"Pete Keillor" wrote in message
...
On Sat, 25 Mar 2017 09:06:45 -0400, "Jim Wilkins"
wrote:

....
Way down on my to-do list:
http://www.agelessengines.com/9cyl.htm
http://www.5bears.com/observe.htm
-jsw

Fantastic! I used to have (lost in a move) plans for a 1/5 scale
A-26. I initially got into machining from 1. workplace envy (I
designed stuff, the shop got to build) and 2. the desire,
unrealistic
though it might be, to power that model with actual radials. If not
18 cyl (your R-2800), then at least 9.

Way down on the list is a good description.

Pete

It was a small fraction of my excuse to buy this 6-jaw chuck:
http://littlemachineshop.com/product...2276&category=

Yesterday I tapped broom threads
https://www.amazon.com/Grizzly-G1869.../dp/B0000DD0T7
in 1/2" plastic electrical conduit to make a tool that fits on a
painting extension pole. Neither a 3-jaw nor that 6-jaw would grip
well enough to resist the tapping torque and I had to use a 27/32"
collet. My main excuse to buy the 6-jaw was to chuck tubing larger
than 5C collet size.

That chuck has a gap in its gripping range. It doesn't open much
beyond 1" before the jaws slip off the scroll and the minimum ID it
will fit is 1.310"

The tapped hole was too small to screw on by hand until I
heat-softened the PVC. Threads in oak fit better so the plastic must
have deformed.
-jsw