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From: http://madmodder.net/index.php?topic=3440.0
Rule zero is using the largest pilot (tap-drill) hole you can for any given task, which makes tapping a whole lot easier.
Rule one is to buy good quality taps. The cheapie taps are cheap for a reason (in most cases). They cost you dearly when trying to remove a broken one from a hole! I am partial to OSG taps, but I designed and built some grinding machines for them years ago and can buy them direct from the factory -- which has something to do with my bias.
Rule two is to keep them sharp! If you do not have the set-up (or access to a set-up) to sharpen them, be very careful as it is easy to make them worse trying to hand sharpen them. When in doubt, throw it out.
Rule three is to be sure that you are driving them straight into your part. Very few people have the hand strength to torque a (sharp) #10 (5 mm) tap to the point of breaking. A six-year-old can break such a tap in bending very easily. Tap guides are cheap at twice the price. A Tapmatic type head is golden (and there's an inexpensive Indian-made head being sold by Harbor Freight and the like that is reasonably good so long as you disassemble it, clean up the burrs, lubricate everything nicely, and reassemble it -- I have seen them on sale for less than US$75 several times in the recent pass and I have "cleaned-up" three of them for friends in recent years).
Rule four is use the right lubricant! Tap-Magic Gold is my current favorite when dealing with obnoxious materials (hardened stainless, titanium, nickel alloys, etc.). Moly-Dee is my more general purpose (steel) lubricant -- though I still use axle grease for plain carbon steels. I use cetyl alcohol (wax) for most aluminum tapping (though Tap-Magic Aluminum works better on non-heat-treated aluminum). I often use lard when tapping copper-based materials. I usually tap cast iron dry.
This video shows a TAPMATIC head being used:
[video=youtube;W_tkCZgNutI]http://www.youtube.com/watch?v=W_tkCZgNutI&feature=player_embedded [/video]
Rule zero is using the largest pilot (tap-drill) hole you can for any given task, which makes tapping a whole lot easier.
Rule one is to buy good quality taps. The cheapie taps are cheap for a reason (in most cases). They cost you dearly when trying to remove a broken one from a hole! I am partial to OSG taps, but I designed and built some grinding machines for them years ago and can buy them direct from the factory -- which has something to do with my bias.
Rule two is to keep them sharp! If you do not have the set-up (or access to a set-up) to sharpen them, be very careful as it is easy to make them worse trying to hand sharpen them. When in doubt, throw it out.
Rule three is to be sure that you are driving them straight into your part. Very few people have the hand strength to torque a (sharp) #10 (5 mm) tap to the point of breaking. A six-year-old can break such a tap in bending very easily. Tap guides are cheap at twice the price. A Tapmatic type head is golden (and there's an inexpensive Indian-made head being sold by Harbor Freight and the like that is reasonably good so long as you disassemble it, clean up the burrs, lubricate everything nicely, and reassemble it -- I have seen them on sale for less than US$75 several times in the recent pass and I have "cleaned-up" three of them for friends in recent years).
Rule four is use the right lubricant! Tap-Magic Gold is my current favorite when dealing with obnoxious materials (hardened stainless, titanium, nickel alloys, etc.). Moly-Dee is my more general purpose (steel) lubricant -- though I still use axle grease for plain carbon steels. I use cetyl alcohol (wax) for most aluminum tapping (though Tap-Magic Aluminum works better on non-heat-treated aluminum). I often use lard when tapping copper-based materials. I usually tap cast iron dry.
This video shows a TAPMATIC head being used:
[video=youtube;W_tkCZgNutI]http://www.youtube.com/watch?v=W_tkCZgNutI&feature=player_embedded [/video]
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