Spool pin size on older box cameras?

[jay moussy]

It seems to me like the camera spool pin diameter is larger on older box cameras, and some folders, as well.

This came to light (heh) when trying on 116-120 adapters from the famous Holga supplier. They do not take the apparently bigger diameter/length of my older camera pins.This results in the spool retaining 'wings" sticking out too much
Anybody experience that?

I can enlarge the adapters by drilling to slightly larger size, and deeper, but then there may be less material left in the slot prong. I may just make metal ones per a DIY method easily found on the web.

BTW, while testing a Rainbow Hawkeye yesterday, I forgot about the shutter release triggering both ways, down AND up. need a new sticker reminder!

 

[Donald Qualls]

If the adapters you're using are 3D printed, it's also possible that you're seeing what's called "elephant foot" -- expansion of the first layer or two laid down by the printer due to "squishing" against the build surface. This causes external walls to flare at the "bottom" (oriented as printed) and holes to shrink. I wouldn't expect drilling the hole to correct size (as opposed to significantly oversize) to weaken the adapter, but it might well be that a plastic drive key is already a little weak, especially with an adapter as thin as 116/120 or 616/120, where the adpter's socket might protrude into the 120 drive key.

 

[jay moussy]

^^ funny, I was thinking of PM you about the 3D aspect of these 3D printed adapters!

A correction: upon closer examination: the adapter hole size is good, but the depth is not.

(measured pin dia. on 1930 Rainbow Hawkeye is 3.55 - 3.62 mm, length 7 mm)
(measured pinhole depth in adapter: 3 mm, thickness of adapter: 3.95 mm)

And yes, drilling would weaken the drive "wings" and they may snap off.

 

[Donald Qualls]

You may have a case where it's not possible to 3D print a "good" adapter because there isn't enough room to accommodate the pins in the camera in the limited space. Another option might be to shorten the pins in the camera, but that's a decision with many other factors than the dimensions of the original and 120 spools...

 

[jay moussy]

The real answer, I think: small diameter metal tubing length, I.D.accepting camera pin (4 mm?), but also O.D. slipping in 120 spool pin cavity (5 mm measured). Thin wall...
There is, or used to be, a mini catalog of small or exotic engineered parts, forgot the name, that would have such.

There is such a thing as 3/16 (.187) O.D. and . 020 wall that would fit, per New England Small Tube in southern New Hampshire, three hours away!

 

[Donald Qualls]

Right, works fine for the supply end (with a fitting washer soldered on to keep the spool centered) but that won't drive the takeup. If you're soldering, though, no reason you couldn't also solder on a couple "fins" from strip stock. I'd start with K&B hobby brass, though I don't know if they have any with 0.5 mm wall (their wall is usually 1/32 inch).

 

[jay moussy]

One more bit on the subject: going through my parts drawer, I found these wire crimp (or shrink?) connectors to fit both the large camera pins and the standard 120 spool recesses:

The ones I tried were same ^^ pink, a size code, I think.
Cut in halves, press in spool. Near friction-free spool rotation, proper centering.
Obviously does not work with the take up, no drive wings.
(Note: there seem to be a gazillion wire connectors in the diameter range of interest!)

I have some success over-drilling my Holgamod spacers described early on, allowing more of the pins going in.
So, if it works, I could then have a 120 as take up.. which means I could send out color 120s!