[rwshooter]

I changed my mind on pitot aoa stuff and bought the safeair kit. My ribs are installed and so are my top skins on the 7a. whats the best way to drill the holes I need for the bushings with all this installed already?

Thanks.....Robb.....7A

 

[andrew phillips]

Heres what I did

I got a piece of aluminum tube with an inner diameter that would allow my step drill shaft to fit snugly inside. I drilled and tapped a hole for a set screw to lock it in place. This extension for my drill bit allowed me to drill all the holes from the root end of the wind without any problems.

 

[RVbySDI]

I got a piece of aluminum tube with an inner diameter that would allow my step drill shaft to fit snugly inside. I drilled and tapped a hole for a set screw to lock it in place. This extension for my drill bit allowed me to drill all the holes from the root end of the wind without any problems.

We did something similar. We took a step bit and ground all the larger steps down to the correct size we needed for the holes. We then brazed that to a piece of 4130 tubing that would chuck into our drill. The 4130 is stiff so very little flexing occurs. It worked out very well.

 

[uk_figs]

angle drill and flex drive

I also changed my mind and added the dynon AoA after I had completed the wings on my -7 and I also bought the safeair kit, I used the existing pitot tube rib holes and bushings for one of the tubes (pulled the 1/4 inch aluminum tube out) and I used an angle air drill through either the root or the access panels to drill a second pilot hole and then I used a step drill. The step drill I used was from Harbor freight with the hex shaft and I mounted this into a power screwdriver flex shaft drive so I could hold this in place with the drill outside the wing, worked slow and it came out fine.

 

[rwshooter]

I forgot that I had van's supplied snap bushings that fit the factory hole...DUH!....worked great.....made the unibit work using the grind down method and stuffed it in a piece of al tubing.....perfect except for one hole...I just enlarged it a little and RTVed the bushing in place.

Thanks again for the tips

Robb......7A