I put an aftermarket steering wheel on my '86 and stripped one of the channels to the three little side bolts. Is this even something with which I should be concerned? I want to use a tap to re-thread the bolt channel. Anyone know what type of tap I use: bottom, intermediate, or tapering? What material is best bang-for-buck (I've heard tungsten carbide is the best, but is it best for the money?!?) Also, I have idea what kind of metal the steering wheel's bolt threads are made of. I've never used a tap before. It should be fun. Any tips?
My priorities are:
(1) not snapping some cheap tap off in the bolt channel;
(2) I prefer buying one good tap and then adding to taps to make a set;
Thanks in advance.
First things first, can you post a picture of the offending stripped channel? I can't quite visualize your problem.
Bottoming taps are for blind holes (as opposed to through holes). If your threaded holes go completely through the work, use a tapered tap. They go in straighter.
Your basic high-speed tap is more than adequate for this kind of work. In fact, when I'm paying out of my own pocket, I use the cheapie HF taps. They are actually less likely to break (but dull more quickly) than better tools. And really, breaking taps is *all* about technique.
You can get the HF set with 10 taps and ten dies for the price of a single high speed steel tap. But don't use HF's cheapie tap handle. Throw it away and buy a quality tap handle such as Starrett . It will give you sure control and last a lifetime.
For what they're worth, a few tips on using a tap successfully:
(1) Look up the hole size your tap requires. Get a drill of that size, or even a few thou larger. Then measure the drill to be sure. Even new-from-the-package drills are often the wrong size.
(2) The tap must go into the hole straight. Sight check it from the front and side as soon as it grabs, and again after 1-1/2 turns. Tip #5 assures success on this point if you drill and tap with the same set-up.
(3) Lubricate the tap well with a light oil. ATF works great.
(4) The tap won't give you any warning that it's about to seize up in the hole. Stop, clean away chips and relubricate before you think you need to. After a turn and a half with the tap, back it out and brush the chips out of the flutes. Blow the chips of the hole. Then go an additional turn and a half and repeat. When you say to yourself "I can cut more than this before cleaning chips", visualize the broken-off nub of a tap sticking out of your work.
(5) If there's any was you can do it, support the back of the tap handle. In the shop, I like to clamp my work in a vice and put the tap in the drill press chuck, which I turn by hand. That assures the only forces applied to the tap are downward and torque. Turning a tap handle by hand, you get some sideways force - the kind that breaks taps.
Sure, some of that advice is anal retentive. But for a beginning machinist, it's better to be safe than sorry.