Rear Spar Drill Fixture

[Mikeyb]

I put the wings on my plane today. I’m a hazard with a hand drill and would have died of a heart attack if I would have messed up the hole that attaches the rear spar

I made a little drill jig. It’s just a piece of 1X2.75X.5” aluminum bar with a .500” hole bored in the middle to hold removable drill bushings I bought from McMaster.

I clamped them in place when I was setting the incidence. It’s easy to judge the edge distance. As long there is an 1/8” of material above and below the bar you are good.

I stepped the hole size up from #30 to an N drill and bushings then reamed it to 5/16. Nice round hole that is square to the spar fittings.

 

[mburch]

Great idea - I'm saving this for when I get to that step!

 

[Mikeyb]

Thanks
Send me a message when you are going to drill yours and maybe I can lend you the brackets and bushings.
Mike

 

[Taltruda]

That’s simply awesome! Great idea! I am going to either copy this or hit you up in 4 years when I’m at this point!

 

[Mikeyb]

Thanks!
Mike

 

[JRichichi]

They say great minds think alike...

I did essentially the exact same thing. A nice, round, perpendicular hole with good edge distance. It took all of the "excitement" out of drilling/reaming the rear spar attachment.

 

[Carlos151]

I put the wings on my plane today. I’m a hazard with a hand drill and would have died of a heart attack if I would have messed up the hole that attaches the rear spar

I made a little drill jig. It’s just a piece of 1X2.75X.5” aluminum bar with a .500” hole bored in the middle to hold removable drill bushings I bought from McMaster.

I clamped them in place when I was setting the incidence. It’s easy to judge the edge distance. As long there is an 1/8” of material above and below the bar you are good.

I stepped the hole size up from #30 to an N drill and bushings then reamed it to 5/16. Nice round hole that is square to the spar fittings.

Looks really nice. I’m sure that bolt in the picture is just a placeholder but make sure that AN5 bolt is installed front to back with the castle nut on the aft side of the spar bar on the final install.