DIY Compression spring

Hi everyone,

Just after some advice, I have made the spring winding tool from Hemingway Tools and it works very well when making some practice springs.

Now the spring I need to make is a simple compression spring for the front bar on the Quorn grinder. I have made one that looks reasonably ok, I made it out of music wire and the correct swg, so my question is do I need to heat treat it?

Hemingway's instructions say I should temper it in the domestic oven for an hour at such and such temperature....that's fine the wife is at work today!, but interestingly Tubal Cain (aka Tom Walshaw) in his book about springs makes no mention of any heat treatment after creating a spring...

So heat treat (temper) after making a spring or not?

Thanks

Derek

Leave it as it is and put it to use. If it breaks make another and temper.

regards Martin

If it fails you can get a suitable spring from here for about £4

<online>

John

Edited By Neil Wyatt on 12/08/2021 19:31:36

Tempering usually follows hardening? Different metallurgy of the wire would determine what treatment might be required, so the instructions from Hemingway may only be appropriate for the wires supplied with the kit.

I initially thought it was expensive, but it looks like a well designed piece of kit and does include a range of piano wire for starters.

If I needed to make compression springs, that piece of kit looks impressive but I’m not sure of the advantage over using a lathe (with a QCGB) to space the coils quickly and easily.

Music wire springs are typically stress relieved after forming, and a domestic oven can be hot enough for that. The stress relief can reduce chances of breakage in service.

A domestic oven won't be hot enough to temper steel (i.e. controlled softening after hardening).

'Heat Treatment' covers a variety of processes, and the names are often used somewhat loosely, which can confuse.

Gas mark 6/7 (experiment) is hot enough to temper steel cutters.

You do need hotter to temper springs though.

I wouldn't bother with any heat treatment. The Quorn makes minimal demand on that srpring in terms of cycling etc. As long as it very approximately meets the Prof's spec. of about 10lbs. force without coil binding then it will be OK.

Mine's probably a bit light and does not overcome the static friction of the bar until it's rocked, but that's never been a problem. Might even be helpful if too much cut is inadvertently put on, so don't make it too strong.

I had some custom springs made for me some years ago and had the opportunity to watch them being made. After winding and then grinding the ends flat they were heat treated and them tempered. I have no idea of the steel used though.