Dressing Assembly For Toolpost Grinder In Lathe

[rgray]

I had a bright idea to buy say a 10" diameter surface grinding wheel in exactly the desired thickness, grit & composition I wanted. And then have a water jet cutter make a whole bunch of custom size wheels for me. But I can also envision some danger signs. Not sure how accurate they could cut the axle hole & maybe stressing the wheel with jetting cutting action? The wheels I see look like some sort of molded process.

I make them with a carbide hole saw set from harbor freight. The set was cheap and it cuts the wheel easily.
Pic shows the hole saw set, the wheel and a couple of ID mandrels I made for my dumore tpg. One has been trued up and used the other not yet trued and you an see by it that the saw can cut some what crooked. Just start truing with a carborundum or the carbide file that comes in the set (I haven't tried that yet) then finish with the diamond dresser.
Glued my wheels on with metalset A4. It's alot like jbweld just a little tougher. JB weld would probably work fine.

For some unknown reason those wheels seem to be cheap on ebay they are 1" wide (that may be why) and a 60 K grit. They are recessed so approx 1/2" in the recessed area. It's a 7 x 1 x 1 1/4 wheel.
The hole saw set will put about a 3/8 hole in the cut wheel. I enlarged to 1/2 for my arbors with a drill bit. Changing the supplied drill to 1/4 might come in handy also. That's next on my list for some jig grinder wheels.

 

[petertha]

Hmmm.. I never thought of a diamond hole saw.Do you drill the blanks dry or wet? I see those all over the place like in lapidary or glass suppliers. Maybe I can find some in my diameter size & I'm home free.

Do those spade center bits do a decent job of making a center hole? I don't have to have a counter bore recess in this particular application, but imagine it should be semi decent fit to the shank OD. I have some smaller wheels supplied with grinder in the .5" diameter range which have a hole for 5-40 retention bolt. Its just your ordinary clearance hole. I think the grip comes from the obligatory card stock washers on either side of grinding wheel & the bolt itself is just applying enough force to safely secure the wheel axially to the arbor.

 

[rgray]

Hmmm.. I never thought of a diamond hole saw.Do you drill the blanks dry or wet? I see those all over the place like in lapidary or glass suppliers. Maybe I can find some in my diameter size & I'm home free.

Those are just carbide. Diamond would probably work even better but these were cheap http://www.harborfreight.com/1-14-in-3-14-in-carbide-grit-hole-saw-assorted-set-9-pc-68116.html
The spade bit does make a decent center hole. A plain old drill bit works well also. Seems I always have an old bit that I don't feel to bad about using. I drill them dry.
The center fit would save alot of wheel truing if it fit decent. If loose maybe a wrap of solider or strip of lead like is used in the center of the surface grinder wheels would fill the void and help with centering.
If you have enough arbors a wheel could be left on till used up.
Yes the card stock "blotters" are necessary. Definitely make some for new wheels.

 

[MikeWi]

Seems like making a dressing fixture to clamp on to one side of the ways like a carriage stop would be a good solution. Easy to take on and off and doesn't get in the way of the work.

 

[dbassing]

Hi all,
Thought I would show what I did to make a holder for dressing the wheel for my tool post grinder. Mine clamps to the bed ways. I found the base at an estate sale and modified it to work on my lathe. The 1/4" flat piece of steel fits on the flats under the bed. The part I found (the painted piece in the photo) clamps to the front edge of the bed. Since the back part has nothing to rest against I drilled and tapped for the carriage bolt that you see pointing down that rests against the top of the cross piece. This is adjusted so that when tightening the clamping bolt the forces are even and level in the area that squeezes against the front edge of the bed. This carriage bolt is treaded into the end of the vertical rod that is clamped by the body of the dresser. This can be raised or lowered to get the proper height for the diamond point in relation to the wheel.
I included a diagram copied from the users manual for an Atlas Tool Post grinder showing the suggested angles that the diamond should be set to for dressing the wheel.
It is fast and easy to set up and can be reset at any time to dress the wheel while the part is in the chuck.
Cheers,
David
Dresser on lathe

Bed Clamp detail


Diamond dresser angles

 

[petertha]

Thanks David. Well, that gives me some more confidence to what I drew up. The below center dressing was something I hadn't realized so I'll have to pay attention there. Thanks!