Drilling For The Answer

little_sparky

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hello all,

now i know that this question has probably been asked before, maybe not, i dunno there is 7000 discussions here so im asking again.

I need to drill a 16mm or 5/8 inch hole in 16mm steel plate. Simple hey? The catch is i need to drill about 700 of them. So how should i go about it? Its for a fixture welding table much like the build pro ones and i have access to a mill with a DRO so i will set it out on that, i just need to know what cutting tool to use.

here are the options
1) HSS or Cobalt drill bit
2) Annular or broach cutter
3) please specify.

I originally thought an annular cutter but when talking to my school teacher he said "your drilling holes so use a drill bit". My concern is how long the drill bit will last, althought it may be a bit more accurate than the annular cutter. My teacher also thought that annular cutters are slow. Ive never used an annular cutter only drill bits and they arnt exactly that efficient. Please leave your opinions it would be greatly appreciated
 
A drill bit is about the most efficient method of removing material. Given the number of holes required I would go with cobalt, a 135° split point if you can get it. Buy a few of them. Not going to be cheap, but that's a lot of holes.

Good time to learn how to resharpen the also. The way I learned to sharpen drill bits is to: With the grinder off, take a new bit and act like you are sharpening it. Follow the factory grind and your ''muscle memory'' will take over after a time, you don't even have to think about it. Hint: Don't turn the drill bit, move in a straight line, and push forward.
 
As Jim said.
Low(ish) speed and fairly high feed, do not let the drill just rub, and plenty of lubrication.
John.
 
Another thought. If you don't need to do any other machining (like tapping) on the holes, then laser cutting would probably be the best answer. Another option would be water jet cutting. Might actually be cheaper than buying drill bits, and certainly a lot less work.
 
If you have a drill press, warm up your guns (biceps) and brains. I'd make a jig if there is any location repetition involved to keep them accurate. For example: if your running a series of holes down a length at the same distance from the edge and between holes, put an edge stop and peg the first hole - to drill the next (or whatever works for your project). I would also set-up the drilling process with flood coolant. Lower speed (maybe 150), good firm pressure. You should be able to knock it out in a couple of hours. When I worked in production shop, we made brainless drilling jigs all the time with drill bushings, no center punching involved.

If your popping holes one at a time in various locations, break out the center punch and a squirt can of cutting oil, it'll take a while.
 
This guy
600 holes in 3/8 I-beam

https://www.youtube.com/playlist?list=UU4yNI_H824z6WygTVbNFFrg


Hi Brian, Looking fantastic!! One Hugh hurdle over. How many drill bits / roto-broaches did you go thru? At least you've been blessed by the weather, so far. I'm looking forward to seeing you machining in this shop. Keep up the great work! !

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bcbloc02 1 week ago
+Jerry Long How about still on the 1st rota broach! I can attest that the German made Milwaukee cutters are very good quality, of course I only run the bit about 300rpm and used Rapid-tap lube on every hole.

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Jerry Long
1 week ago
+bcbloc02 Nice. Like Tom said, "The roto-broach, she don't care" or something like that. lol I've only used them a couple times. Have to start a collection. Thanks
600 holes drilled means 600 bolts to tighten lol. I feel your pain, but drawing near the end of the steel work and looking good.

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bcbloc02
1 week ago
+Richard Schmidtendorff Well its only 300 since I counted the holes in each piece of steel and the bolts join 2 pieces together, but it is still a lot of big hardware to tighten and each one is tighten to as tight as I can pul

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With 700 holes the table may be large enough that getting to the middle of the table may be too big of a reach unless you have access to a large mill or radial drill. Hope you have considered that...
 
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