Panther Sport Aircraft Forums

Got some of the double margin bits from Pan American, they are very good. Also, you are correct, quality chucking reamers work well on the frame. I am having good luck with MORSE brand. Thanks for the recommendations.

I updrilled most of the holes, but I had to spend a bit of time looking through the BM to identify and mark the holes that will require other skins/firewall to be fitted later — there are a lot. For example, rear fuse joint, the firewall on the side and on the bottom where the exhaust fairing goes, the top deck, the cheek fairing and probably a few others.
For updrilling I used a HSS reamer mostly — works just as well as on aluminum. Except for the firewall fitting.., which is a different topic. I also really like the double margin cobalt drill bits that Pan American sells — very high quality and last me longer than other #40 and #30 drill bits and give a cleaner cut — IMHO.

I am currently fitting bottom and side skins to steel cage. Any reason not to upsize holes at this time? BM does not specify. Also, any ideas on best bit for upsizing these holes? In aluminum, I’ve used chucking readers to get a nice round hole. They won’t cut 4130 very well. Thanks