PSA: Mount your own fucking skis.

This ^^^ is great!
I have a pair of swiss cheese lotus 120 I need to remount, they have 2 dynafit vertical mounts (5 hole pattern) about 2 cm apart. Since the distance between the holes of the toe piece is just a bit over 2 cm apart I'm dealing with a line of 4 holes about a cm away from each other (and that's not counting the 5th hole).
I'm a bit worried about structural integrity so I was going to enlarge existing holes and insert them (the new Speed turn mount pattern seems to magically overlap with the front holes of one mount & the back hole of the other) but they were drilled a bit off center then plugged really poorly. I've had issues with wandering bits when trying to rectify existing holes and was worried about how I'd manage to make things work, even with a really good drill press. No that I've discovered the end mill tool I feel like there's chance I can pull this off.
The big question at this point is whether I should redrill the plugs so I can use your method (my OCD really wants that) or just epoxy the top to make sure they don't soak water and save myself some time...

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.

I'll measure and post pics tonight but I have about 1 cm between the edge of each hole to I won't need to go the AB screw way.
The plan was to enlarge 4 of the existing holes (some opened, some plugged) and put inserts in them for the new bindings. I feel like that's probably not affecting structural integrity any more or less than drilling fresh holes...
For the other 6 holes, I was considering your method to plug the 3 empty ones and to replace 3 shitty plastic plugs that are already in (with visible gaps in the epoxy).
You don't seem to put much faith in plastic plugs and I don't have any wood plugs lying around so going with metal option could be good.

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Originally Posted by Boissal

The plan was to enlarge 4 of the existing holes (some opened, some plugged) and put inserts in them for the new bindings. I feel like that's probably not affecting structural integrity any more or less than drilling fresh holes...

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Absolutely do that, perfectly fine. I misunderstood and thought you were going to install inserts that wouldn't actually be used in an attempt to "restore" structural integrity.

Quote:

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Originally Posted by Boissal

You don't seem to put much faith in plastic plugs and I don't have any wood plugs lying around so going with metal option could be good.

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Plastic plugs are fine for keeping water out and stopping a "bridge" of material between holes from migrating into the old holes, and I use them regularly if that bridge is 4mm or more wide. They just don't add any vertical pull-out support to a narrow 0-3mm bridge of material between holes like an aluminum screw will.

I'm pretty OCD though, so take it all with a grain of salt.

Quote:

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Originally Posted by 1000-oaks

Once core fibers are cut in the middle of the ski, they're cut. .

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This ^^ so IMO filling holes with golf tees and epoxy are going to do fuck all for strengthening the ski core to like new so you might as well use plugs which are easiyer to do and they will keep moisture out

I had a remount on a dynafit Denali where that 5th screw on a set of verts would have put 3 screw holes straight across, so becuz the denali is such a super light ski I didn't drill that 5th hole and the binding has been working fine

So here are a few pics of what I was trying to describe above.
The idea is to enlarge the top plugged holes (1st row) and the bottom opened (4th row) and put inserts in them. The alternative (which is a mount on the line as opposed to a +1) involves drilling new holes on the black dots and putting inserts in the bottom plugged holes (3rd row). Too much swiss cheese me think...

Attachment 199030

Guess I'm really bad at estimating distances because it looks like I have no more than 6ish mm of material between holes...

Attachment 199031

Attachment 199032

Just for reference, this is what the enlarged 1/4" hole looks like.

Attachment 199033

Thoughts?? I have an end mill on the way and I'm itching to play with it...

I personally wouldn't hesitate to go with Plan A. IMO, that's enough real estate.

Agreed, plan A is fine, there's enough real estate. Which end mill did you get? For skis it doesn't matter if it's two or four flute, but cutting with four flutes would probably be more horizontally stable in a drill press.

I have a 1/4" stop collar on my end mill set at the height of an insert, so I can run the collar down to the topsheet. You can also use the vertical stop on the drill press to control hole depth, but then you have to adjust it for every row of holes due to changing ski thickness.

That 120 probably has the same thick layer of carbon under the topsheet as the 138. It's serious beef and those inserts won't be pulling out. Wear a dust mask when drilling carbon, that stuff isn't good for lungs.

Thanks for the replies!
Plan A it is, and I assume you guys don't think it's necessary to go the AB screw method to plug the holes so I'll use plastic.
I plugged a pair of Yvettes 112 with plastic a couple days ago using orange double bubble epoxy, cleaned things up this morning, I'm really impressed with how well that epoxy sticks to topsheets. If only it were less viscous so you didn't have to fight with it to get it in the holes...

I got a 4 flute end mill and I have a collar sitting around I can use. I don't have a go to tool store so I asked amazon and settled on this, hopefully it's not a giant POS...
https://www.amazon.com/4Fl-SE-Carbid...rbide+End+Mill

^ That'll work fine, and is actually fancier than necessary. Carbide will stay sharp a lot longer than HSS (high speed steel) or a cobalt alloy, but is more fragile. Be sure to wear safety glasses while using it, and if it chips due to vibration, replace it with a cheaper HSS one (that can handle chatter better). Skis are so soft compared to the intended usage though, I doubt you'll have any trouble. It'll go through a ski like butter. Don't drop it or over tighten the stop collar, the carbide could crack.

It'll be tricky to put the holes exactly where you want them. You could draw your mount pattern on the ski and use a short drill bit to position the ski on the drill press and then clamp it down, then swap the pointed bit for the end mill. Tedious but more accurate than eyeballing it with the end mill.

Or first do one toe insert on each ski, and attach the binding toe with one screw. Snap in the boot and align with heel pins, and trace around toe with Sharpie. Remove boot, align toe on tracing, and use toe as a template to mark hole positions with Sharpie.

