There are many occasions in model making where there is a need for small (0.2-0.6mm) holes. If you are building a kit these holes may be present, but undersized. You can, of course, use the correct drill to open out holes but you may not have the ‘correct’ drill on hand. In any case drills are relatively expensive and quite brittle – opening out holes is a classic use where they might grab and break.
For many years I’ve used root canal files to open out existing holes, generously supplied second hand by my dentist. If you have a good relationship with your local house of pain this remains a good source, but I’ve simplified the issue by getting pristine files into stock.
These little reamers have a number of useful features:
- The tips are incredibly fine (0.15-0.4mm for the set shown here), so you can get into holes that you can barely see (handy for underdone etches).
- The cutting angle is such that they tend to stretch materials rather than breaking out as drills do.
- They last a VERY long time if used on brass and plastic. I still use some I had 20 years ago. They are not brittle and virtually never snap.
- They are quite flexible, so you can open holes even if you cannot get square to them.
- They come in a range of sizes
A selection of root canal files with a 0.5mm drill for comparison.
Simple to use. Just insert in the hole and with gentle finger pressure rotate anti-clockwise. Rotating clockwise will rapidly pull the file into the hole and possibly damage the file or the hole, so do this only cautiously.
A box set of 6 assorted root canal files as offered in the Emporium.
- opening up etched holes
- opening holes to provide a little clearance to fit wires etc
- cleaning up holes in cast handrail knobs