Re: Twist Lock Caps and Right Angle Machining

hmm...getting inside a tiny tube to cut flat bottom grooves...ugh!
you may consider making the female bayonette slots inside the cap by
using a separately made part, soldered or epoxied in.

but i suggest that the simplest way of all is injection molding for
that end cap if it's to be plastic. delrin is no fun, though as its
boiling point is close to its melting point. easier to use is celcon -
feels like gristle- they make gears of it - and you can get it in
black (i happen to have some). it's pretty much ungluable, i think.
ABS is tuff, eminently cementable and black is available, too.
an aluminum mold can be made very cheaply if you have your own cnc
mill. i doubt it would take a whole day to do it, or more than 20$ of
materials. i could almost see it done with a drill press and a
jewellers saw if there were no other tools and one were properly
motivated...lol
desktop injection molders run less than 3k$ suitable for short runs-
only cuz they are not automated in any way and require user.
i have ultron mega from http://www.iasco-tesco.com/inject/injecti.htm
of course with such a simple mold, it makes sense to do multiple
cavities. you'd be able to shoot perhaps 10 at a time with the ultron
2 0z version.


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Bob Muse" <mtebob1@s...>
wrote:

> Hi Tom
>
> A cnc lathe would be able to cut that groove in one pass in delrin

with a

> properly configured single point tool.
>
> Bob
> ----- Original Message -----
> From: "Tom Hubin" <thubin@e...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Sunday, September 25, 2005 2:35 PM
> Subject: [CAD_CAM_EDM_DRO] Twist Lock Caps and Right Angle Machining
>
>
> > Hello,
> >
> > I want to make twist lock endcaps for a 1.88 inch OD, 8 inch long,
> > silver annodized aluminum tube. The endcaps might be brass or

delrin,

> > just for an attractive contrast with the tube.
> >
> > The kaleidoscope optics stacked inside the tube are spring loaded

so the

> > natural length is a about 1/8 inch longer than the tube length and

the

> > compressed length fits comfortably within the tube.
> >
> > I would like to carve a small track in the wall of a 1.9 inch

diameter,

> > 3/8 inch deep, pocket. The track is a little wider than a dowel

pin that

> > travels in the track. Dowel pin diameter is not important but in

the

> > range of 1/16 inch to 1/8 inch diamter would be best.
> >
> > A right angle drill like a dentist uses comes to mind.
> >
> > I have in mind 2 or more dowel pins protruding outward from the

ends of

> > a long tube. Drilling and press fitting would be straight forward.
> >
> > The endcaps would twist lock onto the tube ends like a BNC

connector or

> > a child-proof pill bottle. I prefer that the track not effect the
> > outside appearance of the endcap so I really don't want to cut

from the

> > outside if I can avoid that.
> >
> > I am also looking at things that cut sideways like threadmills,

keyway,

> > and Tslot cutters. I have done threading with a threadmill but

this is a

> > very skinny track so not my first choice. A keyway or Tslot cutter

might

> > work if I can find the right one.
> >
> > I could also mill the track on the outside of the tube and use

dowel

> > pins on the inside of the endcaps. But I would still need a right

angle

> > drill to make the dowel pin holes from the inside of the pocket.
> > Drilling through and press fitting from the outside would

certainly work

> > but, as above, I prefer that the pins not show.
> >
> > Or maybe I can jazz up the exposed pins so that they are

attractive.

> > Perhaps screw them in then cover with fancy cap nuts.
> >
> > Anyway, machining from the outside presents no challenge so I

would like

> > to explore methods of drilling or milling from inside a pocket.
> >
> > I have a Sherline 4400 manual lathe and a Sherline 5410 (metric

5400)

> > CNC mill and a short 1/2 inch drill press. I have access to more
> > complete shops if need be.
> >
> > Comments and suggestions?
> >
> > Tom Hubin
> > thubin@e...
> >
> >
> >
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