Dynafit Radical Torx (Star Drive) Tooling

Post by WildSnow.com blogger | November 19, 2012      

WARNING, January 2013: For removing torx/star drive ski binding screws, use a high quality and impact driver rated torx bit rotated by hand, possibly with the help of a wrench cheater, with extra care to prevent breaking the bit off in the screw. Pre-heat stuborn screws with a good quality and hot soldering iron. I’ve been having a lot of trouble torx bits breaking during screw removal.

Ski shops already know this, but here is the info for any readers upgrading to new Dynafit Radical FT or ST bindings with non-removable brakes and doing home mounting. When inserting the rear screws you’ll need a longer star drive T-20 driver with a narrow shaft, otherwise known as a hexalobular internal driving feature tool. Yeah, I was reading the Wiki.

A regular type hand T-20 star drive screwdriver will work fine, but if you’re using insert bits with a power driver or bit holder screwdriver you’ll need 2-inch (or longer) insert bits rather than the little shorties. As shown, the longer bit fits nicely between the brake parts. If you use a shorter insert bit the holder shaft doesn’t get enough clearance. In a pinch, you can grind clearance notches in the plastic brake plate, but if you use insert bits it’s better to just buy a few 2-inch T-20 drivers. I got mine at Lowe’s, and they’re easy to find on Amazon and elsewhere online. Buy a few for friends and for your repair kit.

Insert bit holder with a two inch T-20 bit fits perfectly between brake parts of the Dynafit Radical FT/ST.

Insert bit holder with a two inch T-20 bit fits perfectly between brake parts of the Dynafit Radical FT/ST. Former binding models had removable brakes. With the permanently installed brakes you have less room to work so tooling up is the order of the day.

If you want an even more elegant solution you can get longer Torx bits, but we’ve found the 2 inch to be fine. See Amazon links below for some shopping options. Stocking stuffers for the ski mech in your life?

TORX Driver Bit -T20 – 2″ – Quick-Change Shank

Torx impact rated size 20 is probably stronger and might be best.

TORX Driver Bit – T20 – 3-1/2″ – Quick-Change Shank

Felo 0715731419 Set of 6 Torx Bits, 2-Inch Length, sizes T10-T40, 036 Series

Klein 19555 5-Piece TORX Screwdriver Set


Please Enjoy A Few Suggested WildSnow Posts


35 Responses to “Dynafit Radical Torx (Star Drive) Tooling”

  1. Dan November 19th, 2012 9:29 am

    Thanks Lou. I always feel much better when crusing a hardware store with purpose.

  2. Bill November 19th, 2012 10:04 am

    I would suggest getting a good quality bit.
    I have twisted T20 bits. I beleive they were kobalt brand.
    I, and have heard of others, stripping the T20 screws.
    I have never had an issue with the old Phillips style ( posidrive.)
    Not sure if the the screws were not hardened properly, or it is something
    just you have to be careful of.

  3. Lou Dawson November 19th, 2012 10:34 am

    Bill, good point. But with ski mounting, if you’re twisting the insert bit you might be needing to be tapping your holes in the ski or something. Otherwise, when driving wood screws without pilot holes and stuff like that, yes, quality in insert bits of all types is something I’ve been noticing for years and has caused no small amount of bad words to escape my otherwise pristine visage.

    How do the Amazon links look, good quality?


  4. AndyC November 19th, 2012 11:04 am

    Amazon links look great. A big surprise to me is that I am using Amazon more and more to shop for practically everything but ski gear and clothing … it is so much easier to find what I want.

  5. Lou Dawson November 19th, 2012 11:27 am

    Andy, I’ve been doing the same thing. I keep finding stuff on there I need that I can’t buy local. Sure keeping UPS in business!

  6. Bill November 19th, 2012 11:53 am

    I was removing a screw, and it was not epoxied.
    Twisted pretty easy.
    Like I said, I have never had an issue with the old phillips style.
    The stress area on the T20 is a lot less than the old phillips ( another words it is a lot smaller).
    1/5th to 1/10th.

