I guess that we need to start somewhere, so here are some quick tips and tapping strategies...
1) Plan your project....try not to have to tap hard material and try to make all your holes thru holes, to avoid having to use bottom taps.
2) Make sure that you have enough meat in the area to be tapped...i.e. don't try to tap a 1/8" deep hole that goes into another bolt or interference
3) Use gun or machine taps...don't use hand taps, they take too long and are usually lousy
These are usually 2 flute taps that DON'T need to be backed out....You just turn in a clockwise direction till you are bottomed out and then back the tap out. Use caution and feel how the tap is working. If it binds, the flutes could be clogged. In these cases, back it out, clean it off and start again.
Note: Some gummy materials will require that you work the tap in and out....other materials retain heat and will expand onto the tap and cause it to bind..in these cases, walk away and come back when things have cooled down. examples are copper and Titanium.
4) Use a good quality tapping fluid...I like tapmajic for most materials. Make sure that you read the specs on health and safety as well as compatability with materials to be tapped
5) For small holes, use a small, light tap handle to avoid breakage. This also gives you a good feel for how the tap is working.
6) Get rid of dull taps...they do have a life span and will cause headaches if they break in the material
7) Broken taps are normaly removed with an EDM machine, but even tho they are hard, sometimes they can be removed with a carbide endmill, or broken into smaller pieces with a punch or chisel and then removed.
8 ) It takes some practice to get a tap started straight. Nothing is more frustrating than a bunch of crooked holes, so take your time, line it up from a few angles and start slowly. Once you're sure that the tap is starting square to the hole, go for it. Practice makes perfect, so start with the less important holes FIRST.
9) Needless to say, a drill press or mill with a tapping head make good production tools and tend to keep things square, but with time and practice, some can master the hand tappping chore easily. Some people will never get it right, so allocate these types of jobs to those on your team with good hand skills if possible.
10) On a side note: Screws, bolts, nuts and taps all have a fitment class. While a normal tap is usually ok, there are instances where you might want a tighter or looser fit....Do some research and get informed.
11) A note about drilling: Always start with a center drill, especially on non-flat surfaces. Then use the correct size drill for the hole to be tapped. You can get a drill/tap chart free from any supplier of these items.
12) It is good preactice to chamfer all holes. This helps to start the tap and eliminates thread pulling...(which is hen the first thread pulls out and leaves a nasty butt at the entrance to the hole)
13) If the hole to be tapped is big, work up to the tap drill size in increments withing the rigidity of your setup. i.e. don't try to drill a 1" hole in one shot.
14) Small drills are inexpensive, but learn how to sharpen the larger drills. THis can be done by hand with a bench grinder, but it takes practice. Dull drills or badly sharpened drills can make oval holes...then you might be toast.
15) Use gray wheels for hss drills and a green or diamond wheels for carbides.
I'll add to this as I think of other tips
Feel free to comment and add or correct anything....and good luck tapping your holes