Craftsman Block motor Bench Grinders - What's the Fuss (with resource information)

[vertguy]

Yeah, I was surprised those details were not already part of this thread. Open to whoever can get me the info

 

[EOC_Jason]

Let me know if I left out any measurements or something doesn't make sense.

The bolts are standard 5/16" coarse thread x 1" long (and a washer too).

Obviously the L bracket is a flip-flop with the lip for the other side. You want the lip to face towards the wheel. For simplicity you could omit the lip (my 1/2 HP doesn't have it), or make it even bigger on both sides if you want a larger surface area to work with.

 

[vertguy]

Let me know if I left out any measurements or something doesn't make sense.

The bolts are standard 5/16" coarse thread x 1" long (and a washer too).

Obviously the L bracket is a flip-flop with the lip for the other side. You want the lip to face towards the wheel. For simplicity you could omit the lip (my 1/2 HP doesn't have it), or make it even bigger on both sides if you want a larger surface area to work with.

This is perfect!! Thanks for all the details.


Sent from my iPad using Tapatalk

 

[cajunfirehawk]

Let me know if I left out any measurements or something doesn't make sense.

The bolts are standard 5/16" coarse thread x 1" long (and a washer too).

Obviously the L bracket is a flip-flop with the lip for the other side. You want the lip to face towards the wheel. For simplicity you could omit the lip (my 1/2 HP doesn't have it), or make it even bigger on both sides if you want a larger surface area to work with.

If someone made extra sets I am sure they would sell, just saying...

 

[lafester]

Let me know if I left out any measurements or something doesn't make sense.

The bolts are standard 5/16" coarse thread x 1" long (and a washer too).

Obviously the L bracket is a flip-flop with the lip for the other side. You want the lip to face towards the wheel. For simplicity you could omit the lip (my 1/2 HP doesn't have it), or make it even bigger on both sides if you want a larger surface area to work with.

Thanks, that is some good info to have. Would like to figure something out for the 6" grinders to get better angle to the wheel.

 

[EOC_Jason]

Oh, forgot to dimension the slot in the angle-bracket is centered (though it is probably obvious from the picture).

 

[Kent_B]

OK. Now you folks have gone and done it. I'm now on the hunt for a block grinder. What's a fair price for a 1/4 - 1/3 hp block grinder in good operating condition?

Thanks!

 

[Outlawmws]

Quite a number of prices have been quoted in the thread and like many things it can be area dependent, its always condition dependent, and what extras come with, (base? and which one? Drill bit guide? Are all the parts there? (light, outer guards, cooling tray...)

Then there are the USUCK buys...

Personally I'd be looking for a 1/3 to 1/2 HP.

 

[Cruzan80]

I paid $25 each for my commercial 1/2hp, and the square top 1/2 with stand. Just sold the 1/2 with new paint/bearings/label for $80. Denver area.

Sent from my Moto G (5) Plus using The Garage Journal mobile app

 

[Kent_B]

Thanks, Drives & Cruzan. I'm sending Mrs. B on a scouting mission in the morning. Wish me luck!

 

[Bockscar]

At a auction Saturday.....is it worth trying to get

Sent from my SM-G950U using Tapatalk

 

[lafester]

At a auction Saturday.....is it worth trying to get

Sent from my SM-G950U using Tapatalk

Nice clean 1/2 hp commercial.
That is a good one.

 

[larry4406]

Nice clean 1/2 hp commercial.
That is a good one.

I paid $75 for a 1/2 hp commercial with stand and eye shields. It was missing the quench tray.

 

[lafester]

Sounds like a deal.

I paid $75 for a 1/2 hp commercial with stand and eye shields. It was missing the quench tray.

 

[dschmit]

I have a 3/4 hp I got from work when it quit. Guy using it said it popped and smoke came out of it and quit running. Took lower cover off and found the stator field coil burnt on one end. Can parts be found or is it a machine to get rid of complete or part it out?


Sent from my iPhone using Tapatalk

 

[lafester]

If it were mine I would look for another that is missing parts and make one good one. I bet it can be fixed though.

 

[torqueman2002]

I tried repairing one like this, the start-up winding (thin wire, with lots of turns) was shorted OPEN.

It can happen when the stone/wheel is prevented from turning, or if the start/run relay sticks ON at power up - when it energizes the start-up winding.

The wire is thin and has a varnish like insulation that is difficult to clean and get a good solder joint.

I was actually able to repair one spot but there turned out to be at least one other OPEN that was not accessible.

I wound up parting out the good pieces.

BTW - if you can get it to spin fast enough ~75% of operating speed, it should run OK.

 

[Outlawmws]

If it were mine I would look for another that is missing parts and make one good one. I bet it can be fixed though.

