On Fri, 16 Mar 2012 18:26:26 +0700, John B. wrote:

On Thu, 15 Mar 2012 23:52:55 -0400, Ed Huntress
wrote:

On Fri, 16 Mar 2012 10:41:45 +0700, John B.
wrote:

On Thu, 15 Mar 2012 13:43:35 -0500, Tim Wescott
wrote:

http://en.wikipedia.org/wiki/Schnuerle_porting


Set up a fixture to hold the cylinder liner at the angle you want the
port. Drill a hole to the largest diameter that fits your square port
and file to final shape.

If you are persnickety then leave the sleeve bore a few tenths
underside and lap of hone to final diameter after finish filing the
ports.

I'm thinking that he will have a file stroke length of around 6/10 of an
inch...

I don't think he mentioned the engine size but I've done essentially
that with .049, .15 and larger engines with out getting too many scars
on the opposite side of the bore :-)

With good sharp, clean, jewelry files 6/10" is a long stroke. :-)

I did. About 0.20.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com