Sanford SG (Part 2) Magnetic Chuck Wiring

Part 2 of my trip though the Sandford SG benchtop surface grinder. In this video, I rewire the entire machine and upgrade the rectifier for the magnetic chuck.
(As a note, the motor sounds terrible because it was sitting on the fan. Oops.)
Here's the link to the wiring diagram: www.practicalmachinist.com/vb...
If you like what I'm doing here and find some value in it, consider supporting my work on Patreon: / jeremymakesthings
I promise I'll still mostly make stuff out of rusty junk and not just buy shiny things with your money.

[@jonmeadow2449]

Nice job.Formee owner of Sanford Manufacturing Corp.

[@craigtate5930]

Must be the day for wiring projects...I just did a window lift motor repair on my f250 this morning

[@michaelfink1017]

Great job, brother. I picked up a big 8×24 Covel surface grinder that I'm trying to work up the courage to tackle. You make it all seem pretty doable! 😅

[@yogeshakolkar2978]

Please make a full video on Electromagnetic chuck working and control repairing.

[@sierraspecialtyauto7049]

Nicely done and nicely edited. Makes me more eager to get my DoAll 612 up and running. Thanks.

[@JeremyMakesThings]

Interestingly, In my reading about Sanford, I read that they made the 612's for DoAll. Which could be true.

[@mhdm]

Great result and video quality/edit! General safety tip: after you're done wiring double check your ground is actually connected before plugging in for the first time. Check for connection between the ground pin on the plug and say the grinder bed or base with a multimeter. (And if you're there with a multimeter you could also check for no shorts between the plug ground and power pins).

[@kentuckytrapper780]

The wiring looks a hell of a lot better now, I bought a box off Amazon for my mag chuck 90 bucks, great job.

[@kentuckytrapper780]

New subscriber, love the content.

[@ronwilken5219]

As you connected the bridge rectifier the first time I was shouting wrong wrong. Diagonally across the block is ~~ AC and + - DC. Also I think your fuse is a bit underated. 4 amps for the motor and one for the magnetic chuck comes to 5 amps but makes no allowance for any inrush (startup) current which, depending on the motor, can be quite high. There may also be some for the magnet. If you find that, after turning on the magnet and then starting the motor, the fuse trips you probably need to up the fuse rating to 7.5 or even 10 amps. You will still have protection in the event of a short in the wiring but it won't trip un- necessarily. Good luck on the rest of the reno. Merry Christmas to all from Canada's banana belt . ✨🤞🇨🇦👍✨

[@JeremyMakesThings]

I wish you would have shouted louder, I didn’t hear it! So far the fuse size doesn’t seem to be a problem- it seems pretty happy. It’s a pretty small motor.

[@jonmeadow2449]

Specs. on the motor? H.P.? Motor Mar? These would be clues to which edition of the SG you have but I'm betting that it is an SG-2. Former owner of Sanford Manufacturing Corp.

[@desertTooHot]

Dude you deserve more subscribers. Good video.

[@quickturn66]

It maybe half wave on purpose so the workpiece is less magnetized when removed

[@c4t4l4n4]

The nut holding the power switch is suspect. The motor and motion of the surface grinder will introduce vibration, which over time could loosen the nut. Since some of the connections of the switch are exposed and not insulated, it is conceivable that a loose switch flopping around has the potential to make contact with the metal casing. Lock washer, added insulation and some kind of restraint for the switch is advisable!

[@JeremyMakesThings]

Good advice, I’ll see what I can do. I tried to get all my T’s crossed and I’d dotted, but it’s nice to have a few more sets of eyes check my work.

[@g2rdon]

@@JeremyMakesThings A bit late to the party, but hey ho. The metal bodies of the power resistor and the rectifier are actually heatsinks. A bit hard to make out, but it looks like they'd been fastened to the unprepped innards. Since you have the mother of all heatsinks anyway, it might worth making the surface under them clean (shiny flat metal) and throw a bit of a thermal compound into the mix. There's no such thing as overdone thermal management :)

[@CraigsWorkshop]

I think you have the sign off message worked out now :D

[@jackdawg4579]

This electronics? Did I just see Jeremy use all new parts and not reuse / cleanup any old rusty lumps of crud? :) Say it isn't so!

[@georgegowland9753]

Nice Job Mate :)

[@joerogi8401]

Figured I wait a couple of years to comment to let everyone else tell you you messed up with your wiring design. I would suggest that you do not run both your motor and your mag chuck through the same fuse/cb Should your motor pop the fuse it will instantly convert your work piece into a projectile. Ask me how I know. I now have my chuck on a separate dedicated circuit. As my brain often misfires too, I also have an empty tuna fish can with a slot on the side that fits over the hydraulic table control lever. When I reach for the lever I first have to move the tuna can to the mag chuck controller where I turn the mag on. Turn the mag off, the can goes over the lever. Stupid does as stupid is. Thanks for all your great entertainment and ideas. Cheers John 🇨🇦

[@matthewheaton4421]

I just got almost the same grinder and the wiring was really shotty. Where did you get all the components?

[@JeremyMakesThings]

Mostly Amazon, I think I got the resistor off eBay. The link in the description has the specs for the components.

[@matthewheaton4421]

@@JeremyMakesThings Thanks I'm going to get to it, Not sure if you would have any recommendations, the motor is original, but someone removed the start capacitor and just bypassed it. From my knowledge that will work but can cause all sorts of issues. I am not sure what start capacitor to use to replace it?

[@JeremyMakesThings]

@@matthewheaton4421 I’ll see if I can pull mine off and find something on it.

[@JeremyMakesThings]

Mine has a “Mac” brand motor, 1/4hp. I believe it’s original, but I know they also changed the motor size on these at some point. The start capacitor is “72-88 MFD, 110v”

[@matthewheaton4421]

@@JeremyMakesThings Thank you, if you are a member on hobby-machinist, I just made a post on there. If I can help you in any way I would be happy to! I subscribed and liked, good luck in you rebuild!