There’s some really good resources out there on this subject (check out WildSnow) but I thought I’d add my experiences to the subject as well.
I could mount a pair of adjustable-heel tech bindings like Dynafit Speed Radicals with a jig in about 20 minutes if I really had to. The fore-aft positioning is adjustable and the toe piece has enough wiggle in it before you tighten the screws that you can make up for any jig inconsistencies pretty easily. Fixed heel race bindings would take more time, even with a jig. Jigs aren’t perfect and I’ve seen them not line things up correctly before on several occasions. You can get dead nuts accuracy with a paper template, but it comes at the expense of time.
Placing a paper template perfectly on a ski takes patience. You not only have to have the paper aligned front to back, side to side and rotationally, but you need to have the toe and heel pieces align perfectly with each other as well. All of this can lead to a long, frustrating experience in your garage or basement. But, when you understand the mechanics of what you’re doing, it’s actually not at all complicated.
The first thing you’ll often see paper-template tutorials tell you to do is to mark the center line on your skis with laser accuracy. Everything relies on this line and if you mess it up then your skis will be ruined and your life is over as you know it.
First of all, if you mess up mounting your bindings, it’s not the end of the world. You can make high strength repairs to drill holes on your skis. Don’t listen to the internet.
Second of all, while a highly accurate centerline is useful and speeds things up, you can mount bindings without it.
I’m not going to delve into every single nitty gritty detail, but rather supplement the info that’s out there with my own knowledge and tricks. Read through Wildsnow’s tutorial and then look at this because I’m going to skip a lot.
Having the right tools is essential.
Quality Combination Square
If you do any kind of tinkering or building this is an essential tool to own. I use mine all the time. I would prefer to have a combination square that has a metric or 1/100 inch scale on it. It’s far easier to read and surmise alignment when you’re not thinking about fractions. But a standard square that reads to 1/32 inch works too.
Fine Point Mechanical Pencil
When you’re trying to make millimeter accurate mounts, why would you make your marks with something that makes fat lines, like a Sharpie?
Standard Masking Tape
Your pencil will mark masking tape easily. I prefer the cheap stuff for this since you can your see ski’s top sheet through it a little easier than blue tape.
Sharp Center Punch
Don’t use an old, blunted punch. You want your drill bit to find your marks easily. You can place your template with NASAesque precision but it’s all for nothing if you center punch the wrong part of the template.
Everything else you need you’ll probably already have if you’re the handy-dandy tinkering type: a tape measure, razor blades, epoxy (if you want to glue your screws). But there’s a few things that will make your life easier that you may not have already:
Ski Drill Bits
These are expensive and they seem to dull really easily but they’re fool proof. You can relax and stop worrying about drilling through your ski. 4.1x9mm for skis with metal, 3.5x9mm for skis without metal. Easy. If you tap afterwards a 3.5x9mm will work just fine with metal skis as well.
If you don’t have ski specific drill bits make sure you have a proper stop-collar for the drill bit you’re using. It takes a lot of force to drill through a metal topsheet but as soon as you get through the top sheet the wood core goes fast. Drilling through the ski would be easy if you’re not paying attention.
Not 100% necessary but very nice to have. Makes a nice path for the threads on your screws to follow and you’re less likely to strip a screw.
Proper Bit Driver
If your screws have a Posi-Drive head, which it seems most Dynafits do not nowadays, a fat handled Posi-Drive #3 is a much more pleasant way to drive your screws. A Phillips #2 will work but it tends to mangle the screw heads after a while and you’re likely to strip the heads eventually. Otherwise you can get a bit handle and a number of bits to fit it. They might even be magnetized. Weee! Posi-Drive bits can be tricky to find, check Amazon. T-20 bits for Dynafit can be found at the hardware store.
To start, find a template and print it out. Make sure it’s scaled correctly: Place your bindings over it and make sure the holes line up correctly.
Next, mark your ski’s center line. Remember how I said it wasn’t necessary? Well, it isn’t, but it does make things easier. The easiest way I’ve used to find a ski’s centerline is the folded paper technique.
Run a strip of masking tape down the center of your ski through your mount region. This is just to make your marks more visible and keeps your top sheet clean.
Cut a strip of paper.
Mark a spot on your ski.
Wrap the paper around the ski with the uncut side of the strip on your mark (the part that is straight from when it was manufactured, not the wiggly side of the strip from where you cut it off your sheet of paper). Make sure you wrap tightly across the top sheet for consistency.
Press the paper against your ski edges.
Remove the paper and fold it in half so the edge creases line up and then sharply crease the half way mark.
Place the paper back on your ski mark and match up your edge creases with the ski edges. The fold you put in your paper is the center of your ski.
Mark this spot carefully with your pencil.
Repeat this process farther down the ski then draw a line connecting the center marks you made. You now have a super accurate centerline on your ski.
Confirming Your Marks are Centered
Easy, right? But how do you know your centerline is correct? The same way you can check to make sure your template is accurately aligned when we get to that step.
Grab your combination square. Lock the blade, doesn’t matter where, just make sure it doesn’t move around.
Make a small mark somewhere on your centerline, wherever you want to check it.
Place your square against the edge of the ski ensuring that the blade sits flat on the top sheet and the blade runs through the mark you just made on your centerline.
Note the measurement or draw a tick mark with your pencil right on the blade. This mark is easily removed. Flip your square around to the other side of the ski, making sure its sitting flat and running through the same mark. If your measurement is the same from both sides, your centerline is in the center of the ski. Simple. (This is where an easily read scale on your combination square comes in handy).
