Criterion Dynascope RV-6 Project: "Dead Motor, No Shaft!"

Recall from the first post in this series that the person I purchased this old scope from kept the pier, including the RA motor, outside in the rain and snow for the better part of thirty years and that, while loading the pier into my car, a significant flow of water came streaming from the motor box.

Needless to say the original Synchron 6-RPH motor, irreparably damaged with corrosion, would not make the slightest peep when plugged in to power.

I was clearly going to need to find a replacement motor and after Googling around a bit I determined that the exact model was still being sold from Herbach and Rademan, a company specializing in electro-mechanical and scientific supplies.

At first, I thought this would be a simple swap-out, "out with the old, in with the new" type of replacement but after comparing the motor I received from H&R to the old corroded Synchron, I realized that I would have a problem connecting the new motor to the worm gear of the clock-drive.

The shaft on the new motor was too long and didn't have any ability to make the connection with the worm gear which appeared to use a simple "tongue and groove" type of fitting.

After Googling some more, I discovered the excellent Criterion Dynascope Yahoo user group which, aside from being an great resource for Dynascope related issues, lead me to contact Ken Poshedly, an extremely nice and helpful group member who had solved this problem already and was happy to help others.

During his Dynascope restoration, Ken had a fitting made by a machinist that could be fastened onto the shaft of a new Synchron motor to make the connection to the worm gear.

Lucky for me, Ken didn't just have one fitting made, he had many (I believe he said something like 50 or 100) and he was selling them at cost (... just a couple of bucks) to anyone that needed them and, even more lucky for me, he still had a couple left.

I sent Ken my order and he sent me back two of the shaft fittings along with a hex tool for tightening the fitting onto the shaft and some great installation instructions he had printed up.

Sadly though, after tightening Ken's fitting onto the new Sychron motor shaft and attempting to reassemble the motor-worm mechanism, I discovered that the diameter of the fitting was slightly too big to fit inside the worm gear housing... there must have been some slight differences in my RV-6 and Ken's... drat!

Further still, the mini hex nut used to hold the fitting onto the shaft was sticking out from the side of the fitting even after being fully tightened further exacerbating the diameter issue.

Finally, the shaft, particularly with the fitting installed, was just too long to fit correctly when reassembled.

What to do?

After some time pondering this major set-back, it occurred to me that I might seek the help of a local clock repair shop... surely they would have the skill and the tools to deal with such an issue.

Lucky for me it was recommended that I bring my troubles to Jim Peghiny of the "Clock and Watch Shop" in the Auburndale section of Newton MA. 
 
Jim is not only a great guy, but a true expert and craftsman with over 30 years of experience repainting intricate clocks and watches.
  
He took an immediate interest in my project and was fully acquainted with Synchron motors (... apparently they are routinely used in some clocks) an even knew a thing or two about Criterion so I handed over all the crucial parts (new motor, old motor, shaft fittings, worm gear) and upon leaving his shop, I had the distinct feeling that my problems were solved.

A few days later Jim called to tell me that the fitting was now the correct diameter and that he would like to shorten the shaft to make it the correct size as well as glue (with some sort of epoxy) the fitting to the shaft instead of using the hex bolt.

I was elated!... I had just assumed that Jim was going to get the diameter of the fitting right but now he was going to whole route, making the complete mechanism correct end-to-end.

Of course, I quickly gave him the go-ahead and he said I would be able to pick it up the next day.

Well, when I got to Jim's shop I could see that he took great care in getting the mechanism right as he had fully assembled the pieces and even hooked up the motor to test how it functioned powered.

The mechanism was now perfect and it cost just $15 for Jim's work. 

In this day and age for that much work, care and attention to detail to cost just $15 seems undervalued to say the least so I thanked Jim and assured him that I would be bringing all my future clock, watch and telescope repairs to his shop.

Heading back home, I had the distinct feeling that I had just overcome the last show-stopper of this project.

The clock-drive needed reassembly and a new cork clutch but that was minor by comparison to the other issues I had encountered.

The optical tube assembly needed some serious cleaning and some repair (as we will soon see) but overall I did not anticipate any seriously problematic issues...

"It's all smooth sailing from here on out!" I thought.

Next up: "Clock Drive and Cork Clutch!"

Best to all,
BBG