  7. Lou Dawson November 19th, 2012 2:08 pm

    Phillips are designed to cam out before the bit is damaged. Torx is not. In other words, unless you’re careful or set your drill torque you can twist off a torx while the phillips will just cam out, damaging the screw and sometimes both bit and screw. Torx is much better for modern fastening. I’ve put in hundreds of torx now, and thousands of phillips/pozi. Once you use torx star-drive from day-to-day, you’ll be very happy with the difference.


  8. Tom November 19th, 2012 2:16 pm

    Wait til you try Torx-Plus.

    It’s like the difference between a regular Phillips and a #3 posi, but ten times better – which may turn out to be too much for screws in skis (strip potential) without a torque clutch. Maybe that’s why Dyna didn’t go straight to Plus.

    A good source for drivers is an industrial supply place such as msc dot com.

    I like the Wiha brand. Nice handle, even with gunked hands.

  9. Chris November 19th, 2012 3:06 pm

    Lou, have you tried using a smaller torx to remove the top plate of the rear of a Vertical? do you know if it possible to bolt on a Radical top plate? i.e. upgrade the volcano to the Radical flip up version?

  10. Lou Dawson November 19th, 2012 3:31 pm

    Chris, it might be possible but you’d have problems with binding heel rotation due to pressure of the boot heel on the flip-up lifter. Oh, yeah, you could also put the anti-rotation gizmo on the binding… but what’s the point? The flip up lifter is nice, but not exactly rocking the world of skiing.

  11. Bill November 19th, 2012 7:37 pm

    With power tools torx are nice. You do not need to maintain firm pressure down.
    The big thing about the Phillips #3 is you can chuck a bit in a drill press chuck , hold it down with the quill and apply enough torque to break the head off. Way more than the t20 torx can withstand. Being so much smaller, the torx just can not transmit the force. With the the aluminum toe pieces and flat head screws we are liable to see screws seize and with the limited load the t20 torx can take may have issues. I use torx all the time in my machine shop on tooling along with hex. No magic in em, they strip like anything else.

  12. Lou Dawson November 19th, 2012 7:42 pm

    Bill, thanks, main thing is they just don’t cam out like pozi and phillips, leaving the screw head ruined. I’m having much much more success with them in my work, both ski mounting and carpentry. Yeah, torx can break, but in my experience they transmit more torque more reliably, and that’s what I need. Along with that, when it comes to wood screws I try to always buy the self drilling type, loving those… Lou

  13. SCM Troy November 19th, 2012 10:37 pm

    In our shop, I originally used a Wiha driver and came across a situation where it spun in the “star” when attempting removal. On Dynafit’s recommendation I purchased their tool and it was a tighter fit and removed the screw without slippage. Just sayin’.

  14. Lou Dawson November 20th, 2012 4:50 am

    SCM, huh, that is quite interesting! I’d find it hard to believe that the Dynafit screws are not simply T-20 torx, or perhaps they are torx plus? This stuff does get confusing. I have a few torx bits that are slightly tapered and fit snugger then the straight variety. Those bits are nice for work where there is zero off-angle, but the standard bits allow a tiny bit of miss alignment. I’ve turned quite a few Dynafit star drive screws now by using T-20 drivers and haven’t had any problem, but that’s for the warning. If one has to indeed buy a special driver from Dynafit for the screws, that’s not great… We’ll keep experimenting.

    It should be said that any screw can strip out, and any driver bit can break. It’s all about having a feel for things, as well as stuff like adjusting the torque limit on power drivers to the correct levels.

