Recently bought this Craftsman bench grinder for $6 but i wanted to add a switch but I’m not sure of the proper wiring and what switch to buy. I’ve looked in other posts that say that you can just cut the black wire and connect the switch in between but I want to confirm first since my electric knowledge is limited.
Vintage bench grinder
- Thread starter George110
- Start date
Zeke
Well-known member
You can look the grinder up by make and model and see what the original was. No bench grinder was ever sold w/o an on/off sw.
I did look it up, but the grinder doesn’t have any holes/openings for a switch and I’ve read in other posts that they did sell grinders without switches and they were just hardwired.
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American Locomotive
Well-known member
To answer your question, yes, putting your switch in between the back wire coming from the cord will allow you turn the grinder on and off.
But I am also with Zeke that it seems really odd to build a grinder without a switch. Doesn't make a whole lot of sense to me.
But I am also with Zeke that it seems really odd to build a grinder without a switch. Doesn't make a whole lot of sense to me.
I find it odd and unbelievable that Craftsman supplied grinders without a switch.
but, yes, you switch the black ( Hot) wire. that's assuming the black is wired hot as it should be and if not, correct that too
show us a picture of the front of the grinder, particular the lower portion where switches normally are
but, yes, you switch the black ( Hot) wire. that's assuming the black is wired hot as it should be and if not, correct that too
show us a picture of the front of the grinder, particular the lower portion where switches normally are
Zeke
Well-known member
Is it unswitched?
Zeke
Well-known member
Craftsman 39719581 Grinder OEM Replacement Parts From eReplacementParts.com
Shop OEM replacement parts by symptoms or model diagrams for your Craftsman 39719581 Grinder!
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Item no. 30. But that model no. is one number off. It is possible that CM made a grinder dedicated to a remote switch. Why, though?
That grinder is supposed to have a toggle switch installed. And a wall cord. It was NOT made to be hardwired to a wall switch.
www.ereplacementparts.com
Notice the switch in this ad picture:
my bad, that ad pic is for a 19581 grinder, not a 19571 grinder. and the ereplacementparts schematic also isn't the right exact model either.
The 19571 parts list at ereplacementparts doesn't show a schematic and doesn't list a switch in the parts list either.
www.ereplacementparts.com
Craftsman 39719581 Grinder OEM Replacement Parts From eReplacementParts.com
Shop OEM replacement parts by symptoms or model diagrams for your Craftsman 39719581 Grinder!
www.ereplacementparts.com
Notice the switch in this ad picture:
VINTAGE SEARS, ROEBUCK CRAFTSMAN BENCH GRINDER 1/3 HP GRINDER MODEL 397.19581 | eBay
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my bad, that ad pic is for a 19581 grinder, not a 19571 grinder. and the ereplacementparts schematic also isn't the right exact model either.
The 19571 parts list at ereplacementparts doesn't show a schematic and doesn't list a switch in the parts list either.
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FredWanaker
Well-known member
someone has already been into that wiring. This is a photo from online what the switch should look like.
FredWanaker
Well-known member
I found this on a 397.19581. Yours is a 19571. Can't tell you if this will work but might compare. For sure someone has tampered with the wiring on that already with black and white and green all tied together. I would not be plugging it in without looking carefully at the wiring.
FredWanaker
Well-known member
also - thinking about it. I am a child of the early 1950's and dealt with a lot of dad's tools / appliances / radios etc when they needed repair. I am not an electrician, but I was trained in electronics of that and later eras. That grinder is supposedly from 1963-64. It may have been a two wire plug originally. When rebuilding something like that I always made sure a three-wire plug was upgraded and that the case was grounded as an upgrade. I also checked the two power wires to see if one showed some voltage/amperage leakage to the case - if so, make sure that the leakage is on the neutral leg and not the hot leg. That motor has a starting winding most likely and that has to be properly wired in. As a kid I can remember being lightly shocked by appliances where one would have to turn the plug over to be able to use it.
if it don't come with a switch, easily enough to drill a hole and put in a toggle switch . and yes, ground the case too .
Sorry for not responding sooner but I ended up replacing the power cord since it was all busted up and installed a toggled switch in between the hot black wire and it seems to work properly but let me know if there’s anything I can improve in the future since I’m planning on restoring the whole thing. Thank you for all the guidance. I attached pictures of the grinder before I drill a hole for the switch.
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FredWanaker
Well-known member
what is the green wire going to? Is there a lug on the relay?
wyliesdiesels
Well-known member
A hardwired grinder without an on/off switch would be really odd. Especially a small portable one….
FredWanaker
Well-known member
from the photo it looks like it was sold with a grinder stand, and the switch was on the stand.
dave*99
Well-known member
Edited
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cherokee
Well-known member
I am of the school that if it is impossible to make the thing work without altering it, I will alter it. If you can make it work like in the photo by @cgrutt I would do that.
To me keeping these things as original as I can while still having them be useful is where I am going. Actually with something as simple as a grinder if it was something like this and I did not have a good option for a switch somewhere else I would just set it aside and buy another grinder. This thing is over 50yrs old. I would love to use it, but I would not want to be punching holes in it to do so.
torqueman2002
Well-known member
I don't have a copy of the owners manual for this model Craftsman grinder, but I have see other examples of the 1/4-HP models with out an ON/OFF switch.
0.25 HP m-397.19300 a
Above is a wiring diagram from a 1/4-HP model, showing factory wiring, with white/neutral going to the start-up relay.
Be sure the switch is motor rated.
0.25 HP m-397.19300 a
Above is a wiring diagram from a 1/4-HP model, showing factory wiring, with white/neutral going to the start-up relay.
Be sure the switch is motor rated.
Zeus36
Well-known member
Foot switch! Solves all your problems and is safer too.
DrFeelGood
Well-known member
Not many are horsepower rated many are pilot duty, intended for controlling relays, contactors, & such, and a foot switch is not necessarily safer, all depends on how it is set up.
Doozer75
Well-known member
I know a bit about antique conservation, and I have or at one time had
machines in my shop that were 150 years old. Steam engine driven
type stuff. But your ideals about not wanting to drill a 31/64" hole
in a grinder to mount a toggle switch are a bit off the map.
You are entitled to your opinion, but I think reading this GJ board
has warped your sense of priorities. You will be dead in the grave
and your un-used grinder will be on the shelf, waiting to be thrown
in the dumpster when the next generation cleans out your stuff.
-Doozer
dave*99
Well-known member
My wife already showed me the special moving van she will hire to take my stuff to the museum when I’m gone.
Did you know my old dog went to live on a farm?
