Repair guy

[Dr Stan]

Well you're entering the universe of the alchemists as most of us job shop types hardly ever get to use the "correct" wheel. Only whatever is in inventory so we end up picking & choosing something we "feel" will be correct, add in experience, gut feeling and which way the wind is blowing to determine the "best" wheel. Norton published one of the best, if not the best grinding wheel selection guide ever. Of course that was back in the stone age pre-Internet. You can go here: Norton Abrasives United States of America & Canada to see what they have to offer. Or Google grinding wheel selection.

Another very good reference is the Machinery Repairman 3 & 2 found here: https://eric.ed.gov/?id=ED203130 it contains a boat load of info and is the book used to train new MRs in the US Navy.

[metric_taper]

Well you're entering the universe of the alchemists as most of us job shop types hardly ever get to use the "correct" wheel. Only whatever is in inventory so we end up picking & choosing something we "feel" will be correct, add in experience, gut feeling and which way the wind is blowing to determine the "best" wheel. Norton published one of the best, if not the best grinding wheel selection guide ever. Of course that was back in the stone age pre-Internet. You can go here: Norton Abrasives United States of America & Canada to see what they have to offer. Or Google grinding wheel selection.

Another very good reference is the Machinery Repairman 3 & 2 found here: https://eric.ed.gov/?id=ED203130 it contains a boat load of info and is the book used to train new MRs in the US Navy.

A photo or 2 of the TPG I have:

So the recessed wheel for this size hub and shaft, should be fun to find. Unless you've seen these before. At least the internet search recognized Drukov as a tool post grinder.

[Dr Stan]

Interesting brand as I've not seen one of those before. Mine is a Dumore and has 2 HS internal spindles.

[metric_taper]

Interesting brand as I've not seen one of those before. Mine is a Dumore and has 2 HS internal spindles.

Thank you Stan,
Ya, all the internet had was 3 for sale, all in the past. One site said it was made in Taiwan (not true), that might be easier to find wheels for.

So I just took some measurements of the spindle. The spindle shaft is 10mm, with a bushing for the stone mounted of 20mm OD and 9mm thick. The lock nut is 28mm OD. So any wheel will need to have a recess mounting thickness of 10mm with a ~35mm minimum recess opening for the nut (current wheel dimension). Any shaft hole size probably from 10mm to 22mm, as I can make a bushing, limit is the nut and backing flange diameter of the drive shaft. The 10mm mounting thickness probably can be a few mm more just so there's enough threads caught to not strip them off the end of the shaft or nut.

That said I can make a much larger backing washer, and special nut that has a flange with and extension (that will also serve as the centering bushing for the wheel). Just what I want, kill more alligators to drain the original swamp problem. I guess this site is all about making tools, at least this would have future use.

The existing wheel is very coarse, and as the spindle bore needs to be mirror smooth, I'm pretty sure I need a finer grit and softer stone after the rough in.

I'm looking on eBay now. Problem is there is not enough dimensions in any of the adds. So will need to see if the original vendors web site for the brand of interest has dimension drawings.

I had better luck finding grinding stones for my antique Black and Decker valve seat grinder.

So is there a procedure to remachine a grinding wheel using a 3 jaw on the lathe and diamond stone? Just in case I need to make a larger diameter deeper recess opening. Big RPM difference between a grinding spindle and lathe spindle. Just wanting some ideas of how this can be done with some precision to maintain balance, big problem making the square inside corner with a diamond dresser. The grit in every part of the lathe jaws is not what I want, but.....

[Dr Stan]

I would be very hesitant to reduce the size of a grinding wheel by mounting it on a lathe. You would produce a lot of grinding dust that would get into every nook & cranny of the lathe causing problems down the road.

Instead mount it on a motor and use a star dresser for sizable changes in OD. I would also do so outside to keep from spreading the dust all over your shop for the same reason. Wearing at least a dust mask would be another good thing to do. Don't forget the eye/face protection.