I would agree; Parts machine, or this ^^^

 

[ssdave]

Not sure if this qualifies as a block grinder, part # is 397.19340 and it's 1/2 hp. The manual makes a big point out of it being RATED HP, not Developed. Manual is dated 1968. All there including shields, light and manual. Price was right at $10.

I'm not into these, I've gotten a preference for Baldor, the only other one of these I have is one that I bought that is set up as a buffer. It works okay for that. Is this one of the Block Grinders that I see talked up here?

 

[torqueman2002]

Not sure if this qualifies as a block grinder, part # is 397.19340 and it's 1/2 hp. The manual makes a big point out of it being RATED HP, not Developed. Manual is dated 1968. All there including shields, light and manual. Price was right at $10.

I'm not into these, I've gotten a preference for Baldor, the only other one of these I have is one that I bought that is set up as a buffer. It works okay for that. Is this one of the Block Grinders that I see talked up here?

Nope. Sorry.

Send it to me and I'll give you your $10 back.


Just kidding! That is a YOU **** deal!

Nicely done.

BTW - Buffing requires more HP than wire wheeling/grinding. This was a surprise to me, plus speed is important. 1800 rpm for plastics and soft materials.

I too, have a Baldor. It is a 3/4-HP 2-speed buffer. Great machine, so are Blocks but not the same grade as the industrial built Baldors.

 

[RiseAbove]

Picked this up recently. It's in real good shape, so just breaking it down and cleaning it up with some Green Soap.

One thing i did notice is that the power cable grommet that holds the cable to the body is broken. Does anyone know where i can pick up a new one?

What are the best brand/model buffing wheels and wire wheels to use with these grinders? I'm mainly going to be using it for cleaning up vintage rusty tools.

 

[cajunfirehawk]

Picked this up recently. It's in real good shape, so just breaking it down and cleaning it up with some Green Soap.

Wow on the dining room table, your SO must love that...nice lil unit.

 

[RiseAbove]

Wow on the dining room table, your SO must love that...nice lil unit.

It's a back n forth...i caught her resting her 16oz joe on my Kennedy box one day. I restored the balance with the grinder/table

 

[torqueman2002]

It's a back n forth...i caught her resting her 16oz joe on my Kennedy box one day. I restored the balance with the grinder/table

LOL


I've used wire zip ties on the cable inside the grinder, which helps with preventing 'pull-out'. Also, to keep the power cable from chaffing on the grinder housing, I've used heat shrink.


I have also used Round Strain Relief Bushings - available on Amazon and in the box stores. Since these bushings are double D shaped, they can twist in a round hole. Maybe a bit of epoxy could keep them in place.

These crimpers make it easier to work with them.
Pro'sKit 300-151 Strain Relief Crimper

Ha ha, the pic sizes are a bit wanky.

 

[torqueman2002]

For wheels and stones: Grainger, Amazon, MSC.


I like Norton, but there are many good brands out there.

 

[RiseAbove]

LOL


I've used wire zip ties on the cable inside the grinder, which helps with preventing 'pull-out'. Also, to keep the power cable from chaffing on the grinder housing, I've used heat shrink.


I have also used Round Strain Relief Bushings - available on Amazon and in the box stores. Since these bushings are double D shaped, they can twist in a round hole. Maybe a bit of epoxy could keep them in place.

These crimpers make it easier to work with them.
Pro'sKit 300-151 Strain Relief Crimper

Ha ha, the pic sizes are a bit wanky.

For wheels and stones: Grainger, Amazon, MSC.


I like Norton, but there are many good brands out there.

Aweome, thanks

Going to order one of those Strain Relief Bushings. Did you use heat wrap as well as that? I was looking at getting a vintage looking cord for the CM grinder and drill press to match. Something like this, though i don't know how durable they are, and if it would be a case of fashion over function.

 

[cajunfirehawk]

I was looking at getting a vintage looking cord for the CM grinder and drill press to match. Something like this...

I priced some of that "vintage" cloth wrapped electrical wire for my 36' ford, I passed after I got the price. I have those strain relief pliers, they work pretty good, fwiw. DO us all a favor and PLEASE do NOT use those old stones, plenty of good safety info on using old stones in this thread. Eyesight is too valuable

 

[RiseAbove]

I priced some of that "vintage" cloth wrapped electrical wire for my 36' ford, I passed after I got the price. I have those strain relief pliers, they work pretty good, fwiw. DO us all a favor and PLEASE do NOT use those old stones, plenty of good safety info on using old stones in this thread. Eyesight is too valuable

I found a ebay store that sells the cord, and also some other cool looking vintage style fixtures, bulbs, etc but it seems too cheap of a price to be durable, although they have good feedback. The spec on the cord i was looking at was Max: 300 Volts, 105 Degrees Celsius. Diameter: 7.1mm, or about 1/4". Made in the USA. $1.69/foot. Just seems a little too good to be true. Here's the store:

https://www.ebay.com/str/Snake-Head-Vintage?_trksid=p2047675.l2563

I looked at some of those safety links on the front page...defintely put me off using the old rings for sure. They look to be the original ones from back in '69 judging by the labels. They did pass the ring test though which surprised me.

