plasma cut holes

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leggman
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plasma cut holes

Post by leggman »

So as this journey continues I have learned a lot and one of the things I have learned the hard way is yo cannot use the plasma table to cut holes in a part the try to drill them out to a finished size. After burning up a couple of bits it seems the plasma cut holes are hardened quite a bit.
now I am cutting the part without the holes and then drilling them. Lessons learned the hard way are the most remembered.
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djreiswig
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Re: plasma cut holes

Post by djreiswig »

Yes, it's called nitriding. Depending on how big the holes are, you might be able to remove the nitriding with a carbide burr in a die grinder and then drill. I use the double cut cylindrical ones to clean up parts, but I haven't tried drilling them afterwards.
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robertspark
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Re: plasma cut holes

Post by robertspark »

cobalt 8% drills sharpen with a drill doctor use a bit of oil before drilling

too many poor HSS drills about which couldn't drill a hole in butter without going blunt imo ymmv
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acourtjester
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Re: plasma cut holes

Post by acourtjester »

I use the plasma to mark the holes with a divot and use a spot drill to clean out the divot for normal drilling.
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adbuch
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Re: plasma cut holes

Post by adbuch »

Tom - that is a great idea! I do similar with my Plasmacam table - it can make very small "points" to mark the center. Then I use an annular cutter to do the "drilling". The center of the cutter rests in the "point" while the cutter creates the hole. This method can give very nice clean holes precisely located on the part.
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SegoMan DeSigns
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Re: plasma cut holes

Post by SegoMan DeSigns »

adbuch wrote: Sun May 15, 2022 4:58 pm Tom - that is a great idea! I do similar with my Plasmacam table - it can make very small "points" to mark the center. Then I use an annular cutter to do the "drilling". The center of the cutter rests in the "point" while the cutter creates the hole. This method can give very nice clean holes precisely located on the part.
David

annular cutter assembly.jpg
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My drill press has a MT 3 so I bought the adapter and used the system to drill the holes for my press brake, the annular cutters are about 1/3 of the cost of the same size drill bit. You can also buy an oiling attachment if your in a production environment:
IMG_20201025_145550958.jpg

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adbuch
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Re: plasma cut holes

Post by adbuch »

Nice!! I bought the R8 attachment for my Bridgeport to fit the Hougen cutters. The thing I like about using them in the Bridgeport is that I can really slow down the speed (RPM). I use maybe 100 rpm or so for the larger ones. I find that my Hougen Mag drills really turn much faster than I would like - at least for what I am doing.
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AREA
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Re: plasma cut holes

Post by AREA »

I have had some luck with cobalt drills but still a pain in the butt. Now I just use my easyscriber to mark the holes before I plasma cut the part. Once the parts cut I just center punch where the scribe marks are and use the drill press to drill the holes. Much less frustrating.
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Joe Jones
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Re: plasma cut holes

Post by Joe Jones »

I bought a mag drill several months ago from Grizzly Tools. I haven't taken the opportunity to try it out yet.

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