Black Silicon Carbide For Shaping Carbide Tool Bits?

[intjonmiller]

My lathe isn't powerful enough for me to want to do much with carbide, but I received a lot of carbide bits (as well as HSS) and there are a couple that seem like they would be great for specific uses, such as threading and boring (and internal threading), but only if I shape them correctly first. I have diamond sharpening "stones" that will work for honing, but would my black silicon carbide wheels work for shaping? How much difference is there between black & green silicon carbide wheels? These are photos I took a year ago of mine:

View attachment 100363
View attachment 100364

If that's usable, great. I'll make a simple bushing to mount one of these on my bench grinder. If not I probably won't bother, as I don't care about this enough to buy more tools just for carbide bits on my low-ish power, flat-belt lathe. Too many other things on my list of future purchases.

 

[intjonmiller]

Actually I do have one of these diamond wheels for my angle grinder:

http://www.lowes.com/pd_325798-353-79507C___?productId=3142675

In theory that could work for rough shaping (bit in a vise, handheld grinder), but again it doesn't really seem worth it, particularly with the segmented blade.

 

[Bob Korves]

Silicon carbide will indeed grind carbide tooling, but it more crumbles the edge than sharpens it. You will be messing with a diamond lap for a long time getting the tool sharp after roughing it with a silicon carbide wheel. Your angle grinder diamond wheel will work, and you can mount the grinder rigidly and make a simple rest for the tool. Either way, please be extremely careful and wear the proper protective gear. Angle grinders are not intended to be used in that way. Do not grind steel with diamonds. It will ruin the wheel. If it is a brazed carbide bit you can first grind the steel away below the carbide on a bench grinder, and then grind just the carbide on your diamond wheel.

 

[intjonmiller]

I'm basically "Mr Safety" that way. Safety glasses or goggles as appropriate, respirator, ear muffs, etc. My son won't even come out in the shop with me, even without anything running, without a play mask that he's decided is like my safety gear (and honestly would probably work if he ever held still long enough to be there when it was needed).

 

[Bob Korves]

Keep the guard on the angle grinder, maybe even add additional guards, make sure everything is mounted solidly...

 

[Andre]

Keep the guard on the angle grinder, maybe even add additional guards, make sure everything is mounted solidly...

And don't hold it too close to your crotch!

http://hobby-machinist.com/threads/definitely-not-how-to-use-a-grinder.46627/#post-396187

 

[RJSakowski]

My lathe isn't powerful enough for me to want to do much with carbide, but I received a lot of carbide bits (as well as HSS) and there are a couple that seem like they would be great for specific uses, such as threading and boring (and internal threading), but only if I shape them correctly first. I have diamond sharpening "stones" that will work for honing, but would my black silicon carbide wheels work for shaping? How much difference is there between black & green silicon carbide wheels? These are photos I took a year ago of mine:



If that's usable, great. I'll make a simple bushing to mount one of these on my bench grinder. If not I probably won't bother, as I don't care about this enough to buy more tools just for carbide bits on my low-ish power, flat-belt lathe. Too many other things on my list of future purchases.

I use these diamond disks for sharpening carbide tooling. The have a reasonably high diamond density and I have been using the first on for several years now. They also work well for pointing tungsten TIG electrodes.
I made an adapter for a small motor to mount the disk. It does a quick job on carbide and leaves a fairly good finish.

http://www.harborfreight.com/replac...-volt-circular-saw-blade-sharpener-98862.html

 

[intjonmiller]

That's interesting. That is much cheaper than I have seen for anything but ebay green silicon carbide wheels. Hmmm...

 

[JimDawson]

For the last 20 years I have just been using the standard gray aluminum oxide wheel that came on my Chinese bench grinder. Seems to work well for rough shaping, you just have to push a little harder. I use it for finishing also, I just don't push as hard.

 

[benmychree]

The shop that I apprenticed in back in the mid 1960s used both black and green grit silicon carbide wheels for sharpening carbide tools and they worked satisfactorily, especially for the softer grades of carbide. Using fine grits of wheels did not cause edge crumbling to any high degree, and we did not have any diamond wheels available to the machinists on the shop floor, who, for the most part ground all their own tools. The wheels used, so far as the black wheels were concerned were A.P. DeSanno Radiac brand, C100 H02 VD2, 8" x 1 x 5/8 even after leaving the shop after 7 years, I was still in line for the worn down wheels that were still nearly 6" in diameter and just right for my grinder in my own shop, which I used until I could afford a grinder with diamond wheels.