Making Automotive Leaf Springs

More often than not the kit suspension springs leave a lot to be desired, usually just a blob of plastic trying to pass as springs. Even the better kits can often require considerable time and effort to make them presentable.
Due to these shortcomings in kits I tend to disregard kit parts and make my own rather than try and clean-up kit parts. Also I tend to scratch build vehicles that often have quite visible chassis details, and there are no suitable "donors".

While what follows is aimed more for the 1/25 -1/24th scales it is quite easily adapted to suit smaller scales, and is well within the capabilities of the average modeler (if I can do it, anyone can).

Equipment Requirements:
  1. a. Standard modeling tools
  2. b. MDF or wood offcut (jig base)
  3. c. Sheet or strip brass (approx 0.4mm (.015") thick for 1/25th scale)
  4. d. Selection of plastic strip
  5. e. Pliers
  6. f. Butane torch (or similar for annealing the brass)
The Process:
Step 1.As usual gather together your reference material (photos/plans etc). With this info, you need to work out the length between spring end eyes and the basic curve of the spring and the width of the spring. Mark this info onto the MDF/wood piece. Drill and insert two brass rods at the spring eye points, and one at the apex of the curve (see photo), for 1/25 - 1/24th scales use 0.75mm (.030") rod (approx), adjust to suit smaller scales, or an alternate to brass rod is dressmakers pins.
See Image 1

Step 2.Either find some brass strip of the required width and thickness or cut a strip from some brass sheet. Handy Tip: Brass sheet can be cut using the scribe and snap technique the same as plastic sheet, with an old blade (or machinist scribe) scribe the required line on both sides (do a few passes) then clamp the sheet in a vise and bend back and forth till it snaps. Then just a quick swipe with a file or W/D sandpaper to clean the edge. For 1/25 - 1/24th scale models I normally use 0.4mm (.015") brass sheet/strip. Cut the strip longer than needed, this is to allow for the bending step.

Step 3. Anneal one end of a brass strip, and with the pliers wrap around one of the brass rods/pins in the jig to produce a closed eye. Harden the brass leaf when happy with the eye produced. Then gently bend the strip to create the curve. Next up is to anneal the other end and wrap around the other brass pin - this will require doing a half wrap then trimming to the required length and then finishing the wrap to close the eye. Lastly, harden this end.
See Image 2

Step 4. Now you can lay the individual spring leafs. Using some plastic strip of the same width and thickness (0.4mm x 3.2mm (.015" x .125") looks good for this scale); epoxy the first leaf to the brass leaf. Clamp each in place and allow each to harden. Continue adding each additional leaf (using plastic glue) till the required number/thickness is reached. Before gluing each of the plastic strips, gently pull them over the edge of the workbench in a slight downward motion. This will give the plastic strip a gentle curve making it easier to mate to the already curved piece.
If the 1:1 version has shaped ends and you want to recreate this, itís best to trim this before gluing the strip. Also if you want to depict slightly splayed leafs don't glue the full length. Glue sparingly as you don't want fused plastic seeping out between the leafs, if this does happen, when cured just run an Olfa cutter along the join lines to tidy.
See Images 3 and 4

Step 5. Remove from the jig and add the retaining clamps/mounting plates etc as required from plastic strip or your chosen medium.
See Image 5

Step 6. Attach to the modified kit spring hangers or use some scratch built hangers. Continue with your build as usual. If the model will not sit level (i.e. all wheels touching the ground) a very gentle bend at the spring center or a very careful "tweak" at the eye will solve that problem.
See Image 6

As with most scratch building techniques all that is required is a little patience and thought before committing knife to plastic. Although not an essential modification to a kit I personally think itís just one of those little details that helps create a truly individual model with the added bonus of a strong component. Of course there is little point in doing this if the body panels cover this detail, but for a 1920's - 30's engine that has exposed springs (especially the fronts) it will certainly create a more realistic appearance.
  • spring2
  • spring2
  • spring3
  • spring4
  • spring5
  • Spring6

About the Author

About Roger (casper)

Former SSgt RNZAOC (RNZALR) An "occasional" modeller with a preference to model 1/24th-1/25th scale (scratch) demobbed soft-skins, especially the more obscure and 'quirky' types.


those look Great!! thanks for sharing!
NOV 29, 2006 - 06:15 AM
This will be useful, I need to make a pair of them for my Monogram amphibious Weasel.
NOV 29, 2006 - 08:10 AM
Good tutorial, Casper! I've used a similar technique recently to build some springs for a scratchbuilt motorcycle trailer I am doing. It works and came out looking good. Cuhail
NOV 29, 2006 - 07:24 PM