Aerotech Mega Initiator #89541, Part 19, Drilling The Rail Buttons

The rail buttons are centered between two fins, on the other side of the INITIATOR name sticker.

It's difficult to find the center on a round tube.

I used a piece of paper pressed into the root edge fillets.

Mark the two fold sides with pencil.

With your ruler, find the center and mark.

    

The lower hole is to be placed about 1/2" above the lower engine mount centering ring. That puts the hole position at about 1 1/2" from the rear of the body tube.

The upper hole is 8" above that.

Drill a pilot hole using a 1/16" drill bit.

Sight from the rear and make adjustments using the larger 1/8" drill.

Using the pilot hole as a guide,

Enlarge the rail button hole to 1/8".