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

[6PTsocket]

I always say, the more info. the better.

Thanks M George, and everyone.

Also, 6PTsocket - can you post the link where you found the Klixon relay?

I wonder how critical the drop-out current is for the relay. Perhaps a relay from another 1/3-HP Block will work, but will one from a 1/2-hp? How about 3/4 or 1-HP?

Isn't the current draw through their start-up circuits/windings likely to be different?

I took the numbers off the photo in the Sears ad for part number 534220174 that they describe as a grinder starter relay. The relay in the photo was marked 24H5V 3CR-736-268. When I started searching, I discovered that 3CR is a series of current type starter relays from Klixon. From physical appearance, it appears from the 100 series. I could not match the rest of the number to their listed models. It has the right pin out and configuration and Sears may have used the same relay for a number of grinders of different hp. I did not check, but how many of the grinders used that old number that the new number is supposed to replace? I see your point about different hp grinders having different starting currents and when the relay should drop out. The 3CR series has a lot of models with different current specs.

I always say, the more info. the better.

Thanks M George, and everyone.

Also, 6PTsocket - can you post the link where you found the Klixon relay?

I wonder how critical the drop-out current is for the relay. Perhaps a relay from another 1/3-HP Block will work, but will one from a 1/2-hp? How about 3/4 or 1-HP?

Isn't the current draw through their start-up circuits/windings likely to be different?

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[6PTsocket]

More info. Like the lamp shade, the relay is coming from AYP/Husqvarna and the relay number also shows up on all the sites selling Husqvarna/Poulan outdoor equipment parts. In addition to the Sears number they also show 3CR13. All the 3CR Klixon relays have numbers like 1xx covering the various current ratings so maybe they dropped the leading 1 and it is 3CR 113. Just a guess.

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[torqueman2002]

6PTsocket Thank you, that's a good bit of research.

 

[ndfan6464]

Man you all have created a monster..Lol.. 5th grinder on its way from my buddy in Las Angeles. It's what I've been looking for, a mailbox style one...

Also on a side note. If you want bearings I've dealt with a company on eBay now for a bit on some other restoration of some drill presses. They are called discountbearings. They always get my order out same day and usually receive them two to three days later. Willing to answer any question I've sent them photos so they can match the right bearings. Even made sure that the US made bearings were stamped US so I know I am not getting **** China or Japan ones. Just thought I'd share.

 

[EOC_Jason]

If you want a period correct grinding stone, I found a nice CMan Crowntop 6"x3/4"x1/2" at a garage sale yesterday.

 

[cajunfirehawk]

Man you all have created a monster..Lol.. 5th grinder on its way from my buddy in Las Angeles. It's what I've been looking for, a mailbox style one...

Also on a side note. If you want bearings I've dealt with a company on eBay now for a bit on some other restoration of some drill presses. They are called discountbearings. They always get my order out same day and usually receive them two to three days later. Willing to answer any question I've sent them photos so they can match the right bearings. Even made sure that the US made bearings were stamped US so I know I am not getting **** China or Japan ones. Just thought I'd share.

I understand totally on the monster thing, Dr Block is like Jekyll, we are infected with his block virus, I won't say how many I am up to now or by the end of today ...but I will say, I have you beat...
Been meaning to ask, did you get your decal(s) yet? I noticed a guy on ebay (member here too) who was selling a nice rebuilt block recently and he is using repro decals too, I inquired from where but have not heard back.

 

[torqueman2002]

You all sound like you need to take the Pledge again!
'The Pledge' --> http://www.garagejournal.com/forum/showpost.php?p=4832270&postcount=5478

 

[torqueman2002]

If you want a period correct grinding stone, I found a nice CMan Crowntop 6"x3/4"x1/2" at a garage sale yesterday.

That is an OEM grinding stone.

I don't want to be too paranoid or cautious, but please see the
Grinder Safety
section above on page 1.

Basically, even if a vitrified stone passes the Ring Test, the bonding material can be compromised by improper storage - damp/wet conditions.

Here's the other side of an OEM CM stone. These things can and do fly apart with sometimes nasty results.

 

[ndfan6464]

I understand totally on the monster thing, Dr Block is like Jekyll, we are infected with his block virus, I won't say how many I am up to now or by the end of today ...but I will say, I have you beat...
Been meaning to ask, did you get your decal(s) yet? I noticed a guy on ebay (member here too) who was selling a nice rebuilt block recently and he is using repro decals too, I inquired from where but have not heard back.

Oh I am sure you all have me beat. I need to catch up. Haha..

I am waiting for the guy to send me the proofs of the decals. He just received the special silver media in the mail so now he has to do his computer magic then send me the proofs. Hopefully I'll have them this weekend. I'll post the proofs as soon as I get them. But after the few he's done for me I have no doubt they will be amazing

 

[EOC_Jason]

That is an OEM grinding stone.

