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How Many Holes can you Drill in a Ski?

Bookmark and Share            By Lou

We got this email yesterday. Steve, sure, we re-mount skis all the time. Our comments below yours…

Lou- Sure have enjoyed your blog for the past year or so, in fact, it’s the only blog I make a point of reading nearly every day. You motivated me to take up randonee skiing humping up & down A-basin every weekend while my wife was learning how to snowboard at an enthusiastic 54; get up to Jackson for closing week, (yes I was there in the award tent scamming free beer after the race thinking, “man with this kind of swag, I’m definitely entering next year”), and regret tossing that lime green pair of 175cm TUA skis with the old Ramer bindings I bought new back in ‘85 or so. Which leads me to the point of this email. I picked up a pair of Havocs at the end of the season that were mounted with tele bindings. I love the ski but want to take off the tele bindings and put on a pair of Dynafits. Have you done this type of retrofit before? My guess is lots & lots. I have some basic questions like what should I fill the old holes with and what if the new layout partially overlaps the old holes? Fill then drill? I thought this might be a good subject for a blog, what with the current ski sales frenzy, other folks might be in the same situation. Any advice would be appreciated and thanks. Saw new snow high up in the Mosquito range this weekend. It won’t be long now!!Still as crazy about skiing as 30 years ago– Steve

Steve, thanks for throwing away those lime green Tuas with Ramers — they’re now for sale on Ebay as valuable antiques (grin).

As for re-drilling skis, there is a traditional view in ski culture that drilling extra binding holes devalues a ski and weakens it to the point where one should be cautious about using it hard. This might still be true for large aggressive skiers using non-release telemark bindings or DIN 12 AT binders set to max. Otherwise, drill away.

Thanks to the needs of telemarkers, most of today’s backcountry skis have an incredibly beefy reinforcement in the binding mount area. More, nearly all modern skis are super strong, exceptions being purpose built race skis and that sort of thing. I’ve skied for years on planks Swiss-cheesed with up to four sets of binding holes and never broken a ski under the foot or had a binding rip out in normal use. (Bear in mind I’m not an aggressive skier, don’t fall that much, use release bindings set to release (not telemark bindings), and mount bindings using the methods detailed below.)

So, how to do the deed? Lay out your new binding holes on your backcountry skis; mark with Sharpie dots if your paper template makes it hard to see how close to the old holes you’re getting. If the new bores don’t overlap the old holes, re-mark with your centerpunch and drill away. If you overlap by only a few millimeters, simply move your binding location accordingly, usually rearward for recreational and backcountry skiing. A small change in binding location is totally within spec for ski performance, and as long as the edges of your new holes are a few millimeters from the old, you’ll be fine drilling and using the new ones. (You’ll still want to fill the old holes, but 5-minute hardware store epoxy will suffice.)

If your new holes must overlap the old, then you need to do some careful fill work. I usually fill the old holes with something like JB Qwik Weld or epoxy steel, and poke some steel wool in the hole as well. It’s important to fill the holes completely with some sort of hard filler, do so by poking the epoxy and wool in with a small probe such as a tiny drill bit. I use the 5 minute types of epoxy for this, as the quick hardening stuff makes the work go smoother, and I believe has less chance of softening any of the resins in the ski since it doesn’t sit there for hours curing in contact with the ski internals. It may be necessary to mix several small batches of epoxy, as it cures quickly.

After the epoxy hardens in the holes (give it a few hours at room temperature), I smooth it off with a sanding disk in a grinder (while watching my fingers). Whatever works for smoothing is fine, just avoid anything but cosmetic damage. If the holes don’t overlap but are super close to your new ones, still fill with epoxy steel and steel wool, otherwise fill the holes with regular 5-minute epoxy, or even use the plastic plugs available from ski shops.

Drilling overlapping holes is the tricky part. If the ski doesn’t have a metal layer, start the drilling with a small bit, then step up through successively larger bits to your final size. The idea is to prevent the edge of the existing hole from forcing the bit to the side and only drilling the epoxy out of the old hole.

Dealing with a metal layer is tougher. If your drilling starts in the metal, stepping the bit sizes will usually work. If you start in the epoxy fill, do the step-up routine till your bit encounters the metal edge. Then, instead of going to the next size bit, pull the drill most of the way out then hold the spinning bit against the metal edge so it eats sideways a small amount in the direction the hole needs to grow, thus “egging out” the hole. We’re talking a millimeter or less of this, so no big deal. If you’re a craftsman and have a rotary grinder, you can “egg” out the holes using a small rotary cutting bit, which works much better. Take care not to “egg” too far.

