Re: Sensitive Drill Feed, and drills


Denny Anspach <danspach@...>
 

I have used for about 20 years the sensitive Drill Feed chuck that John Swanson mentions, but with a German-made Albrecht instead of a Jacobs chuck. It is very good and very accurate. However, this assembly is only as good as the drill press that holds it. So many of the cheap presses now available, or a worn older press do not have fine tolerances, or have loose fitting or worn bearings or spindle that result in some almost imperceptible eccentricity. these eccentricities are of no consequence when doing ordinary drilling, but can become a serious issue when using the tiny .013-.030" drills that we so commonly use. The tiny carbide drills that we find at the train shows are even less tolerant.

I finally fixed it by removing the pricey chuck from the drill feed mechanism and mounted it directly on to a precision miniature 12V rheostat-controlled Bragdon drill press designed specifically for such fine work (no longer available). The difference was immediately noticeable.

An advantage in using a standard drill press with speed control is that you can on many (most?) presses actually get the spindle speed down to about 600 rpm. If one is careful with his or her technique, you can at this speed then safely drill handrail/grab holes in styrene without melting the plastic, or otherwise mucking things up. What a time saver!

To a great extent in many instances how long these tiny drills remain sharp, or withstand slight lateral movements without breaking depends upon basic quality. Often we have no idea whether they are carbon or high speed steel.

So many of the tiny drills that we go through in daily hobby use are from cottage industries in Southeast Asia, or the Indian subcontinent. Occasionally, you will find good drills, but overall quality control is so unpredictable that I now completely shun drills from these sources. Instead, I look for drills made only in the USA, UK, Germany, or Switzerland.

Fortunately, the Mascot drills sold pretty universally in most hobby shops are all made in Germany.

BTW, the premium Dremel battery powered tool also rotates slowly enough to also drill styrene. As with all methods of power-drilling styrene, however, there is a short learning curve to contend with (i.e. learn by drilling scraps, not your models!).

Denny
--
Denny S. Anspach, MD
Sacramento

Join main@RealSTMFC.groups.io to automatically receive all group messages.