A chat list member who is also modeling the YVRR (yes, there is more than one) e-mailed me off-list with the same general question regarding drilling speeds. The slowest that my drill press runs based just on the belt setting is 9500 RPM. Therefore, I have an old Dremel "Solid State" rheostat that I use (you can tell it is old when the manufacturer advertises it as "Solid State"!) I keep it very slow for styrene (enough to drill a hole, the smaller the bit, the slower the speed) so that the styrene won't melt. I use a moderate speed for resin and wood. I never run it at 7500 RPM even when drilling metal...if I'm getting chips coming out of the hole, I feel that I running it at a reasonable speed...I never add an lubrication since I don't know what to use and that would one more thing to clean up. List members such as Dennis, Brian, and others could add some real knowledge here...I was a civil engineer in my prior life and have never taken any kind of machining class.
(At the highest belt "setting", my drill press runs at 30,000 RPM...I have no idea what one would drill at that speed but the drill press was designed for electronics R&D shops, jewelers, physics labs, etc. This list certainly doesn't include model railroaders.)
I use carbide drill bits in sizes 71-80 for a lot of things including styrene, resin, and especially brass. Wire drill bits tend to wander and "draw circles", especially on brass but the carbide ones don't. But they are also very brittle and can't take any side pressure. So, in situations where I'm drilling a deep hole, I'll start the hole with a carbide drill bit and finish up with a wire drill bit. I get all of my drill bits from Drill Bit City.
I will echo Jack Burgess’s comments on the advantages of precision drilling. Pin vise drilling for handrails is more akin to trudging through deep sand than it is to joyful modeling. (I shudder, brace up, and take a deep draft before tackling any one of my stash of un-grabbed Walthers cars).
However, the comments about drill speed are confusing. Doing this in styrene is hazardous, only less so in resin. It CAN be done is one is disciplined to get in and back out fast. But, slower speeds have been better in my hands. Although I use a MicroMark drill press for most common things, I also have a 12 volt super- precision drill press made by a machinist in Alabama (Braxton??- memory infarct) (who also taught and played violin before his death about ten years ago). He preached a mantra of *slow *drilling with these tiny drills.
Well, intuitively I would guess that high speed might have some considerable value in metals, but all? What types of lubrication might tip the scales one way or another?
Denny S. Anspach MD