If you have ever spent any time wrenching on your bike, we can guarantee you have stripped a bolt or damaged some threads. Perhaps you were mounting a bracket in a new place or just tightened about one extra turn: either way, one can't deny the horrible feeling you get when a bolt breaks off in the hole. The good news is that with the right tools all of these potentially expensive problems can be fixed without having to replace parts. If your home garage is not set up with drill presses or lathes, the repairs can be done by hand.
The most important thing in thread repair is to have a good quality tap and die set. Remember that you get what you pay for, so if you buy a cheap set, don't expect it to last long. You will find that the better the grade the better the cut. This goes for the drill bits as well, and you will need a set of those too. Some other items that will help get you out of trouble are HeliCoils and TimeSerts. These can save the day.
We had Joe Warren, owner of SGV Chopper, in Covina, California, show us the how-tos and what not-to-dos on thread repair.
 Warren started by demonstrating...  Warren started by demonstrating how to tap a hole. First, a pilot hole was drilled in a block of aluminum to the size that was needed for the threads. Remember that the drill size needs to be smaller then the thread size, so that there is still enough metal to cut the thread pattern into. |
 Here is a small sample of...  Here is a small sample of taps from spiral points and multi-flute to dual-cutting flute. (Too many to name!) |
 There are two basic tap handles...  There are two basic tap handles -- the clamp vise handle and the ratchet handle. |
 We lubed the tap with some...  We lubed the tap with some cutting fluid, then ran the tap slowly into the hole, going about a quarter to a half turn at a time. Backing the tap out every couple of turns will help clean the shavings out. A little grease on the tap will also help keep any shavings from falling into the hole. |
 When it hits the bottom or...  When it hits the bottom or the depth needed, back the tap out all the way, then use some compressed air to clean out the hole and some brake clean to wipe up the cutting oil. |
 Next, Warren showed us how...  Next, Warren showed us how to repair some damaged threads. First, we had to determine the thread pitch. He used a pitch gauge, so that we had the right size and didn't damage the threads even more. |
 The die was started by hand,...  The die was started by hand, and once it was on and straight... |
 ...the T-handle was placed...  ...the T-handle was placed over the die. Warren put the bolt in a vise to keep it straight and allow some leverage. Just as the tap was used, we took our time and rotate the die a half turn at a time -- this allows the repaired thread to clean up. Don't forget the lube. |
 On to the HeliCoil. This kit...  On to the HeliCoil. This kit is a 1/4-20 and comes with everything needed to do 10 inserts: a drill bit, a tap, and the install tool. The first thing Warren did was drill out the hole to simulate stripped threads. |
 Remember that the tool will...  Remember that the tool will need to go past the depth of the coil, so drill out the hole a bit deeper than the coil. Next, he used the tap and cut the threads in the hole. |
 The coil was started by hand...  The coil was started by hand first, and then the tool was inserted into the coil until the tang seated on the end of the tool. |
 Next, the coil was screwed...  Next, the coil was screwed into the freshly tapped hole until it was fully inserted. |
 If you could see in the hole,...  If you could see in the hole, the bottom of the coil looks like this. After, the tang will need to be removed with some needle nose pliers. |
 A TimeSert is like the HeliCoil,...  A TimeSert is like the HeliCoil, and it is also a thread replacement. However, the insert is a solid piece and is tapered at the bottom so that it expands as it is getting threaded into the hole. This kit has a drill, a counter bore, a tap, and the installation driver. |
 After the hole was drilled,...  After the hole was drilled, Warren used the counter bore to cut the top of the hole to allow the TimeSert to sit flush. |
 Looking closely, the step...  Looking closely, the step can be seen, and it will stop cutting at the right depth. |
 The insert was then threaded...  The insert was then threaded onto the installer tool. |
 With a little threadlocker...  With a little threadlocker and the tapering on the end of the coil, it was then screwed in until it bottomed -- helping to ensure that it won't pull out. |
 On the left side is the TimeSert...  On the left side is the TimeSert and on the right is the HeliCoil, now they are ready for the fasteners, and you can get back on the road. |