Thread: DMT D8C 325 DISAPPOINMENT!

I agree with Glen. You can choose to believe me or not. I have four DMT's including the D8xx and D8c. I"ve used the D8C countless times, lapped hundreds of Coticules, and hundreds of C12k slurries. It still works great. Yes, it is smooth, but it works, it's broken in. As Dylan pointed out, I always do so under running water. It has no build up. I clean it after each use. Works fine, lasts a long time....

I did not put a lot of pressure. The Swaty take about 1 hour both faces,and coticule 45 min . It was done under running water.
Livio

I have had absolutely no problem with any of my DMTs. I have 8" Coarse, 8" fine, 8" extra fine and 8" extra extra fine. With the 325 I sharpen everything from my axes, to damaged knives, initial bevel setting on used chisels, and everything else in between. I've had them for over 2 years and they still cut like they were new.

Don't give up on DMTs, they can take a joke and are the best lapping stone I've used. Your plate is not ruined. I agree that the continuous-surface 8 x 3" plates do load up during lapping, and can be difficult to clean. The best cleaning method I've found is Barkeeper's Friend liquid, and my fingertips, repeatedly rubbing and rinsing under running water.

Some time back, I switched to using the continuous surface plates for razor honing only, and now use only a big perforated Duo-Sharp plate for lapping (coarse on one side, extra-coarse on the other). The perforated surface really seems to avoid loading up when lapping under running water, and cleaning is far easier because they don't load up in the first place. They can really remove material in a hurry with pressure, but leave little surface scratching when used with light pressure.

I use the big 10 X 4" Duo-Sharp like the one pictured below. They've gotten a little pricey now, but I lucked out and got mine on sale for only $20 more than a regular 8 x 3 plate over a year ago. The big 10 X 4 size really helps. I do x-coarse, then coarse, then move up through 600 grit and 1000 grit wet/dry sandpaper, the sheets laid right on top of the big Duo-Sharp as a base. Works beautifully.

I'm pretty sure the only thing DMT recommends for a lapping plate is the extra coarse.

I think I've gouged out some of the diamonds in a 1cm strip along one of the short edges - there is something very shiny peeking through and it develops rust spots there if I leave it to dry propped with that side down, so I'd say it's the steel backing. I attribute that to user error, I've probably lapped around 10 barbers hones on it, three sides of a chinese, and a dozens of belgians, thuringians, nortons, naniwas.... I am sure I can lap at least a dozen more barber hones on it, but since my honing interests have changed, I can't forsee lapping anything but the naniwa supers, so that dmt is definitely more than enough for the rest of my life.

I've always used the comet/ajax (whatever I have at the moment) to clean up the steel of my DMTs and that works really well. I don't bother with detergents after lapping though - most of the mud goes down the drain and any leftovers don't affect the honing and go away next time anyways.

I always wondered about those perforated plates. I have a continous and it's been weird since I've used it to lap. I take it from what you are saying, they're good for lapping, but not for razors?

Thanks

Originally Posted by FatboySlim

Don't give up on DMTs, they can take a joke and are the best lapping stone I've used. Your plate is not ruined. I agree that the continuous-surface 8 x 3" plates do load up during lapping, and can be difficult to clean. The best cleaning method I've found is Barkeeper's Friend liquid, and my fingertips, repeatedly rubbing and rinsing under running water.

Some time back, I switched to using the continuous surface plates for razor honing only, and now use only a big perforated Duo-Sharp plate for lapping (coarse on one side, extra-coarse on the other). The perforated surface really seems to avoid loading up when lapping under running water, and cleaning is far easier because they don't load up in the first place. They can really remove material in a hurry with pressure, but leave little surface scratching when used with light pressure.

I use the big 10 X 4" Duo-Sharp like the one pictured below. They've gotten a little pricey now, but I lucked out and got mine on sale for only $20 more than a regular 8 x 3 plate over a year ago. The big 10 X 4 size really helps. I do x-coarse, then coarse, then move up through 600 grit and 1000 grit wet/dry sandpaper, the sheets laid right on top of the big Duo-Sharp as a base. Works beautifully.

Originally Posted by Zomax

After following all of the pros and cons of different flattening stones on this board, I decided to try the ever popular D8C.
Got and went to work on a few bad blades. It did good. Then tried lapping my JNat and Nortons and before long, the D8C was smooth as smooth as my strop. Cleaning it is also a bear. The thing developed a black shadow around the middle of the hone and I took for granted it was metal from honing some blades. I tried everything I could think of to clean it. But the bottom line is, I don't know how a diamond hone could get so smooth after just a couple weeks. It's like honing on a Norton 8000. Can anyone give me the scoop of what I've dome wrong? I do clean after each use by the way. All comments and suggestions welcome.

This is why the only DMT that should be used for lapping is the DMTXXC all others are just a waste of time and money when it comes to lapping and offer no benefit.

Excellent thread!

I just purchased a set of DMT's, 125-8000, that includes 2 of the 11" 220 grit. The 220 will be the main hone lapping plates. I had considered the perforated surface version and will probably purchase 2 of those as well in the 220 grit if they are available.
I had tried the 125 grit loaned to me from Bruce but I did not like the very deep scratches it created so I settled on the 220 grit.

A number of years ago I purchased a 400 grit & 1200 grit EZE Lap diamond hone set and learned that they get destroyed by lapping hones on them.

Frankly, the next thing I will have is a cast iron machinists lapping plate to do those jobs.

Originally Posted by pelicano

I always wondered about those perforated plates. I have a continous and it's been weird since I've used it to lap. I take it from what you are saying, they're good for lapping, but not for razors?

Thanks

To be honest, I don't really know if the perforated plate should only be used for lapping, and continuous plate only for razors. But that's how it's shaken out for me trying both. The perforated plate is just less hassle and more effective for lapping in my experience.

I've lapped a number of stones with a coarse continuous plate, but I've never put a razor on my coarse perforated plate at the same grit. I'm pretty sure it would work fine, but something about running a razor's edge (even a damaged razor) across a perforated diamond plate just gives me the willies.

Originally Posted by FatboySlim

To be honest, I don't really know if the perforated plate should only be used for lapping, and continuous plate only for razors. But that's how it's shaken out for me trying both. The perforated plate is just less hassle and more effective for lapping in my experience.

I've lapped a number of stones with a coarse continuous plate, but I've never put a razor on my coarse perforated plate at the same grit. I'm pretty sure it would work fine, but something about running a razor's edge (even a damaged razor) across a perforated diamond plate just gives me the willies.

If your perforated plate is well broken in it is okay for damaged razors. I tried and was able to take out a few chips from a couple of blades I did not care about. I agree the continuous plates are better for blades, but the others do work. And, yes, it feels creepy the first time you try it.

My DMT 325 is gray and grungy but still works just fine. I have a DMT 1200 for bevel setting that I like and alternate between that and a couple of 1K stones.