Working leaf springs

[John RutzenParticipant @johnrutzen76569]

Hi, I am trying to make working leaf springs for my 31/2 gauge Lion. The leaves are 3/16 wide. I can't buy any spring steel strip that size so I have been trying different ideas, I would like to know if anyone has a successful method for making these this small. I have used old bandsaw blade on a 5 inch model successfully but the difficulty is cutting it to width. I just ground a bit off the standard 1/2 blade before but I can't do this here. I have some o.5mm nickel silver and am trying that but I don't know if it will be successful long term. Anyway any ideas or sources of supply of 3/16 wide material please.

[John RutzenParticipant @johnrutzen76569]

[ManofkentParticipant @manofkent]

I helped a colleague at our club make some for a 2.1/2 gauge loco. He used clock springs which can be bought at various sizes on the bay.

I got involved because I have a spark eroder which we used to bore and shape the spring steel, although others may explain how you can soften them by heating.

John

[John RutzenParticipant @johnrutzen76569]

Thank you. I searched eBay for spring steel but couldn't fine any the right size. i'll look for clock springs.

[JasonBModerator @jasonb]

Can't you mill some wider strip down to 3/16" wide. Reeves sell it unhardened so it machines OK.

[HOWARDTParticipant @howardt]

I bought some from Reeves about 12mm wide 1.2mm thick, it is intended for 3 1/2 loco tender springs. The job is on the todo list soon, the hangers are roughly made awaiting the finishing of the slots.

[BazParticipant @baz89810]

When I was an apprentice, more years ago than I care to remember, the tool room foreman was building LBSCs Virginia, most of it being done in company time of course and one at he came back from lunch with a bag full of small steel tape rules, narrow ones about 3/16 to 1/4 wide, longtime ago so cannot remember size exactly. He got me to remove the cases and then he dipped the steel tape in chemiclene and set fire to it, this removed all the graduations etc and left a nice strip of spring steel. I was then presented with drawings to make a tool to cut and radius the ends and to punch an oblong hole in the ends, I think he used a couple of Tufnol leaves but it made beautiful leaf springs.

[Perko7Participant @perko7]

Would the mini-hacksaw blades be of any use? They are 6mm (1/4) wide across the teeth, grind them off and they would be just on 5mm wide which is a smidgen over 3/16.

[John RutzenParticipant @johnrutzen76569]

Thank you for the replies. I've thought of mini hacksaw blades and have one with the teeth ground off. I don't think it's possible to still get 1/4 wide tapes. i've got some 3/8th wide spring steel I got from Reeves years ago. It's pretty springy so I think it will be tough to mill down.

[JasonBModerator @jasonb]

I've milled, drilled, sawn and filed the material they do. While not as easy to work as a free cutting mild steel it can be done, more like working with Silver steel or gauge plate or any other high carbon steel. If in doubt just anneal it.

[Nigel Graham 2Participant @nigelgraham2]

I would suggest for milling such thin spring strip to with, clamping it rigidly between two pieces of sacrificial mild-steel and milling along the sandwich with a carbide tool, entering both support-pieces a little.

For tempering after hardening, a lead bath is about the right temperature for a tempering colour of dark-blue. Keep the lead just on melting-point, starting to crystallise on its surface – and avoid breathing any vapour! Leave the springs in long enough to ensure full soaking, though at the sorts of sizes here, that won't be long, a couple or minutes or so perhaps.

Note that the tempering colour is by oxidising, and the steel will stay bright (from post-hardening polishing) except when exposed to the air.

I used this technique for new springs for a 7-1/4"g Ken Swan-designed "Wren", and have known other constructors do so, successfully. I quenched them in oil – and carried out both operations outdoors, in the evening so still day-lit but not in sunshine.

[BazParticipant @baz89810]

Junior hacksaw blades would be worth a try, I think I would mill the teeth off with a carbide cutter. Holding the hacksaw blade in the vice will act as a heatsink and perhaps an air line or plenty of coolant to keep the temper. Any holes could also be done with a carbide milling cutter.

[John RutzenParticipant @johnrutzen76569]

Thanks for the replies. I've made one with junior hacksaw blades this afternoon and it looks good! I ground the teeth off which didn't affect the temper and put it through the rolls to give it a curve. I applied as much pressure as I could and that got rid of most of the remnants of the wavy edge. I drilled it by taking some of the temper out in a flame. The hacksaw blades are only about 0.4mm which is better for these small springs.

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