On Feb 25, 6:54*am, bildan wrote:
On Feb 25, 6:47*am, Mike125 wrote:

I don't know why I didn't ckeck W&W first. Duh. Do you think it is
better to drill smaller holes and increase the size or just go for it
on the first try? *Thanks for the input. BTW, this ship is on the
market (but not yet advertised on W&W). Painted w/Imron 5 years ago,
with trailer located in NJ - asking $20K.

Mike


I just finished drilling and countersinking 60+ holes for my Open
Cirrus last week. I would pick up the old hole locations from the
frame by just drilling enough to make a slight mark, then dismount the
canopy and drill full size. the 60 deg angle of the plexiglas drill
bit seems to preclude drill wander.

In addition to all that was said so far, you should back up the holes
with a piece of wood or equal and carefully control the speed and feed
at the point the drill bit breaks through. Touch c'sink both sides of
hole. I used the bits sold at A/C spruce. If you can produce perfect
holes and countersinks on the old plexi, should have no problem with
the new stuff. Biggest problem is getting tired and not paying
attention after the first couple dozen holes. A typical flaw is a
small radial crack or chip at the back side of the hole, this can be
removed by countersink, and I would omit the screw in that location.

Lastly, the CFR title 14 part 21 has requirements for parts on type
certificated aircraft. Might want to research this before going
aftermarket.

aerodyne