Banjo Wheels

[Larry Lyons]

I will post a pic here soon of my Banjo Wheels, just got all the chrome parts back and reassembled one last night. However I do have a question, I replated the control column (shaft, pipe) as they were wore to the point where there was no chrome left where they went through the phenolic bearing in the panel. Now I wonder, did I destroy their integrity as I did not get any heat treatment done afterwords? They are beautiful now though!
Larry

[Hank Jarrett]

Re: Banjo Wheels

If the steel is mild enough it will yield microscopically and Hydrogen embritilment relief will happen naturally over time. The higher the strength of the steel, the quicker there will be cracks. 300M steel will split open like an over ripe melon within the hour. I would think old 1010 steel might be fine (but I wouldn't try it anyway). An imbritilement relief should start within 30 minutes of removal from the plating solution and consists of a bake at 375º F for 23 hours (plus or minus 25º).
Got a REALLY big roast you would like to cook? I doubt it would change the flavor if it is clean when it goes in.
Hank

[Larry Lyons]

Re: Banjo Wheels

Well I have the ability to cook'em no problem there. I belive they are not 4130, but not sure. However there is not much stress put through these just a little pushing and shoving. Larry

[flyguy]

Re: Banjo Wheels

If it were my tail flying wires I would be concerned.
As for the control column shafts I don't think you should panic yet.
You should try to find what the material is though.
Most information I have seen emphasized the problems at higher tensile strengths.
DC

[Hank Jarrett]

Re: Banjo Wheels

Yea, this is really NOT a panic situation. If it is a problem you will probably see a crack at the bolt hole sometime. I really don't know what happens if you delay the relief bake since it was standard procedure to get parts in the oven within 30 minutes. The one time when we had a break buzzer sound before that happened on an F-14 landing gear and they left it sitting on a bull dog wagon through break. The strut split up the side and it sounded like a shotgun blast. Pretty good lesson for the guys pulling parts from the tank to the oven. After that they delayed break for critical parts. Of course the F-14 landing gear was 300M steel and REALLY high strength. It was very sensitive to Hydrogen embritilememt. I wish I still was in contact with the metallurgist from the NADEP. He was a real artist and taught me all I know about the subject (which is a small percentage of what he knew).
If there is a problem it won't happen because of the load you put on it. It's the load the metal develops internally from Hydrogen atoms being trapped between the steel crystals, forcing them apart. The bake drives those free atoms out of the steel.
Hank