[Arm-netbook] 15.6in laptop progress

[Luke Kenneth Casson Leighton]

On Thu, Jul 23, 2015 at 8:58 PM, Christopher Havel
<laserhawk64 at gmail.com> wrote:
> Ah. In that case...
>
> Small rectangular notch in one side of each hinge barrel (I think barrel's
> the term... the part that goes around the pin). Little teeny ball bearing
> (like 2-3mm dia, you know, the sort of stuff you find in a BB gun) with a
> stiff spring behind it (either a coil spring, or a leaf spring with a long
> lip and a dimple to hold the BB). One on each side ought to do it. You can
> even have the notch on the same side for both hinges, if there's room... if
> not, I say notch both sides of the hinge so it'll work in either direction.

 yeahhh you remember i said there's an 8mm barrel to work with?
that's the outer dimensions.  printing a part to fit in there needs to
be a maximum of a 37mm radius, and there's a 20mm diameter bolt down
the middle as well.

 but the accuracy of the printer is, when creating parts, esp. complex
ones, limited to about 1.5mm *if that*.

 so there's no way i would be able to fit even a 1.5mm diameter ball
bearing inside... and still have it be strong enough.  the only way
i'm confident about what i've created with the friction hinge that
i've designed is that it's reasonably chunky.  when i made things too
thin (1.5mm or below) they just... broke off.

 no, what i considered reasonable would be to have a D-shaped ring
which you push-fit onto one end of the friction hinge, then house a
simple flat spring that bends against the D.

 when the spring hits the flat of the D, that's when it helps keep the
lid closed.

 when it's bent, it helps act as a friction hinge.

 .... but even just sourcing steel flat springs and D-shaped rings i
just... i can't be having with it.  i've had enough.  really.  i want
this done, and i want it out the door, no delays dealing with
suppliers or with creating experimental prototype mechanical
custom-made custom-machined parts.

 i have a 3d printer, i have some 2mm threaded bar, i have some M2 8mm
screws, and i have a spring from a biro.  once product is sold, *then*
we can get fancy.

l.