Is this normal for diamond stones?

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Forum topic by nerdbot posted 03-29-2015 09:17 PM 1351 views 0 times favorited 6 replies Add to Favorites Watch
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97 posts in 2366 days

03-29-2015 09:17 PM

Topic tags/keywords: sharpening diamond stone

I have a couple cheap sets of bench chisels (HF and Craftsman). I had previously sharpened the HF set with my sandpaper setup – lapped the backs and honed by hand (because the cheap honing guide I had didn’t hold the chisels very well, even after I did the modifications suggested in the Lie-Nielsen Youtube video). I was actually surprised how well the HF set worked when sharpened, but it took so long for me to do the 5 HF chisel set that I held off on tuning up the Craftsman chisels, and just got back to making sawdust.

I just recently upgraded my sharpening setup from granite slab and sandpaper to a Veritas MKII and DMT diasharp diamond stones – the Extra Coarse, Fine, Extra Fine, and Extra Extra Fine set. I decided now was a good time to do the initial tune up on the Craftsman chisels, as well as regrind the bevel on the HF set to fit one of the settings on the MKII guide. I also sharpened 3 plane blades.

The tools sharpened fine, but what I noticed was that I was getting some pretty deep scratches in the stones themselves. I’ve read that these diamond stones require a small break in period, and also require a light touch. So, I’m not sure if either of those are the case here. I don’t think I was pressing down too hard, but I did apply about the same pressure as I did when I used sandpaper. I’ve attached pictures of the Extra Coarse, Fine, and Extra Extra Fine stones as those are the ones with the most pronounced scratching. So is this normal, am I doing something wrong, or should I contact DMT? Thanks!

Extra coarse:


Extra Extra Fine:

6 replies so far

View TheFridge's profile


10863 posts in 2491 days

#1 posted 03-29-2015 09:32 PM

Contact dmt. I got a coarse/ extra coarse double sided interrupted 8×3 for Christmas and wore it out in some HF chisels and lapping some plane irons. I sent them a courteous message noting my problems and how I foll the instructions and the next day they actually called me. I wasn’t expecting anything. They just told me to clean my stones with an abrasive cleaner and call them back if it didn’t work. Still have to call them.

Long story short, contact them and see what happens. It can do no harm.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View Don W's profile

Don W

19889 posts in 3572 days

#2 posted 03-29-2015 11:42 PM

I agree. Mine do not scratch like that.

-- - Collecting is an investment in the past, and the future.

View Tim's profile


3859 posts in 2966 days

#3 posted 03-29-2015 11:49 PM

I have eze-laps not DMT but that definitely doesn’t look right, so I agree with Fridge, calling can’t hurt. The diamonds are bonded to the steel base with nickel I think and your bonding looks to be getting damaged. There definitely is a break in period on these stones where the diamond particles that aren’t fully bonded wear off, but I don’t think it should do what you’re showing. Could you have transferred a lot of the extra grit from the extra course to the other stones by not wiping off your tools as you went from stone to stone? Again though, still don’t think it should do that.

View ElChe's profile


630 posts in 2341 days

#4 posted 03-30-2015 01:18 AM

I have imited experience with diamond stones. So this is a wild ass guess based on researching dmts and atomas. Could it be too much pressure combined with not using enough fluid? Paul Sellers uses window cleaner and i’ve read soapy water is also good. Sellers gives the stone a generous squirt of window cleaner in his video. I’ve also read that during a busy session it helps to clean them with soap and soft bristle brush to get rid of swarf. I am in the process of getting that same set of stones or aromas to try out Paul Sellers’ method so this post is interesting to me.

-- Tom - Measure twice cut once. Then measure again. Curse. Fudge.

View nerdbot's profile


97 posts in 2366 days

#5 posted 03-30-2015 05:53 AM


It may have been too much pressure, but I too use window cleaner after watching Paul Sellers videos. I kept the stones damp with window cleaner at all times, occasionally wiping it clean and reapplying more window cleaner. As I progressed through the grits, I would quickly wipe the chisel with a Scott shop towel (the blue kind). I also considered I might be transferring coarser grits, but didn’t think it could be that damaging. I even thought about having a separate wiping rag per stone to eliminate the possibility the rag was transferring particles. But, that felt a bit excessive since I’ve never seen anyone do that in sharpening videos I’ve watched…

When I saw scratches forming on the stones, I thought perhaps maybe the window cleaner was the problem so I stopped using it. I gave the stones a good scrubbing wth some abrasive cleaner (Bon Ami powder cleanser) and a nylon scrub brush and then finished sharpening my tools without any liquids. But scratches still occurred with the dry method as well.

Thanks everyone for the responses and sanity check – I’ll be contacting DMT in the morning.

View MrRon's profile


5990 posts in 4248 days

#6 posted 03-30-2015 11:23 PM

My guess is: the steel in your chisels is too soft and clogging the diamond surface. Diamond is used for very hard steels like high speed steel (HSS) and carbides. Softer materials will clog the stone.

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