I’ve you’ve got steady hands and a courage, perhaps thread tapping ski screw holes without a tap guide is ok. I do it myself quite often, but in general do not recommend it.
Tap guides are simple. They’re a block of steel or plastic, with a hole that holds the tap somewhat perpendicular to the ski topskin. They’re inexpensive and easy to find. No reason not to get one and use it.
(Back to basics, what exactly is a “tap?” Just a tool with sharp “cutting” threads that makes grooves inside a hole you drill, so a screw can follow the groves. Why is this necessary? Ski screws are just glorified wood screws. They cut their own threads if asked to, and sometimes can damage the drill hole if the threads don’t catch and pull the screw downwards. More, the specified diameters for ski binding mounting screw holes are tight, and without tapping the insertion of a screw can inordinately bulge the ski’s structure.)
We have lots of content here at WildSnow dot com regarding ski binding mounting, drilling screw holes and tapping. For example, check out this post. And be sure not to miss our series listing recommended tools for ski work.
(A previous post in this position was written by Jonathan Shefftz. As part of our ongoing effort to currat our existing content, the original post required updating and general rework, as a result Lou entirely rewrote the post so we changed the authorship.)