Spring Winding Calculations

[kevin]

I have created a spreadsheet to help with spring winding calculations (This is actually version 3, and will be the final version unless any errors crop up which need to be corrected).

The spreadsheet offers three options:

1. Mandrel: Calculate the mandrel size needed to wind a spring of a specified diameter.
2. Equivalent: Given a set of spring parameters, find the parameters for a spring with the same spring rate but with a different wire size, diameter, number of coils, etc.
3. Table: A simple lookup table to find arbor (mandrel) diameters for winding music wire springs of a designated size.

Option 2 is useful when you want to make a spring designated in a plan, but you only have spring wire approximately equal to the size specified in the plans.

Option 3, in theory, would give the same results as Option 1, but in testing I have sometimes found small differences. My guess is that the table probably is more accurate for large lathes in a production set up, and that Option 1 is more accurate for small lathes in a hobby set-up (but this is purely a guess).

I have tested the spreadsheet as best I can, and I believe it to be free of any errors, but of course I cannot guarantee this; if anyone else tries it out and finds a problem (and lets me know!), I will make the necessary corrections.

You can download the spreadsheet in LibreOffice and Excel versions here:

https://sites.google.com/site/lagado...g-making?pli=1

P.S.

The above link also includes links to other information on spring winding.

 

[RJSakowski]

I have created a spreadsheet to help with spring winding calculations (This is actually version 3, and will be the final version unless any errors crop up which need to be corrected).

The spreadsheet offers three options:

1. Mandrel: Calculate the mandrel size needed to wind a spring of a specified diameter.
2. Equivalent: Given a set of spring parameters, find the parameters for a spring with the same spring rate but with a different wire size, diameter, number of coils, etc.
3. Table: A simple lookup table to find arbor (mandrel) diameters for winding music wire springs of a designated size.

Option 2 is useful when you want to make a spring designated in a plan, but you only have spring wire approximately equal to the size specified in the plans.

Option 3, in theory, would give the same results as Option 1, but in testing I have sometimes found small differences. My guess is that the table probably is more accurate for large lathes in a production set up, and that Option 1 is more accurate for small lathes in a hobby set-up (but this is purely a guess).

I have tested the spreadsheet as best I can, and I believe it to be free of any errors, but of course I cannot guarantee this; if anyone else tries it out and finds a problem (and lets me know!), I will make the necessary corrections.

You can download the spreadsheet in LibreOffice and Excel versions here:

https://sites.google.com/site/lagado...g-making?pli=1

P.S.

The above link also includes links to other information on spring winding.

Kevin, Thanks for sharing!

I haven't looked into the details yet but this looks like an useful tool. In the link, you mention tempering the spring. I have always used spring wire which is tempered. Are you retempering after winding?

When selecting springs for projects, I have used Lee Springs online catalog. They have a huge selection of springs and give all the necessary parameters to define the spring. If you were building something from scratch, it is an excellent starting point and your spreadsheet would furnish the winding details. I have wound quite a few springs in the past but had always figured the mandrel size by trial and error so this should be a major improvement

I had created an Excel spreadsheet where the parameters given by Lee Spring would be entered in and the force in lbs. would be calculated for various compressed lengths. It was useful in determining which spring gave the best match to our desired performance goals. Unfortunately, it doesn't look like I can upload the spreadsheet so if anyone wants a copy, PM me with e-mail details and I will send it.

Bob

 

[kevin]

Bob -

Re tempering: I do re-temper after winding, as I understand that this helps to "set" the spring into its wound shape. I temper by wrapping the spring in steel wool and aluminum foil and heating in a toaster over at 450 F for an hour. The steel wool and foil are probably overkill, but I figure it can't hurt.

Thanks for the heads up on Lee Springs; I assume they are OK with small "hobbyist size" orders?

I'll PM you about your spreadsheet.

 

[RJSakowski]

Bob -

Re tempering: I do re-temper after winding, as I understand that this helps to "set" the spring into its wound shape. I temper by wrapping the spring in steel wool and aluminum foil and heating in a toaster over at 450 F for an hour. The steel wool and foil are probably overkill, but I figure it can't hurt.

Thanks for the heads up on Lee Springs; I assume they are OK with small "hobbyist size" orders?

I'll PM you about your spreadsheet.

Thanks for the info on tempering. I did a search and found this article on heat treating: http://www.heat-treat-doctor.com/documents/Stress Relief.pdf

Lee Springs will do small orders as far as I know but their small quantity pricing is horrendous. You can buy a quantity of 100 for about twice the cost of ten (their minimum qty.). We used them because we didn't have to compromise parameters as much as buying from McMaster Carr. For the purpose of pre-selection for your winding spreadsheet, though, it should work great.

Bob

 

[kevin]

Wow - that's a great link on heat treating wire for stress relief; I just added it to my Useful Links page (which includes some other good links on spring winding from a hobbyist perspective).

It never fails: When I share my work on forums like this a always get repaid with good comments, suggestions, and additional information.

 

[4GSR]

Thanks for sharing. I've always wanted to make a few springs for myself once in a while. Luckily, my local True Value Hardware store keeps a decent stock of springs that have gotten me out of a bind or two. I've notice they stock a pretty good selection of music wire, too for anyone who wants to make their own springs. I've got to give it a try! Thanks, Ken

 

[ARKnack]

This is a old thread. Is the Excel spread sheet still available somewhere? I followed the links, but they are dead going to the download page.