotive department. It costs less than $3 and has 5 half sheets [which makes 85 replacements for a 28mm cutter!]. I also found it listed at Ebay.

Glue [even better, a glue stick...better yet, a temporary glue stick].

Small pointed scissors.

Trace the O-shaped sandpaper that's currently on your sharpener, and make a cardboard or template plastic pattern [something stiff enough to trace around].

Trace this pattern on the back side of the sandpaper, over and over [see main link above], then cut the shapes apart. It's important that the inside of the circle is cut big enough to slide easily over the sharpener's handle as shown here. The outside circle just needs to be big enough, and doesn't need to be cut perfectly.'s easiest to cut the inside circle first, while you have more paper to hold on to.

Remove the old black sandpaper on your should peel off easily. If it won't come off, just leave it and glue the new ring of sandpaper on top of it. Over time, as more and more layers of sandpaper accumulate, you may want to soak them all off in a basin of warm water. The tool is plastic, so soaking won't hurt it.

I left the old beige sandpaper on the other side, to now be used as the finer, finishing side. I'm not convinced that the use of this side is even necessary.

Voila, all fixed!

Rotary Sharpener Tips

The directions for this tool say to twist the blade a few times on each side of the blade. This really depends on how hard you push, and how dull your blade is. I twist the blade back and forth as I count, that way I know to count to the same amount after flipping the blade. A really dull blade may take to the count of 40 for each side. I think this is another reason many people thought this tool was no good...they didn't sharpen long enough.

A tiny drop of oil may be used with this sandpaper, so I've got an insulin syringe [ask a diabetic friend for one] filled with oil in my kit, for convenience. It's also good to give your rotary cutter a tiny drop of oil so it turns freely.

After sharpening, I test for sharpness on a scrap of fabric, while the blade is still in the sharpening handle. Use both hands to hold the tool's handle, and roll into the fabric about 1/4 turn. Reposition your hands and test the next 1/4 turn, etc., as shown here [except one hand is holding the camera ;)]. This way if it's not sharp enough, you know before putting the blade back in the rotary cutter's handle. Much easier to sharpen more, if needed.

Use a magnet to move the blade from cutter to handle and back, so you can't get cut shown here.

You may have noticed the red felt covered box I made for mine. That's how much I like this tool. I'll now have a place to keep the extra sandpaper O's I've cut out, so I'm ready to easily replace when necessary. This box has a unique Velcro closure as shown here. The staples really work!

Bonus Side Effect...when I was done cutting, my little craft scissors were so sharp! Apparently the cutting action through this sandpaper works the same as grinding a blade on it :)

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ibdeb said... (5/19/11 9:09 PM) Reply
I was able to follow your written instructions, however the links no longer work. Great tip as blades are getting more expensive. Thanks!
ibdeb said... (5/19/11 9:07 PM) Reply
I was able to follow your written instructions, however the links no longer work. Great tip as blades are getting more expensive. Thanks!
lady a said... (1/31/08 0:39 AM) Reply
this is a very economical tip. will try it tomorrow. thanks so much
ryansmumAria said... (11/18/07 8:11 AM) Reply
thanks for taking the time to educate us with a well written and thought out explanation. You have saved me a great deal of time trying to figure out how to replace the paper and which to use. I loved how the sharpener worked the first two times. after it stopped working I used an emery board to sharpen the blade which worked well but was a pain.
Sew What Teri said... (9/17/07 4:47 PM) Reply
I rigged up my cordless screw driver to spin the blade in the sharpener, this really helped.
Sanibelle said... (9/7/07 12:35 PM) Reply
Thank you so much for taking the time to write this up, Ardis!
Nancywin said... (9/7/07 1:20 AM) Reply
Thank you for the tip. I have been wanting to buy one of these sharpeners, but was discouraged after reading the reviews. Now I will have to go buy one!
misschris said... (9/3/07 7:05 AM) Reply
fabulous tip! I've been putting off buying one of these - going out tomorrow to get a sharpener and some sandpaper. Thanks!
pakrk said... (8/31/07 5:22 PM) Reply
Is there such a thing as a super-duper helpful rating?!! I'm definitely going to buy a sharpener now - I had always wondered if they were worth the price.
SewTwin said... (8/31/07 0:22 AM) Reply
Yea, saved those expensive blades.Couple cuts through denim, or fleece can really dull 'em. I love adhesive sandpaper for bottom of presser foot, or the bottom of rullers instead of the expensive dots.
dollieo said... (8/30/07 3:31 PM) Reply
Dito to what Kempcor wrote. I'm going to try this one. Simple and very inexpensive.Thank-you SewVeryTall.
cindyann said... (8/30/07 1:10 PM) Reply
What a fabulous tip!
Grammy Gin said... (8/30/07 11:10 AM) Reply
You are absolutely amazing, Ardis !! Thank you for helping us all save money on those very expensive blades.
Sewliz said... (8/30/07 8:11 AM) Reply
Brilliant! Thanks for all the detail.
NoraNora said... (8/30/07 8:02 AM) Reply
OMG...if there was a rating of super wonderful, extremely helpful I give it to your tip!!! Thanks for all the tips you've included and for helping make a so-so tool so very useful!
vasallese said... (8/30/07 7:33 AM) Reply
You gave very good written instructins. Thanks.
SusiM said... (8/30/07 0:38 AM) Reply
What an informative and very well-written tip! Thank you for taking the time to share your knowledge with the rest of us. This is very helpful to know.
DrFill said... (8/29/07 9:29 PM) Reply
Ardis, thank you for an extremely helpful tip! It is so well written, so thoroughly and clearly explained. I knew I'd been saving my old blades for something. Now when I exhaust my supply, I will be sure to buy one of these sharpeners and recycle them. Thanks again.
NanJones said... (8/29/07 8:22 PM) Reply
Thank you ever so much. I was really freaking out at having to buy blades all the time. I am buying one of these at the earliest opportunity.
Donna H said... (8/29/07 12:22 PM) Reply
Ardis, you're amazing! I have avoided buying this contraption because of the bad publicity it receives. Now, of course, I'll have to get one and do what you do to keep my blades sharp. Again, amazing!!! Thank you so much!
KempCorr said... (8/29/07 10:42 AM) Reply
Excellent tip - I'm always amazed at your creativity in the tips arena.
utz said... (8/29/07 7:08 AM) Reply
This is a great tip! You reverse engineered this sewing gizmo - made your own grindstones -and now you don't have to throw away perfectly good blades in need of sharpening. Love it! Thanks, I'll be doing this too.
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