Cutting Slots in Brass Bar and Sheet Stock
I need to cut small (1/8-inch or less in diameter by 1/4 to 1/2 inch in length) slots in 1/8 to 1/4 inch thick brass bar and/or sheet stock. I have a drill press, but not a dremel. What options are out there? I currently drill several small holes along the desired mark, then file out the holes to connect them into a slot (using small files, which takes a while). The resultant slots never look very good, but are functional. Other than stamping (which I don't have means to do), I haven't found a bit or tool small enough to do these cuts cleanly. Thanks for any info. Paul
Take a look at this...
I'm going to get one of these soon.
Some people are like Slinkies. They're really good for nothing, but they still bring a smile to your face when you push them down a flight of stairs.
If your drill press will hold a 3/8 shanked tool, then you might be able to use a bit like this : http://www.kbctools.com/usa/Navigati...m?PDFPage=0118
and a guide fence to mill the slot. Start with a hole the correct diameter, lower the mill into the hole, lock the plunge and then hand feed ?
If you try to hand feed brass into a milling bit you will certainly lose at least one finger. The workpiece will either fly out at high speed or catch on the bit and become a whirling fan blade. I bought a micro mill/drill from Harbor Freight Tools a couple years ago. I was about $200 plus a few accesories, but it cuts slots wonderfully and is relatively small. You are limited to pieces smaller than 4x6 inches. And it doesn't cut hardened steel.
Take what Gregdavis says about hand feeding brass to the bank! Sooner or later it will get you! Having more than two cutting flutes on the cutter might help a bit, but the idea simply is not safe! Milling slots in thin brass sheet stock is always a coin toss, even when secured to a heavier base in a good vice, it can still grab and tear.
Sponsored Ad. (Subscribers to APUG have the option to remove this ad.)
I disagree with Greg. Sort of. The fact that you lost a finger in the first few milliseconds of the operation will be of minor concern compared the being skewered by the bar when it flies off the bit and penetrates your chest.
I have a little Unimat machine, a combination micro-lathe and mill, that I bought years ago that is ideal for small work like this. Unfortunately, they ceased production back in the '80s, but units might be found on the used market.
[COLOR=SlateGray]"You can't depend on your eyes if your imagination is out of focus." -Mark Twain[/COLOR]
Rio Rancho, NM
Tsk, tsk, tsk - c'mon guys - a bit of imagination here eh? . A hardwood board with a dado groove cut the same width as the metal and twice the depth. Use a featherboard to keep the metal from lifting and a push stick to keep your fingers out of the way. Clamp the guide board securely to the drill press table and Bob's your uncle.
BTW - at 48 I have all my fingers, all my toes, both eyes, both ears and some of my hair
Can't tell how big the files are. I need something pretty small (1/4 inch or so). Any ideas?
Originally Posted by bobfowler
To answer my own question:
Originally Posted by middlecalf
Dear Micro-Mark Customer:
The cutting portion of the file measure 0.051" thick, 0.230" wide, 0.949" long. The mounting portion of the file measures 0.044" thick, 0.160" wide, 0.280 long.
Micro-Mark Technical Service
This might work for my application.
Just for the heck of it, I went out to the garage, found a chunk of scrap brass, 1"w x 1/4"thick x 4" long. I took out a 5/32" 4-flute end mill and then headed in to the basement to dado out a groove in a chunk of scrap pine. Here's the results.
The pictures are :
1) the setup - metal can't lift or fly out of either end
2) milling bit and workpiece are securely clamped in a sandwich and in the spindle
3) the finished milled slot - 1/2" long - took about 30 seconds in this 1/4" thick stock
I didn't bother to research cutting speed, but the press was set at 480rpm for a circle cutter bit and it "seemed" about right. It cut very smoothly and left nice cool clean shavings.