Alternative Material for Spring Back Springs

[Steve Smith]

I am (slowly) in the process of making a folding 5x4 field camera after my first effort which was a non folding heavy beast.

Before I start cutting up wood, I decided to make some of the parts out of materials I had at work to check that everything works.

In the attached pictures you can see the back plate with a spring loaded ground glass frame.

The grey parts are cut from 9mm thick nylon, the brown parts are a 3.2mm thick composite material and the green parts, the springs, are 1.6mm thick FR4. This is the fibreglass material used for printed circuit boards. In this case with the copper etched away.

I will probably try to get some spring steel when I make the back properly from wood but these fibreglass 'springs' work surprisingly well.

I have use of a CNC drill/router intended for PCB production so it is quite easy to try out various options - much easier than if I had to cut it all by hand.

There was a thread a while ago about spring material with various suggestions like pallet knives and spatulas but has anyone else tried a non-metal or unusual material for their springs?


Steve.

 

[Mark Fisher]

I wanted to make a quick 8x10 camera out of gatorboard to play with some home made lenses, but wanted to make the back a little more precise so it could be repurposed later. I ended up using music wire for the springs because I could get it at the hardware store. I think that Wehman cameras use the same approach. It is a bit hard to work with since I was too lazy to anneal it and reharden it....plus it will rust eventually.....it did work, though. Stainless string wire would be a decent way to go, though.

 

[epatsellis]

I keep toying with the idea of using some allen bolts and compression springs, the kind you can buy at any decent hardware store. with some care in design, it could work quite well, I think.


erie

 

[Steve Smith]

I keep toying with the idea of using some allen bolts and compression springs.

Like this? http://homepages.ihug.com.au/~razzle/Razzlok_/razzlok_.html



Steve.

 

[Jim Chinn]

Actually as crazy as it sounds, I made a mock up of a back for a 12x20 camera using elastic bands. About 1/4" wide and about a 1/2" long when not under tension. I left it outside one night in temperatures in single digits and there was no problem with the bands being brittle or breaking under load. If I ever finish the rest of the camera I think I will just keep using the bands. Simple, inexpensive and light, which are the parameters i try to stick to when I build a camera.

 

[greyhoundman]

I've used metal banding strap cut to size. And the tines from a metal leaf rake.
The neighbor still doesn't know how some disappeared.

 

[Steve Smith]

Before I got a spring back for my first camera I made a dummy film holder with ground glass in it (frosted polycarbonate actually). This was used to focus then the film holder was put in place and held there with a couple of elastic bands.


Steve.

 

[DannL]

Here's a simple solution to a non-spring back. Though not perfect, it worked on an 8x10 (gg wise) and appears to work on my Ernemann HEAG XI (10x15cm). I wanted to convert the 10x15cm Ernemann to 4x5 because I simply could not find 10x15cm film holders. I don't think they exist. So I used 5/8" aluminum channel (aka 5/8 aluminum plywood trim) from Lowes (or home depot), and attached it to the side rails of the film pack holder. (three screws countersunk for each rail.) I lined the insides of the two channels with strips from the fuzzy part of sticky-backed Velcro. Very tough fibrous stuff, and a perfect fit. In order to make this work though, I replaced the septum of a 4x5 holder with acid etched ground glass. Since the ground glass is positioned on the same physical plane as the film in a holder, it works very well. You have to remove the gg holder to insert a film holder in this scenario.

I am currently working on the gg hood.

 

[dogzbum]

After getting frustrated with hacksaw blades rusting (I live in the Tropics) I've found another readily obtainable spring material. The piece of metal from inside replacement windscreen wiper blades is ideal. It is springy, does not rust and has a good profile to work with (rectangular, about 4mm x 1.2mm).

It also doesn't require hours grinding the teeth off like hacksaw blades do

 

[Jerevan]

DannL,

Nice job! It looks similar to my 5x7" Argentum (photo 4/5): (there was a url link here which no longer exists)

The only thing I have to be careful about is where I put the groundglass when I expose film. Otherwise it works very well.

 

[Steve Smith]

The only thing I have to be careful about is where I put the groundglass when I expose film. Otherwise it works very well.

That's why I wanted to make a spring back rather than use a filmholder shaped ground glass frame. That's a nice simple and efficient looking system on the Argentum though.


Steve.

 

[Dan Dozer]

I made the original springs on my 8 x 20 from ordinary brass and they have seemed to work pretty well. However, one is now starting to deform a little where the screw hole is drilled that holds it to the back. A previous APUG'er suggested to use Phospher Bronze and I just got a sheet from McMaster Carr. I haven't used it yet, but it looks very promising - springier than brass and doesn't seem to permanently deform as much.

By the way, I ordered it online last night at 6:00 pm and it was on my door step before noon today - talk about fast service. I do live in southern California, but delivery that fast is incredible.

The cost was about $20 for a sheet that was 6" x 24" x .025" thick.

Good Luck,

Dan

 

[DannL]

Spring backs are by far the most elegant of the bunch, but I find them the most difficult to design properly, especially when there is limited real estate on the camera. If you'ld like some inspiration for your designs, the following web site . . .

http://www.fiberq.com/cam/ao.htm

. . . displays in detail, numerous view camera designs from multiple manufacturers. I keep going back to this particular web site, not having seen another that compares.

There's only one attribute I have found to using a simple slide version, as compared to a spring-back camera which I already own. The slide version requires much less brute force to replace the film holder, which may lessen the occurances of camera movement in the field. As far as to where to put a ground glass, I usually set it in the camera bag under the tripod. There really is no inconvenience, since I need to get into the bag to fetch a film holder.

 

[Steve Smith]

Excellent link. Thanks.


Steve.