WHEN: Most Friday evenings. TIME:

11 February 2008

Parma Economy transistor part 2 - modding the nylon trigger

The Parma nylon trigger is shown from the rear side and the blue area removed with a dremel, which leaves useful space for a couple of washers and antiwobble nut. I use one of the case bolts, bolted through the pc board and trimmed afterwards (not with the nyloc on cause it melts the plastic, as I found – use another normal slave nut when cutting ;-). I ferreted around until I found some scrap thick walled tube and cut it just a shade longer than the thickness of the narrowed down plastic trigger at that point. I measured the OD of the tube and drilled the hole 0.5mm smaller than the tube OD in the existing trigger hole and the tube is then a neat fit, sticking out a tiny bit top and bottom. The nyloc only winds down far enough to just stop the trigger floating up and down and does not bind it from turning – there is a sweet spot.

The nyloc idea from Professor/Slotworks trigger set up and one could use their upgraded tube kit (their stock tube is the ideal length by the way) and put in a longer bolt with anti wobble nut, if the home brew tube part is tedious:

This is why I am excited about getting imperial stuff from Pinetown nut and bolt, metric does not work too well with K&S imperial tubing. ;-)

The trigger must only just clear the PC board or the whole caboodle will battle to fit in the case. This took longer to type out than do!
NB - If working ahead and creating you own cradle board from other similar boards, please note that the Parma Economy trigger is more rear set than other triggers like the turbo (about 2.5mm) so jig the set up for the trigger's own unique spot or the front of the trigger will bind on the case.

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