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Building Tips and technical articles. => Building techniques => Topic started by: Mike Scholtes on October 07, 2016, 11:33:19 PM
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Need to drill mounting holes and axle holes in a CF landing gear that has no pre-drilled holes. I want to avoid cracking or damaging the gear, so want to know in advance what type of drill is appropriate. The mounting holes will be 3/32 (four) and axle probably 1/8 (two). What drill material would be best? Also, what about more pointed drills as used for Plexiglas, which is very prone to cracking if wrong drill is used? Lastly, what about drill speed? Relatively slow, or relatively fast? I am aware the drill will probably be a throw-away after drilling CF but that's fine. The drill will be in a drill press and the gear will be jigged and held securely.
Anyone have advice based on experience? Thanks, may save me from an expensive and irreversible mistake.
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Bob Parker put me onto the carbide drills in the picture below. ST-something. My source for these dried up, alas. You can get sets of little carbide bits at such places as Harbor Freight. They are cheap and work fine, but are very brittle. If you can't get carbide, a regular old high speed steel bit will work. They are good for about four holes. Drill speed should be fast.
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Just use regular drills, medium speed. Drill a small pilot hole first then drill in from both sides a little with your full size drill then break through. You can just hold it tight by hand with a piece of 1x2 pine backing it up.
MM
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Then throw out the drill bit. LL~
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Thanks everyone, I can probably avoid a $50 mistake by getting a good $5 drill.
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You can indeed degrade the material by drilling it wrong, particularly if there's not much edge margin.
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Bits are easily sharpened on a grinder. So you have about 2 inches to play with.
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http://ballewsaw.com/onsrud-67-807-sc-8-facet-drill.html?___store=default&gclid=Cj0KEQjw1ee_BRD3hK6x993YzeoBEiQA5RH_BFbMnTPs96bqvq0Yoi3KPOfiknMI0xZxPMVtfhNH4f8aAtoE8P8HAQ
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Figure out what size you need and buy a packet of them at your local machine shop supply store. I might buy "cobalt", which is cobalt/steel alloy. Get "stubby" or "screw machine" drills... they drill rounder holes and stay on location better, being stiffer. Carbide would be another alternative. You might want to ask if a pack of cobalt stubby drills costs more or less than one or two carbide drills. It's been ages since I had to buy that stuff, but a stubby carbide drill is a sweet thing. I wouldn't use a carbide drill except in a drillpress or mill. And wear safety glasses!
y1 Steve