# Disassembly and Cleanup of a Sanford SG48 Surface Grinder



## vtcnc (Aug 16, 2020)

I need a surface grinder for a project I'm about to resume and have had my heart and mind complete wrapped around the Sanford SG for a number of years now. Why? 

small and benchtop size - which is perfect for the size of parts and shop that I have and will continue to occupy.
easy to move around if I need to.
easy to learn on, work on and buy things to put on (it),
relatively inexpensive and easy to pickup when one finally shows up in my locale.
Well, my patience finally paid off. After a few years of looking, waiting and eBay alerting - FB Marketplace won the day.

For you big city folk, I'm about to wrap this story in Vermont context...so skip ahead if you can do without the yokel blathering on here...

The Sanford was in possession of Ken Millay at Springfield Tool, in Springfield, Vermont. For those of you who recognize that town, it is the former home of such companies as Fellows Gear Shaper, Cone Bryant, etc. My grandfather used to work for Cone as a mechanical engineer, he gave me some of his old gear tables that he had to make up for himself while doing his engineering. I'll post those someday in the downloads, but they are huge blueprints. I worked in the Gear Shaper building for a telecom mapping company - this was long after Fellows had gone away. If I recall, there was a bingo hall and gymnastics studio in the converted assembly halls, karate studio and an architect firm in the office areas and the little engineering company I worked for on the second floor. I'm sure there was more but the building was mostly empty. When you drive in and around the "Precision Valley" you really can feel that something great went on there many, many decades ago. It is a bit of a ghost town now and it is kind of sad. Up the road (vernaculur for 20 miles north) is the American Precision Museum. Springfield Tool is out on the backroads, up in North Springfield, where the Precision Park is located with a number of old, unkept buildings, with the exception of Springfield Tool. This is truly a holdover of the old days. Ken is in his eighties, is an old Tool & Die maker and a really nice guy - and my goodness does he have some tooling! One of the funny coincidences we discovered is that Ken asked what I did for work. When I told him I managed the Edlund Co. he was floored. Edlund happened to be one of Springfield Tool's first customers and that his father-in-law was best friends with my predecessor (from the 1960s-80s). When you hear the colloquial, "It's a small world!" - that's Vermont. Back to the Candystore - I counted six to eight aisles of tooling cabinets and shelves. Out back is his tool and die shop and high bay warehouse - MORE machines and stuff everywhere. He says that his goal is to sell off everything over the next couple of years on eBay and from what I can tell he is set up well to do so.

He came by the Sanford by way of an estate sale a few years ago and claims it was one owner. I believe him. It is in good, working condition, doesn't appear to have been abused, it was well oiled, has been fitted to a heavy cast iron (non-Sanford) stand and has the original electro-mag vise. I bought this from him for $500. I consider that a good deal. He claimed the only thing potentially wrong with it was that the belt could use some work.

Serial number:





Can anyone confirm that the mfg. year is 1956, and this is the 2016th unit built?
_______________
Belt Condition:




The belt is Sanford OG. They continued to operate through the eighties. The SG310 belt listed in the manual (thank you @DAT510) suggests this is the correct size for units made with serial number up to 161 (again, assuming that means 1961). So the belt is correct, but it is frayed along the sides and I had to trim off the pieces. The belt works for now, but first thing I buy for this is a replacement belt.
_________________
Longitudinal Table Ways:




Not pretty, but oil grooves are intact. If you look closely on the flat way, you can see a dark band along the right side of the flat. That is higher then the rest, so quite a bit of wear. You can see two dark bands either side of the v-way. Same thing there. Wiped down with a little degreaser, and when I placed the table back onto the cross table, filled the oil cups with SAE-10W.
_________________________
Cross table:




The v-ways and flat on the cross table, that support the sliding longitudinal table. Some scraping to facilitate oil entrapment on the ways is evident here, both on the flat and v-way.

Since these ways are slightly narrower than those on the longitudinal slide, you get the dark, unworn bands of uneven wear. This doesn't seem like a problem at all to me - so more de-greaser, a nylon brush to clean up the oil pockets and will re-lubricate later.
____________________




The v-ways supporting the cross table. I'm a little worried about these -but it is mostly appearances along the edges. They are fairly ragged. Is stoning the edges a good idea? Or leave it well enough alone? The action is smooth and no problem from what I can tell.
_______________________
Bottom of Cross table:




All of this looks good. De-grease, reinstall and oil.
________________
Cross Table Installation:




The table is attached to the lead screw nut by those two cap screws between the flat and v-way.
_________________




The motor bracket removed and exposing the back of the column. Here you can see the back of the spindle and belt. Also, the three cap screw column arrangement is one of the giveaways that this is a second generation Sanford. It was early enough though that it retained the bronze lead screw nut which was replaced shortly after this unit was made - judging from the serial numbers.

