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[mklotz]

I understand what you said. Now you need to show the math to prove that your method works. A verbal description of what you intend to do isn't enou...

[mklotz]

I'll be looking forward to your demolition of a proof that's survived for 184 years. Be sure to publish it here for all to see.

[mklotz]

The statement is "trisection of an angle USING ONLY STRAIGHTEDGE AND COMPASS is not possible", not "trisection of an angle is not possible"....

[mklotz]

I'm not using it as a work surface per se, rather a place to temporarily hold stuff cluttering the main work surface.

The cabinet must be...

[mklotz]

Yes, roll-outs are great. Years ago Sears sold rolling tool cabinets that were absurdly low; they looked like something one might find in a shop where...

[mklotz]

Here's the link again...

https://quod.lib.umich.edu/cgi/t/tex...=image&seq=401...

[mklotz]

Here you go...a page from Whitehead and Russel's Principia...

https://quod.lib.umich.edu/cgi/t/tex...mhistmath&cc=u...

[mklotz]

All measurements in the real world are approximations. The length of the circumference in the world of math is a concept, not a measurement.
...

[mklotz]

One of the most intriguing questions mathematicians (and many physicists) proffer goes something like this...

Is mathematics some sort of...

[mklotz]

Seems to me that these level calibration screws provide a perfect opportunity for the use of a compound thread....

[mklotz]

[QUOTE=darryl;n1928764]... Perhaps the result was so close that for all intents and purposes is was good enough? ...[QUOTE]

"Close enough"...

[mklotz]

A true septagon can NOT be constructed with only dividers and straightedge. Gauss proved that a long time ago; the article I wrote below describes his...

[mklotz]

Probably the best practical two gear pair for a ratio of 1.27 is 80/63 with an error of 0.0125% as this table shows...

Desired ratio = 1.27...

[mklotz]

So far in this thread I haven't seen anyone describe any home shop method for measuring the alignment accuracy of a rotary table. Slapping a vernier...

[mklotz]

It would be instructive if all the people who built something IN THEIR HOME SHOPS that required sub arcminute machining accuracy would chime in and briefly...

[mklotz]

There are many ways to build it so I'll just try to outline the principle which can then be mechanically implemented in a number of ways.

...

[mklotz]

6 * tan (7/60) = 0.0122... is the radial difference. Multiply that by 2 to get the diameter difference and you have 0.0244... which is very close to ...

[mklotz]

Too right. There are 21600 arcminutes in a circle. If you think you can obtain meaningful, repeatable subdivisions of an arcminute with a DIY mechanical...

[mklotz]

With a 90:1 worm gear, one rotation of the crank will move the table 360/90 = 4 degrees.

Provide 4 divisions on the crank disk for 4 degrees....

[mklotz]

More on Anders Malmberg...

http://www.modvid.com.au/html/body_anders_malmberg.html

Here's another approach to simulating reality...