Overlapping and conflicting binding holes

[Jethro]

So you're concerned with screw pullout on a fresh mount? Reused holes? Overlapping holes? Foam (or other weak) cores? Tele mounts?

Correct. I would be worried about screws pulling out with overlapping holes. I’m not real concerned with the skis I ski snapping from some small holes. Usually I don’t end up with holes lined up across the ski either

[margotron]

I've become a recent convert to no delta (Pivots) and flattish boots (Langes). It was a surprise revelation, but I suppose all revelations are ;-)

... Thom

209% agree

[margotron]

Correct. I would be worried about screws pulling out with overlapping holes. I’m not real concerned with the skis I ski snapping from some small holes. Usually I don’t end up with holes lined up across the ski either

I am not worried about skis pulling out on overlapping holes. I used to be. Then I had some horrendous blowouts on overlaps. Now I don't worry anymore.

You mention that you think a ski with a metal and hardwood plugged holes is compromised on overlaps. I think a ski with metal, hardwood plugs and overlaps has more metal holding that screw than an all wood ski.

Maybe we logic different.

[beasttowest]

Here are quotes from all over. Different mags' suggestions for plugging holes if there will be overlap or close calls. Sorry in advance if formatting is shit, will try to fix it up
Obviously, much debate about which hole filling method (if any) helps with structural integrity… i’ll leave that to experts and veteran mags with more experience. just a jong trying to consolidate some scattered info here. Here are the three methods that came up most in response to overlap scenarios:

Screws w/ epoxy
Hardwood dowels w/ epoxy
Fiberglass chopped w/ epoxy

#12AB screws epoxied into old holes

Post 1426 https://www.tetongravity.com/forums/...n+fucking+skis
^^Great pics showing steps in original post so go look at it there

Shot a quick cell phone DIY of plugging old holes with aluminum #12AB screws. If you don't mind the additional labor, this is definitely the most bulletproof way to plug old holes if your new pattern is right next to or overlapping the old holes. (If your new pattern overlaps the aluminum screws, be sure to tap the new holes so threads are cut into the aluminum screws.)

- Grind off the sharp point on the screws.

- Epoxy the screws in place. I smear some epoxy around the threads in the hole, and put a bit on the screw threads. Thread in the screws a little at a time, you'll feel resistance when the air under the screw is pressurized. When the excess pressure is relieved, thread in the screw another 1/4 or 1/2 turn. It'll probably take 5 minutes to bottom out four screws. Don't crank them against the bottom of the hole or you'll get bumps on your base. They don't need to be tight, the threads and epoxy does all the work. When you feel the bottom, back off the screw a bit.

- After the epoxy sets, cut off the screws as close to the topsheet as you can with a hacksaw, Dremel, or air cutoff wheel. (I used an air cutoff wheel here.) If using power tools, cut a little at a time to keep the screws from getting real hot. If they get hotter than about 250 degrees, you'll ruin the epoxy.

- You could use a hand grinder to grind the screw shafts flush with the topsheet, or a 1/4" four-flute high speed steel (HSS) end mill tool (less than $10 on fleabay) in a drill press. Set the vertical stop to the top of the topsheet.

(If you do inserts, it's handy to have a 1/4" end mill for drilling holes that overlap old holes, because an end mill won't walk sideways like a drill bit. Try to find a "center cutting" 1/4" end mill, which doesn't have a hole in the middle. Cheapo end mills with a center hole will leave a shaft of material in the hole in the ski, which you'd have to knock out with a 1/4" drill bit.)

A few posts down in pst mount ur fucking skis thread

Holes are 1cm apart on center, or you have 1cm of ski material between holes?

I hassle with the AB screw trick only if a new hole is going to be right next to an old hole. If there will be 4mm+ of material left between the old hole and the new one, I just epoxy in wood plugs if it's a ski I'm trying to resurrect and there's a chance I might drill a new pattern next to old holes down the road, or plastic plugs if the holes are far apart, or it's a ski I don't plan on keeping for a long time.

If you have two rows of holes in longitudinal lines, the holes are cutting the same core fibers, so one hole or six in a row doesn't make any difference with regard to ski strength. Once core fibers are cut in the middle of the ski, they're cut. It's when the holes aren't in longitudinal lines that you're really losing core strength. If a ski has four holes in a line roughly perpendicular to the ski, it's lost a tremendous amount of structural integrity (unless it's a very fat, very stout ski like a Lotus 138). Even worse if the four holes are fat inserts, or if the line of holes is in front of the toe or right behind the heel. When you see a photo of a broken ski, the break usually zig-zags through a row of perpendicular holes.