When we tested the unit in Springfield, Ken was saying the leadscrew might need some work because he didn't feel the unit was precise enough. He said the leadscrew was dropping a thousandth or two after you turn the feed wheel. After removing the motor bracket, I understand why. It was loose - and my guess is that the motor bracket provides some resistance to backlash on the screw and nut when it is properly torqued. Once I had done that, the feed wheel appeared to hold its position. Actual measurements after grinding will be the true test.
_________________
The Not Original Base and Janky Risers:




I'm not a fan. I will either re-purpose this base at some point in the future or sell it. Would be interesting to know what it's original purpose was for. Very quickly, you can see a couple of features that may help identify it. First, there are four bosses that are cast into the base for mounting whatever machine was originally sold with this base. Second, there is a slot in the base next to one of the mounting positions, you can see it lower left corner. If you let your eye follow that leg down to the foot, you can see another boss protruding to the inside of the leg, just above the caster. My guess is that is a pivot mount to let a motor pivot and tighten the belt, or some sort of lever mounted belt tensioning mechanism.  Photos of the base and leg part numbers:











Anyway, the base it slightly lighter than the machine itself, I would put it at 120 lbs. The machine with the motor mounted (which isn't that heavy) is probably around 150 lb. I don't like the mounting method and the machine should be properly leveled and put on a base that is stable and doesn't risk wobbling on casters. Yeah, I'm being particularly picky here, but I feel like a working collectible machine like this should be treated better. I will eventually give this a thorough overhaul at somepoint in the distant future and repaint as well. There a couple of small issues to investigate in the meantime. The vertical leadscrew cover has a crack in the mounting hold. It wobbles a bit. I'll have to fix that. The vise on the unit currently is a mechanical mag vise. It did come with the original electromagnetic vise and Ken said the circuitry needs work underneath the base. I'll unravel that another time and see what can be done to restore that as well. But that is a future side project and isn't needed right now.

All cleaned up!!


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## rwm (Aug 16, 2020)

That is a cool little machine. I might need one of those!
Robert


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## Dhal22 (Aug 16, 2020)

Very nice.


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## Ulma Doctor (Aug 16, 2020)

very nice machine!


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## ACHiPo (Aug 17, 2020)

What size?


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## vtcnc (Aug 17, 2020)

ACHiPo said:


> What size?


4"x8" travel. 6" from table to spindle centerline. With a 4" wheel, that clearance is reduced to 4".


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## Cooter Brown (Aug 17, 2020)

Wow you are going to make lots of guys here on the forum very jealous. Great Find!


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## chips&more (Aug 17, 2020)

Very Nice! Great find! I also have a SG48. Did not realize at the time the lack of capability I was having until I got it! It has been a must have in my Hobby Shop ever since I got it!!! I think you will have the same happiness!


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## vtcnc (Aug 17, 2020)

I just ordered a 5/8" x 17" polyurethane rubber flat belt off from McMaster for this. Hopefully that is durable enough. I can't see how it wouldn't be.


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## Ulma Doctor (Aug 17, 2020)

poly belts are very nice in that they don't stretch.
(not trying to be a bummer here, just a point to consider )
that may or may not be a desired trait.
a rubber or leather belt may give a bit more, which may or may not produce a better overall surface finish.

i'll be interested to see if the poly belt imparts any vibration to the end surface.
i will be following to see how the lil' gem progresses, regardless.


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## 9t8z28 (Sep 22, 2020)

Very cool machine for a killer price!  Just so you know, according the owner of Sanford, you could special order what speed you wanted the wheel to run at so there were a few options for pulley and belt sizes.  Is yours a flat belt or V-belt?  I cant tell from the pics.  Mine is a flat belt and I had to make a replacement spindle pulley.  You can get replacement belts from wmsopko.com or any vacuum cleaner store.


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## 9t8z28 (Sep 22, 2020)

Very cool machine for a killer price!  Just so you know, according the owner of Sanford, you could special order what speed you wanted the wheel to run at so there were a few options for pulley and belt sizes.  Is yours a flat belt or V-belt?  I cant tell from the pics.  Mine is a flat belt and I had to make a replacement spindle pulley.  You can get replacement belts from wmsopko.com or any vacuum cleaner store.


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## 9t8z28 (Sep 22, 2020)

My SG is serial# 1602278 and was made in the 1960's.  If you need any help with replacement parts or questions LMK.  I have contact information if you want further details about the details of the machine.  Message me if you would like that.


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## 9t8z28 (Sep 22, 2020)

There are a few things that can cause the spindle to drop.  I would check with a dial indicator with the machine off and running.  The vibration along can cause it to drop.  Also, as you mentioned, the motor mount is one but also (2) the backlash in leadscrew assembly, (3) the handwheel shaft bore, (4) , the mesh between the gears, (5) the thread tolerance from the bevel gear to the acme screw and (6) the clearance between the bevel gear and the top plate.  I would check all of these and take note to their condition as they all play a part in whether or not the spindle creeps down.    I have a replacement leadscrew and bevel gear from Mcmaster.  I have yet to cut the acme threads as I need to order a special acme tool.  These machines, as great as they are did not have the best covers in place to keep grinding dust from migrating its way to these key components.  A little bit of dust goes a long way at chewing it up.


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## vtcnc (Sep 22, 2020)

9t8z28 said:


> My SG is serial# 1602278 and was made in the 1960's. If you need any help with replacement parts or questions LMK. I have contact information if you want further details about the details of the machine. Message me if you would like that.



Thanks! 


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## 9t8z28 (Sep 22, 2020)

I forgot to add, this size grinding wheel is tough to come by.  Set up a search on Ebay with alerts as they do come up now and then.


