Making a knob

That's right purty, Don.

--Winston

Hey Don,

Please discuss that anodizing a bit. Does it have a hard surface like the commercial Job? Is this an easy to do thing like nickel chrome, or really involved like triple chrome?

Karl

Disclaimer: I'm no expert on anodizing.

My understanding is that "hard" anodize has smaller pores that don't accept dye as well. The process is the same, and it's easy to do; I think the difference is that "hard" anodizing is done with more concentrated acid at higher current and lower temperature.

The electrolyte is just battery acid from NAPA, diluted 2:1 with distilled water for hard anodizing or 3:1 for a film that is to be dyed. I do it at room temperature. Cooling the electrolyte might result in a harder film. I really don't know how hard the film I get is. I used a current of about 0.1 amp per square inch. I've read that lower current will result in better dye saturation but I haven't tried that yet. My knob isn't really a deep black, more of a gunmetal color. A matte finish (beadblasted) might also result in a darker black.

My "secret weapon" is using Ted Edwards' electrocleaning soup to get the aluminum waterbreak clean. It's in the dropbox somewhere. I don't use any electricity for that, just dip the work in the soup for a few seconds and scrub it with a rag. It really does the job!

After anodizing, the work is typically sealed by immersing it in boiling distilled water, perhaps with a sealant chemical added.

There are some good websites about anodizing, though I don't have the URL's at hand. Google on anodize and telescope.

Caswell's plating manual has a good section on anodizing, and he sells the dyes and some other chemicals like de-oxidizer and sealant.

a FINE knob. We're very proud :)

Now you will discover whether the torque-limiting grip on the original knob was because the part in which it worked could not take any more force than you could put through the wimpy knob. I hope that is not the reason for the original knob being as it is.

Enjoy, DoN.

What a sorry excuse for a functional design that would be. Fortunately, I don't think that's the case here.

There's about 3/4" of 3/8-16 threadlength in the aluminum or magnesium casting, so I don't think I'll jack the threads out barehanded. If that happened, then I'd drill it out and fit a knurled stainless threaded bushing. I want the damned clamp tight.

It won't happen. Some good and thoughtful engineering clearly went into the design of this motor and mount, other than the silly knob. Bow-mount trolling motors see hard use, this one can take it -- has done for 7 years now. Running into submerged stumps and rocks and chewing thru thick weeds are just part of a day's work for such a motor. Chasing bass rquires it. It gets the job done with a shrug.

The engineering team assigned that part to the New Guy and spent their time on the critical parts.

Even if you tried, you'd likely break the bolt. From MH, length of thread engagement required to break the screw instead of stripping for a "screw" of 50Ksi yield in a "nut" of 10Ksi yield is 50E3 10E3 thread_SLe .375

Ted