Looking for Sanford MG-612 Surface Grinder owners

[kevin]

Just ran across this link - it clears up a minor mystery. I wondered why the grinder was mounted on the cabinet with the opening at the back - it's because there was an option with a dust collector built into the cabinet - "Full size rear door gives access for cleanout."

https://factorywhistle.tumblr.com%2Fpost%2F19313759938

 

[projectnut]

What kind of table stops are worth $430? Those I have to see, are they solid gold?

The prices I was referring to in my previous post came from the link provided in Kevin's latest post. I had downloaded this information years ago, but neglected to keep a link to the website. The information is from quote #2:

http://www.d-and-d.com/misc/MANUALS/Sanford/

Note the form was created in 1992 and was valid through 1996 so these are not the prices paid by the original owner of my machine, who most likely purchased it in the 1950's.

My machine does not have table stops. I can understand why at the prices Sanford was charging. Even in 1954 they would have been expensive. Another reason for the opening in the cabinet is that many of the machines could have been purchased with a "wet grinding attachment" I have seen pictures of some with the tank and pump inside the cabinet.

I'm assuming the change from a 3/1 ration to a 4/1 ratio on the down feed was intentional. As I recall the shop I purchased it from was using it to grind spacers for the lower units of Mercury inboard/ outboard drives.

Now to the heart of the matter. I originally stated "the wheel goes directly on the spindle". When I purchased the machine I was told the wheel hub couldn't be removed from the spindle. In my haste to take the machine home I didn't ask any more questions about mounting the wheels. I "assumed" the owner meant the hub was part of the spindle. Now 7 years later I realized he in all likelihood what he meant was that he couldn't remove the hub from the spindle.

This conversation made me a bit curious as to how I would balance the wheel(s) if needed. So far I haven't balanced any of the wheels I have, and have gotten what I would consider an "acceptable" finish. The finish isn't mirror smooth on some materials, but I attributed that to the machine being over 60 years old.

Yesterday I started disassembling the machine and here's what I found. First I removed an end cap that was pressed into the end of the spindle. I should have taken a photo prior to removing it, but it's now hiding somewhere in the shop. I heard it ricochet a couple times, but as always it's final resting place is currently unknown. As you can see there is a nut holding the spindle to the arbor. I removed the wheel nut, spacer, and wheel guard to expose the complete hub.. As the previous owner mentioned the hub would not come off the arbor, at least not without a little persuasion. I didn't want to beat on anything so I got a gear puller out of the cabinet and set it up to attempt to remove the hub. A couple turns later and a heart sinking POP and the hub was free.

I can understand why the previous owner said it was permanent. There was a good coating of rust between the arbor and hub on both tapers. I was able to polish both the hub and arbor as seen in pictures in the next post.

Here are some photos of the wheel and mounting. Note the spanner wrench sitting on the vise is a Sopko brand # 9-424. It didn't come with the machine, but rather was purchased from a used equipment dealer.

 

[projectnut]

Here are some additional pictures of the spindle and hub. I haven't done a critical measurement of the spindle taper, but with a cursory check I believe it is the standard 3 TPF.



Note the flanged ring sitting on the vise in the pictures. I believe it's supposed to be a retainer for the spindle bearing. There is a threaded hole for a set screw, but there doesn't seem to be much room between the spindle housing and the retainer for an Allen wrench.

 

[Bob Korves]

There is a puller tool that fits the I.D. of the hubs. Most hubs are threaded internally for it, but some are not.
http://www.wmsopko.com/sopko_82.htm
The first one on the list, p/n 00116, fits my machine and many or most surface grinders found in a hobby shop. It could easily be shop made if you don't like the price.
https://www.mscdirect.com/product/details/05924253

 

[kevin]

projectnut - great set of pictures - thanks!

If you have time please measure that taper and confirm the TPF; it may be 3" but it may be like mine (I can't be the only one!). I'm hoping to find other Sanford owners with the same non-standard taper as me, who might be willing to get together on a custom buy from Sopko.

Is your adapter left or right hand thread? Sopko says it should be LH, but some people use RH anyway.

I can't tell from your pictures whether your wheel adapter is internally threaded for a puller, but I would guess that it is. I bought the puller from MSC and it works perfectly with my adapter. The spindle nut looks like it might be shop made; all the other Sanford I have seen so far use a 7/8" hex nut (https://www.mscdirect.com/product/details/05924006). The hex nut requires a special thin-walled socket, but some people just grind down a standard socket.

Here's my spindle (before cleanup); TPF =2.787" (not standard). Looks like what might be your flange on the left end of the taper.



Here's my adapter (puller tool just above wheel). My adapter uses something called a "glare gear nut" and requires a special gear wrench to crack it open. You can see the internal threads on the wheel adapter, where the puller screws in. The threads on my gear nut are LH. The grinding wheel in the picture is a once-upon-a-time 7" wheel which has been worn down to 4.9".



I've seen a number of people say they never balance their wheels (but they do dress them). One source I found (lost the link, sorry) said wheels 7" and under don't typically need to be balanced. Others I have read say to get the best possible finish you need to balance. My concluysion is that it is possible to get a perfectly acceptable grind without balancing, although "acceptable" may not be the best the machine is capable of.


For the complete album of all my Sanford photos, look here : https://photos.app.goo.gl/DxA0ndhxk4dyiMED2
For my web page, look here: https://sites.google.com/site/lagadoacademy/machining---lathes-mills-etc/my-surface-grinder

 

[kevin]

Here's more questions for the group:

I just removed the column cover, and got a look at the vertical feed gears (picture below). On my machine, there is no oiler, or provision for lubrication, that I can see. The gears look dry as a bone to me, so if they were ever lubricated it was a long time ago. The Harvey LG (supposedly a "copy" of the Sanford MG) has a top oiler for these gears.