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## vtcnc (Sep 22, 2020)

9t8z28 said:


> My SG is serial# 1602278 and was made in the 1960's. If you need any help with replacement parts or questions LMK. I have contact information if you want further details about the details of the machine. Message me if you would like that.



I got a flat belt replacement from McMaster Carr. Seems to have done the trick.


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## Sblack (Oct 3, 2020)

I took the King scraping class in springfield on the top floor of a gear shop right behind the old Fellows gear shaper works. I agree, kind of sad. The owner of the shop had been a tech for Fellows and restores and modifues the machines for customers and makes custom gears. He showed us a gear shaper in action. I had never heard of one let alone seen one. 

That is a very nice grinder. The legs remind me if an atlas 7 inch shaper base. The base and riser certainly are hoakey and have to go. Lots of iron left for you to machine and scrape the ways if required. I have a slightly larger machine made by delta but it has a few drawbacks. Yours looks ideal for a small shop. Im sure you will find all sorts of cool things to do with it. No you are going to learn how much high precision grinder tooling costs! Meet Mr Harig and mr. herman Schmidt!


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## 9t8z28 (Oct 5, 2020)

Not to highjack your thread but there is a very early model on Ebay if anyone is interested.  He is asking quite a bit, its missing the column sheetmetal covers and there's no description.  The covers are easy enough to make.  It has a mag chuck which is really hard to find and the wheel guard is intact.    The fact that there's no description is a red flag to me but if someone can go look at it it might be worth it if it was maintained.  https://www.ebay.com/itm/Sanford-be...rentrq:fa93fb0c1740aa4852fb3c7dffe738b8|iid:2


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## Sblack (Oct 5, 2020)

That’s amazing. You can pick up much bigger grinders all over the place for $500 but this one is $1500 and likely has a ton of bed wear under that beautiful turquoise paintjob ()  and the handle shafts probably wobble back and forth 50 thou and the spindle sounds like a chain saw. I guess sellers realize that a small machine that fits in a basement is way more sellable than an industrial machine that you need a crane to move. Only hobbyists are buying, well, normal hobbyists, nit tom lipton or keith rucker!  $1500 for that is insane. It would need 50 hrs of skilled work to make it anything more than a paper weight.


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## pontiac428 (Oct 5, 2020)

Yeah, @Sblack, you called it.  There are a lot of 618 type SGs out there (including automatics) that are selling for less than a Sanford.

BUT:  The Sanford is cute and easy to find space for.  You know I'll be watching this thread!


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## vtcnc (Oct 5, 2020)

9t8z28 said:


> Not to highjack your thread but there is a very early model on Ebay if anyone is interested. He is asking quite a bit, its missing the column sheetmetal covers and there's no description. The covers are easy enough to make. It has a mag chuck which is really hard to find and the wheel guard is intact. The fact that there's no description is a red flag to me but if someone can go look at it it might be worth it if it was maintained. https://www.ebay.com/itm/Sanford-be...rentrq:fa93fb0c1740aa4852fb3c7dffe738b8|iid:2



He is taking offers...just because he is asking $1500 doesn’t mean you have to offer him that much.


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## 9t8z28 (Oct 5, 2020)

Agreed but I have been watching the bench model Sanford's on Ebay for a long time now and when they do pop-up they sometimes go for $1500 to $2K on Ebay.  I could see this guy holding on his price because of the vise and wheel guard if he knows what he's got.  Parts for these are ridiculous, more expensive than Atlas shaper parts.  The wheel guard is never seen sold by itself.  I wish I could find one instead of making mine.  


vtcnc said:


> He is taking offers...just because he is asking $1500 doesn’t mean you have to offer him that much.
> 
> 
> Sent from my iPhone using Tapatalk


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## vtcnc (Oct 5, 2020)

9t8z28 said:


> Agreed but I have been watching the bench model Sanford's on Ebay for a long time now and when they do pop-up they sometimes go for $1500 to $2K on Ebay.  I could see this guy holding on his price because of the vise and wheel guard if he knows what he's got.  Parts for these are ridiculous, more expensive than Atlas shaper parts.  The wheel guard is never seen sold by itself.  I wish I could find one instead of making mine.


This will be interesting to see if it sells at that price then. I would be shocked. I got mine for $500 - I never would have considered it if it were north of $1000.


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## ddickey (Oct 5, 2020)

North of a grand? I'll take offers for mine then.


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## 9t8z28 (Oct 5, 2020)

Well if you want or need a surface grinder and have restrictions on power as well as space and will have a hard time getting it in your shop it starts to make a whole lot of sense.  Consider the cost to have a larger machine shipped plus the cost of a rigger to get it where you need it plus the cost of running the electric, it makes a whole lof of sense.  


vtcnc said:


> This will be interesting to see if it sells at that price then. I would be shocked. I got mine for $500 - I never would have considered it if it were north of $1000.


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## vtcnc (Oct 6, 2020)

9t8z28 said:


> Well if you want or need a surface grinder and have restrictions on power as well as space and will have a hard time getting it in your shop it starts to make a whole lot of sense. Consider the cost to have a larger machine shipped plus the cost of a rigger to get it where you need it plus the cost of running the electric, it makes a whole lof of sense.



