3M Abrasive film for sharpening

[Rob Luter]

First off - Not intending to launch another full on sharpening thread here. There are plenty of those to search (and I have).

I've used 3M abrasive film on glass blocks for about 10 years. If starting from scratch, I grind a hollow with a low speed grinder, or if the primary isn't too bad I refresh it with a coarse diamond stone to pull a wire edge. I then cycle through the five film grits from 40 to 15 to 5 to 1 and to .3 microns, with a few strokes on each. If in maintenance mode I just use the film on blocks as appropriate for what I need to touch up. I flatten backs on the film as well. In general the results are quite good and especially so with fresh film. I recently refreshed all my film and it was a stark reminder of how much it wears over time. When new it cuts fast, even my A2 and PM-V11 tools. After a while, not so much.

I'm thinking of adding a water stone or two as a replacement for or a supplement to the film. I like the idea of the "spritz only" stones like Shapton and Ohishi as I don't have a sink at my sharpening station and would rather not keep them in a tub of water.

Any Creekers out there that have made this specific transition, from film to stones? If so, how often are you needing to flatten the stones as compared to how often you were changing film? It's been suggested that two or three grits would be more than adequate, perhaps a 6K and 10K to supplement my coarser diamond.

Thanks in advance for any feedback.

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[Lawrence Burkett]

There's not really a correlation between changing film and flattening. The need to flatten will vary a lot depending on what you've been sharpening (wide blades without camber won't dish a stone as readily as narrow chisel), how you sharpen (do you work the full surface of the stone or just grind in the center), and the stones you're using (for example, Shapton glass stones won't dish easily but a King clay stone will).

Personally, I use the Naniwa Chosera (now called Professional) and flatten them at least every time I use them. It's a trivial amount of work - about 10 seconds or less with a diamond plate.

[Erich Weidner]

I like the idea of the "spritz only" stones like Shapton and Ohishi as I don't have a sink at my sharpening station and would rather not keep them in a tub of water.

I've only ever used King stones and now Ohishi. I know the Ohishi are not supposed to need soaking... but I do soak. Just tried doing spritzing only the other day and the water is gone almost instantly. I didn't like the feel of them without soaking first. (Granted a 5-10 minute soak seems to work fine.)

Take my comments with a massive grain of salt. I've only recently progressed from Raw Beginner to Beginner phase. (I gave myself a promotion).

[Andrew Pitonyak]

I used to use sandpaper, which I expect to not last as long as diamond film. Ultimately, it was much cheaper to move to water stones. I started with stones that you soak, but I really do not like the mess so I moved to Shapton. I have both their pro line and their glass stones.

Like you I hollow grind (on a Tormek) and I rarely need to flatten my stones. Before I used a hollow grind, I had to flatten much more often. I like that I can simply spray some water onto the stone and get to work. Highly recommended. The biggest question is what stones you want or need.

First question is usually (assuming Shapton) is, "Pro stones or Glass stones"?
The Pro line is special in that each stone is formulated for a specific task. Jende Industries has a blog about it, but I don't have the link and I don't think I can link to their blog from here anyway... I can post a list of what they expected you to do with each stone if anyone really cares, I have notes.

THe Glass series is considered softer and it releases the abrasive faster (so they cut faster) than the pro stones. Oddly, the glass stones are denser, but they wear faster (and cut faster) so they are called "softer". The glass stones were made to sharpen very hard and highly alloyed steel such as high end wood working chisels. The glass stones have added a "high carbon" or HC version, which is related to certain hard Japanese knives and they usually say something like "if your knife sharpens poorly on the regular glass stone, get the HC version", or similar. You probably do not need or want the HC version. I think they refer to the standard glass series as HR for High Resistance, but I would need to look back at my notes to verify that. Note that the HC versions will probably work worse on things like PMV-11 because the super hard HC Japanese knives do not apparently have the abrasion resistance; or so I am told.

I also have a chart that suggests which glass stones work best with which thing you are sharpening; for example, Japanese Chef knife, western chef knife, Knife, Japanese Planes, western planes, chisels, scissors, or straight razor. Ignoring the scissors or straight razor, the 500, 1000, 2000, and 3000 were listed as excellent for all of these. The 4000, 6000, and 8000 are listed as excellent or good for all of these. The 16000 is recommended against for the Japanese Plane and for chisels. The 30000 they recommend against chisels.

Initially I only owned the Pro 5K and the glass 16K, so, I went right to the 5K for touch up or after my Tormek. At the moment, I own glass stones 2K, 4K, 16K, and 6K as well as the 5K and 8K PRO.

For woodworking I would avoid the HC versions, and I would then make a decision based on cost or availability.

I took a quick look at WoodCraft to check prices and I saw 2K=$60, 3K=$67, 500=$50, 8K=$95, 1K=$55, 4K=$68 and the 16K is on sale for $100.

Will be interested what you choose to do. if you are near Columbus Ohio, stop in and give some of them a try.

[Will Blick]

IF you dont mind spending the few extra dollars on the glass and sandpaper, then stay with it...
its always flat, that is the beauty.... its fast! less fuss.
if you dont sharpen a ton, stones IMO are more hassle...
I used both, but settle on stones, as I sharpen a lot...
to answer your question, for stones to be really effective...
they must be FLAT... so nearly ever use (or maybe two) a quick flattening is required... put pencil marks on the stone and flatten till pencil marks are gone.
then, as always, the flattening stone needs to be flattened about every 10 uses on a Granite stone with sandpaper on it, or glass of course. So as always, a FLAT reference is the key regardless of which method you use.
YOU can use diamond stones as well for flattening, as they have a flat base, but IMO, they dont last long and can get quite expensive vs. sand paper and granite plate.

the primary benefit of the stones, they are way more cost effective, they LAST!
A great alternative is cutting up MDF and using diamond paste, prob. the mid point between the two... the paste is more cost effective if you buy it cheap on ebay and MDF is flat in the sizes you cut it to, and is very cheap if purchased and cut down from large sheets...

[Andrew Pitonyak]

My shapton stones rarely go out of flat and there is no soaking; spray and go. The Spyderco ceramic stones can be a lot of work to get flat (if they are not flat when you get them) but they stay flat for a very very long time. My Arkansas stones stay pretty flat :-)

[Jim Matthews]

It's just my opinion : the messier stones produce results that differ from what you already have.

That implies faster wear (the slurry paste comes off the top) and more frequent flattening.

You can split the difference with Atoma plates, particularly for coarse work.

Polishing (lapping) with fine diamond paste can be accomplished on finished cast iron or flat milled steel.

[ken hatch]

Guys,

There is one in every crowd, it might as well be me.

A nice set of Arkansas stones are cheap, last your life time, and are zero hassle to use.

ken

[Andrew Pitonyak]

Guys,

There is one in every crowd, it might as well be me.

A nice set of Arkansas stones are cheap, last your life time, and are zero hassle to use.

ken

And they stay flat unless you are very creative (in a bad way).

[Christopher L Everett]

Guys,

There is one in every crowd, it might as well be me.

A nice set of Arkansas stones are cheap, last your life time, and are zero hassle to use.

ken

Down side is they won’t touch A2, and are pretty slow on thick O2 blades too.

So I don’t have any A2 or thick O2 irons.

[Jim Koepke]

Down side is they won’t touch A2, and are pretty slow on thick O2 blades too.

So I don’t have any A2 or thick O2 irons.

The upside is the set up quickly and do not get gouged by an errant stroke of a blade.

Another downside is the softer oilstones are more work to flatten when needed.

jtk