Spring material advice needed

[old martParticipant @oldmart]

The turret indexing spring on a microscope is on it’s last legs and I am considering either 0.5 x 4mm steel or 0.8 x 4 berillium copper or a bronze alloy of some sort. With steel, I would have to anneal and re heat treat after shaping but I’m not sure about the copper alloy requirements.

[Michael GilliganParticipant @michaelgilligan61133]

Depending on your source, you may find the cuprous alloys are already ‘springy’ enough … If not, they usually respond well to hammer-hardening.

MichaelG.

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Edit: __ From one of my go-to reference sites:

https://www.copper.org/publications/pub_list/pdf/a1360.pdf

 

[Paul LousickParticipant @paullousick59116]

If it’s just a little flat spring, making it from a piece of “Band-it” strapping may be suitable.

[DiogenesParticipant @diogenes]

With small bits of thin brass often the forming will ‘fix’ it sufficiently, if you feel it’s still ‘lacking’, a bit of planishing or even a couple of well-placed taps with a broad punch will often do..

 

[John HinkleyParticipant @johnhinkley26699]

There was a short thread on here a little while ago, asking for a suggestion for the use of the stainless steel flat spring to be found in windscreen wipers.  This might be a source of suitable material for you, if the design of the spring lends itself to it.  The size that you quote in your original question looks to be close to those of the sample that I’ve kept “for a rainy day”  (Quite apt, as it happens, since it came from a windscreen wiper!)

John

 

[Andrew CrowParticipant @andrewcrow91475]

Broken mechanical clocks or wind up toys are a good source of light springs ( if anyone can remember what they are).

I generally take apart broken or discarded items so always have a supply of assorted springs.

If you can find the right one of course!!!

Andy.

[old martParticipant @oldmart]

Thanks, John for reminding me about the windsceen wiper spring which had completely slipped my mind. Now I will be searching the garage for one I think is there to add another possible metal. I have started making a little press tool which will make a stretched W in the centre of the spring which is supported at each end by 10BA screws about 2″ apart. The tool is made from two short lengths of 1/2″ key steel pinned together by 4mm dowels which keep them in alignment as they are pressed together. I have not milled out the W shapes yet.

[Russell EberhardtParticipant @russelleberhardt48058]

If you are considering beryllium copper alloy you need to be very careful when working it.  Beryllium is toxic and carcinogenic Fine particles from sawing, filing, and polishing can get into the pores of your skin and can be inhaled with severe consequences.  When I worked at the Philips research labs it was strictly controlled and had to be processed by appropriately trained technicians in a special area.  At least it’s not as bad as the beryllium oxide used as an insulator in microwave transistors those transistors had to be disposed of very carefully if they failed!

Personally I would stick to hammered brass or heat treated steel depending on the required force.

Russell

[old martParticipant @oldmart]

Don’t worry, I started working with beryllium copper back in the sixties and will be showing it respect should I try it for making a spring. I’m not sure just how prone to cracking it would be compared to the other options.

[Nigel Graham 2Participant @nigelgraham2]

I think you would find it difficult or impossible to obtain beryllium-copper these days, short of salvaging some from a scrapped electrical item of suitable age. It was phased out (except perhaps for very special duty??) simply because it is so toxic and safer alternatives exist.

The windscreen-wiper spring thread is still here in this Materials section.

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