I completely agree. It could definitely make sense to spend over $1000 for a Sanford for the right person. Just pointing out that for myself, I would definitely feel obligated to do the mental gymnastics to figure out the best choice given how ubiquitous 6x12 SG are out there in the wild. Many of them can be picked up for $500 locally and if you have a friend to help load and unload it makes even more sense to go bigger - practically speaking - given hobbyists budgets, frequency of use, etc. 

This little Sanford is practical for a hobbyist and IMO just cool as heck. But for the $500 I spent on mine I consider myself just plain lucky and can say that my opinion was definitely bundled with the package price. 


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## WobblyHand (Sep 15, 2021)

@vtcnc in the other SG48 post it was pointed out that your wheel shield had SANDFORD on it.  In post #1, picture #4, of this thread, SANDFORD is also cast into the cross table.  It is also visible in another picture.  You have a curious machine, half SANDFORD, half SANFORD.  If this was an early machine, perhaps it was a foundry error?  In anycase, it is an amazing machine.


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## wlburton (Sep 15, 2021)

It must have been an error by whoever made the mold, not caught by anyone until they were ready to assemble the machines.  That should make it worth even more money, like those double stamped coins and stamps that are worth more because of their rarity!  Someone must have been very embarrassed, but not enough to throw away some perfectly good castings.


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## Dabbler (Sep 15, 2021)

Sorry I missed the thread when you posted it.  Very nice machine - you will have a lot more than 500$ of fun out if it!


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## vtcnc (Sep 15, 2021)

It’s been a great little machine the few times I’ve used it.

I have to say I’m quite embarrassed I missed this typo. It is very hard to believe that this is a foundry mistake, If true though, there must be more out there, right?

On the other hand, the typo was made on two molds? Again, it seems very unlikely to me. A real head scratcher. I’ve been scouring the internet for photos of other machines that have the same name and haven’t turned up anything.


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## vtcnc (Sep 16, 2021)

vtcnc said:


> It’s been a great little machine the few times I’ve used it.
> 
> I have to say I’m quite embarrassed I missed this typo. It is very hard to believe that this is a foundry mistake, If true though, there must be more out there, right?
> 
> ...


Went out to the shop last night and did a walk around the unit. I think those that suggested that "Sandford" is a typo are absolutely correct. Refer to earlier photos in the thread to see the typos in the casting. Below is a photo of the inside of the column I took last night. ( I have the motor removed temporarily) 







It is inconceivable to me that you could spell it correctly on multiple runs of castings but get it right on another. My only guess is that a newbie was assigned to setup the inserts and thought he was working at Sandford until somebody told him it was Sanford.  Regardless, this new discovery gives me some relief and assurance that it is indeed a Sanford and not a cheap knockoff badged and passed of as an original. Until I hear otherwise, that's my story and I'm sticking to it!

This happens at my current employer. The name of the company is Edlund Co. and has been for 96 years. Most locals refer to it as Edlunds. Subtle difference that everyone knows is the same thing. You can tell somebody that there is no "s" but they will continue to write it and say it that way.


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## WobblyHand (Sep 16, 2021)

vtcnc said:


> My only guess is that a newbie was assigned to setup the inserts and thought he was working at Sandford until somebody told him it was Sanford.


Newbie, drunk, malevolent, or a bad speller?  Pretty sure it's a Sanford, but there's still a hidden story there.  Wonder if there are other Sandford SG48's or even on their other models.  Be fun to find out.


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## Dabbler (Sep 16, 2021)

I always thought that "Sandford" was interchangeable with "Sanford".  In Southern Ontario, you saw machines with either, but were obviously from the same manufacturer...


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## vtcnc (Sep 17, 2021)

Dabbler said:


> I always thought that "Sandford" was interchangeable with "Sanford". In Southern Ontario, you saw machines with either, but were obviously from the same manufacturer...



Doesn’t it seem strange though that if true, they would allow it??


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## WobblyHand (Sep 17, 2021)

vtcnc said:


> Doesn’t it seem strange though that if true, they would allow it??
> 
> 
> Sent from my iPhone using Tapatalk


Sure does.  If it was my product, I'd want my product name or brand spelled correctly.  Suppose that's just my personal pride though.  Maybe they were just pragmatic and figured as long as people bought them, they'd keep on making them.


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## Dabbler (Sep 17, 2021)

I wondered if the brand started one way, and changed due to naming conflict or some other kind of external forces...


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## Bob Korves (Nov 9, 2021)

Just found this post...  Nice job on the Sanford, Bryan!


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## vtcnc (Mar 10, 2022)

Trying to rewire and make functional all electrical features on my SG-48.

Sanford Wiring Diagram

I downloaded the schematic provided in this thread from a thread over at PM and after having read through the post a couple of times and then watching the following video, I decided to take this on.






Here is a photo album link to my wiring job.









						Sanford SG
					

31 new items · Album by Bryan Lund




					photos.app.goo.gl
				




Round 1:
I installed a main switch as you can see in the photos. Motor switch flopped to on and spindle turns on and off. Once.

Fuse is not blown. Resister still reads at rated value. I get proper drops in correct polarity through bridge rectifier.

After having unplugged the unit from main circuit power, I checked the cap for voltage and read 0. I turned the mag chuck to on and the cap discharged (spark).

