In , on 07/06/05
at 08:53 PM, Dave Hinz said:

So is this voice of experience here, or are you making this up on the
fly? Either way, it's impressive. The big problem with making this up
as I go along is that I haven't been exposed to creative techniques like
this, but of course once explained they make perfect sense.

Well, I've not drilled directly like this, but I have used a 1/4" punch
made from silver steel ( drill rod in USA) through the hole in the bar. A
slight tap from a small hammer, when the punch is properly aligned with
the scribed marks is sufficient for the drill to pick up in a drill press.

Having said all that, I wouldn't have thought that the precision necessary
just for a caliper retracter would require more than scribing the marks in
the lathe & then centre punching & drilling in the usual way? My rear
calipers ( what a stupid bloody idea on a road car rear discs are by the
way!) are retracted using a nice simple 12mm Allen key, so no need to have
to make special tools. My wifes' old VW Golf GTI had a a pair of
triangular recesses in the pistons - I used to use a pin spanner made by
drilling the jaws of a cheapo Chinese adjustable spanner & pressing in a
dowel of silver steel to each jaw for those - worked for 157,000 miles!!!
-----------------------------------------------------------

-----------------------------------------------------------