I don't want to be too paranoid or cautious, but please see the Grinder Safety section above on page 1.

Basically, even if a vitrified stone passes the Ring Test, the bonding material can be compromised by improper storage - damp/wet conditions.

I hear ya. But this stone I'm pretty sure was stored well as the cardboard box it was in was also dry. The flip side of the stone is in just as perfect shape. Yes, if there was *any* hint of water on the blotters or even the box it was in I wouldn't have touched it.

 

[ndfan6464]

Here's the 5th one I'll be working on. It's only a 1/4 HP but oh well. Beggers can't be choosers. Should have it in my hot hands mid next week.

 

[M_George]

How much torque should I use when I put the mew wheels on my grinder

 

[HSpencer]

ndfan6464

That 1/4 Horse looks like it is in great shape. The label looks really clean too. It still has the paddle switch. A lot of those broke off in use, and were replaced with a metal toggle. Looks like you got a winner there!!

Best Regards
Herb

 

[torqueman2002]

How much torque should I use when I put the mew wheels on my grinder

Not much.

Hand tighten with a medium length wrench.

The nuts will tighten with use, because the LH arbor has LH threads and vise-versa.

I tighten the RH nut, snug with a 6" crescent wrench, then I do the same with the LH nut. Because the arbor will tend to rotate, I use a wedge of soft wood to help 'hold' the RH wheel/nut from loosening.

BTW - When I disassemble a grinder, I'll use a 3/8" drive impact to zip off the nuts. Be sure to set the direction properly to remove the LH threaded nut.

 

[torqueman2002]

ndfan6464 - nice find!

These things kind of grow on you, don't they?

 

[M_George]

Thanks Torqueman, I pickup the new wheels I ordered tomorrow and anxious to put my 1/2 horse to work. And yes, started reading this thread two weeks ago and already have two or them.

 

[HSpencer]

M George

Fantastic machines!! I really like the sharpening device on the left one. I would love to find one for my 1/2 HP.

Best Regards
Herb

 

[ndfan6464]

ndfan6464

That 1/4 Horse looks like it is in great shape. The label looks really clean too. It still has the paddle switch. A lot of those broke off in use, and were replaced with a metal toggle. Looks like you got a winner there!!

Best Regards
Herb

Thanks. Yes I was quite happy with it's condition it was in. Let's just see if it remains that way during shipping. Already had UPS destroy a part of one before.. can't wait to clean it up

 

[ndfan6464]

ndfan6464 - nice find!

These things kind of grow on you, don't they?

Oh man it definitely grows on you. It's fun as well. Easier then building old drill press I can tell you that much..Cheaper too..haha

 

[ndfan6464]

Thanks Torqueman, I pickup the new wheels I ordered tomorrow and anxious to put my 1/2 horse to work. And yes, started reading this thread two weeks ago and already have two or them.

Man those are awesome! Jelaous you have 1/2 mailbox one. That's my unicorn. I know there out there but can't snag one for myself..hahah

 

[6PTsocket]

I did some more research and my previous statements about using the start relay from Sears were definitely WRONG. I apologize. DO NOT USE !!. That relay is a replacement for newer 1/6 hp grinders. As somebody pointed out. The correct current type relay is chosen by motor size. My 1/3 hp grinder has a notor plate rating of 4.5 amps. That is running current Start current starts out much higher and drops as the motor comes up to full speed. I have read that the relay should drop out when the notor reaches 3/4 of full speed. Since none of us has a testing lab and a selection of relays, the normal sizing procedure is to take the motor plate rating and select a relay that has a drop out current that is some percentage above the the running current of the motor. Pick too high and you will get little starting torque. Pick too low and the relay will never open. The Klixon relays are available in a wide range of drop out currents. I think the 4CR series might be physically closer to what was in our grinders. I would call Klixon and give them the run current off the plate on your grinder and ask them how much above that to allow when selecting the drop out current of the relay you need, using their chart. This allows the optimum for different hp grinders. FYI our motor is a split phase type motor with no starting capacitor, at least mine is. If the motor has a starting capacitor, the selecton procedure would be the same. It is poor product support on Sears' part not to have found the correct replacement when the right relay is definitely available. If they do not want to supply it, at least publish a part number. The problem is a department store is out of their league when it comes to technical support. The people they connect you to are just clerks. Somewhere, there may be an engineering dept. but we will never get to talk to them. I love the line in on the parts site that says " there is no replacement for this part. We would be happy to help you select a new machine".

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[torqueman2002]

6PTsocket - Thanks buddy for all the time and effort you have invested in this subject. It is appreciated.

 

[6PTsocket]

6PTsocket - Thanks buddy for all the time and effort you have invested in this subject. It is appreciated.

My pleasure.

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[ndfan6464]

Some serious information just got dropped right there! Thanks buddy. Why I love this forum and especially this thread.