_Lessons Learned:_ test cap voltage at right wavelength. DC not AC. Yes, that was a rookie and nearly very costly mistake. Good news, I wasn't shocked or anything - just spooked and woke me up to making sure I knew what I was doing. This is my first AC to DC wiring project. I wouldn't have tried this without the schematic or some YouTube guidance and now I'm kind of stuck.

Round 2:
After a couple of days of staring at this thing. I decided I made a mistake on the motor switch. I fixed the neutral wires and steeled myself for ignition.

Motor turns on and stays on. Turn off the motor and try the mag-on. Nothing. Mag-off. Turn the motor back on. Nothing. Blew the fuse (10A) this time. Motor is rated for 6A. Schematic says to allow for 1A for the DC circuit feeding the chuck.

Capacitor measures a charge at 155VDC. O.k., I don't want to discharge this the fun way. I step away. Lock the shop and go online and order a discharge pen. 

Round 3:
I think this is wired correctly, but obviously, it is not and I'm unsure how to proceed in troubleshooting. Discharged the cap using the pen. All is good. Replaced the fuse. Now I'm staring at the circuit again.

Is anyone here willing to take a look at the photos and offer some help? Note: the DPDT switch has the neutrals removed and tied together.


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## Dabbler (Mar 10, 2022)

it is very hard to help diagnose from the photos alone.  I'm at a loss as to how I might help.  I wish I were an hour away - sometines it just takes one silly question or its explanation to get to the root of the problem.


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## ddickey (Mar 10, 2022)

Post some photos, why not?


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## WobblyHand (Mar 10, 2022)

Can you post the schematic you worked with?  Without that it's hard to tell if you followed it!  Or the schematic you followed is incorrect.  Can't decipher the puzzle without help from you


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## ddickey (Mar 10, 2022)

Click download.








						Sanford SG48 Surface Grinder Rewiring Diagram
					

This is a wiring diagram of full bridge rectifier for a Sanford Surface Grinder, Model SG48.  It is designed to convert AC line voltage to DC voltage. There is a provision for motor on/off, electromagnetic chuck on/off/degauss.  Included below is...




					www.hobby-machinist.com


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## WobblyHand (Mar 10, 2022)

ddickey said:


> Click download.
> 
> 
> 
> ...


Oh.  See it was posted earlier.  My bad.  Well, that's a simple schematic.


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## WobblyHand (Mar 10, 2022)

So as I understand it you are still at round 3.  So the fuse blows after turning on the mag chuck.  But, before then, the motor worked, right?  Sounds like it is the mag chuck circuit.

One thing I see is the "ground leg of the capacitor" is not grounded.  This may or may not be an issue.  So the DC voltage might be floating, ie. the low side could be a value that is not ground.

The other thing is the magnetic chuck.  What is the rated input voltage?  Is there a rated current?   With J1 disconnected, from this circuit, can you measure the resistance of the chuck?  Can you check if either lead of the chuck is connected to the chassis (machine) ground or anywhere on the chuck surface?


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## vtcnc (Mar 10, 2022)

Here are recent photos of where I am at:








Left to right: mag switch(DPDT), spindle switch (DPST) and main switch (SPST)






I also checked the resistance of the chuck. No continuity. I also checked both connector legs against the various parts of the chuck. No continuity. 

Not sure where to go with this. 


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## WobblyHand (Mar 10, 2022)

vtcnc said:


> I also checked both connector legs against the various parts of the chuck. No continuity.


I think this is good.  A short to the case would be bad.

As for the resistance of the chuck, I don't know what it should be.  However this link, https://www.magnalock.com/post/electromagnetic-chuck-tips-troubleshooting-your-chuck leads me to believe it should have some resistance.  Do you have any information on what the chuck specifications are?   This link https://www.practicalmachinist.com/vb/general/how-test-magnetic-chuck-176302/ seems to indicate a typical resistance of about 400-500 ohms.  So an open circuit is probably a bad thing - as in, you will have to repair the chuck somehow.

The bridge rectifier.  The mounting hole, I see has a metal ring?  Is this ring isolated from the rest of the 4 terminals?  I would think it should be.  Is it?  Make sure you *Discharge the cap*!  Disconnect the wires from the bridge and measure it.  Check each diode (one polarity across the diode should have low resistance, the other polarity of your test leads should have a much much higher resistance) and if the diodes are isolated from the chassis.

What was the DC voltage across the capacitor?  What is your input AC voltage?


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## ddickey (Mar 11, 2022)

Mine was ~800ohm. I can check it again after work.
@vtcnc did the mag cuck ever work?


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## vtcnc (Mar 11, 2022)

WobblyHand said:


> I think this is good. A short to the case would be bad.
> 
> As for the resistance of the chuck, I don't know what it should be. However this link, https://www.magnalock.com/post/electromagnetic-chuck-tips-troubleshooting-your-chuck leads me to believe it should have some resistance. Do you have any information on what the chuck specifications are? This link https://www.practicalmachinist.com/vb/general/how-test-magnetic-chuck-176302/ seems to indicate a typical resistance of about 400-500 ohms. So an open circuit is probably a bad thing - as in, you will have to repair the chuck somehow.
> 
> ...



Thanks for the troubleshooting links. I’ll dig into these sometime today to gain a better understanding of the mag chuck and troubleshooting.


