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papageno
22-Feb-2009, 17:53
I am firmly convinced, that members of this forum can find a good answer to any question related to LF photography or related to LF only partially.

Now I have such a question, related to LF in some ways. The lever securing the front standard to the bottom plate broke off the pin and now the front standard swings freely. The camera is an old Wista, that looks like a Tachihara however.

I think that it will be possible to glue the two pieces together, but need an advice what kind of glue may work here. There will be some mechanical force applied to the glue when the lever is turned in order to press one plate to another and lock the front standard. Ordinary glue may break in time due to this repeatedly applied force.

I heard, that JB Weld might work here, but don't have any experience with it.

MIke Sherck
22-Feb-2009, 18:14
I don't believe that an adhesive on chromed steel is going to work for you; I think that you're going to need a mechanical connection. On the other hand, I'm a computer programmer; what do I know? I think I'll keep watching -- maybe I can learn something!

Mike

Gary Beasley
22-Feb-2009, 18:18
You should remove the metal parts from the wood and silver solder it back together

Robert A. Zeichner
22-Feb-2009, 18:42
I don't believe that adhesive would work very well in this instance, at least not by itself. If you can disassemble the mechanism so that the shaft could be put in a vise, perhaps you could modify it so that the lever could be press-fit back on in such a way that it would not break loose. You could, for example, pound a few dimples into the shaft with a pointed center punch which would create some spline-like spikes that would bind the lever mechanically.

Gene McCluney
22-Feb-2009, 19:28
Yep, this is a mechanical fix-it type of thing, rather than glue, but not an extremely difficult fix for someone who works with metal. You could take the parts (both) to a local machine shop and they could fix you right up.

Kuzano
22-Feb-2009, 19:33
A good gunsmith is creative in remaking metal joints that will not break in the future, and they tend to be "good ole boys" who charge a 6 pack and $10 bucks. Then they say "Awe Helll, it wern't nothin."

I've used them on small metal repairs and been happy with the results.

Nathan Potter
22-Feb-2009, 20:01
I might be inclined to drill and tap then use a machine screw of the appropriate size to keep the two pieces together. Might even put a bead of a high quality epoxy between the two pieces prior to reattachment. Varian Torrseal has a yield strength of approximately 4000 PSI, although it appears that your applied force will be of a shear nature after repair. It's a pretty tricky fix though.

Nate Potter, Austin TX.

bspeed
22-Feb-2009, 20:42
Ok, Nathan's post is it, though maybe clarifiy ?


Drill and tap from the side, use a hex set-screw.

if drilling the center part is too hard, then
just dimple the center part for the set screw to set against.
tighten down, your good to go.

Jim Michael
23-Feb-2009, 04:58
Another vote for the set screw. A dab of Loctite from the hardware store might work as a temporary fix.

Bruce Barlow
23-Feb-2009, 07:36
Call Richard Ritter, 802-365-7807. Ask him about the fix, and ask him about the amusing stories of cameras he gets from folks who were sure they could fix it themselves...

bspeed
23-Feb-2009, 09:51
Call Richard Ritter, 802-365-7807. Ask him about the fix, and ask him about the amusing stories of cameras he gets from folks who were sure they could fix it themselves...



There's nothing a good finishing Nail cant fix.

:D :D

Kevin Crisp
23-Feb-2009, 10:33
JB Weld is good for lots of things but with that small surface area and the torque of tightening it this isn't going to work. If it does it won't be for long. Drill it and tap in and put a screw in the top. I am sure Richard could do this, it is really basic machinist's work.

RichardRitter
23-Feb-2009, 10:52
Call Richard Ritter, 802-365-7807. Ask him about the fix, and ask him about the amusing stories of cameras he gets from folks who were sure they could fix it themselves...

I have seem more simple repairs become real expenses night mares because someone took bad advice and try to do the repair.

papageno
23-Feb-2009, 17:35
Thank you all for your suggestions. I'm already giving up the idea of simply gluing the two elements together.

Ivan J. Eberle
24-Feb-2009, 09:01
Can't tell how thick the lever arm is or what material it's made of, but if it happens to be chromed steel and an 1/8" (3.5mm) thickness or less, you may have a heck of a time drilling, let alone tapping the threads yourself without breaking a tap off in the hole. Even if you could, such a small setscrew would be difficult to torque adequately, you'd need a flat spot on the shaft and it's less than an ideal solution if it's loose on the shaft to begin with.

My suggestion would to disassemble it, take it to a machinist look to ask whether he(she?) could gnurl the post and then press-fit the lever back onto the post with a press.

Though you might first want to assure the right orientation when it goes back together by lightly making a match-mark on both pieces with a sharp scratch awl before taking it apart.

LF-Oslo
2-Mar-2009, 14:08
Will probably be hard getting this done with glue - but if youŽll try here is something that often works well:

Get some superglue/cyanoacrylate. Then cut out a small piece of cloth that covers the area of contact. Apply rather a lot on one of the surfaces, with the piece of cloth in place. Be sure that it soaks completely, and the n quickly press the two pieces together.

BEWARE: it gets hot! And you might get damp from the glue in your eyes - if you are not used to working with the stuff then gloves + goggles is a good idea...

Sometimes this make an incredibly strong bond...

GPS
2-Mar-2009, 15:42
Super/cyanoacrylate glue doesn't hold bellow freezing temperature, becomes brittle and good for nothing.

Kurt Eichenberger
2-Mar-2009, 16:38
One of my other past times is restoring antique tractors. JB Weld is a two part epoxy that is incredibly strong, and is used in all sorts of metal to metal repairs. I think it will work just fine for you, but it may not be pretty. You will want to build up around the joint, as well as apply it to the break. Available in any fine hardware store.

Regards,

Kurt

David Karp
2-Mar-2009, 18:06
JB weld was the first thing that came to my mind, but after seeing the photo, I don't think I would try it.

JB weld is amazing stuff though.

papageno
13-Mar-2009, 22:30
Finally found some time to get it done.

I decided to solder the two parts. Any mechanical work would be difficult, since the parts are very small and the whole mechanism would have to be disassembled. I have always problems with putting things together after taking them apart.

I used silver solder (soft, not regular silver solder alloy), that has a melting temperature of about 221 deg C and consists of 3.6% Ag and 96.4% Sn. It is called Stay-Brite and comes with a bottle of flux. Regular silver solder is stronger, but requires heating the elements to much higher temperature. The common solder used in electronics (based on Pb) is too soft, can not be used for making mechanical connections.

To heat up the elements the micro torch was used - the smallest I could find, powered by butane lighter fluid. As can be seen on 1st picture, camera elements were protected from flame by several layers of aluminum foil.
The solder alloy I used does not seem to be of eutectic type - it melts at a certain temperature, but you must heat it more to become fully liquid, so it will wet the surfaces well. A strong connection is formed when the liquid alloy is pulled into all cavities by capillary action.

I hope, that tips presented in this post may be useful, unfortunately large format photography cameras are not made to be indestructible.

papageno
13-Mar-2009, 22:34
Maybe this time those two pictures will go through.

Gary Beasley
14-Mar-2009, 07:55
Glad you were able to fix it. Looks like you did a good job!