Post #53 https://www.tetongravity.com/forums/...ng-holes/page2

They're virtually impossible to find, but I started using aluminum #12AB screws epoxied into screw holes in situations where there's overlap and it's a high-stress screw location (like the front screws on toes). Epoxy in, hacksaw off, grind flush with topsheets. Basically you end up with threaded metal plugs that sure as hell won't be pulling out.

Drill new holes and be sure to tap, so your new binding screws mesh with the aluminum plugs.

post 5 https://www.tetongravity.com/forums/...r-Swiss-cheese

If you go the aluminum screw route, get size #12AB. The thread is almost identical to ski binding screws. After cutting, take your time grinding the stub down, if the screw gets too hot it'll ruin the epoxy. Be sure to tap the new holes after drilling.

If some new holes almost exactly overlap the old, fill the holes with epoxy. Let set, and then drill 1/4" for Binding Freedom inserts. You'll drill out the temporary epoxy plug, but it will keep the drill from drifting off-course into the old holes.

It would be hard to drill an overlapping pattern into stainless screws, the drill would want to walk sideways away from the screw and into the softer ski material. Even if you managed to get the holes in the rigbt place, the tap would also want to go sideways and cut an oval hole. Go aluminum or wood IMHO.

[beasttowest]

Quality hardwood dowels (lots of votes for bamboo skewers too) into epoxy
Post 25 https://www.tetongravity.com/forums/...flicting+holes

Been there, done that as well! Attachment 252803

pic too big to fit here. click the link
Post #2403 https://www.tetongravity.com/forums/showthread.php/232898-PSA-Mount-your-own-fucking-skis?p=5511684&highlight=dowel#post551168

In my opinion, these are the real tools of the trade — dies. When I plug a hole I use hardwood dowels and a die. I recut the hole w/ a sharp tap, then I inject epoxy into the bottom w/ a syringe (the syringes for dogs are good. Next just screw the wooden plug in. As far as I can tell, it is literally just like new. The pics below are plugged normal and insert holes. I view that ski as brand new for mounting purposes.

I messed up an insert mount by 2mm last year and chose to plug and mount on top of the dowel. Several DIN12 ejects later, everything is rock solid.
I also highly recommend G-Flex. Pricey stuff but you get a ton of it actually and it is just unmatched. I also like gorilla glue brand epoxy better than JB weld for some reason.

Another pic too big to fit here. click the link

Post 2653 https://www.tetongravity.com/forums/...oo#post5547122

I would buy a hardwood dowel/rod from hardware store. Sand dowel w/80g just to abrade(gets rids of mill glaze and helps with mechanical bond) and chamfer leading edge, then epoxy it in and seal the end grain on top(sounds like that's what pd did). You very will could cut the threads into the dowels. It might be overkill, but I do like the idea, especially for the oversize holes margo was dealing with.

I don't like those super tapered plugz from Tognar and bamboo skewers are a no go for me

Post 11: https://www.tetongravity.com/forums/...ing-hole-plugs

(Yeah this is an old thread, but it seemed the most appropriate place for this.)

Being a used gear whore, I usually epoxy wood dowels into old holes instead of using plastic plugs, in case overlapping some holes is necessary on the next mount. Have even used 5/16" hardwood furniture dowels in old holes after removing bad helicoils, just cut the dowels a bit shorter than the hole depth and cover with a skin of epoxy. 1/8" dowel rod works but is a pretty loose fit in old 4.1mm holes.

Finally found 4mm hardwood dowel rods, and they're cheap: http://www.agesofsail.com/ecommerce/...ood-dowel.html

Chopped Fiberglass (/sawdust??) + Epoxy
Post 10 here https://www.tetongravity.com/forums/...ying-used-skis

Years ago, Russel Rainey (the tele binding guy, who should know) advised me that holes filled with a mix of epoxy and sawdust could reliably have holes drilled right next to them, or even overlapping. I've not needed to overlap yet, but have drilled new holes 1-2mm away from ones patched this way, with no issues.

