Spring steel strip

[Leszek DelagParticipant @leszekdelag40763]

[Leszek DelagParticipant @leszekdelag40763]

Hello all, I have to replace a broken lever spring on a mechanism and am trying to find a suitable source of material. The spring steel is bent something like a “V” with a loop at the bottom to go around a dowel, is flat in section, measuring about 3/32” x 0.044” having a total length of approximately 4” when opened out. The section size is not vital, providing it is reasonably near and if anyone could point me in the direction of a possible source of material-preferably in the annealed state- I would be most grateful!

Thanking you all in advance.

[Maurice Cox 1Participant @mauricecox1]

A. J. Reeves stock it in various gauges, in 24inch lengths. I believe it is the annealed state, and will need to be hardened and tempered.

[ronan walshParticipant @ronanwalsh98054]

You can use o1 or silver steel, full harden it by the usual heating to red heat, holding it for a few minutes and quenching. Then you can temper by putting the spring in a bath of lead and quenching.

[Adam MaraParticipant @adammara]

Sounds very much like the description of a rim lock spring. When I left work there was a assorted box of around 150mm lengths of steel for forming into lock springs. The works is closed until Tuesday, and I could find out then if they are still around. If they of interest, please PM me.

[John BaronParticipant @johnbaron31275]

Hi Guys,

If you strip an old car window screen wiper blade apart you will find two, probably suitable strips of spring steel, one on either side of the rubber blade.

[Tim StevensParticipant @timstevens64731]

Quenching in a lead bath does require fairly accurate control of the temperature of the lead. Clock springs were tempered (in the good ole days) by dipping the wound-up spring in linseed oil and burning it off. The oil evaporates at the required temperature. If I remember correctly. It might perhaps have been a different oil?

Cheers, Tim

Edited By Tim Stevens on 25/08/2018 18:47:08

[Sam StonesParticipant @samstones42903]

Never having seen silver steel in flat sections (as suggested by Ronan), and no idea of how the spring is situated/fixed, I question if round wire could be used instead, i.e. piano wire available through model shops.

For the cross section which Leszek nominated, assuming the spring thickness is 0.044" and 0.094" is the width, my equivalent (moment of inertia) calculations suggest that a wire diameter of 0.061" is about right.

This was my 'change-of-direction' when I chose (calculated) 0.008" diameter guitar wire for the balance wheel spring of my clock, instead of the nominated flat wire 0.020" x 0.005".

Other than annealing for sharp bends, heat treat may be unnecessary.

Sam

[Leszek DelagParticipant @leszekdelag40763]

Many, many thanks for all your kind replies everyone..it is so much appreciated!

Because of the nature of it, I have to use flat section instead of round-which would be so much easier! The loop wraps around a pivot and it lifts quite a substantial weight.

Am following up all the suggested sources and sending you a pm Adam-thank you.

Kind regards and thank you again..Leszek

[JohnFParticipant @johnf59703]

Leszek, for supplies look ar M-Machine metals, they have 18 SWG spring strip 1/2” wide, to cut the narrow strip you need I would hold the strip in a vice then use a cold chisel to cut the 3/32 strip of the main piece, it will distort somewhat but it’s quite easy to rework to a flat strip again. I use this method a lot to cut trigger return springs.

John

[JonParticipant @jon]

Know exactly what your attempting to make, has to be done right, done many for the trade worldwide.

To go round the peg thats better done from solid by drilling and shaping up after some what near. The V should be from the flat state left oversize all dimensions, turned flat (folded) hammer forged and annealed then left to cool.
Then its cleaned up closer to final size leaving room for any tags and excess lengths removed. Also thinned down, V end hammered then cleaned up.
Now starts the hard work, the strenghts in the turn what you cannot get by cnc or wire cutting etc, both arms cleaned up and set to a profile by bending. Then hardened and tempered to suit steel used.
Clean up again and pull the spring up (filing in exact area) so both arms dont collapse, should come in even right in to the turn. Highly specialised probably only three people alive with the knowledge.
Easy part is the fitting.

[Sam StonesParticipant @samstones42903]

How about a photograph to let us in on the secret?

Sam

In chilly Melbourne.

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