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Dammit... Another mount issue...

post #1 of 10
Thread Starter 
I really hate the weak-ass cores in some skis. I was mounting some Sali's onto a new pair of Rossi Scratch Brigades last night, and had a heel screw strip - and it was the second to the last screw on the 2nd ski... ARRRRGHHH!!! Everything was lined up beautifully, and the mount was textbook right up to that point...

Facts:
*I was using the right bit - 3.5 x 9
*I used glue
*I used the correct driver bit, and a very light clutch - less than 75%
*I used the low speed setting, and started each screw with a hand driver
*I haven't stripped a screw hole since 1998, and that was K2 foam core ski.
*I don't have a helicoil kit!! Man - those are expensive!!
*Some store guys can be really condescending. I love having "how things work" explained to me when I have already told them that I did tech work for a number of years.

Just kind of a vent here... I did take it in to get a helicoil put in, and it'll cost me $15, but probably worth it. I just with that ski cores were a little more "beefy". I've mounted a number of Rossi Scratch skis, and all of them made me just a little nervous. I finally got bit. I've got two more chances though. I should have a couple sets of clamps arriving in the next day or two, and I've got a couple other pairs of Scratch's to mount them on.

Frustrating, but it happens. Guess I'll quit buying gear, and buy a few more tools!
post #2 of 10
I tell you what, I have found that tapping the topsheet -- regardless of whether or not the ski has metal layers -- dramatically reduces the chances of stripping the holes. The reason is that it allows the screw to thread in with very little torque, and then you can sense the "snug" point very easily. I generally twirl the screws in until the threads are fully engaged, then give a snug-up 1/8 or 1/4 turn and walk away. It really helps. The only time it's still a bitch is when you have to keep snugging the screw to pull the binding flush to the ski for some reason, but tapping helps with that a bit too, by eliminating pucker of the topsheet and eliminating the need to countersink.

I wouldn't blame a weak core -- I don't think any core is really capable of bearing a load from screw threads as they tighten down, given the limited depth of the holes, they typical composite layup of core materials, and the almost machine-like #12AB thread. We're not sinking actual wood screws into solid planks! I really count on the topsheet for the actual thread bite.

Anyway, I am rambling. I know the feeling and it sucks. Even when you do it right things can go wrong. I stripped out some skis many years ago, and it was a sick feeling. Nowadays I drink at least one beer before mounting, in order to relax!
post #3 of 10
Thread Starter 
Hahaha!!!

Yeah, I was just kinda rambling too. I'll pick up a tap though - probably not a bad idea. But I get that "sinking feeling" when you think you've done everything perfect on your brand new skis, and then on one of the last screws...DAMMIT!!!
post #4 of 10
Quote:
Originally Posted by axebiker View Post
Hahaha!!!

Yeah, I was just kinda rambling too. I'll pick up a tap though - probably not a bad idea. But I get that "sinking feeling" when you think you've done everything perfect on your brand new skis, and then on one of the last screws...DAMMIT!!!
I know the feeling.
I also know I'm going to get roasted by some of the anal for saying this, but a litle strip of scotch bright pad put in the hole alongside the screw usually gives a stripped screw enough bite to hold.
post #5 of 10
Thread Starter 
Quote:
Originally Posted by 2-turn View Post
I know the feeling.
I also know I'm going to get roasted by some of the anal for saying this, but a litle strip of scotch bright pad put in the hole alongside the screw usually gives a stripped screw enough bite to hold.
I was thinking toothpick shims myself...
post #6 of 10
Quote:
Originally Posted by axebiker View Post
*I don't have a helicoil kit!! Man - those are expensive!!
After discussing this issue with someone, I agreed to buy a heli coil kit and he could rent it. He blew it off but the idea of tool rental stuck.

I can see this potentially being a PITA but to solicit input about setting up an esoteric tool rental system. Before, the idea was that the customer bought it and upon return, a refund would be sent less rental and material fee.

Any thoughts?

post #7 of 10
Thread Starter 
I wish I had that kind of access around here, but every shop is militantly possessive of even hole plugs. I offered to rent a wide jig for $50 once to mount up three sets of skis, even explaining that I had tech'd for 4 years. NO GO.

Yours is cheaper than Tognar though... May have to talk to you soon!
post #8 of 10
Quote:
Originally Posted by skier219 View Post
given the limited depth of the holes, they typical composite layup of core materials, and the almost machine-like #12AB thread.
I know at least one kayak builder who insists that machine screw threads hold -better- in thin wood than wood screws, to the point of publishing articles on it.

As to pulling the binding onto the ski, I've sometimes wondered why the likes of Snoli bother to thread the full length. A screw with a smooth top shank pulls things together so much better (if the screw thread depth is matched to the receiving hole).

Quote:
Originally Posted by axebiker View Post
I was thinking toothpick shims myself...
0000 steel wool. I've watched some nords use that and then rack the skis upside down so that the glue stays in the threads...

Garrett had a link to a foil version of the steel wool at one point; much cheeper than helicoils. I don't remember where that thread is now.
post #9 of 10
Thread Starter 
I guess it doesn't matter at this point - I should be able to pick them up today. But when I screw up my next two mounts, I'll keep that in mind!!
post #10 of 10
Quote:
Originally Posted by comprex View Post
I know at least one kayak builder who insists that machine screw threads hold -better- in thin wood than wood screws, to the point of publishing articles on it.
Funny you should mention that -- I have debated this a lot with myself. It's a bitch stuffing your arms and head into the end of a kayak to work with a nut/bolt that pairs with it's mate on the other side of a hull, so using just a screw from the outside is a plus. Anyway, I would agree that machine threads have the potential to hold better in wood or polyethylene hulls because they put more surface area (threads) in a limited thickness of material, but unfortunately the shallower pitch and corresponding thread depth makes them easier to strip out (we get more mechanical advantage over the material). So it becomes even more critical to know when to say whoa. This gets difficult with a non homogeneous material like wood; while you can follow torque specs for screws in metals or other homogeneous materials, wood is not usually consistent enough from sample to sample, and of course some types/cuts of wood are more grainy (?) than others. So I think machine screws in wood require some background experience and a very gentle hand.


Quote:
Originally Posted by comprex View Post
As to pulling the binding onto the ski, I've sometimes wondered why the likes of Snoli bother to thread the full length. A screw with a smooth top shank pulls things together so much better (if the screw thread depth is matched to the receiving hole).
What bothers me are the "captive" screws may bindings use nowadays. I say captive in the loose sense, as the screws are typically only held in the binding by molded spines or ridges in the holes, and probably only for shipping or convenience (in other words, no screws rattling around in the box, and the screws are ready to go when you put the binding on the ski). And they are not free to move like a true shouldered captive screw. Anyhow, it's ridiculous to have a nice clean tapped hole in a ski ready to receive that precise #12AB thread, only to have the screw threads bind in the holes in the binding (no pun intended) while you snug it down to the ski. I have taken to removing the screws from the binding and cleaning out the holes before installation, so that the screws pass through the binding more easily when tightened down.
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EpicSki › The Barking Bear Forums › On the Snow (Skiing Forums) › Tuning, Maintenance and Repairs › Dammit... Another mount issue...