Thread: Is this DMT big enough

Hi

I have a Norton DMT 600 mesh 25 micron fine. It's 6"x2". Is it large enough and the right grit to lap a Norton 4k/8k 8"x3".

I have read somewhere that a DMT dosen't have to be lapped, is that right?.

Thanks

I have a 6"x2" diamond plate I bought 10+ years ago that's probably 220 grit. I've used it to do initial aggressive lapping on barber hones and other stones since I feel I can apply way more pressure and be way more aggressive with it (great workout for the arms and pectorals) than I ever would with my Shapton GDLP. The problem with my small plate is that the ends where the plate was cross cut at the factory really took a long time to be "knocked down". They had hefty burrs that scratched like crazy.

It's a good size for barber hones which are smaller and for small natural stones. IMO it's too small to effectively lap 8"x3" stones. I'm sure you could try and probably do a decent enough job to get decent results. 600 grit is a bit fine for a lapping plate, so it will take you longer to lap.

Regarding the DMT being lapped. The short answer is no, they don't have to be lapped. A bit longer answer is that they don't have to be lapped because you couldn't if you tried.

Chris L

For touching up an already lapped stone, it's OK but not the best. For an initial lapping, I think that a larger DMT would do a better job.

Originally Posted by kelbro

For touching up an already lapped stone, it's OK but not the best. For an initial lapping, I think that a larger DMT would do a better job.

A larger hone won't "do a better job", but it will make it easier. That being said, you could use what you have to lap anything you'd need without problems as long as you give all areas of the stone to be lapped equal time and use pencil marks to make sure it's flat.

On top of what the others said so far: if you are starting out, then experiment with what you have.

I think it'll work, though depending on which stone you lap, it'll cost you some elbow grease.
And if it is smaller than the stone you are trying to lap, the resulting flatness will not be as exact as the flatness you get when using a bigger lapping plate.

A 600 grit 6x2 is not what I'd use if a stone has not yet been lapped before.
But otoh, it'll work, it won't cost you anything, and you won't damage any of the stones you are lapping so go ahead and give it a go.

using a true straightedge, as you need when lapping two non flat stones together, taking off the high spots first would probably help in your case as well.

Your 6x2 should work ok. Just lay the Norton down and use the DMT at a 45 degree angle so that the entire 3" width of the Norton is covered. It will not be "perfect" in the strictest sense but it should do the job. Keep running water flowing on the hones when lapping if you can, rinse off the "swarf" from between the hones frequently. Be sure and use a pencil grid.


Hope this helps,

This is not the first reported case of 'hone envy'...

Correct. DMTs don't need lapping. I lap a dozen stones a week and have for the past 6 years and my DMT Coarse continuous diamond 325 stone is still going strong. When lapping, the general rule is to have the lapping stone be bigger than that which is being lapped . . . the lappee so to speak. The reason for this has to do with the concept of flatness which is why we lap. The DMT 8x3 is a much better choice and you'll achieve better flatness with more consistent results.