Posted by Steve Kanavas on May 08, 2000 at 00:59:49:
In Reply to: I'm with you on afteramrket axles and the Detriot. We need a plan posted by Andy T. on May 07, 2000 at 22:40:50:
In business I sell induction heating equipment. I have lots of customers that can make the axles.
A. Forging
Axles are made from bar stock of the diameter you see on the shaft span. The stock on the flange end is heated to 2200 F, for about 6 inches along the end length. The heated shaft is then placed vertically in a nest in the forging press for what's called "upset forging". About a 2500 ton press will do nicely for these "small" axles. The nest has an integral profile die that forms the inside of the flange. On the press ram there is the mating outer die. One good hit forms the flange. There is a hydraulic ram in the bottom of the die to push the formed part out of the die.
After cooling, the other end can be heated and upset for axles we see with splines larger than the bar stock diameter. We may not need this operation, as modern splines can have stress dissipators ground into them at the spline/shaft transitional zone when they are machined. This would allow the spines to be sized as the originals now are. Cut into the shaft diameter.
Got a guy in Milwaukee that can whack these out as he forges 5" diameter ones with 10" flanges for Caterpillar.
B. Machining
Machining of splines and flange surfaces/holes is performed. We gotta machine the flange root to shaft transition a bit smaller than the spline root diameter here to create a stress riser. Dat's where we want it to break if it breaks.
Don't know any machine shops for this, but a few calls can set that up.
C. Heat Treat
To heat treat, we need to select a stock with medium carbon content of the steel. Logically, a 1035 to 1040 alloy. I'll look up the alloy from one of the Eaton or New Venture Gear jobs we sold. Maybe a 1500 series with a vanadium /manganese adder for toughness. The axle is scan induction hardened, running from about .040" from the spline end tip, all the way to the flange root. This hardening will give a case hardness about .100" deep, leaving the core a nice ductile rc25-30 ish. The flange root is the critical area of concern for the hardening. A temper is needed to get the hardness down from about rc56 to around rc45.
Any heat treater with induction can do the heat treat. Got a customer in that business too.
My guesses???
Engineering drawings/procedural specs $800.
Stock per axle $20.
Forge Die set $6000.
Forging $10.
Machining $40.
Induction heat treat inductor $4000.
Harden $5.
Furnace temper $5.
This is based on typical industrial rates.
Plan on wasting 50-75 parts to refine forging machining and heat treat.
Now.... Whats the volume? Nobody will touch an order under 100-200 pieces per side. I doubt if any of us will commit to being the prime contractor for the project either. $$$$$$$ I won't for the same reason and then throw in a good dose of liability for the curse!
How bout those low volume hot rod axle shops???
steve