Repair rack and pinion lock for extension rail

[mikkelangaju]

Hi,
I am working on getting my Korona Royal 5x7 working properly again.
It is equipped with a locking rack and pinion to control movements which I really like, but the front extension doesn't lock anymore.
I have found the following from the catalog showing the rack and pinion:
201349

I have disassembled it and I think I know what is wrong and how to fix it, but I wanted to check with someone more experienced first.

It seems that the ring that the outer teeth goes into to enable the lock is supposed to be attached to the bracket that is mounted to the camera and therefore wont rotate. Currently this ring is loose and can rotate freely. Should I just glue the ring to the bracket, or should I look into welding or some third option?

Thank you.

[mdarnton]

If it's as you describe, it sounds like a job for soldering. If that's the case, I'd try to get the parts out and let a jeweler handle it.

[Jim Noel]

If you choose to solder it,use only silver solder.

[mikkelangaju]

Thanks, I'll take your advice and ask a local jeweler about it. What makes soldering a better solution than glue? I have a soldering iron myself that I use with lead solder, but I think soldering two pieces of metal together likes this would be difficult so the jeweler suggestion is really appreciated.

[Havoc]

Soldering with a soldering iron as in making electrical joints is not very strong mechanically. Silver solder (high percentage silver) as used in brazing is much stronger but this is to be done with flame and flux. So it requires some skill and experience certainly with small parts. Welding means melting the parts to make the joint. And with small parts is very difficult (certainly if it are different materials) if you don't have the right equipment. And the risk of damaging the parts is great while for this use it will not be stronger than brazing.

With solder you can make a very neat joint that will take almost no space. With glue this might not be possible if you need the strength. Some sorts of Loctite might work if you can get it fitting well enough en clean enough.

[Jeroen]

When the wall anchors of our cast iron stair railing broke off, the local blacksmith soldered them back on with silver and gave me 5 y. guarantee when I worried if silver was strong enough for the purpose. That's 9 years ago now and they haven't failed yet. Silver is good for many things other than photography!

[Tin Can]

A Very Brief Introduction to Brazing (http://www.phred.org/~josh/build/brazing.html)