Wheel selection - Surface grinding

[small.planes]

My surface grinder came with an assortment of grinding wheel shaped things.
Some were clearly for bench grinders, or bigger / different machines - they would not fit the spindle or wheel guard. However there were a few the looked possibly correct for the machine:

I think this one might be for off hand grinding?

I can see no markings that indicate abrasive, grit size or bond structure. I tried to find A.VS info from Norton but came up blank. Any ideas?

This is a narrow fine grit surface grinding wheel:

38A alox, 100 grit, J hardness vitrified. No openness marking?

I think this one is for corners / forming to a shape and then grinding that shape into the workpiece?

This is the first wheel I ran. I picked it as it was the most 'surface grindery'

Alox, 46 grit, J hardnesss, 7 structure, vitrified?
I think this is pretty much a 'general purpose' wheel?

Do vitrified wheels have a recommended life? I've had these wheels for around 12 years, and they weren't new when I got them.
I cant see why they would, but I don't know.

Way back in 2008 when I bought my 540 Peter Neill commented:

I'm going to try a new type of wheel out for the next serious grinding job that comes up. I've got the standard white 38A and a blue SG (seeded Gel) wheel which is great for *really* hard stuff, but a hot tip from the toolroom for a great all-round wheel for hard and soft stuff alike is to use a Norton 95A.
These are a blend of standard AlOx with 5% SG grit added, and look like a bowl of oats or a slice of granary bread, but are apparently so versatile that the 38As have practically been consigned to the shelf.

95A was Norton's 5% Seeded Gel Alox wheel - I think its now called Quantum.

Based on this I bought a 'ceramic' 46 grit wheel (Coventry Grinders Ceramic Grinding Wheels | Abrasives) and a white 60 grit alox wheel (White Grinding Wheels - Coventry Grinders | Abrasives)

I havent actually mounted the white wheel yet, but I believe 'Seeded Gel' wheels are the Norton description for 'ceramic'. So far the ceramic wheel seems to work nicely.

This is a tool makers clamp I made recently from some cold rolled steel I have hanging around:

The finish seems ok to me (I'm still learning about speeds and feeds) - the white marks towards the bottom of the pic are coolant hanging around.

I also made my cast iron flat things (see this thread https://www.practicalmachinist.com/vb/abrasive-machining/grinding-practice-scrap-cast-iron-378809/) with this wheel.

Anyone run / running SG wheels?
What other wheels should I look to get?
I'm not a commercial shop, so dont want to have to many wheels. I have 2 wheel flanges at the moment, one is staying on the ceramic wheel - what should I mount on the other?

I envisage generally grinding cast iron, steel in both hardened and 'soft', and the odd bit of HSS / carbide for tooling. When I come across a need in something more exotic I'll ask for specifics.

Dave

 

[michiganbuck]

You may need a recess face wheel, one that your wheel mount will be below the face of the wheel.
With this you can dress the front face and the side grind finish a part that is greater than the normal amount of face you can use.
This is often called side wheel grinding and not often recommended because wheel are weakest with any pushing/grinding on the face.
Often one conventional grind the part for rough in to .005 or less stock to take.

Perhaps you have a flat top on a part and an area that goes up from that flat top.

Another wheel you may alread have is a corner getting wheel. to get a .005 inside corner you need a fine grit wheel.
Often you make the corner with 46 wheel and get perhaps A .020 with dressing a few times.if your lucky depending on the hardness.A 60grit wheel perhaps .015, a 80gt .010, 120gt .008.

I keep a 1/4 wide 120 and a 80 grt AO wheel for a tight corner ..but you/I can only grind the corner because grinnding much flat with a fine wheel can burn the grind.

Most mating parts need a bevel on one part because geinding a dead sharp inside corner is near Impossible...An angle dressed wheel can go to an inside corner and make a needed undercut.

QY: [a tool makers clamp] very nice..often I hand gun blue/black such tools. some parts look nice with only some of the sides blued/black and some still bright.

Having a grind shop nearby you might have some wheels dressed down to fit your geinder.

Mount-up line on every wheel and on your spindle nose keeps them better for next mounting so they run true at repacing..

You can do a lot of chasing wheel for the very best wheel and for some jobs AO is not the best..but often it is better for one-up/few-up grinding it is better to fill the needed size, shape and grit before searching for the very best kind of wheel. I tried a china wheel in a pinch..and it went from first try to that sumpster so good to sitck with nane brands.

 

[AD Design]

In another thread I stated that I had no experience with a seeded gel AO wheel. Apparently Norton describes the "ceramic" wheels as seeded gel and I have used several of them.

These were the preferred wheel for grinding hardened D-2 in conjunction with a spindle speed control. By slowing the spindle speed and using the "ceramic" wheel it helped to fracture the grains, exposing a new edge. This helped to hold down the heat, avoided burning, and reduced needing to redress the wheel as often due to glazing of the wheel.

I saw no need for using one of these wheels on anything but hardened D-2 or the hardened powdered metal varieties. Money is better spent on other things.

 

[michiganbuck]

I see that wheel mount nut looks live it has been hammered on some time in the past. Good to grind that nice and round to make it look better. The way I tighten is to use a wrench about 6-7" long. Tighten as tight as I can with one hand on the wheel and one on the wrench. Then set the wrench on a block and with two hands on the wheel make a little tighter.
Never have a wheel slip on the mount doing that.

I have had some guys say don't turn off a wheel because it may slip on the mount, mine never do that. I have ground so hard the the part will slid on the chuck..that was very common at my first grinding job.
that 150 may be a 150 grt so a very fine finish wheel, its difficult to tell just by looking because som wheel are very opeen so have more space between grits.


Brown Nortons seem to be longer lasting and run a little hotter that a white AO. They are often very good for a production job running wet. still Ok dry but you have to give a little rest for cooling. One job a circular knife that I ground with a 46 I white el ..Had to use a 46 k brown on it for running out of my normal white wheel. job was brought to a knife edge, then bumped to a .005 to .007 radius. The job got a complaint. lucky it was one of my best customers or I would have lost the job. the job seemed to have lost some temped and was running about 50% the normal life.

 

[michiganbuck]

Qt:[Do vitrified wheels have a recommended life? I've had these wheels for around 12 years, and they weren't new when I got them.
I cant see why they would, but I don't know.]

If the ring they are good.. thay can get dried coolant and even just dirty loged and so run out of balance...blotters can get old but if you add new ones be sure to add all the markings...
holes can get big.. ops guess I should say over sized..that is why the up mark is good ..one can marhk a wheel .005 shimif that fill the need..but most often just the mount up is enough.

Some old diamond wheels have a No No fiber in the bond.. so not a bad idea to use a mask with some old diamond wheels. I survived many years breathig some dust but now I often wear a mask.
You dont see anyone making the old clay orange wheels anymore, they were great for super finishing and going in for a inside corner.. I still have a few.