Finish the hole with the correct size bit. Don’t fret if one or two of your holes end up slightly off layout, as rando bindings have a small amount of tolerance for this (place screws in on-layout holes first, then place others.)

If you mess up and end up drilling the epoxy out of an old hole, just re-fill and try again with a little side pressure while drilling. Tap the holes if you’ve got a ski mounting tap, place all binding screws with regular 5 minute epoxy (not the steel variety), don’t over torque, and you’re good to go backcountry skiing!

(Note about taping holes and bit sizes: Ski shops use special drill bits for drilling skis, usually 4.1 mm for skis with metal layers, and 3.9 mm for skis without metal. If you mount a lot of backcountry skis, it’s a good idea to buy some special drill bits from an outfit such as Slidewright, along with such bits, buy a threading tool (tap) to thread the holes. In my experience, it can be okay to use a slightly larger 5/32 inch drill bit for the final size hole, without a tap. But when you don’t use a tap you run the risk of the binding screw augering the JBWeld out of the hole and reversing all your hard work. If you do choose to not use a tap, especially with non-metal skis, use plenty of pressure as twist the screws in so they start to thread right away, don’t over-tighten and strip the holes, and indeed use epoxy in the holes when you place the screws (to remove epoxied screws, lightly heat with soldering iron before twisting out.)

Posted by Lou on September 7, 2006 | Filed Under Binding Reviews, Technique 

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Comments

22 Responses to “How Many Holes can you Drill in a Ski?”

  1. Robin September 7th, 2006 11:01 pm

    Hey – this is great info. I’ve asked myself (without looking for the answer) this same question because the bindings on my (used) teles have been re-drilled once, and I’d like to get a pair of women-specific bindings (because my feet are small).

    Thanks for the info! Have a great day… Ski season is on its way!

  2. Piotr September 8th, 2006 1:04 am

    Lou,

    My personal belief is that it’s a good idea to fill the old holes even you are not going to drill next to them. This way you can
    ’seal’ them and prevent any moisture from getting in the core of the ski and freezing there, which could do some harm.

    As for the bit sizes, I use standard 4mm bit and it works fine.
    Sometimes manufacturers tell you which bit to use -Hagan has nice labels on their skis with ski dimensions which also has the preferred drill size on it, which can be as small as 3.5mm for some light (and soft) skis.

    Also, when you speak of non-metal skis drilling, I think it should be ‘hole edge’, not ’ski edge’ (’The idea is to…’), unless I am missing something.

    regards,

  3. Lou September 8th, 2006 5:06 am

    Thanks Piotr, I clarified the writing.

  4. Dane December 3rd, 2006 6:50 am

    hi,

    Im buying a pair of Salomon 1080 Foils (2006) and i have been looking everywhere forf some info on drilling, i want to drill some freestyle bindings on them but should i drill them in the center? i do all freestyle and nothing else, but i have been told if they are centered i t will be impossible to carve and do anything else besides freestyle. I don’t want that. So what should i do??

  5. Lou December 3rd, 2006 11:35 am

    Hi Dane, I know nothing about that. Perhaps someone else here can chime in.

  6. Will January 23rd, 2007 10:20 am

    Hi Lou,
    Would you forsee any issues with redrilling a pair of Dynafit Carbon FR 10.0 skis? I would be filling the old holes left from a pair of Dynafit bindings and drilling for a new pair of Naxo’s.
    Thanks,
    Will

  7. Lou January 23rd, 2007 11:00 am

    Shouldn’t be a problem, fill old holes with epoxy.

  8. Ted February 23rd, 2007 9:17 pm

    Hi Lou
    I am glad that I found your site. I just had a pair of Naxo’s mounted and the shop mounted the toes off center. So happy to hear that I can shift the toes over just a faction. I will not be going back to Coast Mountain Sports (Alberta) again.

