Aileron Bellcrank

[johnb]

Question:. The center tube of the aileron bellcrank has to be machined for the bearings. Have you guys done the machining before you weld by turning the tube on a lathe, or post machining them after the weld? What seems to work well for these?

[sjt]

I machined the tube first. I then machined two steel plugs the same diameter as the bearing. The plugs of steel keeps the distortion from the welding at least circular.

[S Lathrop]

I machined the tube first. I then machined two steel plugs the same diameter as the bearing. The plugs of steel keeps the distortion from the welding at least circular.

I do things like this a lot but I use brass for the plugs if I want to reuse the plugs. For one time use I like aluminum. Bottom line, I don't know a better way unless you machine after welding. I think the faster heat transfer of aluminum or brass make for better results.

[sjt]

When I was a kid I would read popular mechanics from the 50's.  There was always an article that said something like "Just go over to the junk yard and pickup a piece of brass for this project".

In all of my entire life I have been searching for this pile of brass at the junk yard and I still have not found where they are hiding it.

[S Lathrop]

I also never found that pile of brass at a junk yard. I groan when ever I have to buy brass to use as a heat sink.

I used brass heat sink in the bearings holders on race car wheel bearings. I found that the bore was every bit as true after welding around holder with the heat sink as it was when I machined it. I have some cars that have been racing for well over 30 years with never a bearing issue on parts that I have used brass hear sinks.

[sjt]

I lied. I keep every brass plumbing fixture that comes out of the house in a hidden spot in the back yard. Some day I am going to melt all those water taps into an ingot of brass.

The location in my back yard is hidden because the state of California has determined that all plumbing fixtures made out of brass are a carcinogen. I am willing to take the risk because I am already using MEK on my project.

Fortunately I live in Texas.

p.s.
I also have a barrel full of aluminum scrap that I am going to melt down; I was thinking about making a fly wheel. The only problem is that I do not need a fly wheel.

[svyolo]

I am seriously thinking of moving to the Republic of Texas. Soon.