Springs for extruder idlers - anyone make their own?

I recently switched to Greg's Wade reloaded extruder (i.e. Jonas' version). It uses M4 rather than M3 screws for the idler - hence I need different springs. I haven't found springs of appropriate diameter and spring constant from the usual suppliers though (e.g. Radionics, Farnell) - or maybe I just amn't using the right search terms.

I came across one or two people mentioning that they made their own springs - from "music wire" if I recall correctly. Does anyone know where to source this?

Any suggestions?

mcmaster.com

9434K164

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- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

Thanks. Unfortunately McMaster only accept credit cards, however.

Looking at the Radionics catalogue again, I found this: [radionics.rs-online.com] . It has OD 9mm, ID 8mm, and a load of 33 N at minimum length. Would this be too wide for an M4 screw, or could it work?

Previously I had thought it is good to have the inner diameter of the spring just marginally larger than the diameter of the screw, but this is hardly essentiall, is it? (I mean, as long as the washer prevents the spring from popping over the screw head, that is.)

Edited 1 time(s). Last edit at 08/01/2012 06:30PM by dslc.

dslc Wrote:
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> Previously I had thought it is good to have the
> inner diameter of the spring just marginally
> larger than the diameter of the screw, but this is
> hardly essentiall, is it? (I mean, as long as the
> washer prevents the spring from popping over the
> screw head, that is.)

As long as you have big enough washers, and you don't have interference problems between the two side-by-side springs, then the diameter doesn't much matter. The springs I get would fit anything up to an M6 screw, though I usually use M3 or #6 (approx 3.5mm diam) screws.

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I don't think there's a need to go making your own springs. There's a great spring available in cheap clothes pegs, fits an M4 bolt nicely, and has good strength.



You can get a pack in a €2 shop, for... €2! You can see these springs on my blog here: [numbersixreprap.blogspot.ie] I use them in my extruder, and combine two of them on each M4 bold under my print bed.

If you want to try something you could use rubber washers instead of springs. You'll see these guys use them right at the end of their extruder assembly instructions... [forum.eckertech.com] It looks like a rubber tap washer to me.

Regards,
NumberSix

I don't use spring on my idler, I just use rubber grommets between two washers. After loading filament, I just tighten them up.

-Rob A>

It's actually the seal from a metal roofing screw.

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[www.eckertech.com]
[blog.eckertech.com]
[forum.eckertech.com]

eckertech Wrote:
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> It's actually the seal from a metal roofing screw.
>
>
> [forums.reprap.org]
> name=rubber_washer.jpg

Thanks for clarifying guys! Setting a new trend there.

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[numbersixreprap.blogspot.com]

Thanks for the info guys. I think I'll try your suggestion to begin with NumberSix.

I cut pieces off a 1cm thick IKEA silicone trivet, poke a hole through, and put the pieces between washers. I use these instead of bed springs as well.