My quick & dirty grinder restoration

[evintho]

Neighbor was throwing this away...........it's 75 years old and works perfectly!
1940's Black & Decker 8" with 3/4 hp. Model #74



Tore it apart to check it over and found perfectly good bearings and a new capacitor. All good. It was a little too low for my liking so I extended the stand 5" using 1" square tubing and some scrap steel.



Took it into the backyard and blasted it clean. BTW, thanks to GJ member 'mattblast' for providing the missing guard!



I went with silver hammertone on the grinder and satin black on the stand. Yeah, it's missing the tool rests, side shields and some other things but it ain't tool ****. This'll be a workhorse!





No confusion on which button is which.







I love the homemade stand on this thing. 4" pipe welded to a train hub! It weighs a ton!

 

[toolman9w]

Nice job. Love the hammer tone and flat together.

 

[notlob]

Nice! Love the pushbutton switch.

 

[d.mcfarland]

Nice!

 

[Unruh]

Nice work. I love seeing these kind of rehabs.

 

[AnthAmbassador]

Hey, I can't find info anywhere online. Do you know what the cap in your grinder is? I have the same thing, 3/4 HP 8" grinder from before they put the model 74 on the tag. Type G ser#2199114, and I can't quite figure out what's wrong with it.

It turns well, it runs great once it's spinning. Took it apart and the centrifugal switch mechanism seems to be working fine. There is conductivity through the start windings when it's still, around 30 ohms. Half before the switch and half after, roughly speaking, conductivity through the run windings is good, and again, if I pre spin the grinder, it runs flawlessly after it has a chance to gain RMP, but it wont start from a dead stop.

I thought maybe the cap was the problem, but the cap is good. Reads out 161-193mfd 125v ac 60 cycles. My fluke tells me it's a 178 mfd cap. Everything seems reasonable, but it won't self start at 0rpm. I was wondering if you could peak at your cap and see if my cap is way off, even though it seems like a ballpark fit for the motor.

 

[wayne55]

Don't know why you call it quick and dirty, looks first class to me.

 

[My Old Tools]

Hey, I can't find info anywhere online. Do you know what the cap in your grinder is? I have the same thing, 3/4 HP 8" grinder from before they put the model 74 on the tag. Type G ser#2199114, and I can't quite figure out what's wrong with it.

It turns well, it runs great once it's spinning. Took it apart and the centrifugal switch mechanism seems to be working fine. There is conductivity through the start windings when it's still, around 30 ohms. Half before the switch and half after, roughly speaking, conductivity through the run windings is good, and again, if I pre spin the grinder, it runs flawlessly after it has a chance to gain RMP, but it wont start from a dead stop.

I thought maybe the cap was the problem, but the cap is good. Reads out 161-193mfd 125v ac 60 cycles. My fluke tells me it's a 178 mfd cap. Everything seems reasonable, but it won't self start at 0rpm. I was wondering if you could peak at your cap and see if my cap is way off, even though it seems like a ballpark fit for the motor.

The cap maybe a run cap and not a start cap. It may have a start winding controlled by the centrifugal switch and that winding maybe bad. I have a 7" Baldor with a similar problem.

 

[AnthAmbassador]

I don't know what connection I fixed, but I took 'er all the way apart and put 'er together, and I fixed it and now it's fine. Frustrating, but it works.

 

[PeteH]

I just refurbished a Duracraft grinder with same problem. Found the centrifugal switch loose on the shaft and too far away from the spring washer that closes the points for starter windings. Simply slid the collar assy over until points closed, tightened set screw and it starts up immediately and runs great now.

 

[unslow1]

I like the hub as a base. My grandfather had his on a pole mounted to a plywood base. At first it didn't make sense until I used it. The way it is positioned you have to stand on the plywood to use it. Once your weight is on the plywood it won't move.

 

[The Cobbler]

here's my model 74, it's in the round to it pile for restoring . https://www.garagejournal.com/forum/showthread.php?t=281723