New Surface Grinder

[mcostello]

A hint worth repeating is when Your part is held by a magnetic chuck,the last thing to do before starting to grind it is to grab ahold of it and try to move it. You might never have another chance to see if it is held solidly. The first piece I ground on MY surface grinder was a tool bit. Stellite. Stellite is not magnetic. Almost launched that one! Be careful

 

[Ulma Doctor]

A hint worth repeating is when Your part is held by a magnetic chuck,the last thing to do before starting to grind it is to grab ahold of it and try to move it. You might never have another chance to see if it is held solidly. The first piece I ground on MY surface grinder was a tool bit. Stellite. Stellite is not magnetic. Almost launched that one! Be careful

note to self... stellite is non magnetic

 

[Bill C.]

Sounds good. Be sure to get a demagnetizer in case the parts stay magnetized. Electric magnetic chucks have a built in function. I used to use a .001 strip of steel shim stock to test my finished parts.

 

[Bill C.]

A hint worth repeating is when Your part is held by a magnetic chuck,the last thing to do before starting to grind it is to grab ahold of it and try to move it. You might never have another chance to see if it is held solidly. The first piece I ground on MY surface grinder was a tool bit. Stellite. Stellite is not magnetic. Almost launched that one! Be careful

Glad you check before hand. When I was in training we would routinely make seam welder wheels. About three inch steel diameter with about a quarter thick brass ring pressed on the outside. We would load those assembled wheels on a 30"-36" Bullard grinder to grind them flat about a quarter thick. Every so often one of the outer parts would disappear into the coolant tank. They would find all kinds of parts when the coolant was changed.

 

[Jericho]

Does your magnetic chuck use a Electro-Matic chuck control Patent 2,825,854 Re :25607 ? The one I'm working on has and I've done a bad practice. I cut the 110V AC input wires to it and now am in a quandary as to which lead is hooked to the "hot" leg and which connects to the neutral (white) leg. I just labeled it AC wires when I cut it loose. Both legs are fused. Would it be too much to ask you to take a peek at yours and tell me which it should be ? I'm thinking it doesn't matter but would rather not ruin it by ignorance. Pictures of wire attached .

 

[Dabbler]

As I recall on mine, the chuck is DC and it dowsn't matter as long as the ground is good. I'll check mine tomorrow.

 

[Jericho]

As I recall on mine, the chuck is DC and it dowsn't matter as long as the ground is good. I'll check mine tomorrow.

Did you have an opportunity to check the wiring in the Electro-matic ?

 

[Dabbler]

oh, sorry, I had to clear a bunch of snow before it melts, and i got distracted... I'll unearth it before supper.

 

[Dabbler]

My Walker looks completely different inside, As I mentioned they both are DC units. Mine sends 120V DC to the magnet coils, and then 120VAC for release and demag.

The potentiometer is connected to the SCR to provide 10-100% duty cycle.

I used to have the schematic, and I think I even posted it in the forum years ago, but I no longer have it.

Because yours is different, try using an ohmmeter to check for case leakage from both AC leads. If both are well isolated, then it really doesn't matter. Most of the workings are a full wave bridge rectifier, and if yours is electronic, an SCR lamp dimming circuit.

 

[Jericho]

My Walker looks completely different inside, As I mentioned they both are DC units. Mine sends 120V DC to the magnet coils, and then 120VAC for release and demag.

The potentiometer is connected to the SCR to provide 10-100% duty cycle.

I used to have the schematic, and I think I even posted it in the forum years ago, but I no longer have it.

Because yours is different, try using an ohmmeter to check for case leakage from both AC leads. If both are well isolated, then it really doesn't matter. Most of the workings are a full wave bridge rectifier, and if yours is electronic, an SCR lamp dimming circuit.

Thanks so much for giving the help. I did get a chance to check the resistance to ground and it was off the scale on my digital ohmmeter on both legs so apparently no leakage. Heading out a few days but as soon as I get back I'll smoke test it. The patent (described as a control for a demagnetizer)from the device shows a wiring diagram but I couldn't make heads or tales from it. The only thing I can identify on it appear to be 3 bridge rectifiers, some DPDT switches, and a variac . Looks like mine had been modified considerably from the patent and perhaps simplified. Nothing to gain from that for me. Thanks again.