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## vtcnc (Mar 11, 2022)

ddickey said:


> Mine was ~800ohm. I can check it again after work.
> @vtcnc did the mag cuck ever work?



I’m getting no resistance across the chuck. Good question on the chuck. It may be that it is cooked. I don’t know how that could be. Maybe it is in the connectors. I’ll do a little additional checking this weekend.


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## vtcnc (Mar 11, 2022)

WobblyHand said:


> I think this is good.  A short to the case would be bad.
> 
> As for the resistance of the chuck, I don't know what it should be.  However this link, https://www.magnalock.com/post/electromagnetic-chuck-tips-troubleshooting-your-chuck leads me to believe it should have some resistance.  Do you have any information on what the chuck specifications are?   This link https://www.practicalmachinist.com/vb/general/how-test-magnetic-chuck-176302/ seems to indicate a typical resistance of about 400-500 ohms.  So an open circuit is probably a bad thing - as in, you will have to repair the chuck somehow.
> 
> ...


Arrggh. I read through the PM post on "How to Test Magnetic Chuck" and they indicate zero or near zero ohms means its probably toast. Mine is reading zero.

Another problem I discovered is that the connectors on either end of the cable are reversed. They are "Jones" style connectors, if my memory serves me well. There are two spades per end. One spade larger than the other. When I checked for continuity on the cable, the large-to-large read zero. Large-to-small checked out with continuity. I'm wondering if the previous owner replaced the cable and polarity was inadvertantly reversed and that is what cooked the whole system to begin with???

This project may be dead in the water. I do have a mechanical magnetic chuck and can still use the machine, but it sure would have been nice to get the original electro-magnetic chuck working properly. 

If I can disassemble it and see what might be wrong, I'll post pictures.

Bryan


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## WobblyHand (Mar 11, 2022)

vtcnc said:


> Arrggh. I read through the PM post on "How to Test Magnetic Chuck" and they indicate zero or near zero ohms means its probably toast. Mine is reading zero.
> 
> Another problem I discovered is that the connectors on either end of the cable are reversed. They are "Jones" style connectors, if my memory serves me well. There are two spades per end. One spade larger than the other. When I checked for continuity on the cable, the large-to-large read zero. Large-to-small checked out with continuity. I'm wondering if the previous owner replaced the cable and polarity was inadvertantly reversed and that is what cooked the whole system to begin with???
> 
> ...


Yeah, I didn't want to say that...  My background is electrical engineering, but I have never used a mag chuck before.  However, I wouldn't think that reversing polarity would be harmful.  Basically, the chuck is an electromagnet, which is just a coil, and is passive.  Shouldn't care about polarity, unless there was a fault in it or some diodes or other active elements.  If there is a diode, then maybe it has faulted short.  You may be able to take it apart and figure it out.  If you are lucky you will see some discoloration that may give you a clue.  If there's no active circuitry, then it could simply be that the insulation got shorted out in one or more places.  Maybe it was taken apart once and the cover was not replaced carefully and some wires were pinched.


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## WobblyHand (Mar 24, 2022)

@vtcnc have you had a chance to look at your chuck?  Just wondering if you had cracked it open or not.


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## vtcnc (Mar 24, 2022)

WobblyHand said:


> @vtcnc have you had a chance to look at your chuck?  Just wondering if you had cracked it open or not.


I did. Disconnected magnet wire. Damn if I can't get the enamel stripped and soldered. Anyone have a recommended temperature for soldering fine magnet wire?


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## WobblyHand (Mar 24, 2022)

That should be good news about the wire!  You found the disconnect.  

The "good enamel" resists melting off under heat.  I have found some magnet wire that uses a heat sensitive insulation that you can just solder without doing anything special.  However, most magnet wire is coated with a tough insulation, the "good enamel".  Unless someone else knows of something better, I have often had to resort to mechanical means to remove the enamel insulation.  I have often scraped off enamel with a razor blade, or xacto knife, but you have to be very careful not to knick the wire.  

I am presuming the wire is copper, so any 60/40 or 63/37 lead tin solder would work.  If you want or need to go lead free, there's plenty of choices as well.  Probably want to use some heat shrink or kapton tape to keep it from shorting to case.


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## MikeInOr (Mar 25, 2022)

I usually have to scrape the enamel off magnet wire too.

I am sure I will probably be corrected here but when my father gave me a surplus 6 x 18 magnetic chuck he told me that you put the part on then magnetize the chuck with DC current for a half minute or so.  Something like 60v or 80v dc I think.  Then when you are done grinding you demagnetize the chuck with AC current.  Basically magnetize with the rectifier in the circuit then demagnetize by removing the rectifier from the circuit using the same step down transformer.

I still have the chuck, I just need the rest of the grinder to go with it.  I remember using a VARIC, a rectifier and a momentary DPDT switch to wire it up and it did work.  I might have just been using the VARIAC to minimize the chance of the chuck smoking when I was testing it... I don't remember. Like WobbyHand said there is no polarity in my magnetic chuck.

I figured that the magnetic chuck would be energized during the entire grinding operation but my father was usually right on things like this.

P.S. I have cauterized a mess of server hard drives with my magnetic chuck, it does a great job at that.

Edit: There wasn't an Internet when he gave me the magnetic chuck.  A quick Google search says that I have an Electro-Permanent magnet chuck and it does appear to work as I described.  It also appears that there are Electric magnetic chucks that will not hold a part without being energized.


