I have a small 'diesel' model aircraft engine. The variable compression screw runs in the ali' cylinder jacket to control the contra-piston and hence the compression. The thread in the cylinder jacket is stripped. I wondered if it a helicoil would be a practical solution. Any ideas? thanks
"Recoil" do a repair kit for 6BA No 30560. For a one off I would have thought too pricey. I would consider drilling out 3.3 and tapping M4 coarse or drill 3.6 and tap M4 fine. Assumes contra piston will accept M4 pushing against it. These options will also mean making a new "T" screw. Alternatively ream or bore 4 to 5mm and turn a top hat shaped plug inserted from inside as a "tight" fit, tap 6BA.
Richard
Given that it will need regular adjustment, I'd be inclined to enlarge the hole and put a bush in - a Helicoil _should_ be OK, but they're not really intended for quite that sort of use and might work loose.
I'm also amazed that it's as small as 6BA, nearly all of mine are 2BA on the British engines and 5mm on continental ones, I think the Eta is
1/4x32.rgds Richard
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.