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I keep breaking taps
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Le Chuck:
I'm having to tap a bunch of teeny tiny ass holes I've drilled in some 1/2" nuts.  To mount things in a fixed manner to a round axle I'm adding set screws to bored out nuts.  I have one nut completed!  I have borked 3 others and have broken 3 taps.  I know what I'm doing wrong, I keep putting lateral tension on the tap when I'm turning it.  It doesn't help that the tap is about the size of a thick pencil lead. 

The really cool product that I ordered eons ago to avoid having to do this is not going to be made anymore it looks like (round holed hex bearings).  On the up side the taps are only $3 each and I'm only out 60 cents in nuts.  On the down side if I keep busting taps at this rate the costs will eventually add up. 

Anybody got some sage advice for tapping on a small scale?
recklessindian:
Use lots of lube (oil) and keep backing it out every turn or so (to remove shavings that could bind).
Also make sure you are drilling a large enough hole for your tap. 
Xiaou2:

--- Quote from: recklessindian on November 25, 2012, 05:59:19 pm ---Use lots of lube (oil) and keep backing it out every turn or so (to remove shavings that could bind).
Also make sure you are drilling a large enough hole for your tap.

--- End quote ---

  This. ^

   Additionally, you could probably hand turn a drill press (or tap thats mounted inside a drilled hole in wood) to keep the Tap steady, so as not to put lateral pressure and snap it.

 Frictional heat may also be an issue.  Heat causing the metal to expand, than as it cools, threads tighten up.  Quench the nut in icewater after drilling out the hole, and then every so often, as you tap.  Oil will help with friction, but it only goes so far.  Most industrial cutting machines stream cool cutting fluid constantly.
Nephasth:
Paint thinner works great for keeping the tap cool and lubricated. Little secrect I learned manufacturing LBH drill rigs.
lilshawn:

--- Quote from: Xiaou2 on November 25, 2012, 06:25:06 pm ---
--- Quote from: recklessindian on November 25, 2012, 05:59:19 pm ---Use lots of lube (oil) and keep backing it out every turn or so (to remove shavings that could bind).
Also make sure you are drilling a large enough hole for your tap.

--- End quote ---

  This. ^

   Additionally, you could probably hand turn a drill press (or tap thats mounted inside a drilled hole in wood) to keep the Tap steady, so as not to put lateral pressure and snap it.

 Frictional heat may also be an issue.  Heat causing the metal to expand, than as it cools, threads tighten up.  Quench the nut in icewater after drilling out the hole, and then every so often, as you tap.  Oil will help with friction, but it only goes so far.  Most industrial cutting machines stream cool cutting fluid constantly.


--- End quote ---

sounds like your hole is too small.

http://www.thedirtforum.com/drilltapsizes.htm

also, try mounting the tap in a vise and using a deep socket to turn the nut...you can bottom out the socket on the vise and get it nice and straight the whole time.
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