    Thanks, Ted

  9. Eric March 7th, 2007 10:14 pm

    Lou:
    I would like to mount a pair of Dynafit bindings on a pair of tele skis. I was wondering if there was any diiference in the construction of the ski that would prevent the tele boards from being able to handle the heel piece. Is there any concern about mounting AT bindings on tele skis in general?
    Thanks,
    Eric

  10. Lou March 8th, 2007 8:29 am

    Hi Eric, no general concern and tele skis usually have a massive binding mounting plate that sometimes extends under the heel area. If you’re not skiing with heel at DIN 10 I wouldn’t be concerned, but always mount with epoxy and take care not to strip screw holes. One advantage of release bindings is they usually release before they pull out of the ski… ‘best, Lou

  11. Brian December 13th, 2008 2:12 pm

    Hey,

    Im thinking about drilling my Rossignol bandits , so they could be tied to a shovel as an emergency sled if need be, Probably never get used in anger, but hey since since the shovel is designed for sled construction I might as well. I have a pillar drill etc for accurate drilling etc, but are there any issues with sealing the insides of the holes to stop wwater getting between the layers then freezing & causing de-lamination? All the best, Brian

  12. Lou December 13th, 2008 4:20 pm

    Brian, check this out:

    http://www.wildsnow.com/628/drilling-holes-in-skis/

    Lou

  13. Milos January 16th, 2009 2:45 pm

    Lou,
    couldn’t find this info elsewhere on your site…
    any advice on using the same set of holes twice? Do you recommend fatter screws or epoxy?
    Thanks!

  14. Lou January 17th, 2009 8:50 am

    Twice shouldn’t be a problem unless previous screws were over tightened. Use a bit of epoxy.

  15. brad July 1st, 2009 5:06 pm

    Awesome information. I’m mounting my sons freestyle skis. Any info on proper placement. Most of what I hear is to center them.

  16. kody December 22nd, 2009 4:58 pm

    I am currently in the market for som pow skis and I found some I want but they have three mounts already. Is the 4th too much? I’m a heavy agressive skier.

    Thank Kody

  17. Lou December 22nd, 2009 5:11 pm

    Kody, probably.

  18. Mike D December 24th, 2009 1:05 am

    I have a set of Solomon skis that I got from a friend. It looks like they have been mounted three to four times. I was considering mounting my bindings on them. I heard rumors that mounting more than three times is dangerous. I’m not a crazy aggresive skier. Should I be concerned about drilling into them one more time? If so what should I take into consideration? Thanks for you assistance and help.

  19. Lou December 24th, 2009 7:32 am

    Milos, just use epoxy and don’t over tighten. Mike D, sounds like that might be enough holes!

  20. Mike D December 24th, 2009 10:31 am

    Would it be wise to reuse holes that are already there? Merry Christmas.

  21. Thomas December 26th, 2009 7:25 pm

    My old Rossi Scratch can take another round with drilling.

    Using the as an early/late session ski.

    Rear binding. 16 holes no problem……..!

    Shifted bindings, drilled wrong, loose binding, bu this time its working.

    pic http://thomaskm.blogspot.com/2009/12/holes-in-skis.html

    :w00t:

  22. Rick Boebel December 27th, 2009 5:02 am

    My setup (I live in New Zealand and ski around Wanaka but travel to Canada, Revelstoke area for 2 weeks a year) has been Spirit 4s on feet with 174cm K2 Coomba with Marker Dukes. I had decided this is a bit heavy and after reading wildsnow thought I’d try Dynafits.
    So I bought a used pair of 174cm K2 Mt Bakers with Dynafit Comforts with binding brakes that looked relativily unused at the end of my NZ season. At least I think they are Comforts, they have about 2.5cm of adjustment and look just like the ones in the wildsnow binding brake install post. The Spirit 4s fit this set up very well, boot midpoint within 2mm of ski mark.
    I love the Coomba’s as I use them for everything as snow in NZ is highly varible and was thinking of transfering the Comforts to them. Alternate would be just to switch to skiing the MtBakers or buy new pair of Coombacks and put Comforts on them. Or perhaps suck my wallet dry and buy new skis and new Dynafit FT12’s and sell the old setups. I’m 59 (started skiing in late 1960s when I went to Colorado College) and may as well spend money before my kids do. 8^)
    I’d appreciate any comments, advice.

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Welcome to Louis (Lou) Dawson's backcountry skiing information and opinion website. Lou's passion for the past forty years has been alpinism, climbing, mountaineering and skiing -- along with all manner of outdoor recreation. He has authored numerous books and articles about backcountry skiing and is well known as the first person to ski down all 54 of Colorado's 14,000-foot peaks, otherwise known as the Fourteeners! Books and free back country information here, and tons of Randonnee rando telemark info.

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