 

[M_George]

Put a new set of wheels on my 1/2 HP 397-19340 grinder today and discovered that the left wheel has a wobble. I was able to trace this to the nut and flanges. I pulled the cover off of my 1/3 HP 397-19581 and immediately saw a big difference. The flanges on the older 1/3 HP are much larger 3-3/4in and heaver gauge metal. The ones on the 1/2 HP are 2in and thin gauge metal.

Does anyone have a source where I can get a quality set of flanges for this grinder. I also read that if the nut is not cut straight, this can cause wobble as well.

 

[ndfan6464]

Put a new set of wheels on my 1/2 HP 397-19340 grinder today and discovered that the left wheel has a wobble. I was able to trace this to the nut and flanges. I pulled the cover off of my 1/3 HP 397-19581 and immediately saw a big difference. The flanges on the older 1/3 HP are much larger 3-3/4in and heaver gauge metal. The ones on the 1/2 HP are 2in and thin gauge metal.

Does anyone have a source where I can get a quality set of flanges for this grinder. I also read that if the nut is not cut straight, this can cause wobble as well.

I was in the same boat as you. My 1/3 block came with original 2" Flanges and we're shot due to rust. Took me while but found some on eBay that were 2" and some change. They were 1/8" thick. I think stamped steel but we're solid not the cheap thin beer can stamped steel..I'll look up the sellers name and PM you with it.

 

[EOC_Jason]

Put a new set of wheels on my 1/2 HP 397-19340 grinder today and discovered that the left wheel has a wobble. I was able to trace this to the nut and flanges. I pulled the cover off of my 1/3 HP 397-19581 and immediately saw a big difference. The flanges on the older 1/3 HP are much larger 3-3/4in and heaver gauge metal. The ones on the 1/2 HP are 2in and thin gauge metal.

Does anyone have a source where I can get a quality set of flanges for this grinder. I also read that if the nut is not cut straight, this can cause wobble as well.

eBay is a good source. People will post flanges and sometimes nuts from older grinders that are the nice machined kind and not stamped...

 

[6PTsocket]

My 1/3 horse is pretty stock except for the rocker switch that I replaced the failed original with, after a little hole filing . I wonder how many others rewired the light so the grinder does not have to be running for it to be on. I replaced the lamp socket with one that has a slide switch and moved one wire so there is always power to the lamp. I had forgotten all about it until I was looking at the,wiring diagram during this relay discussion and saw how the lamp was originally wired. It is handy to to have good light to look at your work or adjust a tool rest.

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[6PTsocket]

Another fact that came to light is that the hp ratings of these block grinders are the usual advertising bs. They apply a brake to a running motor and observe the instantaneous impact for a peak hp teading It is nothing like real horse power or they just lie There is a formula for converting current to hp. It assumes 100% motor effiency. It can be worse but not better. There is no free lunch. Under the best of conditions at 120 volts it is abour 14 Amps a horse. My 1/3 horse off 4.5 Amps is a fiction of advertising. But don't feel bad. They all lie except maybe Baldor.


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[exmaxima1]

Another fact that came to light is that the hp ratings of these block grinders are the usual advertising bs... There is no free lunch. Under the best of conditions at 120 volts it is abour 14 Amps a horse. My 1/3 horse off 4.5 Amps is a fiction of advertising. But don't feel bad. They all lie except maybe Baldor.

Think again. Baldor is among the worst in my opinion.

Edit: Among worst "for an industrial rated USA grinder"

 

[M_George]

For sharpening tools, if your grinding hard enough for the power to make much of a difference, isn't the metal going to get hot enough to loose the temper?

 

[EOC_Jason]

6PTsocket - My light is always on, as long as the grinder is plugged in. It came that way, so I figured that just how they were. I don't recall seeing any extra connections, though maybe there was a Y adapter used, it's been a while since I've looked at my electrical.

The only thing I did was add an in-line fuse to my grinder for some overload protection. If anyone wants I can pull it one of these days and take some pics. It was very easy to do, though figuring out the right size fuse was more trial & error.

I don't bother looking at HP ratings on grinders, I look only at the Amp figure... Even Craftsman was not consistent on their amp to HP conversions...

 

[ndfan6464]

The two grinders I have 1/2 and 1/3 blocks, the light doesn't come on till you throw the switch and energize it. Light goes off when you power it off..

Why the inline fuse if you don't mind me asking? I know why it used in equipment but curious as to why you wanted it on your grinder.

 

[6PTsocket]

Think again. Baldor is among the worst in my opinion.

