Help identifying this grinder

[matthewsx]

i wouldn't have guessed 1/4 hp- it's very large for the HP rating!!

Horses were larger back then....

 

[Janderso]

That could make a nice addition to your shop!

 

[Dabbler]

@Ulma Doctor I suspected it was a repulsion motor by its form factor, and since it is 1/4 HP is most certainly is. The greater size is because of how the field windings are done. I have 3 repulsion motors and all have the same form factor. They are less efficient i.e. less torque for the energy input, so they get hot under load, But they have far less drop off of torque as the motor goes under load.

 

[RebelJD]

Well I've spent some more time disassembling the grinder. Under the knob on the front and under several layers of dirt and paint I found a very interesting nameplate.

I've sent an email to the Worcester Polytechnic Institute asking for any information, if it exists. I'll post any replies.

 

[RebelJD]

Thanks for all the help and comments. I'm moving forward with the restoration, although it may take some time, you know how busy us retired guys are. I did an insulation test on the motor and it is fine so I'll be retaining it. I may try a simple static phase converter first using capacitors. I'm doing some homework now on how to pick the right size caps. If I loose too much power (its only 1/4 HP now) I will go the route of a VFD.

Since this grinder uses the side of the wheel I need to find out how to dress the wheel. I don't see any mechanism for this on the machine now. Any suggestions would be appreciated.

The other thing I'm curious about is the function of the knob on the bottom. It turn an acentric which I think will impact the angle of the grind on the tip. Anyone know how this works?

 

[RebelJD]

Here is a quick update. I've not heard back from Worcester Polytechnic Institute but I did hear back from the Smithsonian National Museum of American History. They have some documentation on this but it has not yet been scanned and put on-line. They said they would definately get back to me when it is available but gave no time line. Apparently they are understaffed like everyone else these days.

I decided to go the route of a VFD and mount it separately as to not distract from the vintage look. I purchased an inexpensive Inverter (VFD) on Amazon and it works just fine. I took the motor apart to clean it and adjusted the end play with some shims. It turns nice and smooth. It runs really quiet on the VFD. The quality of motors made in the 40's and 50's is much better than motors you can buy today. A benefit of the VFD is that you can reverse the motor rotation easily and the speed can be adjusted.

 

[RebelJD]

I finished the restoration on this grinder. It really didn't take all that long. I'm still learning how to use it but I did successfully grind a 1/2" bit and it drilled just fine. I mounted the VFD on the rear of my mill since there was already 220vac there. I had to make some bushings to adapt the grinding wheels to the shafts but it spins smooth and quiet. It is a nice addition to my shop. Hopefully I'll receive the information on grinder from the Smithsonian some day.

 

[wachuko]

Great job!!!

 

[frankly2]

Very nice restoration job, that will give you many years of service.

 

[craniac]

That's an old one. Here's a link to what vintagemachinery.org has on this http://www.vintagemachinery.org/mfgindex/detail.aspx?id=1136&tab=4

The brainchild of Ichabod Washburn

Tim