Cirkut #10 key specs, and how to build one from parts

The key that came with my #10 camera was a little undersized and worn, so I thought I'd get a new one. As I've seen on a few websites, you just find a clock winding key of the right size and you're all set. Well, turns out it's not necessarily that easy. From pictures, it looks like the earlier fan-driven Cirkut motors have a square shaft sticking out, and use a crank handle with a square hole in it to wind the motor. THAT is indeed how an old clock is set up.

But the later governor motors have a square hole in the spring casing shaft that sticks through the bottom of the motor plate. All clock keys have holes, the later Cirkut motors have holes, this isn't going to work. After a bunch of misleading measuring and a little bit of trial and error, I finally have the specs, to be able to make my own keys.

First, get some 5/32" square keystock. This is square metal that is used for making shaft keys, like the kind that hold big pulleys onto big shafts. This is the size that will fit nice and snug into the Cirkut motor winding hole. Then get some newly made old-timey clock winding keys with a 4.0mm square hole,often referred to as #8 keys (but the measurement is the important part.) This is the size that will fit snugly around that keystock.

I got 12" of keystock on ebay for about $6 including shipping. I got keys for a little under $4.00 each on ebay plus shipping.

Cut off an appropriate amount of keystock - this will depend on how deep the hole in the key is, but in my case 3/4" was the perfect amount to stick into both holes and still leave a nice little gap between them. Bevel off the edges of the part that will go into the Cirkut motor. Deburr the edges that will go into the key, but no need to bevel them. I put a little JB Weld down into the key hole, jammed the keystock down into the hole as far as it would go, wiped off any that squished out, then waited 24 hours for it to harden. Poof, brand new key.

I believe this same size key was used on other Cirkuts but I don't know for sure. Feel free to chime in if you know the answer. And if you're no good with tools but really need a key just send me a PM - I made a couple of extras and would be happy to send them out to people that need them (probably for free, unless shipping to your non-US country is crazy expensive.)

Duncan

Duncan - You have done a great write-up on making a key. Yours certainly looks much more elegant than the one I made years ago. I took a piece of mild steel strap 1/8" X 9/16" wide X 2 1/4" long (likely what I found laying around somewhere), laid a 2 1/4" length of 5/32" key stock across it at 90 degrees, and brazed the two bits together. It is functional to wind a Cirkut motor but is certainly no thing of beauty. I didn't even bother to polish the black mill scale off the pieces. One possible advantage is if I drop it somewhere, no one will think it is anything of value and bother to pick it up.

I'm very much enjoying all your recent Cirkut posts even though I haven't taken time to post any responses. If you keep updating your Cirkut progress you may inspire me to get out my #8 and run some film through it. Of course that is assuming the snow ever goes away here in E WA State. I know it is possible to do Cirkut photography in cold weather but you won't catch me doing so. I'm definitely a fair weather photographer.

Len

Len,

Well, to help incentivize you to get that camera out once Spring comes, can I send you a fancy shiny key to wind it with, since it sounds like it uses that same size? PM your mailing address. You've helped me a lot with old info and documentation, the least I can do is send you a shiny new key

Duncan

There were a few differences in key size, at least that I've run into. I'd have to break out the different cameras to see though. My #10 and #16 were made the same year (1914 I think) and are similar in a lot of ways except the 16 has a bigger spring. Like you said it has a shaft and you need a square hole clock key for it