boring a 2" hole thru Aluminum Tubing

[psient]

HI:

I need to bore a 2" hole thru the side of a one fool long piece of 6" diameter Aluminum Tubing @ 90 degrees/perpendicular to the wall. The Tubing has a wall thickness of .250".

I have a bridgeport milling machine. I cannot decide how to proceed. There will be no pressure on the bore of the tubing so the tolerance is .005.

How would you do this with a milling machine?

Thanks,

Jon

 

[Maryak]

Jon,

1. Find the centreline or use a centre finder and set up with this line vertical and the bottom in an appropriate T slot, use 2 clamps in the same slot, one at each end of the cylinder with packing between the clamp and the inside of the cylinder.

2. With the mill head now on the centreline of the cylinder. Move the X axis to find your distance in from the edge. Use a big centre drill and drill through, (You should be able to see within 0.002" by observing the drill dimple before it cuts to full diameter that you are on centre, if not use the Y axis to realign).

3.Open out with your biggest dia drill and then bore to size, preferably with a boring head.

That would be my way but others may well have a better way.

Hope this helps.

Best Regards
Bob

 

[Tin Falcon]

Jon
should be a straight forward procedure on a bp. Mark your hole center .clamp the part down, center drill with your # 5 center drill open up to 1/2 with then 3/4 then one inch. (Sizes not critical here you are just removing metal) then set up your boring head and open up the hole to size. Take your time and check hole size and location often.Dial in your location in the beginning than concentrate on finish diameter. when you start to get close to size take a few spring cuts.
You can use your calipers to measure in the beginning but a T Gage and mic will give accurate dimensions for finish cuts.

You may want consider hooking up with a local club http://www.schsm.org/index.html
We are glad to answer any questions. I leaned with an experienced instruct watching over my shoulder. It makes life a lot easier.
Also jon please post and intro about yourself in the welcome area and put a location in personal text or sig line these things help us help you.

Tin

 

[JackG]

Years ago when I was in the Navy, a group of contractors came to the site to make some modifications to some antennas. These antennas were aluminum 12 inch cylinders. They used a hole saw similar to what is used to cut the hole in a door in order to install a door knob. Could you do the same?

Jack

 

[Tin Falcon]

A hole saw would work but it would either hit the mark on size or not. Night not make the plus or minus .005 . Starting with a 1 1/2 or 1 3/4 hole saw could save some time though.
Tin