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I have a Triumph Tiger 800 ABS roadie and they're known for getting loose on the headset bearing nut. I have the factory service manual and instructions for re-torqueing the nut include "Step 1: Remove handlebars."
The nut is not directly under the handlebars, but offset enough that I thought if I had a tool that drove the nut via the six pin holes rather than marring the finish of hex on the nut with big sockets or open end wrenches, I might also be able to drive it with a 1/2" or 3/8" square drive and do so without touching the bars. Here's a photo, it's kind of tight in there.
I did take some measurements with a caliper, but it's hard to judge just how much space I'd have with a tool needing strength and holding pins. Off to the shop to see what I had for stock, a 3/4" long piece of Ø 1-5/8" 303 stainless steel was all I had in something strong yet non corrosive. I whipped up this blank on the lathe.
The only means I had to mill the 38mm hex was to hold onto that short 1" diameter on the back. It's held in a 5C collet that's in what is known as a "spindexer". Six flats milled in a couple minutes with a solid carbide 3-flute end mill.
Now remembering that the aluminum nut on the bike has a crown it and the 3.55mm holes are very close to it, this was going to be the "precision machined" portion of this program. I first used a 3/8" 4-flute carbide end mill to rough out the recess. I didn't want the recess to be deep out to the full diameter, as it might interfere with the 30º clearance angle on the back of the tool. In this photo you can see the roughed out recess and the "bull nose" 3-insert cutter to be used.
Now here's that cutter in action, a roughing pass followed by a .010" finish pass. The machine is only 2-axis CNC, so that's why there's a dwell. I have to position the depth by hand.
Here's the part now with the recess done, and the holes for my 3.5mm pins added using the machine's "canned cycle" for bolt circles.
Now without removing the part from the vise I used a 1/8" solid carbide 4-flute end mill to create the square for 1/2" drive extension, ratchet or )preferably) torque wrench. After a little ScotchBrite wheel deburring, this is what it looked like.
The last step (or so I'd hoped) was to make the 3.5mm pins and press fit them into the tool. Because I didn't have a collet stop and deburred/chamfered the pins by hand, some sunk into the holes a little deeper than others. It still looks OK.
Unfortunately, the 1" diameter on the back of the tool just hit the bottom of the handlebar. If I had the XC version of this bike or it's taller bar risers, no problem. For my stock "roadie", I'll have to make an adjustment. I went back to the shop and cut a bigger radius on the corner, using the only tool I had in my box even close. The radius on the tool is about 4mm (5/32"), and now.....IT FITS! There's little room to the bar with an oversize extension, but normal ones should fit fine. I may make a few more, and could opt for a 3/8" drive because it's only torqued to 18ft/lbs.
I had fun today!
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Originally Posted by SprintPoser
