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Diamond files on the cheap

post #1 of 7
Thread Starter 

My apologies if this has already been covered (I searched but didn't find anything) but I wanted to communicate a way of obtaining reasonable-quality diamond files at a very low price.


Most diamond files consist of an adhesive-backed strip of diamond abrasive tape attached to a plastic or metal carrier. This is true of Moonflex, SVST, Swix, Tools4Boards and Icecut at a minimum. The only major exception that I'm aware of is DMT, which embeds their diamonds into metal strip and bonds that to a plastic carrier. The SVST files in particular use 3M DiamondFlex PSA-backed tape (


My personal workflow for some time has been to use Moonflex stones in a 5-grit progression (100-200-400-600-1500) for my racing skis, and the SVST stones in a 4-grit progression (120-220-400-600) for everything else. I only use the 100/120 stones if I need to take down case-hardened edge sections or if I'm using the diamonds to actually sharpen the edge (I usually sharpen by filing and then use the diamonds to polish out striations/burrs).


I recently was in the market for replacement diamond tape for my SVST files, and on a lark I did a fairly broad search for retailers selling the 3M-branded DiamondFlex tape as opposed to the SVST-branded tape. The 3M tape turns out to be widely used for jewelry-making and is available for remarkably low prices. For example Rio Grande sells a kit containing 7" long strips of all 4 grits for $17-19 (depending on qty) or individual grits for $6-7 each. FDJ Tool sells individual strips for $5-6. See:


The 3M-branded strips have slightly different grit ratings than the SVST ones (120-280-400-800 vs. 120-220-400-600) but they actually appear to be identical even under microscopic examination. I've been using 3M strips cut down to 4" as replacement strips for SVST files (which I bought from SlideWright - highly recommended) and also to make 7" "cheapo files" by laminating them to aluminum bar stock. I haven't seen any substantive difference in quality of results vs the SVST-banded tape. The jury is still out on longevity, though the 3M strips have already lasted long enough to be clearly more cost-effective than the SVST tape.


I still use Moonflex on my racing skis, but I've now completely switched over to 3M tape for everything else.


I've also started experimenting with the 3M MicroFinish strips (aluminum oxide on PSA-backed polyester base) for final polishing.


They seem to work quite well, and are priced low enough ($0.60 per 7" strip or so) to be treated as consumables. This is a significant time saver as it eliminates the need to clean metal filings out of polishing stones and/or lap them on drywall screens to remove scoring. The polyester backing of the strips also seems to be more resistant to scoring than some of the softer ceramic stones. I'm continuing to use the SVST T2 and Al-oxide stones on my race skis for the time being, though.

post #2 of 7

Interesting my only concern would be how flat the tape really is...

post #3 of 7

Good information.  Considering Moonflex and DMT use a plastic backing, I'd expect aluminum bar stock to be no worse.  One can always lap the bar stock dead flat beforehand.

post #4 of 7

Thanks for the info.  It should be easy to find milled strips of plastic or metal to adhere that tape to. 

post #5 of 7
Thread Starter 
Originally Posted by jzamp View Post

Interesting my only concern would be how flat the tape really is...

The tape itself is flexible, and you create a flat file by bonding it (via pressure sensitive adhesive) to a rigid substrate. Flatness therefore comes down to 3 things:


1. Is the tape of uniform thickness?

2. Is the tape compressible (i.e. can you change its thickness via pressure)?

3. Is the substrate rigid and flat?


Both aluminum bar stock and the milled-aluminum SVST file blanks are perfectly flat and very rigid, so (3) is covered.


I was originally trained as a mechanical engineer, and based on informal measurements (comparison to true bar along various axes etc) I think that the tape has uniform thickness, so I think (1) is OK.


I think that the tape *is* very slightly compressible, but if you're putting enough pressure on a diamond file for that to matter then you're using it incorrectly to begin with. I therefore think that (2) is OK in "normal" use. Excessive pressure causes scoring and resultant edge-dulling with ceramic stones, so this isn't a limitation that's unique to diamond tape.


It's also worth noting that everybody in the market except DMT uses similar tapes (and SVST seems to use the exact same tape), so if flatness were really an issue they I expect that there would be a lot of complaining. The Moonflex stones use a fairly flexible plastic substrate and are considered the benchmark even though they aren't as flat as some others (unless you get the Maplus version that bonds Moonflex tape to an aluminum blank)


I *do* think that the Moonflex files produce slightly better results at any given grit. I suspect that this comes down to a more uniform surface texture (better uniformity on the scale of individual diamonds, leading to less striations) and maybe their funky diamond/void layout. Of course the Moonflex files also cost ~6X as much, which is why I only use them on my racing skis.

post #6 of 7
Thread Starter 
Originally Posted by Xela View Post

Good information.  Considering Moonflex and DMT use a plastic backing, I'd expect aluminum bar stock to be no worse.  One can always lap the bar stock dead flat beforehand.

Yep, that's exactly what I did for my "cheapo files" - I put a piece of SiC paper on glass and then lapped the bar stock using that.

post #7 of 7


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