Motor/Motor board work jig

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Brad
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Motor/Motor board work jig

Post by Brad »

I am restoring a C150 Diamond Disc machine and need to clean and adjust the motor. I have not tackled a DD before and found that it was difficult to handle to work on so I decided to build a work jig that would allow me access to the machine.

I built a rectangular box out of scraps of cabinet grade plywood. I also had a spare set of motor mounts. See the pictures below. The locations of all the motor mounts are adjustable. The "2" mount side is along the side of the box and the "1" mount is on movable cross bar. I glued and screwed everthing together (except the motor mounts and movable crossbar) and did not worry about astetics or glue drips.

With this set up I can set the box on any side to access the machine from any angle.

The only thing I would do differently would be to extend the vertical sides several inches above the "top" of the box so I can turn the whole thing upside down. When I designed it I did not consider that the repro mount/horn extended above the box. Since it was all glued together I could not change it, however, I will fashion extentions next time I am out in the shop which will meet the need.

I can easily modify the mounting to hold any motor board.

This should prove a useful jig for working on motors.

Anyone done anything similar or different?

Here are the pictures.
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Re: Motor/Motor board work jig

Post by Guest »

I think this is a great idea-I am getting ready to REALLY work on my 1st D.D. machine and was getting ready to make up a similar jig-I would not have thought to add the high top so that you can turn the machine upside down. I have a mounting top board that I made from a copy of another D.D. but like the adjustable concept in yours-GREAT Project!!
Abe

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Re: Motor/Motor board work jig

Post by Neophone »

Brad,

That's a superb design! Top marks! :D

Regards,
John

Listening to the Victrola fifteen minutes a day will alter and brighten your whole life.
Use each needle only ONCE!


gibsonj
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Re: Motor/Motor board work jig

Post by gibsonj »

Brad

That is an excellent idea and design. Would you mind sharing your overall dimensions for your jig? I'm re-storing two DDs right now, and this would definitely come in handy.

Thanks.

John

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Brad
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Re: Motor/Motor board work jig

Post by Brad »

Sure,

The horizontal top and bottom pieces are all 2" x 21". You can see by the pictures that I just butted the ends together so the dimensions of the box end up being 21" x 22½". The vertical pieces are 1¼" x 16". I would make them longer so as to allow the whole thing to be inverted. I am going to attach new verticals to the outside (since everything is glued) to do this, but if building new, make the verticals longer. I haven't figured out how much longer yet, but looking at the pictures, 7" should do it.

For the piece that captures the vertical horn pivot arm, I just took a long scrap of ¼" oak plywood, drilled the capture hole (I recall that is was 7/16"), placed the pivot arm through it, lined it up best I could, traced where it crossed the bottom horizontals. Cut it then screwed it in.

For the motor mounts, they are attached to both the upper horizontal and to a small block of plywood that has a single screw to hold it to the horizontal (study the pictures and you'll see). I did this because the motor mount hung below the horizontal and I was worried that there might be too much torque. You can always make the horizontals wider and drill a hole for the crank.

The adjustable side should be clear as to what I did. I wanted to be able to "hang" this piece, line it up, then screw it down.

The challenging part was getting the motor mounts at the correct spacing. I did this with the unit on the side with the "2" mount side down. You will have to muscle the whole assembly in and out a couple of times. Once I got the "2" side mounts attached, in the same position I attached the opposite "1" side mount to the cross bar. Then I attached the "1" to the motor. and stood the thing upright, slid the motor and cross bar around to get the holes lined up with the motor mounts, and screwed everything down. I don't know if there are different Edison DD motor boards or if they are all common wrt mounting. Either way, the locations of the motor mounts are easily changed.

Again, I just slapped this together to be functional and did not worry about aesthetics. It's ugly, but it is very functional.

Come back and post pictures of what you build.

gibsonj
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Re: Motor/Motor board work jig

Post by gibsonj »

Thanks, Brad. Great information and again, an excellent idea.

John

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Re: Motor/Motor board work jig

Post by gramophoneshane »

That's a great idea Brad, but I have to ask :)
What did you find difficult about handling the DD motor?
I can only assume that you must have left the horn attached when you removed the motor from the cabinet?

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Brad
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Re: Motor/Motor board work jig

Post by Brad »

I added the taller verticals and can now completely invert the whole thing. Accessing the bottom is now very easy.

(GShane, yes I kept the horn attached, however, I intend on using this with ANY motorboard from any maker. I can work on, clean, and adjust in a solid jig with easy access from any side.)
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Re: Motor/Motor board work jig

Post by Valecnik »

I never saw this thread earlier. What a useful device. How nice it would be to have one, just to demonstrate how a DD motor works. Nice job.

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Re: Motor/Motor board work jig

Post by hillndalefan »

If you ever get the chance [I believe a picture is in George Frow's Edison Disc Phonograph book] to see Edison's personal machine that he used to bite in order to transmit the sound waves to his inner ear, it looks almost identical to this jig you've designed. Fantastic! :D

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