Need to drill a 1" hole through aluminum

[dfowler]

We are using aluminum extrusions for commercial garage door frames such as in a firehouse or service station garage. To fasten them together in the frame shape we have to drill holes through the horizontal ones and fasten through them into the vertical ones.

We currently drill the horizontal extrusion with the fastener hole on edge mating against the vertical. We then take the horizontal piece and on the opposite side of the fastener hole we use a hand drill with a hole cutter on a pilot bit. We saw a hole that is nearly 1" in diameter. This allows us to insert the fastener with a socket and extension on an air impact wrench. But this is time consuming as the slug needs to be taken out of the hole cutter most every time.

I am looking for a large bit such as a "bullet point" style that would shave away the material with out leaving the round slug. The extrusion walls are about 1/8" thick but there is ribbing structure to go through for 1" of depth as well. The hole we need has to be greater than 3/4" dia. and at least 1" deep before we are fully clear into the hollow of the extrusion.

Davey

 

[griffengm]

Dfowler,
Could this be punched in what I've heard called a "nail hole"? I've seen this used in much light gauge steel for a starter hole for a self tapping screw and in other places. Most often it is smaller but in this material You might be able to go to 3/4 - 1"
Advantages: no slug, fast, may be set to generate a collar within the extrusion to hide sharp edges.
Disadvantages: need small c-frame punch with hydraulic unit.

Griffy

 

[CorBlimeyLimey]

I have worked for several architectural glazing companies which use aluminum extrusions within their products. They often used a router to mill out pockets or recesses where other parts were to be attached. You would need a plunge type router & would probably have to create a guide plate or template for the router to follow. I also suggest you use a multi fluted end mill rather than the often used 2 flute slot mill type as it doesn't "grab" the aluminum as much.

from (the City of) Barrie, Ontario.

I tried sniffing Coke once, but the ice cubes got stuck in my nose

 

[AFab]

Greenlee makes a "Kwik Change" carbide-Tipped hole cutter.
size from 5/8" to 3". They have ejector Springs available for 3/4" and above.