Sanford MG owners: Do you lubricate these gears? If so, how, and what lubrication do you use?

 

[kevin]

projectnut -

I just noticed that MSC also sells a Sopko LH slotted nut (https://www.mscdirect.com/product/details/05924154?fromRR=Y), so I assume this is supplied with some adapters. They also sell a wrench to work with it (different from your wrench).

 

[projectnut]

Here's a little more information on my machine. The small end of the spindle taper is .687". The large end is 1.000" The length of the taper is 1.275". There is no provision on the hub for balancing the wheel. In Kevin's last set of photos the gear type adaptor on the rear of the wheel appears to be for balancing. Also there is a flanged ring set screwed to the spindle at the shoulder of the taper that appears to be a dust guard rather than a bearing retainer.

The hub removal tool sounds like a great idea, however there are only 2 full threads on the inside bore on my hub. I believe they would have stripped out long before the hub popped loose from the spindle. The threads on the spindle that retain the hub are left hand. The ones on the hub that retain the wheel are right hand. As for the spindle nut, Travers Tool Co. and other suppliers sell both hex and slotted nuts.

While the taper on my spindle may be standard (haven't done the math yet), I'm not sure the spindle itself is original. When I removed the hub I could plainly see one of the spindle bearings recessed in the housing about 1/2". I could clearly read MRC 205SZZ Made in USA Pat. Pending printed on the seal. First off I don't believe the 205 series bearings are high precision, plus when I Googled them I found they are metric. They are listed as having a 25 mm ID. Maybe that's close enough. to be used for a 1" bore, but I don't think metric bearings were even available in this country in 1954.

As for oiling of the vertical feed gears, take a look at the 3rd picture in my first post. My machine has 2 Gits type brass oilers on top of the column. One is directly over each of the gears. I just put a few drops of oil in each before using the machine.

One last observation. If the Harvey machine is really a copy of the Sanford I can see why the table stop option was expensive. The front of the table is plain, so the T slot channel and stop blocks would be part of what would need to be ordered. Also the stop mechanism bolted to the way cover appears to be cast. I'm sure that's why it was a rarely ordered option. I would think almost any shop could fabricate 10 stop systems for less than it would cost to purchase 1 from Sanford. Over the years I have used at least a dozen different brands and models of surface grinders. About the only ones I've seen where table stops are used regularly are the hydraulic auto feed ones.

 

[kevin]

projectnut -

I calculate your TPF = (1−.687)÷1.275×12 = 2.946", or essentially TPF=3" allowing for the inaccuracies of measuring taper with a caliper; I'm guessing your spindle is original, but certainly not the metric bearings.

You may be interested in this:

https://www.vxb.com/2-Angular-Contact-Bearing-7205B-25x52x15-p/kit1088.htm

Note the related comment: Reviewer: John From Wallingford from Wallingford CT - I use this in a Sanford Model MG612 surface grinder. The grinder calls for high precision ABEC class 7 bearings costing in the neighborhood of $300.00 for the set. But in a non production shop these are just perfect and I can still grind to withing 0.0005"

I don't believe my gear type adapter has any balancing function. I took it apart and took some pictures to give you a better look at it. I bought the gear nut wrench from Sopko via MSC - it came with a spare "glare gear nut" and "glare washer" both of which fit my adapter. I'm thinking the main part of the adapter could be made without too much difficulty, and the gear nut and washer can be purchased, so this might be another way to come up with additional adapters (not a problem for you, as you have a standard taper).





Would you mind taking a closeup picture of your top oilers? What kind of oil do you use in them? Are they original to the machine or added later?

Note: I see what appear to be similar oilers in some of the advertising pictures (but not in others) - maybe Sanford started adding them at some point?

 

[Bob Korves]

The hub removal tool sounds like a great idea, however there are only 2 full threads on the inside bore on my hub. I believe they would have stripped out long before the hub popped loose from the spindle. The threads on the spindle that retain the hub are left hand. The ones on the hub that retain the wheel are right hand. As for the spindle nut, Travers Tool Co. and other suppliers sell both hex and slotted nuts.

The taper on those spindles is quite conical and the wheel adapters should come off easily. I can usually take mine off almost without a wrench. The wheel adapters do not need to be cranked on to the spindle really tight. If there is rust on the spindle taper or in the wheel adapter, then that needs to be addressed carefully, because spindle taper runout should be held to very tight tolerances, not more than .0001". Please do not take sandpaper or a file to it.

If the wheel turns clockwise as viewed by the operator, then the spindle thread and the wheel adapter flange nut should both be left hand thread. A two tooth washer fits into slots in the wheel adapter, and mounts between the grinding wheel and the threaded flange. A surface grinder should not be used with that washer missing. They are cheap and easy to purchase. The flange and wheel can easily depart the wheel adapter without the toothed washer present. In a pinch, a right hand threaded wheel adapter can be used on a clockwise turning wheel, but ONLY if the toothed washer is present, and that is still not a recommended procedure (though it does seem to work.)
http://www.wmsopko.com/sopko_045_78.htm bottom of page

Wheels coming apart from crashes or cracks in them, thrown parts or wheels, and spinning wheels contacting body parts are the biggest dangers around a surface grinder, and all can be debilitating or fatal. Y'all be careful out there...