Thread: DMT D8C 325 DISAPPOINMENT!

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.

What were you doing when you were lapping? Mainly, were you lapping under running water? If you let a slurry build up, it can rip the diamonds out of the nickel that bonds them to the surface, which leaves you with a steel plate. You can see the color change when this happens, and I am guessing that may be what happened.

Always lap under running water. Never let a slurry build (rinse the DMT and the hone you are lapping periodically). I clean my DMT after each lapping so I don't get grit contamination; usually rubbing it under running water with my hand works, but scotch brite or similar also works.

I have the same D8C 325, bought in December 2010, so 2 months , I lapped
a Swaty hone and a coticule, and maybe honed 3 razors at all. Half of the plate is now smoth like not a diamond is there. I will try to talk with DMT to see if they have some kind of warranty on them. I also clean the plate as per DMT . I think , despite they indications, for lapping stones you need a 220 or even less grit.Or just this batch went wrong?
Regards
Livio

Originally Posted by livio

I have the same D8C 325, bought in December 2010, so 2 months , I lapped
a Swaty hone and a coticule, and maybe honed 3 razors at all. Half of the plate is now smoth like not a diamond is there. I will try to talk with DMT to see if they have some kind of warranty on them. I also clean the plate as per DMT . I think , despite they indications, for lapping stones you need a 220 or even less grit.Or just this batch went wrong?
Regards
Livio

Does it still cut? My guess is that you only broke the hone in, and there isn't any problem with it.

Yes is still cut, but just about 3/4 of the plate. And on the sides the color is changing, it can't be cleaned anymore. You can feel with your fingers,
on one side still have the diamonds and one side is just metal.
I think this one was for learning, next one it will be for really working.
It may be becuse the slurry on the hones wash away the diamonds,I don't really know, but for sure in not about breaking in .
Thank you
Livio

Give them a call. Here is the webpage with their contact info. IME dia sharp (DMT) has real good customer service and if the problem is the plate's material or workmanship they'll give you a new plate.

You know I really hate to post this on the open forum because somebody will say it is wrong

You have to trust the numbers behind this statement OK???

You guys either have the worst DMT's ever made, or you did something terribly wrong...

1. Small rule, never lap a stone that is lower then double the grit rating of the plate...

2. clean the plates, I use Comet/Ajax and a stiff nylon brush

3. I have honestly lapped hundreds of Barber's hones on my DMT 120 and 325 and I don't even want to count how much lapping has been done besides that on my 325...

Clean the plates, check the plates for diamonds with a piece of Glass, see if you actually ripped the diamonds out, I doubt it, but it is possible...

Then follow Jimmy's advice above

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.