Author Topic: Vintage Craftsman "Block Motor" bench grinder info -  (Read 57735 times)

Online goodfellow

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Vintage Craftsman "Block Motor" bench grinder info -
« on: May 19, 2011, 03:11:16 PM »
This section is dedicated to the restoration, use, and maintenance of the classic Craftsman bench grinders that were manufactured for Sears by Paramount/Allegretti & Co. from the early 1960's to early 1980's. Affectionately known as "Block Motor" grinders because of their unique shape, these power tools have developed a large following among shop enthusiasts because of their legendary reliability, accuracy, and power.

The "Block Motor" grinder can be readily identified by the Sears manufacturer prefix of 397 or 257 (as in 397.XXXXX); which is stamped on the front label. Popular models include 1/4HP, 1/3HP, 1/2HP, 3/4HP, and 1.0HP Industrial units.

Relevant threads to Block Motor grinder restorations and tips are listed below.

http://www.thegaragegazette.com/index.php?topic=4919.msg66926#msg66926 ("torqueman2002's" excellent and comprehensive resto of a 3/4HP unit)

http://www.thegaragegazette.com/index.php?topic=4659.msg69684#msg69684 ("atlinwi202's" wonderful resto of a 3/4HP unit that was in very rough shape)

http://www.thegaragegazette.com/index.php?topic=4135.msg55745#msg55745 ("goodfellow's" resto of a 1/2HP unit)

http://www.thegaragegazette.com/index.php?topic=4162.0 (making a sheetmetal end-cover for a block motor grinder wheel guard)

Do you need a belt grinder attachment for your Craftsman Block Motor bench grinder? Click the link to find a simple DIY solution

http://www.thegaragegazette.com/index.php?topic=20445.0

« Last Edit: June 30, 2014, 04:10:55 PM by goodfellow »

Offline Uncle Buck

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Re: Vintage Craftsman "Block Motor" bench grinder info -
« Reply #1 on: May 20, 2011, 02:43:11 PM »
Here are two of mine. The first grinder is a 1/2hp version that came to me in remarkably good condition. Many guys would have done nothing to it and just ran it as it was. I wanted mine to look near new so I decided to repaint mine. I did not document my rebuild, but I will describe it as follows. I removed the wheel  guards, stones, and covers first. Next I removed the screws securing the silver panel in the center and the wire leads that went to the switch. I never entirely removed the light or center cover, but instead chose to lay them aside the grinder as far as I could and cover these items before painting the machine (less guards) I really cleaned the old guards on the inside as best I could then set them aside. I did little in the way of prep work to the surface of the grinder because as I said its finish was just that good.

I bought one or two cans of Rust-O-Leum Hammered grey spray paint and after hitting one or two rough spots I sprayed all the grey color with several coats of the paint. I then followed this by doing the same thing with the wheel guards and end covers. Following this I covered all of the freshly painted grey areas of the machine and addressed the center silver panel. I masked off the original (damaged) label with masking tape and sprayed the center cover with silver (I think I just used regular silver spray paint for that part.

After everything dried, I reassembled the grinder and mounted it to the bench as you now see it in the pictures below. The machine is still missing the right tool rest and I will need to replicate that one of these days when I get the time, but for now I simply fitted the right side with an old work rest from another grinder I had in the shop. Unfortunately mine did not come with the cooling tray that usually is mounted front and center of the machine, perhaps some day I will luck out and find one. I bought this machine about a year ago and paid $45 for it. The machine needs new 7" wheels which I will likely have to order due to the odd size, so for now it has the wheels it came with.




Next is the grinder that the above machine replaced. The machine below is only a 1/4 HP grinder, but it is surprisingly stout for its low HP rating. In fact, I believe this machine is every bit as stout as the 1/2HP grinder that was but a few years old that it replaced! By no means the animal of the 1/2HP machines and larger such as the one pictured above, or other higher HP machines you will find in this thread, but very respectable nevertheless. In fact, had I not run across the higher HP machine above to replace it, no doubt it would still be in use as my primary bench grinder. If you should encounter one of these grinders in the 1/4HP version and do not have one of these early models yet I would strongly encourage you to buy it and continue looking for a heavier machine as I did. I know you would not be disappointed.

I did no cleanup painting etc on this machine at all. The only thing I did was remove the center silver cover and hammer out a dent that was in the back side of the cover. I paid nothing for this machine, a generous co-worker simply gave it to me. It looks just as it did the day I got it minus the dent in the cover.



« Last Edit: May 20, 2011, 07:14:18 PM by Uncle Buck »
You boys better hold on cause i'm gonna have to stand on it!

NEED A 1/2" BONNEY STREAMLINE COMBINATION AND ANY OVER 13/16" TOO!



