Carbide grinding implements???

[Glenn Brooks]

Hello all,

so every one says,"you gotta grind carbide tooling", but I havent seen advice regarding what size of grinder to use, proper wheel grinding speeds, or actual composition/grit of grinding wheels etc. Do you need two different grits? If so, what is best??

I'd like to put together a carbide grinder. Looking for what constitutes a proper set up.

thanks,
Glenn

 

[Tozguy]

I only do a bit of carbide grinding so I just switched a 6'' AO wheel for a SiCa wheel in 100 grit. It works fine for sharpening brazed carbide tools.
Not the most sophisticated set up but it got me grinding carbide with a minimum of fuss.

 

[mikey]

Whatever happened to Christian Poulsen? He'd be the perfect guy to take this question.

 

[Doubleeboy]

Picked up a Harbor Freight cheapie diamond grit grinding wheel, probably for saw blades and made a backing plate /arbor arrangement and use it mounted in old HF mini lathe I picked up cheap well used. Makes for a nice tool for doing brazed carbide. When doing brazed carbide if I need to grind much on the steel shank under the carbide I use AO carefully then touch up the carbide part. I use USA made brazed carbide tooling when doing interrupted cuts and touch em up with the above rig.

 

[Eremius]

Silicon carbide (green) or diamond wheels are needed for grinding carbide.

 

[jocat54]

I use a really hacked method. I use and old washing machine motor running at it's lowest speed (1125rpm I think) and made an arbor to fit the cheap Chinese cup diamond wheels (120 grit) about $10.
The motor is probably to fast but sometimes you just use what you have and it sharpens the cheap brazed carbide pretty well. Made a rest for it and use it pretty often.

 

[JimDawson]

Silicon carbide (green) or diamond wheels are needed for grinding carbide.

I'm going to respectfully disagree with that statement. Green wheels or diamond is desired, but not ''needed''. I grind almost all of my carbide on a standard gray aluminum oxide wheel on my bench grinder. You just have to push a bit harder. Carbide grinds pretty fast once it gets red hot. I should note that I normally use only the finest Harbor Freight AR8 bits. I do also have both green and diamond grinders, but I rarely use them.

 

[JR49]

I'm with Jim, All the brazed carbide tools that I use are from HF. Sure, you can spend hundreds on a nice diamond, or silicone carbide grinding set up. Or you could do as I did over 2 years ago. I spent under 10 bucks on some little diamond discs with 1/8 " shanks (like what fits in a Dremel collet). I put the shank of the tool bit in a vise, and sharpen-shape- form, pretty much anything I want to the carbide, If I start getting close to the steel shank under the carbide, I simply switch to an aluminum oxide stone and clear out the steel. In 2 years, I've only used 1 or 2 of the 5 discs that came in a pack with the 1/8" arbor. Now I'm not figuring in the cost of my dremel, I've had it for probably 35 years. If you don't have one, you should have one. Happy Machining, JR49

 

[Glenn Brooks]

So, at what speeds are diamond and silicon carbide wheels supposed to spun? I've heard everything from 250 RPM up to 1750....

Thanks,
glenn

 

[Chipper5783]

I used a silicon carbide wheel on a 6" bench grinder for years. It is set up with the regular tiny little tool rests. It worked okay, but not great. Carbide is hard and I found it ground slow and would heat up. I always meant to make up a good rest - just never quite got around to it.

Because another solution came along: http://www.hobby-machinist.com/threads/carboloy-excello-tool-grinder.37715/

I got a 10" diamond wheel (it is a belt drive machine, runs at about 2000 rpm), designed for grinding on the side, with quite a wide face (I thought I got the grinder at the good price, the wheel cost a crazy amount of $$). It is fantastic, you can grind fast, the tool stays much cooler and it leaves a nice finish on the tool edge.

I'm not saying you should try to look for or duplicate a purpose build industrial carbide pedestal grinder. All I am saying is that a good grinder set up is very nice and I find that a diamond wheel is much better than the SilCar.

Let us know how you make out. Regards, David