Welding on a rear axle hub

[muddstopper]

I am getting ready to build my knuckleboom and thought I had everything figured out, until I decided to actually start. My thoughts are to weld the cyl braceing to the hub of the 48,000rear axle and let the hub be my swivel point for the boom. Not sure what kind of metal the hub is made from. It is some kind of steel, but doesnt look like cast, but not mild steel either. I want to weld mild steel to the hub, but am afraid the hub metal might break out under load. If I can weld to the hub metal, what kind of rods should I be looking for, high nickle, 7018, something else. I dont want to spend a bunch of time, and money, building the boom only to have it break at the base. I know the hubs are probably 1in or more thick and hold tons of weight when on a big truck, but whats going to happen when I put the welder to it. I thought about just making a steel plate to weld to and just using the lug bolts to hold the plate on, but dont really want to do that if its not necessary.

 

[Shield Arc]

Do a spark test to confirm if the hub is in deed cast iron, or cast steel. If it is cast iron built a plate to bolt on using the lug bolts.
If it's cast steel, preheat the hub to a couple hundred degrees. Use 7018, 312 stainless steel, or Super Missie weld. When you're done welding wrap in house insulation, and let set over night.

 

[Stimw]

Axle should be forged steel. Basically hot pounded into rough shape then machined where needed.
Bolting a plate on with the studs makes a lot more sense, you won't compromise the temper of the steel.
Welding can soften it or make it brittle depending on your handling post welding.

 

[muddstopper]

Its dark outside now and snowing. I'll do a spark test tomorrow. If it is cast steel, I'll preheat with a weed burner and let sit on top of the wood stove overnite after welding. I have a spare hub if I cant get the welds to look right, I 'll just build a plate and bolt on.

As a second thought, I have to mount a large dia sprocket on the hub, probably need to look into bolting on the sprocket, using the lug bolts and using the sprocket for my boom base, kill to birds with one stone. Cant mess the sprocket up, they are around $800 for a new one.

 

[Stimw]

A cheap way to allow welded things to cool down is to pack it in Kitty Litter. Preferably not used!!
I buy a 25 lb bag for under $4.00 at Walmart. My cats show me what they think of it at least a couple times a day.

 

[oldtimer 66]

Hubs, shafts are generally 4140 HT and cast would be 4142, not very common. Commonly refer to as "Shafting". Rc about 30. Can be purchased annealed at 10 to 20. Can be heat treated to the upper 40's to low 50's Hammer hard. Not having a hardness tester you can use a file and get an approx. on the hardness. Suspect it is only in the 30's Google that and see what is recommended for welding. This is from my hard drive which is starting to fill up and give me bad info once in a while. LOL Later

 

[muddstopper]

This is the hub I plan on using. The weld area would be around the lug bolts on the flat flange. I took a file to the flange and it cut pretty easily. I also used the file on a cast iron pot which seemed to be harder. Havent done the spark test, to far to run a extension cord for the grinder, and I dont feel like moving the housing to the shop today. Cold, blowing snow, metal I have to work with is outside, no fire in the shop stove, and give me a minute and I can make up some more excuses.

 

[Stimw]

Your not dealing with an axle you are dealing with a wheel hub. That's a totally different animal.
It will be soft and welding on them is very tricky. I have had to weld stripped out wheel studs and most of them were cast iron.

 

[muddstopper]

Even though I said i would be welding to a axle hub, I thought a few folks where confused and thinking axle or axle flange. I figured the pic would clear that up. Being as its cold i have been sitting around (knapping), pondering the situation and think just making a flat plate to bolt to the hub might be my best option. It would also allow me to simply unbolt the boom for mounting and dismounting, making thinks a lot lighter to handle and easier to work on in the event the bearings or something needs worked on. I'll just use a old wheel to get the centerhole and lug pattern right and see what I can find for flat plate.

 

[Shield Arc]

I think that is your safest route! A mechanical connection is a lot safer than an unknown welded connection.