DMT Dia-Sharp Extra Extra Coarse

[Rosewood]

Hi,

I was wondering if anyone is using the DMT Dia-Sharp Extra Extra Coarse for grinding primary bevel duties? Is is coarse enough to do the job effectively and fast?

Many thanks,

RW

 

[marcus]

I have one and it's pretty good for initial stage of lapping etc. but personally I wouldn't grind bevels with it (except maybe on small carving tools or something) - would take for ever surely? Any kind of grinder (corded or hand cranked) would be better.

 

[sdbranam]

Yes, I use one, and it's fast, similar to an 80-grit sandpaper but without wearing out the surface. Faster than a grinder? Maybe not, but still, you can do heavy reshaping in 5 minutes, so it's a nice alternative. I also find the particles of the metal swarf heavy enough that I try to remember to wear gloves, otherwise I inevitably end up with tiny metal splinters in my fingers that I feel when I brush my hand across something.

 

[Derek Cohen (Perth Oz)]

Hi Steve

I avoid diamond plates for grinding. They tend to wear out quickly, at least the DMT ones I have used in the past seem to do so. For grinding my preference is a Tormek wet grinder, which sounds ideal for you if you can spare the bucks. They are pretty much fool proof.

If you insist on diamond for grinding, then you should try diamond paste (40 or 45 grit) on caste iron or mild steel plates. I made caste iron plates from broken Stanley planes, while the steel versions can be purchased from Lee Valley. They are good - I use one from pre-production testing. (Don't be tempted to try the paste out on MDF - it is too soft).

I also would not recommend waterstones for grinding. Few, if any, are hard enoug to remain flat when grinding. They remain effective by exposing fresh grit as they wear. This needs to be often. This is, in fact, my major criticism of diamond stones - they do wear and they d not open up fresh grit. Their life span is quite limited.

You gave a dry grinder. Learn to use it. I have one as well, but prefe the Tormek, nevertheless the dry grinder works well for many other operations. The heart f the dy grinde is the tool rest, and then it is up to technique. That only improves with practice. So practice. No short cuts.

Regards from Perth

Derek

 

[sdbranam]

If you insist on diamond for grinding, then you should try diamond paste (40 or 45 grit) on caste iron or mild steel plates. I made caste iron plates from broken Stanley planes, while the steel versions can be purchased from Lee Valley. They are good - I use one from pre-production testing. (Don't be tempted to try the paste out on MDF - it is too soft).

I also would not recommend waterstones for grinding. Few, if any, are hard enoug to remain flat when grinding. They remain effective by exposing fresh grit as they wear. This needs to be often. This is, in fact, my major criticism of diamond stones - they do wear and they d not open up fresh grit. Their life span is quite limited.

Yes, I've seen your articles on using paste, I've been considering giving that a try. I was indeed tempted to use it on MDF, so I'll skip that. I've been hesitant because I was afraid I would just use it up too quickly, instead trusting that the diamonds bedded in plates would last longer. I originally shifted to diamond plates because I found I was going through coarse sandpaper too quickly. Not sure which is more cost-effective in the long run, but it sure was a pain getting the PSA residue off the glass or granite; that seemed to take longer than anything else.

I gave up pretty quickly on using waterstones for grinding when I saw how quickly the stone wore. A 220 is cheap, but again it's a pain to be dressing it so heavily and frequently.

I note that DMT has a new process which they claim produces more durable plates, which they used on their Dia-Flat. I got one recently, so it will be interesting to compare it. However, I'm using it exclusively as a lapping plate, given that it's cost is based in part on its insane flatness tolerance (Yes, while I refuse to buy a wet-grinder, I apparently have unlimited funds for flat abrasives; but that's driven by the perhaps irrational desire to be able to do this entirely by hand, in any location).

 

[Cheshirechappie]

For anybody wishing to avoid power tools (especially high speed dry grinders - or offhand grinders as our engineering colleagues like to call them), may I suggest scouring the interweb auction sites or secondhand dealers for a hand crank grinder? Not as fast as a dry grinder, but faster than any flat abrasives, and controllable too, and just about light and compact enough for a mobile toolkit. Try to find one with a 6" wheel - replacement wheels will be easier to find if you need to do so. The toolrest may need modifying, but keep it simple - do the guiding with your hand and eye, which with not much practice are more than good enough - you don't need fancy jigs.

If you want to get really fancy, buy a couple of replacement wheels, and with a diamond dresser, reshape them to curved working edges (make a wooden box to keep the profiled wheels seperate from each other and safe, and you'll be set for life.) You can then regrind in-cannel gouges, hollow plane irons and the like; doing these on a power grinder is only really viable if you have lots to do, as setting a grinder up with profile wheels is not really something you'd do for a one-off.

 

[woodbloke]

For anybody wishing to avoid power tools (especially high speed dry grinders - or offhand grinders as our engineering colleagues like to call them), may I suggest scouring the interweb auction sites or secondhand dealers for a hand crank grinder? Not as fast as a dry grinder, but faster than any flat abrasives, and controllable too, and just about light and compact enough for a mobile toolkit. Try to find one with a 6" wheel - replacement wheels will be easier to find if you need to do so. The toolrest may need modifying, but keep it simple - do the guiding with your hand and eye, which with not much practice are more than good enough - you don't need fancy jigs.

If you want to get really fancy, buy a couple of replacement wheels, and with a diamond dresser, reshape them to curved working edges (make a wooden box to keep the profiled wheels seperate from each other and safe, and you'll be set for life.) You can then regrind in-cannel gouges, hollow plane irons and the like; doing these on a power grinder is only really viable if you have lots to do, as setting a grinder up with profile wheels is not really something you'd do for a one-off.

The long departed Alf (where is she btw) was a huge fan of the hand cranked grinder - Rob