Forming spring end

[Peter BellParticipant @peterbell11509]

[Peter BellParticipant @peterbell11509]

I want to make a 6mm od torsion spring using 1mm wire. I can wind a spring fairly well on the lathe after following various instructions online but I am having problems forming the end so that they are inline with the spring and are 180 degrees apart.

The spring fits onto a shaft and the ends go into slots. The left end is fixed and the arm is spring loaded, its part of a printing numbering box. I can form the first end before winding but forming the other end neatly after winding has defeated me so far.

I think I need some sort of jig to accuratly forn the ends but hope some with more experience can offer guidance on its construction?

Peter

[Paul LousickParticipant @paullousick59116]

Its only 1mm wire so maybe 2 pairs of needle nose pliers.

Paul.

[Peter BellParticipant @peterbell11509]

Thanks for the reply.

Should have mentioned that I've tried various types of pliers without success as it tends to deform the end coil and you cannot get the sharp bend needed. to fit into the slot.

[Clive FosterParticipant @clivefoster55965]

Clearly any satisfactory bending jig needs to hold the spring steady and provide an abutment in the right palce to bend the end against.

Consider a nicely fitted screw long enough to pass right through the spring with a sort of snail shaped nut on the end to provide the bend abutment. In principle the screw should keep the spring aligned whilst the wire is bent round the abutment.

In practical its probably not that simple, especially if the wire is quite strong. Obvious issues are that the nut / abutment may rotate when bending. Either moving the whole thing or unscrewing itself. There will also be a tendency for the half coil immediately adjacent to the bend to slide sideways as the bend is made. Such sideways movement will probably happen if the abutment rotates. Making the nut / abutment as a short sleeve about two coils long should prevent any tendency to slide sideways. Holding both spring and nut / abutment simultaneously in shaped vice jaws ought to stop rotation.

But its a lot of work just for one spring and it would seem quite easy to produce a nut / abutment that cannot be taken off afterwards!

No doubt something much simpler could be devised.

Clive

Edited By Clive Foster on 02/06/2019 13:43:16

[mechman48Participant @mechman48]

FWIW; Machine Mart do a spring selection box that may contain the particular type you want; worth having a look ? … usual disclaimer applies.

George.

[John ReeseParticipant @johnreese12848]

You need a hole and a pin in the mandrel to use as a bending form. Wind the spring in the normal manner until the wire is tangent to the side of the hole. Maintain tension on the wire. Use vise grips to clamp the last fer turns of wire from expanding when you release tension on the wire. Insert the pin in the hole and bend the wire around the pin to form a tail.

Disclaimer: I have never done it but this is how I would try.

[Peter BellParticipant @peterbell11509]

Thanks for the suggestions.

A screw through the centre with a washer under a nut just about did it but tended to deform the coils slightly but points towards the coils need restraining while the end is bent.

I have tried clamping the spring to the mandrel after winding but it all tends to come apart as the wire end is bent. Also tried with ready made springs but the dimentions are critical as the sprung shaft is inserted into a hollow shaft when it is working.

Tried more searching on the interweb and found this video of a machine doing what I want. It looks like a plate bored to suit the spring clamps the spring to the base then the end is bent. Never added a vid before, hope it works!

[Clive FosterParticipant @clivefoster55965]

Peter

Maybe a simple sleeve on the outside of the spring in addition to the screw up the middle would keep things stable when bending around your end washer. If the length is just right it would be clamped between the screw and the end washer ensuring it stays in place. Need to have a slot slightly wider than wire diameter all the way down so it can be got off.

Nice video. Effectively that machine clamps the spring in a hole exactly the right diameter and length to hold it steady. Perhaps a cruder version with two half circles on a hinge could be gripped in a vice to do the same job. I imagine simply drilling a suitable size hole in a piece of metal and putting a slot down one side so it would be compressed enough to grip the spring when held the vice won't work as being pretty much impossible to open out and remove.

Clive

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