No, I suggest you think again. Their motors are regarded as some of the best available. People willingly pony up 3, 4, 5 hundred dollars for their grinders and buffers. They are the industry standard. Your statement is so far out in left field I have no idea how you came to that conclusion. Everybody has their own opinion but it is like saying SnapOn makes lousy tools. Also, their product support is first rate, unlike another company that we are all familiar with. They do not discontinue a commonly available part and tell you there is no replacement. Their REAL tech dept will talk you through repairs on an old salvaged motor or grinder. They have done it for me and others I know. Do you really think they could have stayed in business for all these years and charged those prices if they made junk? Where I worked we had hundreds of Baldors running around the clock. They are an industrial brand. About what I said before about ratings; a lot of consumer grade 5 hp compressors say something like "special compressor motor" on the actual motor rather than 5hp. My Eastwood (Chinese) 2 speed, 1hp buffer has the exact same current ratings as the Baldor 3/4 hp version. Consumer specs are bs. That does not mean that the block grinders are not good machines or have enough power for the job, only that Sears and most others making consumer tools lie or find some invalid way to rate the power.

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[6PTsocket]

6PTsocket - My light is always on, as long as the grinder is plugged in. It came that way, so I figured that just how they were. I don't recall seeing any extra connections, though maybe there was a Y adapter used, it's been a while since I've looked at my electrical.

The only thing I did was add an in-line fuse to my grinder for some overload protection. If anyone wants I can pull it one of these days and take some pics. It was very easy to do, though figuring out the right size fuse was more trial & error.

I don't bother looking at HP ratings on grinders, I look only at the Amp figure... Even Craftsman was not consistent on their amp to HP conversions...

They all came that way. I just modified mine for the reasons I mentioned and wondered if I was the only one. My drill press came with a separate light switch. It is not unusual for the lighting to be independent so you can use it to set up your work without running the machine. In fact the latest Craftsman grinders look like they have a switch on top of the lamp. I just replaced the lamp socket with one that has a switch and moved the wire, inside the grinder, coming from the lamp,to before the power switch instead of after it. You are right about using current ratings. They are much more reliabe for comparison purposes. My point was that there is a direct conversion from watts to hp and most consumer grade products are rated with a lot of creativity.

6PTsocket - My light is always on, as long as the grinder is plugged in. It came that way, so I figured that just how they were. I don't recall seeing any extra connections, though maybe there was a Y adapter used, it's been a while since I've looked at my electrical.

The only thing I did was add an in-line fuse to my grinder for some overload protection. If anyone wants I can pull it one of these days and take some pics. It was very easy to do, though figuring out the right size fuse was more trial & error.

I don't bother looking at HP ratings on grinders, I look only at the Amp figure... Even Craftsman was not consistent on their amp to HP conversions...

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[Outlawmws]

6PT you took him out of context. He was talking about the HP ratings.

No, I suggest you think again. Their motors are regarded as some of the best available. People willingly pony up 3, 4, 5 hundred dollars for their grinders and buffers. They are the industry standard. Your statement is so far out in left field I have no idea how you came to that conclusion. Everybody has their own opinion but it is like saying SnapOn makes lousy tools. Also, their product support is first rate, unlike another company that we are all familiar with. They do not discontinue a commonly available part and tell you there is no replacement. Their REAL tech dept will talk you through repairs on an old salvaged motor or grinder. They have done it for me and others I know. Do you really think they could have stayed in business for all these years and charged those prices if they made junk? Where I worked we had hundreds of Baldors running around the clock. They are an industrial brand. About what I said before about ratings; a lot of consumer grade 5 hp compressors say something like "special compressor motor" on the actual motor rather than 5hp. My Eastwood (Chinese) 2 speed, 1hp buffer has the exact same current ratings as the Baldor 3/4 hp version. Consumer specs are bs. That does not mean that the block grinders are not good machines or have enough power for the job, only that Sears and most others making consumer tools lie or find some invalid way to rate the power.

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[exmaxima1]

6PT you took him out of context. He was talking about the HP ratings.

Thank you.

 

[bubinga]

The two grinders I have 1/2 and 1/3 blocks, the light doesn't come on till you throw the switch and energize it. Light goes off when you power it off..

Why the inline fuse if you don't mind me asking? I know why it used in equipment but curious as to why you wanted it on your grinder.

the one I have, the guy used it once or twice, or said he never really used it, I forget, something like that.
But it came with a OEM stand, IIRC I gave $125.00.
But, yes, light doesn't come on till the switch is on.
When I 1st got my 150, it was wired like that I changed it to always hot.

 

[ALLFAST]

Someone needs to run over to Fremont Ca and grab this. Just posted up on CL. Owned by former Kaiser MechanicAL Engineer. Seems to have its original stand. I believe 1/3 HP.
$50. No time for me to link ad. I think the eye shields with original script is a hard item to have ?,

Good Luck,

Shawn

 

[6PTsocket]

Thank you.

Sorry, i totally missed his point. I see what he is saying. His 1/3 hp and even the current Baldors have very low current ratings for the hp. I will go stand in the corner.

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