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New Old Shaper - Atlas 7b

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rockknocker:
Thanks for the link vtsteam! Alas, I cannot open it at work (dang interweb filters), but will check it out when I get home.

Here's a few more pictures of the machine as it was a few days ago. Also, some more notes:
* The original vise is in good shape and includes the wrench
* The original handle is in good shape, and fits on about everything that needs adjustment on the machine!

rockknocker:
How's the image size working for you guys?

The first thing to tackle was the motor. I can't wait to see this thing turn over!

The motor was pretty easy to remove, only three bolts secure it to the motor mount. The wiring is straightforward, but in very bad shape, with a lot of the insulation flaking off as I handle the wires. I think this will need replacing throughout the machine. This isn't a big deal, we're talking about a whopping 2 wires.

The motor came apart pretty easily. Four long machine screws secured the two cast end plates of the motor, with the stator and housing between them. After removing one end plate and the pulley the rotor slid right out. The bearings appear to be sintered bronze bushings, and are lubricated using oil cups on either side of the motor.

With the rotor out, the problem quickly became apparent. This motor uses four commutation brushes in an interesting arrangement, mounted to a floating brush holder. Two springs are used to press the brushes against the commutator, and one of the springs was broken. Without the spring force present, the brush holder itself was rubbing against the commutator. This is what was causing the sparks. Luckily, it doesn't look like this was used for very long at all in this condition, as the scoring on the commutator is minimal and the brush holder and brushes are in good shape. This looks fixable!

Background: 15 minutes of Google-fu identified this motor as a repulsion-type motor. These motors were used between ~1920 to 1950-ish in situations that require a lot of startup torque. The construction of the motor is very similar to an induction motor, but the ends of the squirrel cage are connected to a commutator instead of just being shorted. The speed and torque of the motor are adjustable by changing the angle of the brushes relative to the stator coils. Some modern motors use this technology today in a repulsion start, induction run configuration for high starting torque and good running efficiency.

The motor faceplate is very difficult to read, and all the paint has flaked off. I believe it is a 1/3 hp motor that runs on 110VAC.

rockknocker:
To fix this motor I'll need to buy or build a new spring for it. I can't find a spring that is similar enough for me to be confident that it'll work, so I did some research on spring winding and bought some 0.031" music wire from McMaster-Carr. ($3 of wire and $14 in shipping, next time I'm going to eBay)

The spring I need is a tension spring with ends about 1 1/4" long. The spring is made of 0.030" wire, and has 11 turns. The ID is approximately 0.3".

My first attempt at spring winding did not end up well. I turned an arbor to the right diameter for the ID of the tension spring, then used a vice-grips to clamp the end of the wire to the arbor and wound it up by turning the lathe by hand. The spring looked good on the arbor! According to the internet I needed to remove the spring from the arbor before stress-relieving it. However, before the spring had even come off the arbor it had already re-configured itself as a multi-turn pretzel. oops.

My next attempt turned out better. I modified the arbor to hold the ends of the wire better, then chucked it up in the drill press and wound it up by hand (the lathe was busy). Again, the spring looked good on the arbor, even though I had to tweak it with a pair of pliers to get the ends to look right. This time I left it on the arbor for the stress relieving step. I wrapped it in steel wool and multiple layers of tinfoil (to minimize the smell), then begged my wife for access to her oven in the kitchen. She allowed me access (with several conditions, my to-do list just got longer), so I popped it in and set the heat for 550 degrees Fahrenheit, the highest the oven would allow. After heating for two hours and cooling in the oven overnight, I was able to remove the spring from the arbor and trim the edges. It looks pretty good for the first success, it might even work in the motor!

After a test-fit, the spring fit the motor just fine! I'm very confident that it will work now.

vtsteam:
Another possibility for a quick spring in future is K&E music wire at most hobby or craft stores, and even some hardware stores.

rockknocker:
She's alive!

After assembling the motor back onto the shaper and connecting some temporary wiring, she fired right up! Other than a strange whining/buzzing noise for the first second of running (every time), the motor runs nice and quiet.

Before firing up the motor, I did go through it again and use about 2+ cups of oil lubricating everything.

The shaper runs nicely as well, although I immediately noticed a "clunking" noise coming from the ram lever once per stroke. The bushing that connects the ram lever to the large bull gear must have a fair amount of slop in it. I hadn't noticed it before, but with the machine stopped I can move the ram about 1/16" - 1/8" forward and backwards. I can't see the bushing in question, there is a cover plate mounted on the ram lever that does not come off when I take all the screws out.

Hopefully this is not an indication of a worn-out machine. Everything else has looked pretty good on this unit, although I may be missing obvious signs due to inexperience.

I'll take a video of it next time I get into the shop.

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