Quarantine Doodling

A couple of small screw jacks based on real ones from about 1910-1915.

Acme threads 1 in. dia. by 5 tpi.

And a slightly larger planer jack. Buttress threads 2 in. by 8 tpi.


You are taking things to a new level. :rofl:


Or becoming the great leveler


I don’t know how great. Just trying to keep things on plane.


I was told an anecdote about one of our great Modernist architects by a person who had worked in his office. At his home/office he had built a summer sauna on very poor ground. Instead of building it on piles as normal engineering practice would require, the building rested on large concrete tiles resting on the ground. Every spring, after the frost had melted, he performed a ritual. From a custom-built cupboard he took out an enormous spanner, and used it to level the sauna with the large jacks that were built in at its corners, with aid of spirit levels also permanently fixed on the walls.


Interesting. It seems some architects aren’t especially good in the engineering department. I guess that’s why there are structural engineers.

On the contrary, I think it is quite a good economical engineering solution for a simple structure for summer use. Knowing that the frost would make it tilt, he provided for the movement.
The sauna was built in 1953 and it still stands.
Today, perhaps, he would have built it out of a used shipping container.

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They would be good 3d print candidates. The inherent weakness of printing is the layers letting go, but this is mostly compression so unless they got pressure sideways or the threads stripped they should be very serviceable.

The parts are of course all solid components as you would guess. Later when I get back at my computer I’ll send you the .stl files if you want to have a go at them. I’d be interested to know how the buttress threads print. They are designed especially to have strength in one direction, in this case in compression. The have a rather fine pitch for the diameter so there’s quite a lot of bearing surface available.

Yeah I’ll have a go at them, but save me some work before you send them. The threads need to be different by 1.04, By that I mean I made a nut for your other one by using the original thread inside out and scaled up by 1.04. It works but it tends to bind a bit and I can’t get my head around how uniform scaling changes the shape of the threads relative to each other. I’m pretty sure it’s the reason they are loose and tight at the same time.
So to save me the bother, can you make the threads with a uniform spacing.

I’ll see what I can do. Might not do it right away :wink:

Any time in the next indefinite period of isolation will be fine.

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Fantastic Dave!!

Thank you kindly, sir.

WIP . Demolished train station in Puerto Rico. Im going to model it to the last detail and render an animation.


Pretty cool. Looks like you didn’t screw it up.

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Dave, your stuff always absolutely amazes me!

Thank you, sir.

Beautiful drawings, thanks for sharing!

If you do 3d print these, would be great to see a pic of result. Thanks.