Which makes sense (as does fiberglass mix), as these are the materials the ski is made of (plus it forms a structural matrix, like concrete). Sawdust seems a lot easier to obtain than chopped up fiberglass though, at least in my garage (and who wants to deal with chopping up fiberglass?). JB + steel wool sounds like it would work great too, but would seem tough to get fully into the hole and fully wet the sides/threads. All on the same track here though.
At the very least (even if you don't need new holes right next to old): fill holes with epoxy, not those stupid plastic plugs shops use (epoxy without stuff mixed in is easier to cram into the holes). I don't trust those plugs for a proper seal, and they provide zero structural integrity. Preferred technique for epoxy: fill hole just shy of the top with slow-set epoxy; seal top of hole well with packaging or duct tape. turn skis over, bases-up, and let epoxy cure; remove tape and notice a perfectly flush, epoxy-filled hole.

I use slow set & FG cloth to fix spinners not to fill un-used holes or fix overlapping holes

Once you've cut the core of a ski with a hole its cut, the structural integrity is lost period and you ain't getting it back with wooden plugs or sawdust or FG or any fucking thing. You just hope there was enough overkill in the engineering of the ski for you to still use it without the ski breaking, sure someone will say they mounted with an overlapped hole and it held but I would suggest you don't need the hassles or problems

If normaly mounting a binding means you have effectively cut 1/4 of core material with 2 screw holes, now you have cut 1/2 " of core with 4 screw holes overlapping holes AND you don't have solid material to mount in ... just move the binding 1/2".

I just plug holes with plastic plugs, its good enough, you can even epoxy them in if you want

To give structure to a spun screw hole sawdust is probably better than nothing , steel wool is better and 1/2 chopped pieces of FG is even better, you can buy FG cloth at most hardware stores, its easily cut with scizzors and its by far the smaller part of fucking with messy epoxy & tools

I use wood golf tees with blunted tips, glued in place, to fill old holes on skis that I care about. Takes longer than the plastic pound-in plugs -- glue in tees, let dry, cut flush with dremel, dab paint over wood plug to seal... No idea if it really helps anything more than the plastic plugs, but I haven't snapped any skis so far.

I use tiny bits of fiberglass house insulation, mixed with epoxy, to fix spinners. Haven't had any binding pull-outs doing this.

my ski that broke had those stupid plugs in the toe holes in front of my binding toe fwiw

also, petition to rename this thread: the whole hole overlap issue:

the whole hole overlap issue ...

”

[margotron]

Damn. OP - edit your first post to include beasttowest godly work. /thread


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[AlpiNord]

Just did this. The 1/4 holes figure 8ed with old holes. Installed the inserts as normal, cleaned out the old holes, filled with G-flex, and covered with a binding so buddy wouldn't even have to think about it. Not even a little bit concerned. OTOH, they aren't my skis.

You better go hide now.

[AlpiNord]

http://www.slidewright.com/Bindings/alpine_inserts_taps3.jpg[/IMG][/URL]

[Ted Striker]

This thread is packed with sig. lines

I chuckled at your post too before you edited it.

Just to add a few data points... IME pullouts are often due to water intrusion. The best mount means nothing if the core turns to pulp.

As for breaking the ski at the holes, that's all about leverage. The heel doesn't need to be where the jig/template puts it for a given bsl.

[Jethro]

You can also get larger diameter inserts for overlapping holes. I have never used them, but I’ve seen them online

[skinipenem]

You can also get larger diameter inserts for overlapping holes. I have never used them, but I’ve seen them online

Where are these available? Or r you talking about BF inserts this requiring m5 machine screws.

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[LightRanger]

I've skied the shit out of a wood core ski with nylon plugs overlapping with two screws (on each ski) on Dynafit heelpieces. If they were Dynafit toes, I probably would've done it differently. But, there's an anecdote.

Since that mount a number of years ago, I've use wood plugs epoxied in with slow-set and made sure they're well-sealed. For an alpine mount, I'm just not very concerned about pullout, if the mount is done correctly. Tele might be different.

[galibier_numero_un]

... Just to add a few data points... IME pullouts are often due to water intrusion. The best mount means nothing if the core turns to pulp.

That's an excellent point worth emphasizing. Some things (i. e. G-flex, etc.) become second nature and we forget to mention this.

I recall a pair of Praxis skis that came into a friend's shop (obviously a ski with a reputation for having a robust core) that had mildewed so badly that the screws practically fell out on their own.

The core (at least in the binding mount area) had the consistency of softened cream cheese.

... Thom