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D.L.
11-26-2003 18:27:02
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Re: Need help- What tool- 1/2 thick steel in reply to K.B., 11-26-2003 15:42:28
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K.B. You didn't say what diameter the holes are, but here's what will work, with a minimum of effort (if the holes are a reasonable size). If you have a drill press, just get an end mill of the correct diameter, chuck it up in your drill press, and drill the hole in the correct place. Since the end mill has a flat bottom, you can put the hole where ever you want it (if you're drilling in the center of a piece with no pilot hole, ensure you have an end mill that is "center cutting" meaning it will cut without a pilot hole) For steel, you'll want a 4 flute end mill... high speed steel will work for what you're doing. You'll need to clamp the workpiece to your drill press table (so it won't kick out when you plunge the cutter into the metal) and you MUST use the correct RPM (a 1" cutter (HSS) will turn at approx 400 RPM, a 1/2" cutter will turn at 800 RPM, a 3/8" cutter will turn at 1200 RPM, a 1/4" cutter will turn at 1600 RPM, you get the idea) These values (RPM) are theoretical, but should get you in the ball park... if you get excessive vibration, adjust rpm up or down a bit to get a clean cut. ALSO... sometimes the cutting tool will want to "auto feed" when you start putting down pressure on the quill of the drill press... make sure you've got a good hold on it. You'll easily be able to do this job, just be aware of the forces acting on the tool and you'll be fine. I'm a machinist and do cuts like this all the time. A milling machine is nothing more than a really big drill press with a few more bells and whistles... many times I feed a cutter into the work just as you would on a drill press... just requires a little extra attention. If you're having trouble finding an end mill, you might want to look at router bits (for wood). We use them in a pinch. The carbide ones are a bit softer grade of carbide than we commonly use for steel, but they work... might dull a little more quickly, but they'll get you through in a pinch. As far as spiral cutters, many are sold as router bits, but are actually end mills (used commonly in the machining industry)... especially the solid carbide ones. I know it sounds kind of strange using a (wood) router bit to cut steel... but what are regular drill bits made from??? High speed (or high carbon) steel!!! The only difference is that some router bits are two flute instead of four flute... just means you need to be even MORE aware of RPM and feed rates (the rate you feed the cutter into the work piece) HOPE THIS HELPS GET YOU OUT OF A BIND!!!
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