Shutter Release Cable - connection problem

[Simos Xenakis]

I just purchased two shutter release cables with tapered threads (a 12" Nikon AR-3 and a 20" Pentax 50) but I'm having trouble getting them to seat properly in the threaded hole for my Copal No.0 shutter.

Both cables (which are identical except for length btw) only thread in about halfway with the other half of the threads showing. When I inspect the threaded hole of my shutter, it appears to be straight and not tapered (but it's hard to say).

Do I need a tapered threaded hole for my shutter, or is this as far as tapered threads are supposed to thread in? I feel like there's a little bit of play when I screw them in and I don't want to force them any further because I don't want to ruin the threads.

If I need a new threaded hole, are those easy to come by? Looks as if the threaded hole assembly screws off with some basic flathead screws.

I attached some photos to give you a better idea.

Tapered threads:


Threaded hole for Copal No.0 (hard to tell what's really going on in there):


This is as much as I can thread them:


Another view of the alignment:

[Jim Jones]

Decades ago some American cable releases had a straight 5-44 thread. Older shutters may have this thread. Newer cables and shutters use the so-called European tapered 50 TPI thread. Since this tapered thread can engage only one or two turns, it is common for some threads to be exposed. The two types are close enough that sometimes they can be interchanged.

[Leigh]

I don't know why the tapered attachment exists, but it's used all over the world.

My guess is that way back in the early days of photography, shutters had different thread diameters but with the same pitch.

The simplest way to make a universal release was to create a tapered thread that would mate with all of them.

In any case, the release nose does not seat to the full depth of the thread on the shutter. That's normal.

Just torque it snug and use it.

- Leigh

[Jac@stafford.net]

Dunno if this adds to the topic.

[LabRat]

The block might have been re-tapped at sometime (for some reason) for the straight thread... Was it for some specific application or stripped in the past??? Maybe a cable release tip had broken before and had to be drilled out (or worn out), then re-tapped?

Anyways, another block can replace this if these threads wear out, or one of those external cable release adapters that can trip the external shutter release can be added to the lensboard if this connection ever fails... Be careful connecting the cable release, and don't tug or torque the connection, or lug the camera around with the cable release dangling/swinging around...

Steve K

[Bob Salomon]

Use a loupe and look into the socket to see if a cable release tip hasn't broken off inside the socket. If so place a jewler's screwdriver tip into the socket till it grabs the broken tip and unscrew it.

[cowanw]

Conversely, check your releases and be sure the tips have not broken off.

[Kevin Crisp]

What you have photographed thinking it abnormal is the way all my releases look on all my modern shutters. You just snug it gently in there and it will work.

[Jac@stafford.net]

[...] Anyways, another block can replace this if these threads wear out [...]
Steve K

I got a shutter with no block. Any idea where I can find one?

[Keith Pitman]

I got a shutter with no block. Any idea where I can find one?

I've seen then on Ebay and I've bought them from Schneider. Be ready for sticker shock either way.