QC LAB: REMOUNTING PREVIOUSLY DRILLED SKIS

Our QC Lab posts aim to answer some of climbing's most common gear-related questions. This time, KP and the crew tackle the issue of mounting a pair of skis that have been previously drilled.

Once again, this is not comprehensive, just some info—do with it what you will.

Image: Grant Gunderson

We get two main questions when it comes to mounting bindings on skis:

Which method should I use—glue, epoxy, no glue?
Can I re-use holes in skis to re-mount and/or how close to previous holes in my skis is it ok to drill?

We decided to tackle number 2 today, and we'll leave the first for another day (for the record, BD recommends using a slow-set 2 part epoxy to mount your bindings).

A lot of seasoned ski techs have their own rules of thumb when it comes to re-using pre-existing holes (not recommended) or how close to drill. So we had our tele-charging, QA Engineering wizard, Andy Rosenberg, perform our standard, not-overly-scientific-limited-data-point study to see what kind of differences we got when drilling holes and mounting screws varying distances from pre-existing holes.

TEST SETUP:

3.6x9.0 drill
Standard penetration depth
Pre-existing holes had a screw run in and out (no actual binding mounted)
BD O3 screws
No glue or epoxy used
All tests performed on one BD ski
Distances measured center to center
Each distance had its own baseline data point taken

COMMENTS AND CONCLUSIONS

As usual, this is super limited data - there is much more that could be done to get a more conclusive look at the situation:

Use pre-existing holes that have actually had bindings mounted and have been skied hard
Use many different types of skis (wood only, with metal, sidewalls, etc) Note: the BD ski we used is known as being particularly burly
Try different type of screws; different screw pitch in pre-existing holes
Do the tests with wood glue, or epoxy in the pre-existing, or new, or both holes

However, given this test, it looks like you may want to stay 7mm away or greater in order to attain maximum strength when drilling next to pre-existing holes.

There you have it. Pray for snow.