Which Metal???

[rellimkm]

I am currently designing a 5x7 wood field camera. I have my design pretty much done and

started to think metals for the hardware and movements. I was wondering if anyone had

any thoughts on which metal to use. Brass...Aluminum...Titanium...Stainless Steel....I am

not concerned with which is easier to machine, just weight/strength/appearance issues.

Thanks for your comments.

[lyle_gordon]

Aluminium or Titanium would be the lightest but aluminum can jam or seize up easily so I would avoid that, im not sure about making things out of titanium so I would probably go with brass but im not exactly an expert in the matters.

[jay_de_fehr]

Brass is usually chosen for its maleability, aluminum for its weight to strength ratio, stainless steel for its resistance to corrosion, and titanium for its marketability. If you're building a cost-is-no-object, featherweight camera, then titanium or a composite material like carbon fiber is probably the way to go. These generalizations aside, there is an optimum material for every part, and no one material that is best for all of them. One can learn a great deal about the strengths of various materials in various applications by studying the products of top manufacturers. They have faced all of the problems and made, for themselves, all of the decisions that you will ultimately have to make for yourself. I wish you the very be3st of luck in your endeavour, and I hope you will share your results with us when the time comes.

[User_503771]

I second the notion that aluminum is out for most parts, even though it has very desirable qualities. If you use any, do be sure that two pieces won't be in contact, or better yet, that the aluminum won't be rubbing against anything else. Maybe for a base plate.

 

I've tried machining steel and had very poor luck with it. But I'm a total amateur with a table-top milling machine, and I probably just didn't know what I was doing. But what little I got done took forever.

 

Brass on the other hand is a pleasure to work with. Strong enough, makes good springs, and nice to look at, even after it tarnishes.

 

I wouldn't use it on something like a standard support though because I don't think it's strong enough, unless you make the parts real big. Better to use stainless steel for those, if you can figure out how to work the stuff. (If you've got any tips on that, please let me know off list!)

 

Whatever you do, make sure that your design results in a well-balanced camera. In other words, try to avoid having too much weight differential between the front and back. Some is okay, as the bellows will weigh enough to make the proportionate difference less. (Also, it should balance the best when extended, so that's the consideration to take into account.) And if it's not to be avoided, then you can just put the tripod mount off center, or install two of them.

 

Anyway, let us know how it goes! Good luck!

[evan_clarke1]

HI,

Use aluminum and then have the parts hardcoat anodized. Anodizers will do this on a small quantity with no problem..Evan Clarke

[george_stewart1]

Magnesium is approximately 30% lighter than aluminum. It is difficult to machine because it tends to catch fire.

 

My fantasy expedition camera would be carbon, have a bellows made from hypalon and silk, and metal parts from magnesium, titanium and brass as appropriate.

[gavin_wright]

Hi, I am nearing completion of a 4x5 and have used titanium for the majority of the metal parts. It has been hard to machine, especially with the limited tools I have, but I think it will be worth while in the end. Apart from its light weight it is also very rigid, a quality I don't think you would achieve with anything else short of carbon fibre. I purchased the sheet stock from titaniumjoe at a reasonable cost (if you are in the States). It cost me the same again to ship to the UK!

 

E-mail me off forum if you would like further info on how I've 'machined' it.

 

Cheers

Gav

[conrad_hoffman]

Tough question. Aluminum simply has to be anodized or it will look like crap in a few years. I love brass, but it's heavy and needs to be lacquered or coated to prevent tarnish and corrosion from fingerprints. Depending on the type, it can also bend easily. The better machining grades of stainless can be wonderful. Still a bit heavy, but overall a good choice. Regardless of what you use, try to design with delrin washers and spacers to prevent metal to metal contact. Another possiblity is adhesive Teflon or (can't remember exact description) high molecular weight polyethylene, tape. My experience with titanium is limited. It's light, looks great, but getting precision out of it requires some care and experience. If you have the patience it may be worth it. Also, don't forget the decent engineering plastics where appropriate.

[Sandeha Lynch]

If you've never done any metal-work before then brass might the best choice. Available in many profiles and thicknesses, strong enough, easy to cut and polish, etc, etc. Bear in mind that if it is the first time (no matter if you think your design on paper is perfect) you'll probably find yourself making and remaking more than a few parts to get them just right. Brass doesn't present any working problems compared with the alternatives.

 

 

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<a href="http://www.photo.net/photo/2381900">work in progress</a>

[rellimkm]

Thank you everyone for some great information. It was very helpful...though I am not any closer to deciding. I will have to digest all this and think on it. I am going to do the wood work first anyway...so I have a while until I need to decide. I have found it very helpful to draw all the components in 2D CAD and print them out life size. But even with CAD, I may prototype it in brass and then decide if I want another metal. I'll be sure to throw in a couple of pics once I get some progress made. Thanks again.

[bob_becker]

Hi Matthew...

By now you have already decided on your metal of choice, if you have not, don't be worried about aluminum! Use something like 6061-T6, but make sure that any mating metal parts are either harder or softer. Brass makes a good mating metal. Anodizing is fine, but remember that most anodizing is decorative -- and comparatively soft. Hard annodize is fine, not pretty, but glass hard. It does make the part grow, so be sure you to watch your fit-ups! Best! bob

[ben conover]

I think my Burke and James press is cast aluminium and chrome steel, excellent combo.

 

Cheers.

[rellimkm]

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So, I had to put this little project on hold way back when. There is never enough time in life to play! I have started looking at this again....going through all my designs and I got thinking. Why do I need a camera that will bend in 300 directions and at the same time fold down as small as possible. Its been done, many times. I am looking at it from a different angle. Make is as simple as possible. So, here's what I have so far.....

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-5x7 vertical and horizontal back

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-front rise

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-front or rear tilt

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-front and rear focus

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-simple to take down and setup

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-get the thing into a backpack

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I think by limiting the movements to ones that I will actually use, it will be simple to build and operate.

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