homemade leafsprings

chimeraa

Supporting Member
Hi!

As mentioned in the build thread about my volvo, i want to show you how the leaf springs were made.

material:

I searched for spring steel on ebay. Since spring steel is quite difficult to work with, i bought a roll if 6mm wide 1.1274 steel. To be honest, i dont know what the possible equivalent is named in the US since i have no idea of their norming system. I choose the 0,5mm thick variant. This is only half as thick as a rc4wd or tamiya leaf spring, but it should allow to use more layers on the vehicle while keeping the spring setup still soft enough for driving.

I also can remember several people building their leaf springs out of leaf rakes. This might work as well.

lenght:

One of the most difficult parts is, to get the steel cut to the right length. As first step, i built this jig out of a leftover piece of wood, some screws and brass tubing. The jig already has the form i want the springs to be.

20161022_150711.jpg

You can measure the length by bending piece of material to the jig as shown in this professionel edited picture:

2.jpg

I'll call it the "basic length" for this tutorial

Now, you still need the necessary length for the eyes on both ends.

example:


my bolts for the leaf springs will have a diameter of 4mm. The extent of a 4mm circle is "Pi*diameter"

3,14*4mm=12,56mm

Since the eye is not all around the bolt, we don't need the length to be equal to the whole extent. 2.5 is a good factor to add:

2.5*4mm=10mm.

So we add 10mm per side to our basic length.

bending the eyes:

After several tries, i came up with the following method:

tools:

-steel plate with a hole

-4mm steel bolt

-flat screwdriver

-oxyacetylene welding torch or something similar (we need heat!)

-2 self grip wrenches

-clamp

1. mount the steel plate to your work bench

2. mark the 10mm extra length on your future leaf spring

3. out the spring over the hole, the 10mm mark should be in the middle of the hole, fix it with clamp

4. mount the bolt with the grip wrenches over the spring. the bolt should be on the 10mm mark

5. heat the spring from both sides (that's why you need the hole in the plate) until it glows dark orange

6. use the screwdriver to lift the short end of the spring and lay it around the bolt

7. let everything cool down

8. repeat with other side.

It may need some exercise until you get perfect results, but at least it works

20161022_150726.jpg

After the spring got both eyes, i bent it with my fingers carefully until it fits into the jig.

20161022_160701.jpg

20161022_161911.jpg

hole:

Most available scale leaf springs, as well as most of the real world ones, have a center hole to mount them on an axle. The scale springs usually have three holes since they are screwed directly to the axle. This works, but weakens the spring a lot. I choose to mount them with brackets and u-bolts.

This still reqires one hole, so the can't slip out of the bracket. As mentioned before, spring steel is a pain in the **** to work with. I tried to drill the holes, no chance at all.

So i decided for a rather simple method: punching them out!

I used two small pieces of steel and some screws to build a tool for this purpose:

after screwing them togehter, i drilled the center hole to both of them at the same time for proper alignment. An old pin punch was shortened as tool. The holes have only a diameter of 2mm and the spring is only 0,5mm thick, so they were quite easy to punch out.

20161118_130052.jpg

20161118_130103.jpg

Let me hear of your experiences / suggestions
regards

Flo
 

Kellerkind

New member
Hi Flo! This tutorial is great. Once I find some time I'll have to try this! Thank you very much. But isn't it 1.1248 steel? Can't find the 1.1247 you mentioned!? Regards Jens
 

Halme

Supporting Member
Thanks, nice jig and great tutorial!

Packaging band used to pack stuff in pallets is also a budget option. Maybe bit wide though but is easy to cut with tin snips. Old starting spring from outboardmotor could also work.
 

luckland

Supporting Member
Thank you so much for sharing your precious wisdom. I did a research on the name of the steel in each country.

Germany: 1.1274(Ck101)
Britain: 060A96
France : XC100
Spain: F.5117
Sweden: 1870
US: 1095
 
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