Re: Sunshine resale values..Now tools


Nelson Moyer <ku0a@...>
 

I've had a lot of experience drilling aluminum, and very slow speed and a very sharp bit
works best. A medium weight oil reduces heat. At the proper speed, the shavings will curl in a spiral. If you get small chips, you're drilling to fast. Avoid excessive pressure, and let the bit do the work. Other metals have different properties, requiring different techniques. Maybe a machinist out there will write an article on drilling various metals we use in the hobby.

I find the same approach sans oil works for resin when using a pin vise. CB&Q single sheathed cars have grab iron ladders, and I've drilled several thousand holes using a pin vise and a #79 bit. I use a sharp needle to make a pilot hole, and I have much better control of hole placement then I do with a drill press, mostly because I use an Optivisor when drilling. I use my drill press at medium speed for #50 holes to tap for trucks and couplers and for other less critical purposes. The curl tells me when the speed is right. Drilling resin at high speed will melt it into the bit, and you will have to use laquer thinner to clean the bit. I make far fewer drilling errors with a pin vise, and the time differential for me is insignificant.

Nelson Moyer

On Mar 5, 2014, at 7:16 PM, Tim O'Connor <timboconnor@comcast.net> wrote:


Denny it's been my experience that higher RPM's (and SHARP drills)
in plastic work very well with a drill press, because you can do a
quick down-and-up move and there is no time for the material to heat
up and melt onto the drill. You can drill with very low RPM's and
that will prevent heating (because the heat disappates), but it will
also take a lot longer to make holes.

Tim O'Connor



I will echo Jack Burgess´┐Żs 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
Sacramento


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