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Homemade Leaf Spring Project.

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Denny Graham Silver Member Dennis Graham
Sandwich, Illinois, USA   USA
1950 Chevrolet 3600 "Old Blue"
1954 Chevrolet 3600
Well, this all started wayyyyy back in January of this year (2017) cuz I couldn’t find
springs for the price I was willing to pay. More importunately, I wanted more control
over the sizes and rates so I could do some experimenting with the suspension.
To this point I’ve got at least 10 or 15 times as much invested in my forge/oven and
quench tank than I would have if I’d been satisfied with one set of generic leaf springs
from VKC or the like.
In order to take the leaf spring project from raw bar stock to finished spring I had to
fabricate the bending fixtures for rolling the eyes, and my own heat treat equipment.
Of course I will be using this forge/oven for other “forging” projects and for heat treating
tooling that I make in the home machine shop. But the first job will be the three sets of
springs for the Riley and a couple more.
It’s been a long road to get this new equipment built for the shop. Starting off with my badly
mangled right (prime user) wrist, which shows in the picture of me dropping the leaf into the
quench tank. A very active growing season, which required mowing our 6.55 acres
every 3 or 4 days all summer. Taking down several dead ash and oak trees. A kitchen
remodel that's been promised to sweetie face ever since we moved to Shangri la.
Then knee surgery and rehab for the mutt, who required lots and lots of attention
last month and will for the next three.
But…..here I am, almost fall and I’m at long last, a week or two away from doing my first
heat on the springs. I’ve resigned myself to the fact that since I’m not a metallurgist and
have just the bare minimum experience with heat treating my own parts. that I’m in for a
somewhat rocky honeymoon.
Denny Graham
Sandwich, IL



Edited 2 time(s). Last edit at 2017-09-04 05:04 AM by Denny Graham.

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carChips Avatar
carChips Victor Harnish
Kelowna, BC, Canada   CAN
1933 MG Magnette
1973 Triumph Spitfire 1500 "Chip"
1989 GMC Sierra 1500 "Bush Truck"
I worked in a steel mill for 17 years and we rolled out those automotive leaf springs. When they came out of the mill they got stacked together to cool, we called it pack annealed, by this I mean from 1400C to 500C. The heavy truck spring would only have 5 pieces in a pack, the lite trailer springs would have 10. Those springs were all high carbon and if there was a mess up in the mill and they sent a single bar, that bar would be scrap, as soon as we cut it, it would shatter.

So, if you were to slowly reduce the temp on your box, your spring might hold it's temper.

Denny Graham Silver Member Dennis Graham
Sandwich, Illinois, USA   USA
1950 Chevrolet 3600 "Old Blue"
1954 Chevrolet 3600
Slow cooling after heating to the austenite phase ‘is’ the annealing process. Slow
cooling in still air will remove all of the hardness and leave spring steel in the
normalized condition, which is just a little tougher than the annealed condition.
Annealing can, as you posted, be accomplished by “stack annealing” or packing
in an insulator such as vermiculite. The material can be left in the oven after it is
shut down and allowed to cool. The technically correct annealing process is to
ramp the furnace down using a pre-calculated schedule, slowly cooling the steel
to its full annealed or soft condition.
The material that I’m using for my springs is 5160 annealed spring steel. My schedule for
the heat will be to bring the springs to 1550°F-1600°F (2822°C-2912°C), hold there or
soak, only long enough to assure that they are thoroughly saturated then quick into the
quench, which in this case is soybean oil heated to 130°-150°, at which time the steel
will be very hard, i.e., brittle. I’ll cool the forge/oven down right away for the next or
temper phase.
The temper that I will start off with will be 500°F (932°C) for an hour and possibly a second or third
temper cycle if the first hasn’t drawn enough of the hardness out of them. I’m looking for
around 40-45 HRC before I start load testing them in the press.
I have had some exposure to how heat effects steel since my background for the past half
century was in welding fabrication and machine work, dealing with alloy tool steels and
such.
The point I was trying to make was….I’m just not a full blown certified metallurgist. I’m
simply posting this to let some of the guys see that there are many ways to approach a
project from the very basic getting your feet wet, to getting in way up to your chin.

Oops, forgot to add, carbon steel's melting temperature is between
2600°F - 2800°F (1425° C - 1540° C)

Denny Graham
Sandwich, IL



Edited 2 time(s). Last edit at 2017-09-05 05:30 AM by Denny Graham.

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