Best wheel for aluminum on my Harig?

[jwmelvin]

Good that we both like steves videos, …

That was a ninja edit! Your post didn’t originally have that video in it, right? You turned me on to Steve and I feel like I’ve gotten a good bit from his videos.

 

[michiganbuck]

Yes, I went back to find the web link after posting the text....and re-watched the video..good that I did because I picked up on the "straight coolant"..I had missed that at the first times watching it.

 

[p-moon]

I always found that using a 46 grit wheel with grinding wax was the way to go on all non ferous metals

 

[tdmidget]

All of what I do is for small instrumentation where fine finishes are the rule.

For steel: I keep a 46 white aluminum oxide wheel on the machine most of the time. IMO, the main reason for going to a finer wheel isn't finish, but the ability to hold a small radius in a corner. I've never found much advantage to a finer wheel than a 60, and they tend to burn easily. I have some finer wheels and they're used strictly for form grinding. Many/most people overdress. I use a single point diamond, take off about 0.0005-0.001", and crank that sucker across about as fast as I can. You don't want to go slow and you never want to make an extra pass with no feed. I remove about 0.0002-0.0007" of stock per pass.

For aluminum: I do exactly the same thing with the same wheel! The only difference is I spray the surface with WD-40 between each pass and maybe remove a bit less stock per pass than I would for steel. No doubt one could optimize the process with a different wheel, but that's too much messing about for one-offs. I've found no problem going from steel to aluminum or vice versa.

Avoid fancy expensive blue seeded wheels for small grinders as they don't perform well. Grinding conditions are just wrong for them.

Conrads got it. When I was an apprentice we had a job making parts for the interlock for thrust reversers for aircraft. Don't want it to reverse in flight y'know. The ends of the cylinders for this thing required .0002 tolerance on size and flatness. We ground them with a 38A46H wheel and sprayed WD40 every other pass, taking off .0005 or so. We only had to dress every hour or so and the finish made ekretz' cylinder head look like a bad dirt road. Easy to do, easy to learn.

 

[eKretz]

Conrads got it. When I was an apprentice we had a job making parts for the interlock for thrust reversers for aircraft. Don't want it to reverse in flight y'know. The ends of the cylinders for this thing required .0002 tolerance on size and flatness. We ground them with a 38A46H wheel and sprayed WD40 every other pass, taking off .0005 or so. We only had to dress every hour or so and the finish made ekretz' cylinder head look like a bad dirt road. Easy to do, easy to learn.

The finish on the head is supposed to be a little rough, don't'cha know... in hopes that it will get a better grip on the head gasket. It's not difficult to get a smoother finish if that's what is desired. I have used WD on aluminum and it does work pretty well. But not as well as an induced porosity wheel. I'd guess we could go all the way up to the ultimate and use a porous bond diamond wheel too, and that might be even better yet. But personally, I find it's a lot less hassle to just grind an item flat with a 46ish grit wheel and give it a quick lap if needing a very low Ra finish. High grit grinding is kind of a pain.

 

[Conrad Hoffman]

FWIW, I've found it hard to buy desired wheels off the shelf. As soon as you get fussy about hardness or some other thing, availability dries up. Even finding a 7" x 1/2" x 1 1/4" green wheel for my Boyer-Schultz proved near impossible. Same thing with fancy bonds like resin, unless you want to buy a twice lifetime supply.

 

[Conrad Hoffman]

Aluminum isn't difficult if you go slow. What sucks? 303 stainless steel. I'm running some small plates right now and just got a SiC wheel because that's what Norton recommended, plus Norton was all I could find in quantities of one. That seems to work better, but it's really easy to heat the part and warp it. You can hear the depth of cut increase on the ends on the cool finish passes because on the roughing passes the hot top side expands and warps the plate convex, lowering the ends. Even a 1/2" thick part will move a bit. Serious coolant would be nice, but I'm only set up with a jar and a brush. Given that, I just have to go slow.

(edit- I had it all backwards on the warpage)

 

[FFWD]

All great info to get my feet wet. Thanks guys!

 

[michiganbuck]

All great info to get my feet wet. Thanks guys!

Sometimes when using a 32 to 60 grit wheel of H to M hardness and grinding aluminum or steel with the part held down by the magnet or properly clamped with C clamps or parallel clamps to an angle plate or such device with everything seeming to be going as planned with no heat build-up, parts shifting from their original and proper position or strange noises and you are confident that you will make part surface finish spec and size limits and then you feel your feet begin to get wet you might cut down on the coolant.

 

[FFWD]

Sometimes when using a 32 to 60 grit wheel of H to M hardness and grinding aluminum or steel with the part held down by the magnet or properly clamped with C clamps or parallel clamps to an angle plate or such device with everything seeming to be going as planned with no heat build-up, parts shifting from their original and proper position or strange noises and you are confident that you will make part surface finish spec and size limits and then you feel your feet begin to get wet you might cut down on the coolant.