Drilling the Pitot Mast - 3 hours

I've been looking forward to drilling the pitot into the mast for some time now. I've looked at a number of installations and I think that I have wrapped my head around it enough to tackle the task.

Straight away I can finally see where everyone mentions the 'thick part' of the pitot. I will need to ensure that the pilot holes for the #40 drill bit will be centered on these. Easy enough to do if I drilled directly into the pitot. But the tricky part is that I need to drill through both the mast and the pitot so transferring the holes on the outside the mast will be tough given the curved surfaces and the thickness' involved. So I began to mark out all lines on the pitot with the idea that I will transfer them up to the mast.

When inserting the Dynon pitot into the Safe Air 1 mast the slip fit is a little loose. Enough to make me feel nervous about drilling it that way. So I used a piece of electrical tape wrapped around the pitot (1 layer). The fit was not snug but found 2 layers was too thick. So I used 1 layer of electrical tape and 1 layer of masking tape...nice and snug. 

Then I went to work transferring the lines up the mast. Also placing the holes dead centre between the 0.700" overlap between the mast and pitot.

I didn't not feel 100% comfortable that I had transferred the lines right. There is so many ways that errors could have crept in. So I made a paper template and marked out the lines on that and compared that with the markings on the pitot and the mast. Everything seems to be in order. It's still not the most precise way but at some point I just had to roll with it.

I set up the vice on the drill press and drilled the holes with #40 pilot hole. Once I was happy with that, I opened up the holes to #32. I then pulled it all apart and inspected. I am very pleased with the aft holes. Dead centre. The forward holes are a bit off centre (maybe 1/32") but still in the thick part of the pitot metal. But considering how narrow the forward most 'thick' parts are, I think I did just fine.

I completed tapping treads for #6 screws. Now I just need to countersink the mast. I'll do that tomorrow. Getting late tonight, and it's never good countersinking when tired.

Looking back on it I suppose I could have pulled out my pitot hole template. I could have slipped that over the pitot and marked the lines and used that to transfer to the mast. Who knows it may have worked better, may not. In the end I'm happy with the result.