As for Ebay & grinding wheels I recommend going elsewhere. Aluminum Oxide wheels of the size range you need for the most part are not that expensive. Try Travers Tool or McMaster and buy a made in the US wheel as I seriously question the QC of Chinese wheels. Midwest Abrasives and Norton are my go to brands.

If I read this correctly it sounds like you plan to make an extension for the grinder spindle. Tool post grinders operate at very high speeds and if you have any run-out you'll never get a smooth finish plus it will decrease the life of the grinder spindle bearings. Safety is another factor as a bouncing spindle extension can result in wheel fragmentation. Operative word is can.

[metric_taper]

I'm more looking for solutions to adapt a SAE wheel to this "bastard" metric machine (not really bastard, but looking from USA, not a supported measurement system).

I was just at the MSC site, that was useless. I'll see what Travers has, McMaster has the best web site ever for finding things quick. Just would never think to look there for this. We'll see.

It would be nice to find a metric wheel intended to be easily mounted to this machine. I agree that Norton or some other non China is preferable, as I've thrown away brand new wheels from china made bench grinders, as they ran out of balance, and had a swash plate runout as well. Last thing I would want to experience is an exploding grinding stone.

I understand the RPM, and cantilevering a spinning mass (that is brittle as glass) with tool pressure, the existing wheel is 30mm wide by 65mm diameter, I'm not looking to make this 2" or more. The solution is to find a finer grit for final grinding passes. I know from using the surface grinder that tenths removable per pass is what grinding process with my machines can handle. As I've indicated, I don't do this process enough to do it well, or remember the wheel "decoder ring" info.

The Norton site requires registration, and I can't do this on the weekend, as there appears to be a human on their side needed to approve an account, just to let me see their products. I did get a pdf downloaded, but nothing applicable in size. I did register for their training classes, which launched new browser windows, and locked my computer up this morning. And that account is different then one to see the product. They clearly only want buying customers on their site.

[Dr Stan]

Have you downloaded the Machinery Repairman 3 & 2? If not I highly recommend doing so as it has a section on precision grinding and uses (I believe) the Norton wheel info.

"Last thing I would want to experience is an exploding grinding stone." Yep, they tend to make one change underwear.

[metric_taper]

Yup, have it on my desktop now (Navy training manual) and saved in the metal working sub folder. Mostly basic tool operation, but have not read the grinding section, as finding grinding wheels is current task at hand.

Right off, all the sites (McMasters, Travers, MSC) support in this size of 3" or less diameter, only a cupped tool grinding wheel is found.
Razzle Frazzle frick & frack durn wabbit.
The 1-1/4" arbor hole (31.75mm) is a standard. But that is right on the edge of my mounting flange, and the existing nut is 28mm diameter.

I'm not the first to find the metric (20mm arbor) problem, as I see posts from 2004 in another forum, that never solved the problem.

Continuing the search, but nothing in the 65mm OD, as they all seem to start around 300mm in their tables for Type 6 (straight cup) or 5 (recesses) mounting styles.

[olderdan]

Assuming you only need the morse taper adapter for centre work and do not need the mandrel taper for any other fitments the obvious course of action for me would be to alter the adapter to suit.
A Colchester lathe that I used to use had the same type of adaptor and it was relieved on the centre portion with a .75 inch land at each end, this is common practice on Jones & Shipman cyl grinders also which leads me to think you may have a shop made adapter.
You could do this to yours using a turned service morse taper for mounting and then stone and lap the small end to a correct fit, much easier than trying to grind the mandrel bore.
I always go the simple route if possible.
Hope this helps

[metric_taper]

This adapter came with the lathe. As indicated in the thread, every incorrectly made part clearly was assembled by the Chinese manufacture and exported this special through Grizzly. I have thought of making a new sleeve, I still need to accurately measure the spindle taper just to get something close. I'm retired, and probably will never need anything to fit this spindle hole but a true running center. I can't live with the 5 thou of runout. I've had the lathe since 2004, and just now finding the issue. Most work is always held in 3 or 4 jaw 12 inch chucks.