Re: Size of Apple II+ bottom plate screws

[mwillegal <mike@willegal.net>]

Just checked a spare screw out.
Flat head zinc plated steel machine screw - #6-32 phillips head 5/16"
long (including head)

6-32 is common enough, but I've had issues finding some oddball
lengths of the pan head version in retail stores.

Note that some later cases used pan head screws and didn't have the
countersunk base plates.

Regards,
Mike Willegal

On Feb 28, 9:17 pm, "Michael J. Mahon" <mjma...@aol.com> wrote:
> Linards Ticmanis wrote:
> > Hi all! I wonder if anybody here could help me with a little mechanical
> > question: do you think the following bit of information describes the
> > Apple II+'s bottom plate fastening screws correctly and more or less
> > completely, so that it could be used to order some replacements (the six
> > on the real bottom, not the four below the front edge)?
>
> > ***Major diameter 1/8", 26 threads per inch (TPI), thread length 1/4",
> > 60 degrees angled flat countersunk head with cross slit, made of steel.***
>
> > They definitely seem to be in a non-metric size (even though this Apple
> > was assembled in Ireland), as they don't fit either M3 or M4 size nuts
> > but are in-between those. The dimensions given above are more or less
> > educated guesses that I made from simple metric measurements and the
> > assumption that their size in inches is a simple fractional value. 26
> > TPI was guessed from the fact that the thread-to-thread measurement is
> > pretty close to one millimeter, and from some quick googling it seems
> > that 26 is a fairly common TPI number in inch-sized threads. I don't
> > have any fitting nuts or other threaded things to really test the
> > measurement.
>
> > Since non-metric screws are pretty hard to find here in Continental
> > Europe and I doubt whether I can find any real store that will sell them
> > to me, I'd need to make sure I've got all the facts right before I order
> > something without having actually tested it before. So if you live in a
> > non-metric country and can actually check the dimensions I gave above,
> > I'd be very grateful.
>
> > (let's hope Apple didn't change them during production... my Apple, or
> > at least its case, has serial number A2S2-39763)
>
> I don't have a ][+ with me at the moment, but I don't recall countersunk
> screws.  IIRC, the bottom plate is flat stamped metal, and the screws
> go into metal inserts molded into the plastic case.
>
> They are, IIRC, "English" screws size 6-32 (number 6 size, and
> 32 threads/inch), about 3/8" long and what we call "panhead" with
> a philips ("+") head.
>



> If not 6-32, they would be 4-40, but that seems a little small...
>
> They are extremely common in the US.
>
> Someone will no doubt take a look at his ][+ and settle the matter.
>
> -michael
>
> NadaNet 3.1 for Apple II parallel computing!
> Home page:  http://home.comcast.net/~mjmahon/
>
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