  15. Bill November 20th, 2012 8:06 am

    I am used to using the techinique noted above from the start.
    Installing screws and taking them out with a drill press or, in our case a mill. Screws go in straight without wobbling and avoid stripping.
    Especially when I go to remove.With the torx we do not get the benefit.
    A lot of the small tools in the shop we use small screws that have to be tight or they will vibrate loose and some use tapered design that tends to lock.Torx provides good torque transmission for the size when the screws are high tensile and hardened steel. In th case of the dynafit screws I wish they would have pushed the sizing to t25 as the #3 was pushed for the cross being that the material is not that hard.

  16. stevenjo November 20th, 2012 11:13 am

    I can’t believe this topic was posted just (yesterday?). Last night I was cursing those torx heads and came here to see if there was a place to complain – lucky me.

    Normally I agree that torx are the way to go for a number of reason already mentioned but also as mentioned I’ve found that with the Dyna Rad brakes (and Verts too in other places) its hard to get the your bit perfectly ‘squarely’ to the screw and usually end up with some small amount of angle (we’re all guilty right?) at the bit and screw-head interface.

    In this respect I think the posi #3 is much more forgiving because the bit fits more deeply into the head allowing some forgiveness with angles, whereas the torx head keeps the bit sitting shallow thus little room for poor drill handling. Of course it doesn’t help that I was using a clutchless drill- guilty – and stripped the head all to hell but then again I’ve mounted plenty of skis with the same tools using posi and never had a problem.

    Call me an amateur but I miss the posi.

    PS – Thanks for the post Lou, this was cathartic

  17. Lou Dawson November 20th, 2012 11:16 am

    Steve, you are welcome (LOL).

  18. Tom November 20th, 2012 3:36 pm

    They do make “Ball end” Torx wrenchs (like Allen/hex ball end) where the tip is rounded so you can get some angle. Up to ~20-30° I think.

    My experience is you have to be careful with these “Ball end” types as they are not as beefy and prone to wear. They’re great for angled starting and most of the drive, but if you can switch to standard for the last torque, you’ll be better off.

    I in no way represent Wiha, but there’s lots of good info on these things at their site wihatools, and I should have been more specific in my preference to their series 362 drivers – mostly the handle.

    I imagine other manufacturers site may have this info too.

  19. Mark Worley November 22nd, 2012 10:26 pm

    My two cents: Torx works pretty well in this application. I’ve used 2+ inch bit with small multi-driver to great success. Also tried a Torx tool designed for use on bikes, think it is a Park tool. Recommend staying away from these as they’re a lighter gauge and flex a lot. The little tines on the tool wear quickly and will strip screw heads too easily. Dynafit has 2+ inch bit for shops. Dunno if they sell to general public, but might be worth inquiring about as this is a quality piece.

  20. Phillip December 2nd, 2012 11:50 am

    Hope I didn’t miss this…but…what exactly is correct amount of torque? I will be mounting the Vertical STs and want to get it right.

    [Lou] “….adjusting the torque limit on power drivers to the correct levels.”


  21. Rich December 2nd, 2012 8:33 pm

    Like Phillip, I can’t find a torque spec. I did find some reference material from BD suggesting 4-5Nm for alpine and 8-10Nm for tele:

  22. Lou Dawson December 3rd, 2012 11:14 am

    Hi guys, there are torque specs floating around, but unfortunately there is no single one that’s “true” since ski material varies so much. It has to be done by feel. If you want to set a power driver torque for safety, set it low and finish tightening the screws by hand. What is more, how many power drivers out there allow you to accurately set the torque limit?

    Another thing that varies the reality of torque for ski screws is the lubricity of glue. For example, if you choose to seal the insert holes in Dynafit skis with glue, you will need less torque to tighten the screws without stripping. Don’t ask me how I know (grin).


  23. Phillip December 3rd, 2012 11:24 am

    Lou..thanks for statements on torque…5 Nm = 3.68 ft/lbs [units I can relate to.I never met Newton.] which is damn near impossible, for me, to use a torque wrench on and get it correct..

