Drill sharpening on a D bit grinder AKA Deckel clone.

[brino]

@Flynth,

Thanks for posting such a detailed, interesting and well-researched question.

I would love to find one of those machines in good shape, at a good price some day.

I am watching the thread.

Brian

 

[petertha]

One extra bit of info to mention for anyone wanting to try it. Use a diamond grinding wheel. The aluminium oxide wheel requires more skill not to wear it between drill sides resulting in different cutting edge size and drill cutting oversize. If aluminium oxide is all you have it is doable by using half of the wheel for roughing and half for a final pass. This way you can keep the final side almost unused between sides.

Just to clarify, are you saying diamond wheel on any drill including HSS, or specific to carbide drill? I thought diamond on HSS was a real no-no. And yet I have seen plenty of videos where diamond is being used on HSS. And because its on YouTube you just know it must be OK haha. Does this date back to when diamond wheels were $150 & now they are $25 so who cares as much? I don't have a feel for how long before they would be pooched on HSS (or at least require redressing). Is it minutes, hours, weeks?

 

[GeneT45]

Every wheel that Darex sells for any of their myriad drill grinders is a diamond wheel. I can't tell you why diamond was once considered a no-no, but it's what is used here. I'd be surprised to find a drill grinder with anything else.

GsT

 

[petertha]

That's a good point, which just adds to my personal confusion. I see Darex offers both diamond & CBN. Both are the electro-bonded or whatever they call the principle on the 'silver' wheels. But essentially same as what you see sharpening knife blades & arguably similar to HSS type equivalents. Nobody talks about wearing those out or plugging them, they supposedly outlast AO.

The TCG wheels that I loosely call 'brown' wheels seem to be diamond bonded in a matrix of some sort. They are 5-10mm thick which I thought intended to naturally wear, exposing new abrasive particles. So I'm not sure if HSS was prone to plugging as opposed to 'dullening'?

I've also heard the high carbon content of HSS makes unwelcome bedfellows with high (pure) carbon of diamond, which would not be the case of CBN, aluminum oxide or silicon/whatever based aggregate. But presumably these carbon issues would be at elevated temperature? maybe that's the issue? I really wish I could find an authorative document on all this.

XPS-16+ Archives - DAREX

darex.com

 

[pontiac428]

I have been using chicom CBN wheels for all grades of tool steel, hardened or annealed. I was under the impression that it was a no-no, until Stefan Gotteswinter joked about how he abuses them to no detriment, and I've been doing it ever since (that is a lot). For a while, I kept a CBN beater wheel and a better wheel (both china), and no differences in wear were visible, so now they're all general purpose when I want a slow, mirror grind on HSS or a profile grind on a carbide blank.

I also use chicom diamond lapidary plates the same way, too hone anything and everything. I wash them with alcohol now and again, and they are like new, save for a few gouges I've made being sloppy honing carbide.

Heavy HSS grinding I do with Norton white or purple, those wheels run very cool compared to the finish grind of CBN or diamond.

 

[GeneT45]

That's a good point, which just adds to my personal confusion. I see Darex offers both diamond & CBN. Both are the electro-bonded or whatever they call the principle on the 'silver' wheels. But essentially same as what you see sharpening knife blades & arguably similar to HSS type equivalents. Nobody talks about wearing those out or plugging them, they supposedly outlast AO.

The TCG wheels that I loosely call 'brown' wheels seem to be diamond bonded in a matrix of some sort. They are 5-10mm thick which I thought intended to naturally wear, exposing new abrasive particles. So I'm not sure if HSS was prone to plugging as opposed to 'dullening'?

I've also heard the high carbon content of HSS makes unwelcome bedfellows with high (pure) carbon of diamond, which would not be the case of CBN, aluminum oxide or silicon/whatever based aggregate. But presumably these carbon issues would be at elevated temperature? maybe that's the issue? I really wish I could find an authorative document on all this.

XPS-16+ Archives - DAREX

darex.com

The CBN wheels must be new - I hadn't seen them before. Looks like they save a few bucks over the diamond wheels, but not a lot.

GsT

 

[pontiac428]

The CBN wheels must be new - I hadn't seen them before. Looks like they save a few bucks over the diamond wheels, but not a lot.

GsT

Which is funny, since CBN is superior to diamond, and synthetic industrial diamonds are cheap.

 

[petertha]

I have been using chicom CBN wheels for all grades of tool steel, hardened or annealed. I was under the impression that it was a no-no, until Stefan Gotteswinter joked about how he abuses them to no detriment

My understanding is CBN is perfectly fine for HSS / tool steel etc. But CBN is not diamond. The way I head it (maybe wrong) CBN is not carbon based like diamond & therefore doesn't react to the carbon content within tool steels. What exactly that reaction? A chemical degradation if that's the right wording? But this what doesn't add up to me - carbide is a highly carbon based recipe & everyone seems to universally agree carbide is perfectly fine on diamond wheel. So where is the disconnect? Initially I thought it had nothing to do with hardness, maybe other mechanisms like metal smearing of tool steels? Think grinding an aluminum rod on an OA wheel. Doesn't matter if the particle is hard & sharp if its plugged.

I recall the same comment in a Stefan video to the effect - who cares they are cheap to replace these days, but can't seem to find it now. Anyone have the link? I linked Robin's video. At about 7:30 he talks about his wheels, both CBN & Diamond shown hanging on the wall. The cutoff CBN maybe looks a bit different & I have seen that one specifically at Shars, but all the rest look a similar brown color!

CBN Abrasive: A Guide to Cubic Boron Nitride

Cubic boron nitride (CBN) is a superb abrasive material designed specifically for advanced wear-resistant characteristics. It is a comparatively recent material innovation which has been earmarked as one of the greatest technological advancements of all time for abrasives. But what makes CBN...

www.surfaceconditioning.saint-gobain.com

Carbide | Chemical Compound, Hardness & Uses

Carbide, any of a class of chemical compounds in which carbon is combined with a metallic or semimetallic element. Calcium carbide is important chiefly as a source of acetylene and other chemicals, whereas the carbides of silicon, tungsten, and several other elements are valued for their physical

www.britannica.com

 

[pontiac428]

I recall the same comment in a Stefan video to the effect - who cares they are cheap to replace these days, but can't seem to find it now. Anyone have the link?

Well, that was surprisingly easy to find. This bit really inspired me to abuse these wheels, and I can't seem to hurt them in doing so. The only downside is heat; when grinding HSS it goes so much faster and cooler with a stone. But for small grinds that don't involve halving a round blank or other heavy removal, the mu-shu CBN wheel is more than happy to oblige.

 

[petertha]

That's a good video too. I'll add to my collection, but still not the one I seem to think I'm remembering. In the one you referenced he says he abuses the cheap diamond wheels, but then he proceeds to grind a carbide shank with it, not a HSS blank.

On this one he is grinding hardened / tempered O1 but using OA? type wheel on his different grinder. Shessh this is like a garage sale puzzle set, always missing a piece LOL