Best wheel for roughing in hss tooling

Good afternoon,
I was wondering if anyone had the part # to their favorite bench grinder wheel for rough grinding hss. Something cool running and aggressive would be ideal. Thank you. Jeff

46 k is a good all around wheel.. that is softer than most bench grinder wheels and good for just straight off grinding tool bits..for a special form it is too soft. Good wheel to rough and finish with a good dress. 46 k will wear down faster than most bench grinder wheels...
Best to pick up an abrasive wheel wheel dresser if sharpening often.. cracker jack junior is very good. the steels dresser is not so good but it can be modified to take abrasive dressing wheels.

For form bits a 60 k or J is good as it will hold a corner better..but will get hot faster.
For a real tight corner and super finish even a 120 might be good but will get hotter.
For aluminum one might back off a secondary clearance first..then with a fresh dress or a harder fine gran wheel just tickle the primary edge.. Yes a 46 wheel is Ok for aluminum.

I prefer to start with a thin cutting disc in a angle grinder gets the roughing done in but a minute, then a 46 grit seeded gel blue wheel on the bench grinder, then finish on a 80 grit before switching to low speed diaomnd lapping to mirror finish.

My favorite roughing wheel is a 50 grit Zirconia belt on my belt grinder............Bob

I generally learn from everything Michigan Buck posts & he has worlds more experience than me; but over a lifetime, K just always seemed like the step over the line to too hard for most of my stuff. I do like J for anything offhand ground, and most on the machines. Cylindrical work might take harder wheels, even M sometimes. Obviously YMMV.

smt

Screw using a wheel grinder for roughing. Use a belt sander. Changing grits is cheaper and easier and you are distributing the cutting over a longer length, 6" wheel about 19" circumference. Most belt sanders are 48".

Thank you all very much for your input.

Off-hand grinding,I presume like on a bench grinder?

A good grinding wheel selected for the service is always a good idea but more important than the exact right wheel is keeping it sharp and free cutting. This requires frequent dressing to expose fresh sharp abrasive. Otherwise the surface grains wear and dull turning a grinding wheel into a friction factory. You get a few sparks but not much stock removal and the tool heats like crazy.

Dress the wheel with a diamond dresser on a nicely made hand shank. This is one tool you never put away in a drawer. Keep it on or near the grinder at all times. You want it instantly handy when the grinding wheel needs dressing. A grinding wheel IS a consumable item, you know

I used to bore a lot of copper nickel and CN7M stainless pumps. These materials weren't hard but they wore out we used the most abrasion resistant HSS tools we could find: M42 and T15. These were very hard and abrasion resistant. When roughing out a fresh stick of tool steel, it was frequently necessary to dress the wheel every few minutes.

Tip of the week: quenching a hot freshly ground tool in water? Fill a 3 lb coffee can 2/3 full of water. Holding the cold end in your hand with the hot end out over your palm, dunk your whole hand with the tool so the water slowly rises to the hot end. Regulate the speed of the dunk so the tool barely sizzles. This avoids the high tensile stresses from thermal shock and subsequent cracking at the cutting edge.

You get your hand wet but you won't melt.

I have been grinding HSS for 30 years and the idea of dipping my hand and cold end in first never occurred to me, seems so freaking obvious when pointed out. Thanks


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I'm in the angle grinder camp for roughing. I cut grooving tool and such by marking out and using a thin cutoff wheel. The little block of HSS left after the cut can be brazed to any shape of mild steel shank to make a variety of special cutters... internal grooving tools, internal threading tools, form tools, etc...

For less material removal, I just walk over to what ever big nasty wheel is on the 5hp 12" pedestal grinder and lay on it. You don't care what kind of wheel you are using, it's just getting material out of the way. I have a tan colored fine grit Norton Gemini wheel I prefer for finish and polish grinding.

As Forrest says, don't blast the hot end of the cutter with water. I use the shop water fountain instead of the can dunk. I just hold the tip of the cutter at an upwards angle and start the stream of water on the cold end and slowly walk it down, as said, trying to keep it barely sizzling. The walk to the fountain also lets things air cool a bit.

Angle grinder and 5.5hp belt grinder with ceramic belt -camp here.

Seco WKE45 seems to be a real test for any grinding tool, takes ages to cut a piece of WKE 45 with the same cut off disk that zips trough ordinary HSS like its made of butter..

I use an air grinder with Dremel cut off wheels to rough cut the blanks.
Used to use a 37 grit wheel on a 6" grinder but found the air grinder faster .
mike