Andrew Jackson quote: But you must remember, my fellow-citizens, that eternal vigilance by the people is the price of liberty, and that you must pay the price if you wish to secure the blessing.

Offline torqueman2002

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Re: Vintage Craftsman "Block Motor" bench grinder info -
« Reply #2 on: May 22, 2011, 12:53:47 PM »
Here are two of mine.


UB - gotta say thanks for sharing. I was inspired and found a block grinder on CL in Detroit Metro.

I've found this March 1990 Popular Mechanics article: "Bench Grinder Basics". http://tinyurl.com/79k26ma

It's a nice primer for the beginner and I got just enough information on Buffing Wheels and Compounds, to realize this is a whole science in it's self.

Also, here is a link to Craftsman OEM codes: http://vintagemachinery.org/Craftsman/manufacturers.aspx?sort=1

edited Feb 04, 2012. Inserted a Tiny URL.
« Last Edit: February 04, 2012, 10:19:23 PM by torqueman2002 »
I am a Blockhead, Man! http://tinyurl.com/CM-Block-Grinders-Why-the-Fuss

"I got to show the young boys how not to do it. I haven't showed them everything not to do, yet. It's a big job!" - Otto Kilcher

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Offline atlinwi202

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Re: Vintage Craftsman "Block Motor" bench grinder info -
« Reply #3 on: June 07, 2011, 11:35:12 PM »
Thanks for putting this all together Ray! thumbsup2
-Andy

Offline Bob51

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Re: Vintage Craftsman "Block Motor" bench grinder info -
« Reply #4 on: July 30, 2011, 01:54:32 PM »
My first post; bringing this thread back to ask some questions; I've never owned a bench grinder so excuse my ignorance.  I found a 1/2 HP block motor craftsman for sale, they asking price is 75, from the one photo they sent me it looks like it sat in someone's garage or basement for ?40 years with very little use, just some surface corrosion mostly on the light socket thingy.  They say it runs fine.  Any thoughts, should I grab it?

I really need something to use for buffing, dumb question; is there any way to hook up a variable power switch of some sort to get these grinders to run slower without damaging the motor?

Thanks

Offline chevytrux53

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Re: Vintage Craftsman "Block Motor" bench grinder info -
« Reply #5 on: February 04, 2012, 07:27:19 PM »
75 sounds pretty high to me, offer a lower number and see what they say, it cant hurt.
Sorry no clever saying, I just love old cars and machines, so if you want to talk about that stuff, drop me a line.

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Re: Vintage Craftsman "Block Motor" bench grinder info -
« Reply #6 on: February 04, 2012, 08:27:49 PM »
Welcome Bob51 -- $75 is within reason for a pristine model. These things are starting to get pricey; mainly because our own "tourqueman2002" has been buying them all, and driving up the prices on the entire east coast -- LOL  ;)

Seriously though, the prices are rising and you're "in the ballpark" with that $75.

As for changing the speed, that's not an option in these grinders, unless you want to get into some very expensive electronic changes (not worth it for these old warhorses). For buffing they aren't that great because the arbors don't extend very far. A good buffer will have extended arbors so that you can easily maneuver the parts on the buffing pad.

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Re: Vintage Craftsman "Block Motor" bench grinder info -
« Reply #7 on: February 04, 2012, 08:51:37 PM »
For $75 you will not likely find a better grinder for the money, certainly not new anyway. The only thing you might find better for that amount would have to show up used. If you have no grinder and want one that will not disappoint then absolutely try to strike a better deal, but go ahead and buy it assuming all the parts are there, wheel covers, work rests etc.
You boys better hold on cause i'm gonna have to stand on it!

NEED A 1/2" BONNEY STREAMLINE COMBINATION AND ANY OVER 13/16" TOO!



Andrew Jackson quote: But you must remember, my fellow-citizens, that eternal vigilance by the people is the price of liberty, and that you must pay the price if you wish to secure the blessing.

Offline Frederick Flintstone

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Re: Vintage Craftsman "Block Motor" bench grinder info -
« Reply #8 on: February 04, 2012, 09:35:56 PM »
What are the years of the round top block grinder VS the more squarish ones? IMO the rounder ones look better.
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Offline Uncle Buck

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Re: Vintage Craftsman "Block Motor" bench grinder info -
« Reply #9 on: February 04, 2012, 10:16:10 PM »
What are the years of the round top block grinder VS the more squarish ones? IMO the rounder ones look better.

I do not know right off the top of my head, but I know the round topped ones came before the square shaped ones.
You boys better hold on cause i'm gonna have to stand on it!

NEED A 1/2" BONNEY STREAMLINE COMBINATION AND ANY OVER 13/16" TOO!



Andrew Jackson quote: But you must remember, my fellow-citizens, that eternal vigilance by the people is the price of liberty, and that you must pay the price if you wish to secure the blessing.

