diesel vanagons, and all later vanagons,  have plastic speedometer housings
( and clip type speedometer cable connection.) As in the picture.

if your speedo is metal ..
sounds like it's one from an early air-cooled vanagon ...and those have
screw type speedo cable connections .

so I wouldn't expect there to be any 'knock out' piece like there is on
plastic housing speedometers on your 1981 metal one.

if you are looking to add a Vehicle speed sensor device there ..
you would need a later plastic housing speedo and a clip type speedometer
cable .
( and there are 'one piece long' speedo cables ..like a diesel vanagon uses,
and most gas vanagons have an oxygen sensor miles counter box in them ..so
there are two cables, and upper and a lower.   Speaking of that miles
counter box, those can be modified to be a VSS too )

Just get any later model 2WD speedometer that has the gizmo in it for cruise
control and you'll be on the way to having a VSS, if that's what this is
about.

Scott
www.turbovans.com

----- Original Message -----
From: "neil n" <musomuso@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, May 01, 2011 1:09 PM
Subject: Screw Holes, Cruise Control Sender: Thread? (Diesel Speedometer)

> Hi all.
>
> For a speedometer in a diesel cluster. Knockout on back of speedometer
> P 90.17 shows where I'm looking at.
>
> Maybe I'm seeing things, but the holes in metal for (I think) a cruise
> control inductive sender aren't threaded. I can't imagine one would
> cut threads with the screws so.....
>
> Is there a standard thread count/pitch for this? No point in threading
> in SAE if it's Metric.
>
> Bizzare question of the week......    ;)
>
> Neil.
>
> --
> Neil Nicholson '81 VanaJetta 2.0 "Jaco"
>
> http://tubaneil.googlepages.com/
>
> http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines