DMT Diamond Stones - Which grade is best for sharpening Scrapers?

[Theo Hall]

Hello all
I currently use a Bastard grade file and a 1,000 grit Japanese Waterstone to sharpen my cabinet scrapers. I use the Brian Boggs method for sharpening them (Bastard file>1,000 waterstone>burnisher).
However, I am getting sick of scrapers digging into my Waterstone, and I have decided to buy a DMT Diamond stone to do this with instead.

Which grade of DMT Diamond stone would be the best for scraper sharpening; Fine (600 mesh, 25 micron), or Extra Fine (1200 mesh, 9 micron)?
Which would be the closest equivalent to my 1,000 stone? I am really happy with how that works, so I am looking for a similar stone but in Diamond form.

Bear in mind I use the Bastard file first, so I need something that will take those marks off and give me a nice polished edge.

Any advice would be very helpful
Thank you

[Dan Hahr]

I use a basic 2x6 fine stone for all my sharpening. It works fine. However, I have just used a smooth file and had perfectly good results.. Hold it at a skew angle and make sure the scraper is clamped well in a vise. If you can afford it, get the double sided DMT professional grade stone. They are about 2.5 by 8 and very nice.

Dan

[Andrew Seemann]

If you haven't tried it yet, try using the scraper without stoning it, just the file. Unless you need it extra fine for scraping finish, you may find you don't need to hit the stone. Lots of folks go straight from the file to the burnisher, myself included.

[Wayne Lomman]

Throw out the bastard file. It's the wrong tool for the job no matter whose method. Use a smooth file instead and you won't need the stone, just the burnisher. The method you are using is making work for nothing while damaging your stones. Cheers

[Robert Engel]

Theo,


Not familiar with the Boggs method, but his technique may be related to his methods of work. I am quite confident in saying you do not need to use a file every time you set up your scraper. I file the edge to flatten it maybe once every 10 sessions and I use a mild smooth file.

IMO it is imperative to hone prior to burnishing. The hook left by a file is extremely coarse & the purpose of a scraper is kind of defeated IMO.

I also use both diamond & waterstones (typically 1250 diamond -> 4K -> 8K ). Keeping the scraper skewed prevents digging in. Use a block of wood to keep the card square.

For a fresh perspective, take a look at William Ng's card sharpening video. IMO he has the best one out there.

[John C Cox]

I have used my 1200 grit Extra-fine DMT to very good effect on card scrapers. Micron wise - it's in the range of a 3000-4000 (tel:3000-4000) water stone. I typically file my card scrapers.. But you do occasionally need to hone the burrs off and start fresh... I was really happy with the edge I got off the extra fine DMT....

Their 600 grit "fine" stone has approximately the micron size of a typical 1000-2000 water stone.. It's diamond, so it cuts a lot "harder"...

One thing... I recently bought a new DMT to replace my 10 year old extra fine which has some miles on it.... The new stone was really coarse and scratchy. DMT thought that perhaps the nickle plating bath had gotten a bit of contamination and recommended I give the new stone a quick lapping with the old stone. I did and the new one now works like it is supposed to.. They did offer to replace the stone but I decided to try this first before sending it back. The extra fine does leave a very shiny finish...

One thing I ran into with my files... They don't last forever... And my good 6" single cut fine flat file is now dull and does not produce a good edge on a card scraper anymore... It's a fact of life and I will be buying a new one...

[Theo Hall]

Thank you all for your advice so far, I'm certainly going to change my file now, to a Single cut smooth file.

Any further recommendations re. the DMT stone? Do you of you use a DMT Diamond stone in fine or extra fine for scraper sharpening, and which works best?
Thanks

[Patrick Chase]

Hello all
I currently use a Bastard grade file and a 1,000 grit Japanese Waterstone to sharpen my cabinet scrapers. I use the Brian Boggs method for sharpening them (Bastard file>1,000 waterstone>burnisher).
However, I am getting sick of scrapers digging into my Waterstone, and I have decided to buy a DMT Diamond stone to do this with instead.

That seems like gross overkill to me. Scrapers are tempered to ~Rc50. In order to avoid grooving you simply need a honing medium with a hard binder. Obvious candidates include Arks, India stones, Spyderco stones, etc.

As others have said, a bastard file is the wrong tool for the job, unless you're rehabilitating a heavily damaged scraper and need to blast off a bunch of edge material in a hurry.

[Todd Stock]

- Coarse, bastard, second cut, and smooth...describes an American pattern file's coarseness of cut (as opposed to Swiss Pattern's 00 to 6)

- Single cut, double cut...describes the number of sets of parallel rows of teeth on the faces of the file (we want the plane-like action of the single cut file for the job)

- Mill, flat, hand...the mill file is an American-pattern rectangular file which is always single cut on both faces and both edges and tapers in width (but usually not thickness). Flat files and hand files are similar looking to the mill file (different taper, etc.), but may be single or double cut...so the shorthand for a single cut file of the preferred configuration for a general smoothing tool is a mill file, with a smooth mill having the finest finish off the tool. Yes - a single cut flat or hand file will do the same job, but don't expect them to be found outside of specialty machinist suppliers or Ebay with any regularity.

So a smooth mill file is used for cabinet scrapers and other jobs requiring a smoother finish. I suspect mill bastards are used on a frequent basis these days because that's what is carried most often in the big box stores, and the coarser finish just means more work on a stone as compared to a smooth cut mill file. I'll stone a cabinet scraper when the finish will be used off the scraper (as well as for blades used in a scraper holder or plane), but for lots of jobs we do (e.g., leveling CA'd binding and purfling prior to blocking a body level; knocking the glue off a panel glue-up), the edge off a mill bastard is acceptable, and saves a bit of time.

If I am stoning a scraper, my 40 year old Norton large India combo stone works well. I have the 10" XC/C and F/EF DuoSharps, but not my first or even second choice for a final scraper edge...just too coarse a stone. I know the fine India should give a coarser edge versus the 1200 EF diamond, but it does not...go figure.

[lowell holmes]

I have a diamond stone that I hone my chisels with. I also have a rawhide glued to wood and charged with green stropping compound that I follow up with.
I got the compound at Homestead Heritage in Waco Texas while Pal Sellers was there.