WTD: Old Delta 1/2hp Motor

For the Toolmaker?

I put a half horse TEFC WEG (Brazilian) motor on mine. From what I've read the surface finish isn't going to be perfect anyway, they say 20 microinches. It leaves a visible pattern in the ground surface that I can break up and remove by cranking the wheel zig-zag.

Many motors are available, you will need to know the mounting arrangement (probably NEMA 56 frame) and any other motor peculiarities (for sawdust-filled areas, TEFC motors are best), as well as the shaft (typically 5/8" diameter with 3/16" square key) mating requirements.

Delta has made many machines over the decades, and they didn't make their own motors. New motors for your application will be in the $150 range, used ones nearly free.

Jim Wilkins wrote in news: snipped-for-privacy@j68g2000hsf.googlegroups.com:

Yup, for the toolmaker. Not looking for the "balanced" motor specifically, but the old Delta motor that is 6" in diameter so it will fit under the cast iron motor cover.... I know they aren't the best surface grinder in the world, but they it will come in handy for my needs and it wasn't all that big. The price was right at $250!

Thanks Jim! Marty

whit3rd wrote in news: snipped-for-privacy@k30g2000hse.googlegroups.com:

I understand. Its that the Toolmaker grinder has a cast iron motor cover, some motor are a little big to fit under it. Marty

The motor cover doesn't do anything useful if you have a TEFC motor and the belt guard. I left it off to reduce the load on the badly worn head pivots.

Your e-mail reminded me that I wanted a Univise so I bought one from Jeff. All four dials are graduated in degrees. The country of origin is obvious but it seems well made. I set all the dials to zero and the top indicated level within 0.003". With the base removed it fits under the wheel on the mag chuck. The base would be useful for milling but it's superfluous for grinding across the top.

The hardware is strange. The pivot bolts are 3/8-16. The vise clamping screws are 8mm with heads that measure 0.505" across. They are a loose fit in a 13mm wrench but the one supplied is 12mm X 14mm.

I'm trying to figure out how to attach a rotating & sliding collet holder head to it. I began one for MT2 collets using a 1.000" ground adapter. Maybe a 5C spin index would work better, or I'll stumble upon some Harig fixture.

Jim Wilkins

snipped-for-privacy@j68g2000hsf.googlegroups.com:

The motor in mine looks to be an original Delta, although I don't remember seeing any tags on it. Should be easy to ID, though, as it's a double shaft motor.

Why they wanted a double shaft motor on the toolmakers grinder I can't imagine. The front shaft has a guard or cover over it. It comes very close to the cast motor cover. The motor cover looks like it was made for that motor, though, as it has a bump out for the front shaft that seems to be otherwise unnecessary.

Mine is a 120 volt 1725 RPM motor. The belt guard seems designed for that speed - large motor pulleys driving smaller spindle pulleys to achieve the correct wheel speeds.

John Martin

Jim Wilkins wrote in news: snipped-for-privacy@v39g2000pro.googlegroups.com:

Thanks for the report on the Univise clone. Don't trust the screws, drill them and tap them out for good ol' American standard cap screws.

I do have a TEFC motor for it. I was being anal about it I suppose. :-) Be sure to join the Toolmaker yahoogroup if you haven't already Jim post some pics of your fixture there. Marty

John Martin wrote in news: snipped-for-privacy@r37g2000prr.googlegroups.com:

You are fortunate John if its is indeed the original. They were supposedly balanced motors. Thanks for the info.

I have an old - well it was bought new in 35 by a friend :-) He was into audio - home made amps and needed one.

The double shaft allows for a flex shaft that Delta sold. Dad had one from the 40's and sometime in the late 90's it finally bit the dust. Internal flex shaft broke. It was used to wire brush stuff or polish with a cloth buffer.

Mart> >> Jim Wilkins wrote

innews: snipped-for-privacy@j68g2000hsf.googlegroups.com:

Are you saying that this was meant to be used with the toolmakers grinder?

While the bump-out in the casting accommodates the double shaft motor, there does not appear to be any way to hook up to the shaft. If you put a flexible shaft on it, you'd have to drill a hole in the casting. If you put a pulley on the shaft, you'd have to have the driven pulley below it - and there doesn't appear to be a mount in the casting for such an accessory.

Marty mentioned balanced motors. I'm not sure that these were balanced. The literature mentions that the pulley and motor were balanced as a unit - implying that the motor itself was not balanced to begin with, and that it was corrected by using an out-of-balance pulley. Maybe I'm assuming too much, though.

John Martin

John Martin wrote in news:007004e0-fe91-4ccc-a685- snipped-for-privacy@z6g2000pre.googlegroups.com:

According to the user's guide it states "Operate grinder with a good dynamically balanced motor only"

A couple of us are trying to ditch the V belt drive in favor of a flat belt drive...

Marty

If there is a 1/2" shaft coming out of one end that isn't used - a shaft can be put over it - and set screwed on.

It doesn't attach to the bell or frame, just the shaft.

Mart> >> I have an old - well it was bought new in 35 by a friend :-)

I may have been wrong about the motors. I had recalled seeing someplace that the important thing was to balance the motor and pulley together. To me, that implied that if you started with a motor that was not perfectly balanced, you might bring it into balance by drilling the pulley. I'm not sure that would bring it into perfect dynamic balance, though.

Here's what the Operating Instructions (PM-1628, dated 4-15-60) say:

"To insure the maximum efficiency of the Delta Surface Grinder, it is offered complete with a motor. The motor, motor pulley and spindle pulley are each independently dynamically balanced. In addition when the spindle is being "run in" and the table ground, the motor and motor pulley as a unit are balanced, and this unit is then shipped with that machine.

It is IMPORTANT therefore that the motor pulley and motor are not separated. If the motor or pulley requires replacement or repairing, return both items to the factory so that they can again be balanced as a unit.

It is possible that other motors which are properly balanced might give satisfactory results, but because of the importance of good balance between all operating parts of this type machine, we do not recommend using other motors or pulleys and cannot be responsible for results obtained."

John Martin

I agree.

My question was specific to the Delta Toolmakers Grinder. On that machine, there is a heavy cast iron guard which fits over the motor. While that guard looks as though it was made to accommodate a double shaft motor, it also prevents easy access to the unused end of the shaft.

John Martin