 

[torqueman2002]

Aweome, thanks .... Did you use heat wrap as well as that?....

You are welcome.
I didn't use any type of wrap, but I did use a 'modern' style power cord with an outer cover.


Thanks for the link to Snake-Head's store. Makes me wanna build something vintage, circa 1920's.

 

[cajunfirehawk]

Thanks for the link to Snake-Head's store. Makes me wanna build something vintage, circa 1920's.

That was a killer find!

 

[RiseAbove]

Does anybody know off hand what arbor size my 397.19580 6 inch grinder is? I'm not around it atm to measure it, and was gonna drop by a store and pick up a buffing wheel on my way home but not sure which size.

 

[torqueman2002]

I show 1/2" dia.

 

[RiseAbove]

I show 1/2" dia.

Awesome, thanks

 

[AfterburnerOne]

Hi - I just got a Sears Craftsman grinder model 397.19340 for $0 - Literally found it in a dumpster and it had most of the parts. It is in nearly perfect condition externally. It has a few issues which are:

1. It needs a spin by hand to get the motor spinning. It also makes a wonderful buzzing noise until I get the motor spinning. I've read this might be the starter relay and it might be darned near impossible to get a replacement. I've heard that tapping these to break loose oxidation might give them a second life.

2. The bearings are pretty trashed - The PDF I did find for the grinder on VintageMachinery had everything BUT the bearing size info. If anyone could tell me what size/model # of bearings this beastie takes, I'd be very grateful.

3. Does the 1/2 hp motor for this grinder use brushes and would it be a good idea to change them out?

I'm a newbie at this sort of thing, so pardon the elementary questions. Appreciate any replies and advice...

Jon

 

[torqueman2002]

Hi, welcome to the forum and Block grinder ownership. I will reply in RED, below.

Hi - I just got a Sears Craftsman grinder model 397.19340 for $0 - Literally found it in a dumpster and it had most of the parts. It is in nearly perfect condition externally. It has a few issues which are:

1. It needs a spin by hand to get the motor spinning. It also makes a wonderful buzzing noise until I get the motor spinning. I've read this might be the starter relay and it might be darned near impossible to get a replacement. That is a symptom that the start-up coil is not energized/not functioning. This can have a number of causes, which can be faulty relay, and/or an OPEN in the start-up (thin) coil wires. I've heard that tapping these to break loose oxidation might give them a second life. I haven't tried this, but it works for British SU electric fuel pumps. LOL
Some relays can be disassemble and points cleaned and put back into service.
I haven't seen any relays fail, what I have seen is start-up coils burn OPEN, because the rotor/arbor/wheel assembly was jammed/seized and would not turn when first started. The thin wires cannot sustain the current of a stalled motor.

2. The bearings are pretty trashed - The PDF I did find for the grinder on VintageMachinery had everything BUT the bearing size info. If anyone could tell me what size/model # of bearings this beastie takes, I'd be very grateful. The best way to get the correct bearings is to measure them (metric size) and find replacements as outlined in the following post:
https://www.garagejournal.com/forum/showpost.php?p=7658463&postcount=11330
3. Does the 1/2 hp motor for this grinder use brushes and would it be a good idea to change them out? No brushes in this style of motor.

I'm a newbie at this sort of thing, so pardon the elementary questions. Appreciate any replies and advice...

Jon

I suspect the start-up coil circuit is OPEN. Check to see if any internal connections have come undone. If the thin coil wire is burnt OPEN, it is very difficult to repair, because there is a varnish like insulation covering the wires and it is difficult to clean and solder.

May be look for a Block that is working and needs some of the parts you have, and part out the rest in the classified section or eBay.