Line Up the Toe
Now that you have a centerline you can use this as the basis for lining up your paper templates. I like to use little squares of masking tape for securing my templates so the template can be moved around easily.
Figure out where your toe piece is going to go. The easiest way to do this is to snap your toe piece onto your boot and then align your boot center mark with the mounting mark on your ski. Then carefully mark the fore-aft (front to back) position of one of the mounting holes on the toe piece or of the pin line. This doesn’t have to be crazy accurate. If your boot is a millimeter or two off from your exact center you’re not going to notice. You might notice 10 millimeters, but maybe not. So don’t go crazy.
What is important is keeping this consistent from ski to ski, so after making the toe piece mark measure from the rear of your ski to the mark and note this distance. This way you already know where your toe piece is going for your next ski and you won’t have an inconsistent feel between skis. It’s good to double check your mounting point with your boot snapped into a toe piece for the next binding just to make sure something isn’t totally out of whack with your skis. But there may be some variation in the mounting point between two pairs of ski depending on how the marks were made at the factory.
Line up your toe piece template with your centerline and the fore-aft mark you made. For this particular mount I actually had access to a jig that worked for the toe piece so you won’t see pics for the toe piece alignment. The heel needed a template. Take your time and make sure it looks pretty perfect. Then double check it the same way you double checked your center line: measure the position of the holes with your combination square. Each opposing hole should measure the exact same distance from the ski edge. Make sure you have the blade of the square run through the hole center marks on the template so you’re measuring from the same portion of the ski’s sidecut. Make any adjustments and tape the template down firmly.
Center Punch and Drill
Next you’ll need to center punch your top sheets to guide your drill bit. I prefer to use a small scratch awl to get things started accurately. Use the small, precise awl to mark the center of you template holes as accurately as you can. A very light tap with a hammer helps things along. Then, use your center punch to make the marks deeper. Double check everything again. It’s way easier to fix a center punch boo boo than a miss-drilled hole.
If everything looks good, drill away. Making sure the holes are perpendicular to the top sheet is important for their pull out strength. A lot of people recommend using a drill press or some sort of other fixture to make the hole perfect but I haven’t found it to be necessary. With some careful eyeballing you can make this hole plenty straight.
If you want to tap the holes, tap them. I’ve seen it suggested that you use a drill press and manually rotate the chucked tap by hand to make sure the threads are perfect. I just go by hand, carefully. Get one rotation of the tap done, check the alignment and then you’re probably good to go. Your tap is going to follow the holes you drilled unless you really apply a lot of force to drive it askew.
Now you can mount your toe piece. Keep the screws kinda loose at first so the toe can wiggle around a bit. Snap your boot in and bring the heel down to your center line. Move the boot side to side to get the center of your heel tech fitting aligned with your centerline. Gently snug up the screws on the toe piece. You may only be able to tighten the front two screws with the boot snapped in, this is good enough for now. Now, using the rule on your square, mark where your tech fitting sits on your ski centerline.
Some templates will have marks with the recommended tech gap so you can align your heel piece’s fore-aft position with the boot’s tech fitting. If your heel piece has fore and aft adjustment this template mark will work fine. If you have a non-adjustable heel piece like a Dynafit Low Tech Race, insert your heel piece into the rear of your boot while it’s still snapped into the toe piece. Use a spacer, either the manufacturer supplied shim, or a metric hex key of the proper size, to set the gap of the heel piece.
Now, bring the heel piece down to the ski on top of your template and align the template to the heel piece. Make sure the heel is in the tech fitting as straight as you can get it. Now mark where the back of the template sits on your center line so you’ll have a steady reference for the fore-aft position. Lift the boot/heel piece assembly out of the way. You can now ensure your template is sitting on the ski nice and straight using the same technique you used for the toe. Make sure the template is aligned with the fore-aft mark you made earlier. Once everything is perfectly centered, tape the template down and drop the boot/heel piece back down and check the alignment of everything including the tech gap. You might need to loosen up the screws on the toe piece so you can wiggle everything around to get it in place. If the holes on your heel piece in the boot line up on the template perfectly you’re ready to drill.
After you have your bindings mounted up on both skis and everything looks good, you should put some glue on the screws. This will help prevent the screws from vibrating loose and will help seal up the holes to prevent water intrusion. A water resistant wood glue like TiteBond II or III will accomplish these task nicely with little fuss or expense. If you want to add strength to the mount then you’ll want to use a slow cure epoxy, something that will cure in 5-8 hours. 5 Minute hardware store epoxies aren’t very moisture resistant and don’t offer a lot of working time. The epoxy adds strength more by providing a good, consistent surface for the screw threads to key in to rather than by providing a chemical bond with the screw.
To glue, remove a single screw and dab a small amount of your glue or epoxy to the threads of the screw. This is way easier than trying to get epoxy into the screw holes and far less messy. You only need a little adhesive. If you go crazy with it you’ll have a big mess to clean up. Reinstall the screw, torque it correctly and then move on to the next screw. By only removing one screw at a time you don’t have to worry about messing up the alignment of the bindings.
If you’ve taken your time and worked carefully you’ll get good results with a paper template. While I’m typically all about drinking beers while I work on projects, this is one task where I’ll leave the beer for the end.
Hopefully this little write up adds a little clarity and some new tips to the info that’s already out there.