Offline torqueman2002

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Re: Vintage Craftsman "Block Motor" bench grinder info -
« Reply #10 on: February 04, 2012, 10:43:39 PM »
What are the years of the round top block grinder VS the more squarish ones? IMO the rounder ones look better.


Is this the style?
http://www.thegaragegazette.com/index.php?topic=6053.msg82011#msg82011

If it is, maybe searching this link to Craftsman OEM codes will help: http://vintagemachinery.org/Craftsman/manufacturers.aspx?sort=1

And goodfellow - I'm cured, I haven't bought a block grinder for months now. Hey, I even gave 2 away to my brother back East. Call me the 'Johnny Apple Seed of Block Grinders' even!

I will not look for grinders, I will not search CL for grinders, I will give grinders to the needy, .....   panicx
I am a Blockhead, Man! http://tinyurl.com/CM-Block-Grinders-Why-the-Fuss

"I got to show the young boys how not to do it. I haven't showed them everything not to do, yet. It's a big job!" - Otto Kilcher

"Well, I don't wanna be a superman, I just wanna go somewhere, use my hands, and keep it simple. Oh real simple" - Keb' Mo'

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Re: Vintage Craftsman "Block Motor" bench grinder info -
« Reply #11 on: February 05, 2012, 10:50:25 AM »
What are the years of the round top block grinder VS the more squarish ones? IMO the rounder ones look better.

A point of clarification. Sears sold many "block motor" designed grinders from several manufacturers, but the block design must be considered secondary. Of primary concern is the manufacturer. The best engineered, most durable, and desirable "Block Motor" grinders were made by Paramount/Allegretti & Co. These grinders have the 397 or 257 serial number prefixes.

Overall, the "Block Motor" designs were also made by Rixon, Royal, and B&D -- just to name a few. These grinders do not have the higher quality field windings and castings that the Paramount/Allegretti units had.

Offline torqueman2002

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Re: Vintage Craftsman "Block Motor" bench grinder info -
« Reply #12 on: February 05, 2012, 11:29:43 AM »
The best engineered, most durable, and desirable "Block Motor" grinders were made by Paramount/Allegretti & Co. These grinders have the 397 or 257 serial number prefixes.

Good point gf. He doesn't want to make the mistake I did on my first purchase of a CM grinder - 1/3HP model: 115.7566. Turns out it was a pre 397 /257 series.

Once I discovered my error the quest was on and I was hooked. Since then, as alluded to, I've acquired the 1/4, 1/3, 1/2, 3/4 (x2), and 1 HP series 397 grinders in various stages of completeness and  types of condition. The best condition were the 1/4 and 1/3 HP ones; now with my brother back East.

Best of luck. BTW - saw some listed in Detroit CL this morning.  frustratedx
I am a Blockhead, Man! http://tinyurl.com/CM-Block-Grinders-Why-the-Fuss

"I got to show the young boys how not to do it. I haven't showed them everything not to do, yet. It's a big job!" - Otto Kilcher

"Well, I don't wanna be a superman, I just wanna go somewhere, use my hands, and keep it simple. Oh real simple" - Keb' Mo'

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Re: Vintage Craftsman "Block Motor" bench grinder info -
« Reply #13 on: February 09, 2012, 01:52:50 AM »
What are the years of the round top block grinder VS the more squarish ones? IMO the rounder ones look better.

A point of clarification. Sears sold many "block motor" designed grinders from several manufacturers, but the block design must be considered secondary. Of primary concern is the manufacturer. The best engineered, most durable, and desirable "Block Motor" grinders were made by Paramount/Allegretti & Co. These grinders have the 397 or 257 serial number prefixes.

Overall, the "Block Motor" designs were also made by Rixon, Royal, and B&D -- just to name a few. These grinders do not have the higher quality field windings and castings that the Paramount/Allegretti units had.

AH! I SEE! now I know what to look for. and torqueman you can scour CL for me and pick up a 3/4 HP for your "freind"

after a quick scan of my pictures, only one is a good enough one to read the modle # fourtunatly my 1/2 is a #397, whoo hoo!
« Last Edit: February 09, 2012, 01:58:21 AM by fflintstone »
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Offline Frederick Flintstone

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Re: Vintage Craftsman "Block Motor" bench grinder info -
« Reply #14 on: February 14, 2012, 11:21:05 PM »
well I consider myself lucky all three of my Craftsman bench grinders have the 397 prefix!
now I need to find a 3/4 HP version.
torqueman keep looking!
“Unless someone like you cares a whole awful lot,
Nothing is going to get better. It's not.”
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Re: Vintage Craftsman "Block Motor" bench grinder info -
« Reply #14 on: February 14, 2012, 11:21:05 PM »

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