    Glue acting as a lube also rings true..in engine head bolts, dry vs lubed bolt torques are very different..but again different applications..engine bolts are best measured by elongation under torque…on my skis, well, not a good idea!

    This will be my first set of bindings that I have mounted…hope to find a screaming deal on Vert STs for my new 2012 Shuksans [last of the Shuksan]…yes, I am old school but as mentioned I have my Slus to fall back on….

  24. Lou Dawson December 3rd, 2012 11:26 am

    Phillip, you shouldn’t have any trouble doing it by feel. But if you’ve never mounted bindings, simply get a pair of dumpster skis and practice on those first. That’s what any ski shop would do when training a new employee (or should do, anyway…). Lou

  25. Rich December 3rd, 2012 1:06 pm

    Lou, thanks for the additional torque info, do you care to estimate the necessary torque for Dynafit Radical ST mounted to 2013 Voile Vectors drilled using 3.5 x 9mm, tapped, and using 1 hour epoxy? Sorry to push, but I just don’t have a feel when I’ll strip the threads or twist the head off of the screw.

    Thanks for the great “do it yourself” Dynafit mounting article, template was most helpful, all that’s left is the gluing.

  26. Phillip December 14th, 2012 4:13 pm

    About brakes for the Dynafits Radicals…or “stoppers” as they call them…where can I get 82mm brakes? My 78mm waisted skis would appreciate 82mm and not the 92mm now available.

    Tried to order Vert ST w/82mm from SnowInn [Spain] but they wanted a copy of my passport for ID; not going to happen…so I know 82mms are out there. but where?

    Thanks for any help..

  27. Phillip February 2nd, 2013 2:01 pm

    Question On Length Of Drill Bit

    I see in SlideWright that the bits are 9.5mm in length…Dynafit manual specs at 9mm…but my question is more generic …what is the range of depths for drilling binding screws into to different skis? If I buy the 4.1 x 9.5mm bit will that work on a variety of skis?

    Sorry if this off the topic of drivers…could not find another thread on this topic

  28. Lou Dawson February 2nd, 2013 3:07 pm

    Philip, yes, the core is very forgiving in terms of exact length of screw vs bit. Don’t worry about it.

  29. Phillip February 2nd, 2013 3:16 pm

    Lou…yet again…thank you!


  30. Lou Dawson February 7th, 2013 2:59 pm

    I’ve been breaking torx bits. Warning added to blog post.

  31. Mike March 25th, 2013 3:23 pm

    Lou – Since you broke so many, have you found a source for torx head replacements? I have had good luck and want to switch my phillips stuff over and would like to order some. Can’t find any reference to their specs/size

  32. Lou Dawson March 25th, 2013 4:43 pm

    Mike, didn’t you see the links above? Also, I’m thinking I might start using only impact driver rated bits, assuming they’re quite a bit stronger. I’ll add a link for those. Lou

  33. Mike March 25th, 2013 5:28 pm

    Sorry Lou – meant for screws. Want to replace the posi screws with torx across the board. Just haven’t found a good place to buy and have scavenged all I can from ski shops. Got a link for mcmaster carr but their infinite selection and autocad drawings have my head spinning. Guess I can email dynafit and get specs for the screws but they are practically the same (except interface) as onyx screws with the exception of the rear onyx being 1/8″ longer

  34. Lou Dawson March 25th, 2013 6:44 pm

    Mike, I really wouldn’t bother if I were you, they’re pretty specialized screws, I wouldn’t be surprised if only available in Europe. Try calling Dynafit customer service, they have spares, but probably not enough to start selling them by the bushel.

  35. Clark September 29th, 2017 1:24 pm

    Wiha makes some high quality Torx screwdrivers. Precision machined tip and hardened blade. Will fit snugly in the screw and won’t break. Some good Wiha Torx screwdrivers with different sizes can be found at https://besttoolz.com/torx-screwdriver-buyers-guide/.

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