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## Weldingrod1 (Mar 26, 2022)

With the right parts you can set up a chuck to demag with a capacitor. That's how my home built Magnabend works. Choosing the value is a but tricky, though.

Sent from my SM-G715A using Tapatalk


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## 9t8z28 (Mar 26, 2022)

I wish someone made a mag chuck to fit the Sanford SG's.  They are all 4" x 7" which is to wide and can't be ground.   Those that do offer one are more expensive than the grinder itself.


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## TorontoBuilder (Oct 8, 2022)

wow long project... but so nice. 

I tried for literally decades to find a miniature surface grinder to no avail. Now my brother and I have an 8x24 monster


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## ddickey (Oct 8, 2022)

@TorontoBuilder I've had one for sale for probably three months now. Can't sell it.


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## TorontoBuilder (Oct 8, 2022)

ddickey said:


> @TorontoBuilder I've had one for sale for probably three months now. Can't sell it.


What are you asking for it? What condition is it in? 

Can you post a pic? 

If  there was a serious buyer would you crate and ship it freight?


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## ddickey (Oct 8, 2022)

$825. I scraped in all surfaces and added turcite to the saddle. The wiring for the chuck was in bad shape. Planned to redo the electronics like the print in this post but never got to it. I will probably do that this winter. My guess is that's why it hasn't sold, which is understandable. The chuck and motor ran great before.
I guess one could screw it to a pallet and wrap with cellophane? IDK


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## Dabbler (Oct 8, 2022)

ddickey said:


> Can't sell it.


Shipping to those who are in the machine tool desert is a killer to sales.


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## TorontoBuilder (Oct 8, 2022)

ddickey said:


> $825. I scraped in all surfaces and added turcite to the saddle. The wiring for the chuck was in bad shape. Planned to redo the electronics like the print in this post but never got to it. I will probably do that this winter. My guess is that's why it hasn't sold, which is understandable. The chuck and motor ran great before.
> I guess one could screw it to a pallet and wrap with cellophane? IDK
> View attachment 422682


In Toronto that would sell very quick. We are very space constrained in our shops and few machines fit handily into a basement.

I'd screw it to a half pallet, and build walls around with it with 2x2" and aspenite, and add a top rather than shrink wrap. 

Shipping and rewiring would likely take it beyond my budget. 

As an example, a 5x10 delta toolmaker's surface grinder has been for sale in Ontario for $2500 for a year at least, but two others have sold in that time for $1500


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## TorontoBuilder (Oct 8, 2022)

Dabbler said:


> Shipping to those who are in the machine tool desert is a killer to sales.



Yep. It would be $405 CAD to ship 15 KVA transformer from Winnipeg to Toronto, but I can drive to Drummondville PQ for ~$250 and pick up both a 15 KVA transformer and a 7.5 HP phase converter. That's why I have to drive to Drummondville tomorrow...


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## Subw00er (Oct 12, 2022)

This is a great thread! Can I crash the party?! I just acquired an old sg48 (#47-1198 - 1947 model?). It appears to be in good shape, but I see no scraping on the ways. I'm trying to learn about it, and I need to find a flat belt. How is that McMaster 5/8"x17 poly belt working for you @9t8z28 ? I heard some grabbed a 1"x18" rubber/plastic core (I found this one: https://www.mcmaster.com/6082K12-6082K613/ )






I also have to figure out the wiring. It has some weird connector malarkey going on - the cable wont go into the chuck - screws are too large, so someone has been in there messing about. Is that two pin connector stock? Also, it looks like where the cable goes into the body has been modified with a little plate. I haven't plugged it in yet, and I want to investigate a bit more before I do. I guess there are tubes in the base?! I tipped my machine over to look, but there is cover there. 









Also, my unit has been painted I think, and I doubt that chrome is standard - has anyone seen that before? Someone must have loved this previously.  Its in fairly decent shape and complete.

One last question, does anyone know what this threaded chrome piece on the side could have been used for?


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## ddickey (Oct 12, 2022)

Not original at all but it looks nice.
All the electronics will be attached to the bottom sheet metal. Guessing not original.
I believe there is a source in MPLS. that can make you a belt. Let me know if you want the info.


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## pontiac428 (Oct 12, 2022)

Did Amphenol/ITT/Canon circular connectors even exist in 1947?  I think those came 20 years later.  Luckily those components are widely available.


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## Subw00er (Oct 13, 2022)

ddickey said:


> I believe there is a source in MPLS. that can make you a belt. Let me know if you want the info.


Sure, what is MPLS?


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## ddickey (Oct 13, 2022)

Sorry, Minneapolis.


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## wachuko (Oct 13, 2022)

I never considered a surface grinder because of their size... This is very cool!! 

@vtcnc  Do share photos and, if possible, a video when you have it all back together.


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## pontiac428 (Oct 13, 2022)

wachuko said:


> I never considered a surface grinder because of their size... This is very cool!!
> 
> @vtcnc  Do share photos and, if possible, a video when you have it all back together.


Oh, great, just what we need, one more person to compete with looking for a Sanford.  Look, buddy, you stay east of the Mississippi, I'll stay west.  By the time we end up in the nursing home, we might both find one.


