AmericanLongRifles Forums
General discussion => Gun Building => Topic started by: Ken G on August 14, 2008, 06:01:06 PM
-
Greg's recent post about breaking a tap off got me thinking. Do those tap extractors work? The ones with the prongs that slip in flutes. Thank goodness I have yet to need them but do theywork?
Ken
-
Ken, sometimes, not a 100%, a broken tap is usually the result of a chip getting hung and,or a little too much side pressure. when you feel the tap tightening up, back it up to clean out the chips. back to the extractors, they are better than nothing and here's hoping you never need them
-
Worked in a machine shop my whole life and I hate them. Rarely do they work. For real expensive parts, the tap can be blasted out using a EDM machine. Some times you can heat the tap to soften it and drill it out with a carbide drill, but this is also a hit and miss proposition. When your working on a per piece price/parts per hour rate, it's usually cheaper to throw it away and make a new one.
99% of broken taps are mis-aligned when they are started. And all the special tapping oils on the market.......for hand tapping WD40 works as good as any of them. Use a starter tap, make sure it's started straight, keep the chips out of the hole and reverse often.
A dull drill can work harden the metal and cause tap breakage.
Bill
-
In my opinion, they NEVER work, especially the smaller sizes! And they cost you an arm and a leg >:( I try to work with old fashioned carbon steel taps as much as possible, but they are getting out of stock rapidly. If such a tap breaks, you can heat it to soften, and then drill it out more easily.
To remove a modern tap, I once degreased hole and tap, and dribbled strong hydrochloric acid in the hole to dissolve part of the tap and the chips that blocked the tap in the hole. Took me several hours, but then I could use very small needle-nose pliers to get the thing out.
-
Tap extractors are a very good tool for extracting broken taps, but only when the part of the tap that is broken off and stuck in the hole is in one piece and not shattered. However, the smaller taps used in gun building usually shatter into pieces and negate the usefulness of tap extractors.
Randy Hedden
www.harddogrifles.com
-
That was a good question and it was enlightning. ...Geo,
-
Thanks for the good info guys. Sounds like tap extractors are at least an option but not something I want to depend on. The What Causes a Tap to Break information might keep me from ever needing one.
Cheers,
Ken