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favorite surface grinding wheel for hardened steel?

razoredgeknives

Plastic
Joined
Sep 6, 2019
Hey guys! I routinely grind hardened steel blades with some really hard tool steel and stainless. Any favorite wheels?

Also, what do you think about this finish in the video? (I didn't spend time getting it perfect but there does some to be some dotted lines about every 1/8" that look kinda weird and inconsistent in it). This is from a blue Norton SG wheel, 46 grit rated I

 
Try Norton 38A60G8VDB for general purpose. When grinding hardened steel a slightly smaller stone in the grinding wheel works better because there are additional stones doing the cutting. The wheel your using is good for general purpose grinding for cast-iron and low carbon steel.

Roger
 
Also check wheel balance, especially if you grind with coolant and then shut down without allowing the wheel to spin the coolant out first. You can also check to see if the spindle bearings have any looseness.
 
Also check wheel balance, especially if you grind with coolant and then shut down without allowing the wheel to spin the coolant out first. You can also check to see if the spindle bearings have any looseness.

Yeah I did balance using the Suburban tool method...

I was under the impression that you wanted to balance the wheel dry with no coolant in it because that can throw it off?

What do you guys think about Radiac wheels?
 
It might help to state what material your "really hard tool steels" are. Grinding D-2 isn't the same as grinding A-2 or S-7. The powdered metals will also likely grind different too, although I haven't the chance to test that assumption. I've no idea what Damascus or laminated material would want. The 400 series of SS aren't used in general die stamping very often so, unfortunately, I don't have an opinion about that either. For hardened D-2 I've most often used ceramic wheels with a speed control and lots of coolant to keep heat down. Your finish, the amount of material to remove, and level of detail often dictate the grit size but a 46 grit was good enough for general flat work. Dressing method/speed and a speed control can/will help grinding with a less than optimal wheel by slowing wheel speed and increasing the grinding force. If I understand this correctly (anybody want to confirm this?) it tends to crush off the dull peripheral grains exposing sharp new grains underneath. Radiac wheels were a good brand in the 80's when I was still grinding, don't know if they've changed. Your "dotted lines" may just be a loose grain in the wheel. Are you checking for this after dressing the wheel? Hope this helped.
 
Yeah I did balance using the Suburban tool method...

I was under the impression that you wanted to balance the wheel dry with no coolant in it because that can throw it off?

Yes, the wheel should be dry if possible, my reference was to the wheel going out of balance due to coolant residue "settling" to one side of the wheel after shutdown without allowing the wheel to spin for a while first to fling out remaining coolant. But this does depend on wheel type, a more open matrix would allow more ingress.
 
It might help to state what material your "really hard tool steels" are. Grinding D-2 isn't the same as grinding A-2 or S-7. The powdered metals will also likely grind different too, although I haven't the chance to test that assumption. I've no idea what Damascus or laminated material would want. The 400 series of SS aren't used in general die stamping very often so, unfortunately, I don't have an opinion about that either. For hardened D-2 I've most often used ceramic wheels with a speed control and lots of coolant to keep heat down. Your finish, the amount of material to remove, and level of detail often dictate the grit size but a 46 grit was good enough for general flat work. Dressing method/speed and a speed control can/will help grinding with a less than optimal wheel by slowing wheel speed and increasing the grinding force. If I understand this correctly (anybody want to confirm this?) it tends to crush off the dull peripheral grains exposing sharp new grains underneath. Radiac wheels were a good brand in the 80's when I was still grinding, don't know if they've changed. Your "dotted lines" may just be a loose grain in the wheel. Are you checking for this after dressing the wheel? Hope this helped.

Yeah sorry about that. I grind everything from D2 to A2 to M390 to S90V and 10V. Mainly I want to be able to focus on getting a good finish on M390 with the capability to get decent finishes elsewhere.

I'm normally using an open dress (such as in the video below) which finish was better than the first video but is a different wheel (aluminum oxide white norton wheel) which has been balanced and side wheel dressed.

Yes, the wheel should be dry if possible, my reference was to the wheel going out of balance due to coolant residue "settling" to one side of the wheel after shutdown without allowing the wheel to spin for a while first to fling out remaining coolant. But this does depend on wheel type, a more open matrix would allow more ingress.

Gotcha that makes sense!!

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What do you guys think about this finish? looks like it still has some cosmetic waviness it seems. I'm thinking about trying out a Norton Quantum ceramic wheel as those seem to be more friable than the SG series and open structured.

 
38A and 32A Norton Grinding wheels

Try Norton 38A60G8VDB for general purpose. When grinding hardened steel a slightly smaller stone in the grinding wheel works better because there are additional stones doing the cutting. The wheel your using is good for general purpose grinding for cast-iron and low carbon steel.

Roger

Norton wheels are manufactured by crushing stone to size or with individual stone. 32A is made with individual stone and have sharp points that break away presenting fresh sharp points. It will tend to maintain a sharper acting wheel due to it friability. 38A will tend to stand up a little better because it is crushed stone and therefore not as friable. A sharp dressing diamond can also affect the finish as well the speed that your passing across the wheel dressing the grinding wheel.

Roger
 








 
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