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## wachuko (Oct 13, 2022)

pontiac428 said:


> Oh, great, just what we need, one more person to compete with looking for a Sanford.  Look, buddy, you stay east of the Mississippi, I'll stay west.  By the time we end up in the nursing home, we might both find one.



So many machines available far, far from me...  just a quick search and these two showed up... but in California!

Delta Rockwell... for 750.00!

And one Sanford for 1,295.00

But you do not have to worry about me... I don't even have anything remotely needing a surface grinder... Also, my next purchase is the welding table... then I am in lockdown for any major expense until the detached garage is finally built.  I need to make sure I have the $$ to finish paying for the workshop...

Back to normal programming... apologies for the hi-jack...


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## pontiac428 (Oct 13, 2022)

wachuko said:


> And one Sanford for 1,295.00



Would it have killed the seller to post at least one photo that indicates the condition of the machine?


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## Subw00er (Oct 13, 2022)

ddickey said:


> Sorry, Minneapolis.


Ok, thank you for the lead. So its a 1/2" x19" leather belt? I am curious on the original length spec'ed for earlier sg48. I've seen people using belts from 17-19".

Any opinion on leather vs poly vs rubber? Seems like leather would stretch/absorb oil..



pontiac428 said:


> Did Amphenol/ITT/Canon circular connectors even exist in 1947?  I think those came 20 years later.  Luckily those components are widely available.



I think those type of Amphenol connectors have a long history with the military, but I doubt they were standard on the Sanford - no standardization existed really back then across companies. I'm going to likely re-terminate both ends with better strain relief, but there appears to be zero slack in the wire inside the mag chuck jack. I wonder if I take the chuck off, is there is a bottom plate where I can gain access to the wiring?


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## ddickey (Oct 13, 2022)

No. You have to tip it on its side. To get that bottom sheet metal off.
Yes on the belt size.


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## ddickey (Saturday at 10:39 AM)

@vtcnc What did you end up doing with the chuck?


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## vtcnc (Saturday at 10:55 AM)

I couldn't get it to work. I think the coils are shorted (if that is the right term). The connectors are good.


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## ddickey (Saturday at 10:57 AM)

Bummer.


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## 9t8z28 (Saturday at 3:47 PM)

Subw00er said:


> This is a great thread! Can I crash the party?! I just acquired an old sg48 (#47-1198 - 1947 model?). It appears to be in good shape, but I see no scraping on the ways. I'm trying to learn about it, and I need to find a flat belt. How is that McMaster 5/8"x17 poly belt working for you @9t8z28 ? I heard some grabbed a 1"x18" rubber/plastic core (I found this one: https://www.mcmaster.com/6082K12-6082K613/ )
> 
> View attachment 423213
> 
> ...


Sorry I am just now seeing this.  I got a rubber belt from Sopko and Sons.  It took a week or 2 to get it but in the meantime I decided to go to a vacuum cleaner store and see what they had.  Sure enough they have exactly what I needed in many different lengths.  i installed the Sopko belt and it runs super smooth.  I never installed the VC belt but I doubt their would be a difference.  Vacuum cleaner belts run pretty fast and take a lot of abuse so I am sure they would be able to put up with the dust from surface grinding.  
As for the chromed surfaces on your SG (not an SG48), I believe if the bottom surface of the cross-slide is chromed it was  done for the purposes of wear resistance.  As to wether thats a good idea or not, I am not sure.  
The tapped holes on the side of the column covers was probably for measuring fine downfeed of the spindle.  There was probably an indicator mounted in some fadhion and those items are now missing.  Thats my guess.  I made an indicator mount for my SG to read spindle downfeed in tenths.  There was to ways of going about making a mount and I think whats on your machine is the method I didn’t use but now in hindsight might have been better.


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## Subw00er (Sunday at 1:16 AM)

9t8z28 said:


> Sorry I am just now seeing this.  I got a rubber belt from Sopko and Sons.  It took a week or 2 to get it but in the meantime I decided to go to a vacuum cleaner store and see what they had.  Sure enough they have exactly what I needed in many different lengths.  i installed the Sopko belt and it runs super smooth.  I never installed the VC belt but I doubt their would be a difference.  Vacuum cleaner belts run pretty fast and take a lot of abuse so I am sure they would be able to put up with the dust from surface grinding.
> As for the chromed surfaces on your SG (not an SG48), I believe if the bottom surface of the cross-slide is chromed it was  done for the purposes of wear resistance.  As to wether thats a good idea or not, I am not sure.
> The tapped holes on the side of the column covers was probably for measuring fine downfeed of the spindle.  There was probably an indicator mounted in some fadhion and those items are now missing.  Thats my guess.  I made an indicator mount for my SG to read spindle downfeed in tenths.  There was to ways of going about making a mount and I think whats on your machine is the method I didn’t use but now in hindsight might have been better.


Great info! Thanks. What is the difference between a sg and sg48? I bought a green belt from mcmaster that looks right, but I havent tried it yet. I'm refreshing a emco 7 mill/drill first. 

The indictor idea is a good one. I can try that later too.


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## ddickey (Sunday at 7:46 AM)

@Subw00er The SG (second generation) was changed to SG-48 in 1961. Several revisions were made. All the info is on lathes.co.uk.


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