Screw Size for K2 Skis' Factory Inserts?

[TallGrass]

Inserts on K2s are M5 (5mm) with 0.8 thread pitch, correct? The Targas are from G3 which is in Vancouver, but K2 is in Seattle, so there's an off chance they're #10-32 (inch size).

Reason: https://telemarktalk.com/viewtopic.php? ... 81&p=56889

[Krummholz]

@TallGrass You might just have to take the ski in to the hardware store and try some different screw/bolts, especially stainless ones. I read on the Altaiskis.com site that they use zinc coated stainless, so the machine screws don’t seize in the stainless inserts. They are m6 screws. I would think a coating of loctight would prevent seizing and keep it from coming loose.

[TallGrass]

Nominal Dimensions
32.00 threads per inch for 10-32 imperial.
31.75 threads per inch for 0.8 metric.
------
4.763mm or 0.1875" dia for #10 screw (3/16", rounds to 0.19")
4.876mm or 0.1969" dia for M5 screw (5/25.4 = 0.196850393...)
M5 dia is 5% bigger, nominally.

Major Dia (aka actual "outer" dia if measured with calipers; top of threads)
4.763mm for 10-32
4.876mm for M5 0.8 (avg of 4.826mm Min to 4.976mm Max)

Minor Dia (aka "root" dia, shank dia if threads removed... the "strength" part; bottom of threads)
3.881mm for 10-32
3.989mm for M5 0.8 (avg of 3.869mm Min to 4.110mm Max)
M5 is 2.78% bigger.

Thread Angle
Both use 30-degrees off perpendicular for a 60-degree wedge.

Summary
A 10-32 machine screw will thread into a M5 0.8 hole, but not a snug nor with as much "meat" in its core.
A M5 0.8 machine screw might thread into a 10-32 hole, if the M5 is closer to it's Min and the 10-32 closer to its Max.

With the inserts not exceeding 10mm in depth, either may "work" though go with M5 if possible. A 10-32 would be fine for a Field Repair and it was all you had, or one could hide an extra M5 or two under each heel or toe riser wrapped in some anti-rattle plastic.

@TallGrass You might just have to take the ski in to the hardware store and try some different screw/bolts, especially stainless ones. I read on the Altaiskis.com site that they use zinc coated stainless, so the machine screws don’t seize in the stainless inserts. They are m6 screws. I would think a coating of loctight would prevent seizing and keep it from coming loose.

Thanks. Hardware store testing only goes so far, but isn't fine enough per the above. It it were for a light switch cover or other low-load, sure. However, there's the potential for enough force to strip or distort a front binding insert -- screws are cheap and disposable by comparison.

Altai may use M6 (likely 1.0 tpmm), but these K2 skis do not, and I'm assuming they're the original factory inserts.

I'm not too worried about cold-welding as they don't see road salt. IME, I think a touch of grease, RTV, or wood glue would be sufficient. Unfortunately, M5 0.8 x 12mm is not easily available in Pozidriv, so it's either Philips, Torx, or Allen/Hex. I'm leaning to Allen so I can keep a key so I can check them in the backcountry.

When they're this small, sometimes you run into Grade 4.8 in metric versus 8.8 common to larger screws. Then A2 stainless has its own strength grades. Regardless, I will not go with the black ones which flash rust once wet or from humidity.

[jalp]

Inserts on K2s are M5 (5mm) with 0.8 thread pitch, correct? The Targas are from G3 which is in Vancouver, but K2 is in Seattle, so there's an off chance they're #10-32 (inch size).

Reason: https://telemarktalk.com/viewtopic.php? ... 81&p=56889

Here's a source for M5-0.8 pozi screws in many lengths:
https://www.bindingfreedom.com/pozi-fla ... al-screws/

I actually prefer screws without serrations under the heads as they don't chew up the binding holes. I buy mine here: https://www.albanycountyfasteners.com/F ... 490000.htm

As far as loctite or other thread treatments are concerned, I would highly recommend using only this on screws for threaded inserts:


Hope that helps!

[phoenix]

Can't help with the bolt measurement. Can suggest you call some dedicated tele shops, ask for the service dept, and ask them if they have some of the originals.
Would it help you to have an original to get your measurements?

[TallGrass]

Here they are mounted* to my "12 Pairs Skis for Case of Budw' " K2 WorkStinx. I just went with Philips M5x16mm, 0.8 flat heads. I think I'll just cover the unused, exposed insert holes with button head ones (see toe), the truss head ones are just a hair to big to fit adjacent to either riser (see heel riser), and the pair under the front riser with a little electrical tape. Not sure how I'll polish off the old risers' scuff marks, maybe Magic Eraser and some finesse. These skis have some damage on some top edges, so I'm going for the 10/10 look "looks good at 10mph from 10 feet away."

Overall, not a bad look nor color scheme, if I do say so.

Here's a source for M5-0.8 pozi screws in many lengths:
https://www.bindingfreedom.com/pozi-fla ... al-screws/
I actually prefer screws without serrations under the heads as they don't chew up the binding holes. I buy mine here: https://www.albanycountyfasteners.com/F ... 490000.htm
As far as loctite or other thread treatments are concerned, I would highly recommend using only this on screws for threaded inserts:

Loctite has various flavors, and I would NOT be using their tougher stuff. They have some light duty that is meant to be easily unscrewed which I might go with, or just keep screwdriver with and see if they give at all in the field.

Nice source for BF. For either, shipping can be a factor. I can find SS Allen flat heads as well as Torx locally at Ace Hardware, though some want $1.19/screw (a bargain in a red light district, but not for fasteners).

Can't help with the bolt measurement. Can suggest you call some dedicated tele shops, ask for the service dept, and ask them if they have some of the originals. Would it help you to have an original to get your measurements?

I think I'm good, though I'll keep in mind your tip regarding asking about used bolts at ski shops.