Member postings for James Winkler

A couple of primers on bolted joints which discuss bolt shear:

Machine Design: What’s the Difference Between Bearing, Shear, and Tear-Out Stress?

Engineer's Edge article Bolt or Pin in Single Shear Equation and Calculator

Edited By James Winkler on 04/12/2019 10:40:33

SillyOldDuffer - As far as I am concerned Australia can keep the America's Cup. I admired the NSFW 1983 tee shirt with an eagle in front of a kangaroo with the caption "Australia's America's Cup". I wish I had bought one or two of those. Of course, the order was reversed when America won it back. I didn't find that unoriginal version nearly as amusing. I'd rather be machining.

Brian G: Thanks for the translation! I spent way too much time on Wikipedia which uses most variants of English. I can no longer spell anything properly. My spell checker has been 'updated', so even it no longer helps. I lived in India for two years, and on Bougainville Island (TPNG at the time). Got into an argument with an Aussie whether to build something out of "Aluminum" or "Aluminium". (Which one is the American variant again?) I had to hide for a week when I asked a bunch of Aussies who were in a very serious discussion - "What's America's Cup?"

Cheers -Jim

Thank you everyone!

Hopper: My wife uses a boar bristle hair brush. I wonder if that would work?

I'd steal a washing up brush from the kitchen, but I'm the one usually doing the dishes.

I'll try the 'paint thinner' - I don't know why they call it that, it doesn't thin my water-based acrylic paint a bit! I'll try a nylon bristle brush. See if that dissolves onto the leadscrew.

Thanks for all your help!

Cheers -Jim

I have noted that it occurs if a black-oxide steel alloy screw has been installed for awhile. I seem to remember that tightening then quickly removing a steel alloy screw from aluminium alloy threads does not have nearly the break-free torque. Maybe the steel removes the aluminium oxide which reforms after awhile? There is a characteristic "smoke" and odour when the screw / bolt breaks free.

I have a question about cleaning the Super 7 leadscrew instructions I was hoping someone would clarify for me.

Page 20 of the Super 7 manual states: "At regular intervals, the leadscrew should be thoroughly cleaned with a stiff brush and paraffin, and oiled freely along its entire length."

What kind of paraffin should I use? Will canning sealing wax work or is there something better? For a "stiff brush", I presume a stiff nylon brush would suffice? What is the purpose of the paraffin? Dirt and grime will stick to the paraffin and be removed from the leadscrew?

Being a Yank, I'm not sure if your paraffin is the same as what I'm familiar with.

Many thanks! -Jim