I have a 1/8th thick aluminum bar 36 inches long and 2 inches wide that I want to drill some 5/16 inch holes into and bend to 90 degrees. Could a hand held drill be used to drill the holes or would I be better off taking it to a machine shop. If a hand held would do it what specifications would the drill have to have to do it?
Thanks.
On Mon 01 Sep 2008 05:33:03a, told us...
When you say hand held drill, are you referring to a manually operated or electric drill? I would only use an electric drill. Aluminum is relatively soft, so nothing special is really required in the way of the drill itself. An ordinary twist drill bit designed for drilling metal and other materials will work fine. I would recommend using a pointed punch (I know there's another name for it) to mark and dimple the location of each location you plan to drill. This will prevent the drill bit from skipping across the metal.
HTH
Make a jig out of four boards- a base, 2 side rails, and a thick top plate with a guide hole in it to guide the drill bit and keep it perpendicular. Hard part will be making the hole in the top plate, unless you have some piece of metal in your junk box that would work. Pretty much any corded drill would work- aluminum is soft. If you don't have the material on hand, a machine shop would be pretty cheap- they could knock it out on a proper drill press in a few minutes, and even do the bending for you on their jig.
-- aem sends...
Any drill that will take a 5/16 bit should be able to put a 5/16 hole in 1/8 aluminum unless there's something you aren't telling us.
If this is just a one time job then center punch the holes Accurately. Buy a center drill and start the holes accurately.
Secure the aluminum over a piece of wood.
Drill to finish size by hand keeping in mind that the drill will catch slightly when breaking through.
I learned YEARS ago that aluminum can be easily worked with common wood working tools.
Miter saw, table saw, router, drills just use sharp carbide blades / bits.
What alloy are you using? Most common extruded shapes are 6061 or
6063.Flats (what you have) can be a wider range.
I would strongly suggest laying out the hole pattern & center punching the holes locations BUT bend the material BEFORE drilling the holes.
The hole will change the local stiffness of the bar & the bar might have a tendency to "kink" at the holes when you bend it.
Once the bar is bent you can grip the bar in a vise or "work mate" or clamp it to a 2x
Drill 1/8" & then go for it with the finished size...... a little kerosene would help but anything is better than nothing, high speed is better than slow speed.
If you have any waste material do some practice drilling
cheers Bob
Date: Sun, 31 Aug 2008 13:43:38 -0700 (PDT)
Almost any drill should do the job. Maybe cleaner with a hole punch - don't know if it comes this small, my smallest hole punch is something like 1/2". Don't expect problem bending it to 90 degrees, but with aluminum, you never know until you've tried it.
On my press I find something in the moderate range works best. Probably about 3200 rpm but I'm guessing. Too fast and you get too much heat, too slow and all it does is grab.
Kero tends to make the bits grab a lot harder unless you're using low angle bits. Regular thread cutting oil (not a lot different, I know) doesn't seem to cause that "grabbing" so badly, especially just before punch-thru. It's also better to drill from both sides if you can. If not, just back it up with apiece of wood is usually enough.
On Mon 01 Sep 2008 09:33:01a, BobK207 told us...
Thanks, Bob. I couldn't think of the name.
(His drill spins counter clockwise. Shhhhhh. Don't tell anyone I reversed the direction.)
Very gentle feed pressure, and lots of RPM works for me.
" Frank" wrote in news:NIydnaY47PyGhiHVnZ2dnUVZ snipped-for-privacy@comcast.com:
those step drills make a nice *round*,clean hole,but 1/8" thick AL is right at their limit.Maybe the smaller step drill can do 5/16" hole in thicker,I don't know for sure. I HAVE used the bigger step drill to drill 1/8" AL,though. Using a cordless 9.6V Makita drill.
A couple of years ago one of the guys in our shop was having trouble drilling a hole. He asked the maintenance supervisor to sharpen the bit for him. After it was done he came back and said "you can't sharpen bits for shit, it still won't drill." Yes, you can guess the problem.
Your drill bit really ought to be specifically for aluminum but few people have them handy. They have fast spirals and 118 degree points like ENCO 301-3336. If a nice clean hole and a decent bend in your work piece matters, then consider a local machine shop. You are the best judge of how it should turn out.
Joe
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