Dynafit/Ski equipment failure question

I've heard of problems with the skis breaking after installing T-Nuts flush into the ski.

I carry T-nuts in my field kit -- but as last resort get me home option with the T-Nut base exposed on ski base.

If the holes aren't too big the Puderluder Binding Inserts

www.quiverkiller.com/

www.facebook.com/notes.php?id=1397411127...s_tab=app_2347471856

Are quite a bit sturdier than HeliColis -- Puderluder have been discussed ad-nausem on TelemarkTips.com

I found installing the Puderluder inserts in my Voile Drifters to be not particularly more difficult than a regular binding mount -- but then I've mounted dozens of skiis.

leavenworthmtnsports.com/ carries them "locally" perhaps they offer installation as well.

Puderluder Binding Inserts . . . . Are quite a bit sturdier than HeliColis[sic]

If you are talking about pullout strength, this is the converse of my experience. Do you have a link? Thanks.

If you are talking about pullout strength, this is the converse of my experience. Do you have a link? Thanks.

QK are pretty new and I haven't done any measured pullout tests on them or any other fasteners.

Zeno on TelemarkTips.Com did do some measurements and concluded that regular binding screws are the strongest -- but I don't think he tested using a regular screw is a repaired hole. Search telemarktips.com if you want to see his measurements.

My own "clinical" experience is that I DIY installed similar inserts (obtained from a wood working shop) in several pairs of skiis about three years ago and they have all withstood the rigors of what my friends call "Oakley Test Labs"

I weight 245lb, ski telemark and play in the terrain park -- so I can put a fair amount of load on the binding screws.

The other nice thing about QKs or similar wood working inserts is they allow you to move bindings around between skis or if you are a nut job like me have inserts installed in both a Dynafit and G3 pattern

The other nice thing about QKs or similar wood working inserts is they allow you to move bindings around between skis or if you are a nut job like me have inserts installed in both a Dynafit and G3 pattern

Right, that's the obvious advantage of QK/BF.  My concern is whether a machine screw thread is the right thing for a wood core. 

I've seen Zeno's tests.  He tested screw only with and without epoxy and a 8mm-1.25 EZ Lok insert, which is quite similar to QK/BF, i.e., machine screw O.D. thread, similar diameter, ~20TPI vs. 18TPI. Zeno did not test helicoil AFAIK.  If there are pullout tests re screw only vs. helicoil please advise.  That would be helpful. 

Also, I may have failed to point out that I'm talking about soft cores or soft spots -- and I've seen lots of soft spots in K2 cores.  BTW, I'm roughly your weight had a Dyna or tele pullout on my skis (which are always mounted by me).  My experience is that in soft cores helicoils (larger cross section) are stronger than a screw only -- e.g., the rear screws in BD O1's, which are vulnerable to pullouts in soft cores.

Maybe I'm misunderstanding, but the BF/QK inserts only have an internal machine screw thread, for the binding mount. The exterior thread that grips the core is a pretty deep pitched thread, more like the stock mounting screws.

QK/BF external thread and tap are 5/16-18 TPI machine screw thread like this guy .  (Internal is 5M, i.e. 5mm - 0.8mm, but that's irrelevant to this discussion).  I assume that the decision by jondrum and puderluder to use a machine screw thread was due to the availability of machine screw taps.  Helicoil uses a proprietary tap which is the same TPI as an ABS screw and coarser/deeper, like a lag bolt (i.e., untapered wood screw).