So far, I've measured 2 different size bearings - 5/8" dia Arbor (17mm ID), 1/2" dia Arbor (15mm ID).
<table width="396" cellspacing="0" cellpadding="0" border="0"><tbody><tr style="height:30.75pt" height="41"><td class="xl64" style="height:30.75pt;width:48pt" width="64" height="41">

</td><td class="xl64" style="border-left:none;width:48pt" width="64">
</td> <td class="xl64" style="border-left:none;width:48pt" width="64">
</td> <td class="xl64" style="border-left:none;width:48pt" width="64">
</td> <td class="xl64" style="border-left:none;width:51pt" width="68">
</td> <td class="xl65" style="border-left:none;width:54pt" width="72">
</td> </tr> <tr style="mso-height-source:userset;height:14.25pt" height="19"> <td class="xl91" style="height:14.25pt;border-top:none" height="19">
</td><td class="xl91" style="border-top:none;border-left:none">
</td> <td class="xl91" style="border-top:none;border-left:none">
</td> <td class="xl91" style="border-top:none;border-left:none">
</td> <td class="xl84" style="border-top:none;border-left:none;width:51pt" width="68">
</td> <td class="xl92" style="border-top:none;border-left:none" align="right">
</td> </tr> <tr style="mso-height-source:userset;height:14.25pt" height="19"> <td class="xl73" style="height:14.25pt;border-top:none" height="19"> Best of luck. Let us know how you make out.
</td> <td class="xl73" style="border-top:none;border-left:none">
</td> <td class="xl73" style="border-top:none;border-left:none">
</td> <td class="xl73" style="border-top:none;border-left:none">
</td> <td class="xl85" style="border-top:none;border-left:none;width:51pt" width="68">
</td> <td class="xl71" style="border-top:none;border-left:none" align="right">
</td> </tr> </tbody></table>

 

[RiseAbove]

Firstly, i apologise if this is in the wrong thread, as the questions i'm asking relate to a pre-block, so please move/delete accordingly if need be

I just picked this up this morning. The label says 1/2HP Model: 115 7575 255...underneath that it says Type CR 22 E and below that in small read 5219015.

It seems to be in good shape, no cracks etc, and it seems to be complete with the lamp, eye shields, tray etc. It looks like its missing something from the left tool rest. I like the collection bag!

I noticed that when i turn the shaft/wheels in the direction that they go by hand, i hear a kind of inconsistant tinging/tapping noise, almost like a wire hitting something or something being loose. When i power it up it completley goes away, and makes no noise and runs perfectly. But when i switch it off, around 30 seconds into slowing down, the noise comes back. Do you think it could be the clutch? I have no idea on how the clutch system works on these, i've only really taken them apart for cleaning.

I'm going to clean it up the best i can and put it into use with my '69 block grinder.

 

[Wazzu11js]

I am hoping someone can give me a little guidance. I purchased a craftsman 1/3 hp bench grinder, model 397.19580. It's in great shape. I would like to remove one of the grinder wheels and add a wire wheel to it for light polishing and rust removal. I think I would use it for this purpose as much if not more than grinding. Can anyone tell me what I need to look for in a wire wheel in order to get one that will be good quality and a proper fit for this bench grinder? Here are some photos. It is in amazing cosmetic condition as well, especially since it is dated 9/2/69.

 

[rickhigginshtbr]

Wazzu - 6" or 7", I usually run the fine brass wire wheels. 7" is hard to find though.

Rise - That thing is awesome! Not many 1955's posted!

 

[torqueman2002]

Rise - I'll make my comments in RED, below.

Firstly, i apologise if this is in the wrong thread, as the questions i'm asking relate to a pre-block, ..... No problem, this guy is a pre-block though.
...

It seems to be in good shape, no cracks etc, and it seems to be complete with the lamp, eye shields, tray etc. It looks like its missing something from the left tool rest. Nice shape, that LH tool rest looks home-made. I like the collection bag! A swarf/dust collection bag is a good idea, but I use non-flammable material. ie: welding arm protectors.

I noticed that when i turn the shaft/wheels in the direction that they go by hand, i hear a kind of inconsistant tinging/tapping noise, almost like a wire hitting something or something being loose. When i power it up it completley goes away, and makes no noise and runs perfectly. But when i switch it off, around 30 seconds into slowing down, the noise comes back. Do you think it could be the clutch? I have no idea on how the clutch system works on these, i've only really taken them apart for cleaning.

You maybe hearing the centrifugal switch assembly, for de-energizing the start-up winding circuit. It has weights mounted to the arbor that swing-out at ~75% final speed to open the contact on a RH end bell mounted switch.

Best of luck, and please continue to post pictures and feel free to ask questions.

 

[torqueman2002]

Wazzu - 6" or 7", I usually run the fine brass wire wheels. 7" is hard to find though.

Rise - That thing is awesome! Not many 1955's posted!

x2


BTW - Weiler makes very good quality wire wheels. You may need to use an arbor adapter to step down to your 1/2"

Try: Grainger, MSC, Amazon, Google, ...

You may find a 1/3-HP won't have a lot of 'umph' for medium to heavy wire wheeling; but a 1/3-HP is ideal for light clean up, esp. for nuts, bolts, screws, ...

Be sure to keep a good grip on them. I use small vise grips, or pin vices.