On Mon, Mar 24, 2025 at 04:17 AM, Sigur?ur ?sgeirsson wrote:
I've never seen such a thing (/g/TekScopes/album?id=301415),
how strange. I wonder if anyone here knows what sort of plastic Tek used
for these?
I have some (PG506 for one, IIRC) cam switches that are cracked on the ends, and I expect they're on borrowed time. Nothing as bad as in Clark's photos, though.
I've never looked closely at one of those drums, but it looks to me that it
would be relatively straightforward to 3D print a replacement nowadays.
I've had the same thought, more recently with 7A29 cam lobes. Those are a slightly different beast, but suffer severely from cracking (and I have one that's missing entirely).
Thinking about this for the more typical long cam drums, I suspect one could convert the dotted alignment diagrams in the service manual to a table, and produce cam rings for an individual contact using a given column of on/off sequences for a given contact to generate the lobes (assuming equal intervals?) on a given drum diameter. I think this would be straightforward in OpenSCAD, but have never looked closely at the ramp geometry. Stacking those rings would give you the full cam drum, and then there'd be a mildly annoying detent gear and/or bearing section at the ends, plus grooves for circlips. I suspect that would be tedious, unless it could be parameterized somehow.
All purely academic speculation, as my free time is about to go towards outdoor chores instead of playing with the 3D printer.
Adam