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Originally Posted by 1000-oaks

It'll be tricky to put the holes exactly where you want them. You could draw your mount pattern on the ski and use a short drill bit to position the ski on the drill press and then clamp it down, then swap the pointed bit for the end mill. Tedious but more accurate than eyeballing it with the end mill.

Or first do one toe insert on each ski, and attach the binding toe with one screw. Snap in the boot and align with heel pins, and trace around toe with Sharpie. Remove boot, align toe on tracing, and use toe as a template to mark hole positions with Sharpie.

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I was going to use option 1. Fill in all the holes first and let everything cure, shave off everything that sticks out of the topsheet so I don't have to fight with my paper templates, line up everything so the new holes overlap the old holes but I still get to correct the small issues on the existing mount, centerpunch everything, then use the smallest bit to line up the drill press before clamping the shit out of the ski and moving to the end mill...
We shall see. I'm still really tempted to try the metal plug method for practice.

Where are you sourcing you Alu screws again? I'm sure you said somewhere but I'm not finding it.

McMaster Carr is always a good resource.

Edit: I don't see 12AB screws on their site. Never mind.

... Thom

My local old-school harware store happened to have them (I bought all they had), but they are rare for sure. I'll post when I find an online source. Brass should work fine too, just gotta make sure they're #12AB. #12A has fewer threads per inch and isn't close enough to ski binding threads.

Stainless is easier to find, but would be a lot tougher to cut and grind down, and probably wouldn't tap if your new hole overlaps the old. (It's too hard compared to the ski material, and would push the tap sideways and cut an oval hole.)

Since 1/4" holes for inserts are shallow, the most accurate drill bit is a "spot drill" like this: http://www.destinytool.com/uploads/2...95334_orig.png

Long drill bits + play in the drill spindle can make you think you're centered on your template when you're not, and cheap drills aren't always straight. If you get a spot drill, select one that has a tip angle similar to inserts (don't get one with a really pointed tip).

Quote:

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Originally Posted by 1000-oaks

Since 1/4" holes for inserts are shallow, the most accurate drill bit is a "spot drill" like this: http://www.destinytool.com/uploads/2...95334_orig.png

Long drill bits + play in the drill spindle can make you think you're centered on your template when you're not, and cheap drills aren't always straight. If you get a spot drill, select one that has a tip angle similar to inserts (don't get one with a really pointed tip).

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What a great write-up a few posts ago - about plugging holes. I was unaware of end mill bits for use with drill presses. All along, I thought you had a mini machine shop in the garage - a full-on end mill.

I haven't found a source for #12AB aluminum screws, and the last time I plugged skis, I pressed some plain 'ol 12-24 aluminum screws I had on hand into service. Those can be sourced at McMaster Carr. Obviously, they weren't a perfect thread match, but it was a pretty tight fit.

Cheers,
Thom

I do have a Bridgeport, but I'd think a four-flute end mill would plunge into a skj just fine in a drill press. Might jog around a bit at the very start, but ought to settle in to a bore.

Boissal, drill a few test holes in a 2x4 or old ski first, just to be safe. If I get over this flu tomorrow, I'll give it a try.

Went to a couple of hardware stores this weekend and got nothing but puzzled looks when I mentioned #12AB aluminum screws. Nothing online either, guess they're not the most common piece of hardware...
As far as the spot bit goes, yet another good point. I can see the end mill wandering off if it hits an area with lower density (the plug vs the ski material). Going extremely slowly will probably help, along with drilling a pilot to center the drill press.

Played with another project yesterday and mounted those for my gf. The previous owner had different size feet (full shell size) and I ended up having to mount one ski at + 0.5 and the other at + 1.25 to avoid getting too close to the old holes. I can't imagine it will be noticeable. Maybe I'm being too conservative with minimum distance between holes but this worried me:

Attachment 199255

Odd, the 168 is the only size which is thinner...
I don't have a straight 4.1 mm bit and a collar won't fit on the stepped bit. Good thing any random washer is about 1.5 mm thick...

Attachment 199256

The screws went to the grinder, again removing about 1 mm to get to just under 6.5 mm of protrusion. Taping the holes really helped get these guys started, along with being careful not to destroy the 1st thread.

Attachment 199257

Done. Now to see if I get bitched out for the 7.5 mm difference in mounting point...

Attachment 199258

Mounted Kopi_Red's Lotus 138's tonight.

Sth16 @0 for 305mm

Damn sexy skis if I may say so. https://uploads.tapatalk-cdn.com/201...a370e03adf.jpg

Rad! That will put me at -1mm, right on the sweet spot.

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Originally Posted by NW_SKIER

Mounted Kopi_Red's Lotus 138's tonight.

Sth16 @0 for 305mm

Damn sexy skis if I may say so. https://uploads.tapatalk-cdn.com/201...a370e03adf.jpg

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Will you update once a month so we can see the calendar progress?

https://uploads.tapatalk-cdn.com/201...da31dd21be.jpg

Wanted to replace the fugly and sloppy Griffon demo binders on my Bodacious with a sexy orange Attack 16. Unfortunately there is a hole conflict at the rear screws of the toe. It's the old (and new) metal version.

https://uploads.tapatalk-cdn.com/201...5b2dcb5f9e.jpg

Would it be safe to fill the old holes with epoxy, redrill and mount the new screws with epoxy? Other suggestions?
I wouldn't like to move the mounting line. The ski is just so friggin dialed as it is.

I've used a hardwood dowel and 24-hour epoxy to plug and drill through a similar dilemma. Seemed to work fine (not my skis though).

I'd go back a cm; you will not notice it skiing. Seriously.