DMT Extra Fine - Coating is peeling off

[Strokes77]

I'm curious if anyone else has seen this or had this happen.  I was under the impression these were relatively indestructible and long lasting.

I have the P.S. sharpening setup of course, fine, extra fine DMT diamond stones.  I leave them on the bench, and freehand sharpen quite often.  Had the stones about a year and a half.

The extra fine has 3 spots where the diamond coating is peeling off.  One spot on the very far left of the stone on the business end of the ruler trick, and another 2 spots about in the middle of the stone.  Noticed it about 4 months ago, they are slowly growing.

I contacted the company, and they are offering an exchange.  It has taken over 2 months, and we are still corresponding back and forth, I believe they will eventually send me a new one, but haven't yet.


Has anyone else seen this kind of damage from a very gentle use diamond stone, in this period of time?

[Adnick]

Have a new (3 months old)Trend and the 1000 is doing the same thing....

Andy

[JimReed@Tallahassee]

I had some nice diamond stones a while back. They were fast cutting but one day I got too aggressive with a chisel and scraped all the diamonds off. So I went back to sandpaper. I think diamond stones have a small envelope of effectiveness that ham fisted me never figured out.

[Timberwolf]

I had some nice diamond stones a while back. They were fast cutting but one day I got too aggressive with a chisel and scraped all the diamonds off. So I went back to sandpaper. I think diamond stones have a small envelope of effectiveness that ham fisted me never figured out.

.............................
Most of the ones I have are made primarily for woodworking...The diamond is electroplated onto to the surface in a thin application..I have a couple of small ones made for machine shop use and they are "sintered" onto the surface in a much thicker application..Unfortunately, they are much more expensive.

[Mike Brady]

Contrary to the OP statement about the durability of diamond lapping plates,  they are probably to worst of all sharpening media, other than sandpaper, at holding their designed grade of aggressiveness.  Too bad they don't use the coating that is applied to the DMT Dia-Flat on all of the various grades of diamond plates.

[bridger]

other than one disc made in china for glass grinding which popped off a bit of the diamond after I abused it vigorously by grinding tool steel with it, all of my bonded diamond tooling has held up very well.

[Bill Holt]

This is a very interesting post.  Some time ago I bought a set of three diamond "stones" where I was taking a woodworking course.  I was very impressed at first.  After I realized they had lost their effectiveness, I remembered the instructor saying not to apply heavy pressure.  I'm pretty sure they were Chinese knock offs.  A few years later a demonstrator at one of the Wood Working Shows told me the Easy Wood cutters could be re-sharpened...but...not on just any diamond cutter.  He suggested I go on line and order the Trend 3000/10000 combination.  There is a world of difference!!!!  Sometimes I forget and get a little heavy handed but the Trend has shown no signs of wear.  It may be true "you get what you pay for".

[Adnick]

It's my Trend 300/1000 that's coming apart on the 1000 side.....it works great, tool bad it's failing...


Andy