Metals used in LF cameras

[nick mulder]

If youd care to join me I'd like to discuss the metals used in large format camera design, specifically the metals used in the actual form/frame/bulk of the camera ...

Couple of quick questions:

Why not so much aluminium around ?
Titanium, workable for a home build ?
Why brass ?

thats it for now

[Ian Grant]

There are Aluminium (or alloy) bodied cameras around, rather a lot actually, MPP, Linhof, part of Pacemaker Speed/Crown Graphics, Super Graphics etc.

Titanium is harder to work with.

Brass, because the first cameras where made by cabinet makers and instrument makers who had long been using brass as it's the easiest metal to work with, and looks good with wood

Ian

[Rick A]

Chief reason for brass, is it is machinable with basic woodworking tools. Its is easy to work with hand tools, and as Ian stated, looks good with wood. Metals technology in the 19th and early 20th centuries didn't have alloys we are accustomed to in these modern times, and it became the tradition to continue to use them.

[David A. Goldfarb]

I know someone who makes titanium bicycles and bicycle parts, and he once told me the cost and difficulty of working with titanium mostly have to do with the wear it puts on tools and cutting blades and bits.

[Martin Aislabie]

Brass is fairly inert (doesn't corrode) and is easy to work with. It can also be welded (silver soldered) together. Most local machine shops will be able to machine and weld brass parts for you.

Titanium will be a serious challenge to anyone working with at home - unless you have access to Laser Cutters, Laser Welding and heavy duty CNC machines - its stronger than high grade alloy steels, so will be very difficult to work with. However, if you have contacts in the high end Race Car Engineering and Aerospace Industry, they should have experience of using it, F1 Teams use it a lot and its pretty standard issue in military fighter aircraft.
On the other hand it is much lighter than steel, its is stronger than steel, is reasonably inert to corrosion and has an attractive colour (it looks great on my Ebony)

Aluminium is easy to cut and machine but difficult to weld (but easier than Titanium). It also doesn't work well in sliding joints. It suffers from a problem called "pick-up" - where two smooth surfaces rub together and become rough and don't slide past each other easily.

Have you considered Stainless Steel (but its heavy and can be difficult to weld - but not as difficult as Aluminium or Titanium).

Another alternative is to use Carbon Fibre in parts of your construction - it is both very light and very strong

You will have to choose one metal and stick to it throughout almost the entire camera - otherwise you suffer problems with bimetallic thermal expansion issues - do you might adjust your camera to work smoothly in cool ambients only to find it either very sloppy or very very stiff to operate in the sunshine on warm/hot days or visa versa.

Good luck

Martin

[Mark Fisher]

I've done a lot of metal fabricating, but never for cameras (I'm a design engineer). I suspect that brass is used for historical reasons. Back before World War 1, aluminum was insanely expensive and probably out of range of the camera producers.....plus it isn't particularly strong without proper alloying. Today, modern alloys are strong and easy to work. I'm not sure why someone would use brass today except for the beautiful way it looks.

Titanium isn't a home project. That said, I think that if you can make 2D drawings on the computer (CAD, or even something like Corel Draw), it can be water jet cut pretty easily. That is the approach I'd take. There are quite a few companies who could do that for you. I think you might be able to bend it with the right equipment, but I'm not sure. In case you can't tell, this is on my (long) list of things to do...(:

[Wade D]

Titanium is easily cut by water jet or laser. Forming or bending is very difficult without
the proper heat treating and annealing. It has a memory and when bent will go back to the original form. A case in point are the frames for glasses. They were expensive but I've smashed them flat numerous times and they spring right back without breaking. The company I retired from used exotic metals in the fabrication of turbine engines for industry.

[Q.G.]

I'm not sure why someone would use brass today except for the beautiful way it looks.

And it is still cheap, very easy to machine and work in other ways, very easy to achieve a high grade of finish, and strong enough for the job.

[nick mulder]

I was thinking titanium and/or alu ...

Titanium I read isn't necessarily 'stronger' (I really need to read up on the technical terms pertaining to metal characteristics) than all steels, but much lighter per 'strength thingy' (:rolleyes.

I have read that it is its low thermal conductivity that causes issues with machining, without ample coolant or feed rate (which in turn determines cutting speed and bit size) the part will heat up and do something bad like work harden which will ruin the tool, which will ruin the ... and so on. So basically you're looking at carbide bits instead of HSS and you're looking at throwing them away before they dull. I guess the cost would have to be be factored in with the weight savings and gravitas of having made your own Ebony clone, and/or compared with a bit of CADCAM at the local CNC/water/pla$ma joint...

I understand that Aluminium would results in larger profiles to account for the loss in strength, but it would be made up for in stiffness at least (?) any sliding parts could be made of wood or HDPE (?) - I don't need to build a Canham clone

Once your part is machined in Alu or titanium is there any process it can undergo to harden it or otherwise make it er... better ?

[nick mulder]

Titanium is easily cut by water jet or laser. Forming or bending is very difficult without
the proper heat treating and annealing. It has a memory and when bent will go back to the original form. A case in point are the frames for glasses. They were expensive but I've smashed them flat numerous times and they spring right back without breaking. The company I retired from used exotic metals in the fabrication of turbine engines for industry.

You've reminded me of Nitinol - I have some wire here I got ages ago for a robotics project - I wonder if it could be used in photography ?