In the post discussing fixing a broken horn (which I presume is referring to the one on a diesel) one response involved using a sharp xacto tip to make a small impression in the plastic as a starter hole for the drill bit.
I use a different method with an easily-made tool. Take a pencil diameter-sized wood dowel rod and drill a hole in one end the diameter of a standard sewing pin. Nip off the head and glue the pin into the dowel rod. Then you have an easily held tool with which to make a precise impression hole for starting a drill bit. I use this when making grab holes and it always works. One other tip- when making starter holes I always use a piece of thin (Harbor Freight brand) plain masking tape to locate measured points on the tape with a very sharp #3 or #4 drafting pencil, then make my starter hole with my dowel and pin tool exactly where I want it. Then I drill. The tape protects the plastic shell against accidental slips when drilling.
I use the pointy parts on a draughting compass, or set of dividers to “centre-punch” for drilling. The advantage to using the latter is that you can use it to “walk-off” identically spaced drilling points.
In fact, after a #11 blade in my X-Acto, dividers might be my second most-used tools for modelling. They’re great for doing layout work directly on a model - grabiron-style ladders on a freight car, for example: set them in relation to the car’s end and use one point to guide the tool, and the other to lightly scribe a vertical line to define the mounting position, then adjust the spacing to scribe a second vertical line indicating the width of the needed ladder. Next, re-set the points to the vertical spacing required, and “walk” the dividers, in-turn, up the two scribed lines. The result is perfectly spaced and perfectly vertical ladders…
I use the point of a scriber for most hole-spotting in soft material, getting it centered and twisting it between my fingers. Sometimes, and always when drilling into harder metal such as soft steel, I use the same method, then follow up with a center punch. I have a General spring-loaded one with adjustable tension. You find the scriber dimple by Braille, with the point of the center punch.
