Thread: Used DMTs

I have found some used DMTs for pretty cheap and I was wondering how well they wore. Would it be worth $15 each for them? I have a choice of 120, 220, 325 and, 1200. the 1200 is in a smaller 6inch size and I have emailed the seller about the sizes of the other ones. Since a new DMT D8C is $54 I'm hoping these are usable for me. I can get multiples for cheap. 120 seems too rough but the other 3 grits interest me.

Well firstly we (per forum rules) cannot provide values. Secondly without photos it would be impossible to tell you how worn they are or whether they are too damaged to he usable.

120 is not too coarse for lapping and many of us get away with only lapping to that. Secondly I know where you saw these used DMT's but only you can make that choice on if it's worth it or not. For that price you're not out much if they aren't good but contact the seller and ask about refunds..

Worst case you have something to tape your sandpaper too..

I was asking less about the value and more about any experiance on how well they held up over extended periods of time and use. I guess I wasn't too clear on that.

Originally Posted by S0LITARYS0LDIER

120 is not too coarse for lapping and many of us get away with only lapping to that. Secondly I know where you saw these used DMT's but only you can make that choice on if it's worth it or not. For that price you're not out much if they aren't good but contact the seller and ask about refunds..

Worst case you have something to tape your sandpaper too..

The seller is a great guy to deal with so I'm sure something could be worked out if it was overly worn. I just wanted to know roughly how well they usually held up so I could base its lifespan with me on something. I've only ever heard of DMTs wearing out when people abuse them butnI wanted more people's opinions before I made a decision.

Originally Posted by DduckyMark

The seller is a great guy to deal with so I'm sure something could be worked out if it was overly worn. I just wanted to know roughly how well they usually held up so I could base its lifespan with me on something. I've only ever heard of DMTs wearing out when people abuse them butnI wanted more people's opinions before I made a decision.

I used to abuse my lapping plate by lapping low grit sic with pressure, some diamonds ripped out but it still flattens wonderfully and will continue to do so for years.

Skipping over what is abuse and what is not, how long they last depends on what they're used for. It they were used to sharpen chisels, plane blades, lawnmower blades, machetes.....you get my drift...not indefinitely. Used properly to lap Naniwas or similar, they'd last a LONG time. Whether those grits are suitable for that purpose is outside of my expertise.

I have the 120 and have used it to lap very tough stones. I find it leaves too much scratching for my liking so I rarely use it anymore. Still would rather have it if in case I need it. The 325 is the workhorse for lapping stones, and for sharpening kitchen knives. Personally I would have no use for any plate but the 8".

I have a 600 that is only used for bevel correction on straights, and that rarely. A 1200 and a '8k' that I use for bevel setting on tougher steels like AS-34, S30V. So if all you want to do is flatten stones, go for the 120, and the 325. I don't sharpen tools, so depending on use, you might want all the guy has.

DMT recommends no lapping of hones on any plate finer than 325, and that under running water.

I've been flattening stones and occasionally sharpening kitchen knives with that 325 for 8 years. Still works, but not as well as it did years ago. I also have a different 325 that has been used alternately, so that may have contributed to the longevity of my D8C.

I do quite a bit of lapping. I use the DMT lapping plates. They stand up pretty well. They need a good scrub periodically with soft scrub and a stiff nail brush and they spring right back. Without having them in hand and trying to clean them or use them it is impossible to tell.

OK, I'll take the counterpoint.

Diamonds are hard, but the nickel holding them are not. Honing steel on the plates gradually wears out the diamonds but lapping hones wrong quickly can undercut the nickel, causing the release of the diamonds. There have been many threads about this exact thing happening, so it is not uncommon for these plates to get trashed by misuse. If you treat them well they will last for a long time, but you have to wonder how many of the used ones up for sale were treated well.

Caveat emptor.