Q&A response - new interpretation of R16

[dlavery]

Originally Posted by jgannon

I don't totally understand the geometry behind it, but the second sentence in the linked article was "No - you can't drill square holes", so I'm guessing there's some reason that doesn't work.

The article is pretty good, but actually the second sentence is incorrect. You CAN drill square holes! Although fairly rare, wobbling drill bits that describe Reuleaux Traiangles have been around for years. There is a great article about drilling square holes from the October 1993 issue of The Mathematics Teacher. One of my friends used to have one of the Watts Brothers square hole bits (after we stumbled across the Mathematics Teacher article several years ago, his immediate reaction was "I've gotta have one of those!"), and it was fascinating to watch. As best as I can tell, the Watts Brothers Tool Works is still the only U.S. manufacturer of these drill bits, but you can still get them.

-dave



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[purduephotog]

Originally Posted by Gdeaver

The 80" rule is very restrictive. So far our team has worked out the bottom part of the arm geometry and extend out a maximum of 76". To get the top part to be with in is the hard part. If we get it right it should be about 79". To get to this point has given our team lots of problems. So much to do and so little time.

Same here.

We're weak on mentors- very little mech Eng, very little programming... great machinists though! This year we were going to experiment with a 4 bar- team put it to a vote and it won- and then the design headaches started.

I guess (from today's build session) we've scrapped the 4 bar and now have a simple arm that just goes up.

Oh, and square holes are easy:http://www.hartvilletool.com/product/11429