The handle of my mitre saw has cracked and is about to break. How can I repair this to be able to keep using the saw?
With the possibility of the handle breaking and my hand slipping down into the path of a spinning blade, if it were mine, I'd search online for a factory replacement handle. (Yes, I know many tools have electric brakes, but even so, I'm rather fond of my fingers and would like to minimize the possibility of their separation from my person.)
I've found numerous on-line suppliers that sell factory original repair parts for a wide variety of tools, usually for significantly less than the manufacturer sells the parts. Use your favorite search engine to search for
<brand> <model number> replacement parts and you're very likely to find several resellers of parts. In my experience, they'll have exploded drawings of the tool, well labeled for part identification, and often written or video instructions on how to do the repair.
I upgraded the handle of my miter saw (the upgrade included a shadow-line light for the blade). The installation involved removing the blade guide and several other cover bits and routing wiring for the new light, as well as the upgraded handle (including an on/off switch for the light), and wiring updates to tap the new light into the existing wiring. All told, it took about 30 minutes to remove the old handle, remove all the other parts, install the new light and updated covers, and install the new handle.
Of course, repair vs replace is a dollar cost vs time cost vs potential for injury judgement call that each person must make for himself. IMHO, even at full manufacturer price, I would replace instead of repair.
Find a way to clamp the handle back together, perhaps with a large woodworker’s clamp, so that the crack line is nearly invisible and the the switch is retained solidly where it belongs; this is key to this type of repair working. (If this is not possible, do not continue.) Clean the handle of any soil or skin oils with something that will evaporate quickly such as Windex or isopropyl alcohol.
Cut a sheer nylon stocking into narrow strips perhaps 1/2" wide and several inches long.
Mix up some 2-part epoxy. Saturate the nylon stocking strips with epoxy, squeegee off any excess epoxy from the strips with a pop stick or dowel and start wrapping the broken area of the handle with the strips of epoxy-soaked nylon. Overlap the strips, criss-cross them and build up an epoxy/nylon “bandage” around the crack and beyond to the intact area. Use your judgment to determine how thick to make the bandage. Think of it like a cast for a broken arm. Thicker is stronger. Depending on how fast your epoxy hardens, you might have to mix several small batches. You may find it most convenient to manipulate the nylon strips with tweezers, chop sticks and gloved hands.
Allow the epoxy to fully harden – at least 24 hours – before stressing the handle.
I’ve made repairs like this on cracked and broken plastic parts inside machinery, and some repairs have lasted for years under daily stress. It makes an incredibly strong repair. And remember, at this point you have nothing to lose but a couple of bucks in materials, so it’s worth giving it a try!