• Jesse Young

GEARWRENCH 5/16 x 18 NC Taper Tap Review



I purchased this tap from Amazon on September 13th of 2019 to repair damaged thread holes on the primary mounting flanges of a aftermarket Harley S&S 107ci Super Sidewinder Evolution motor.


First let me preface this by saying "I typically have had good experiences with Gearwrench products".



GEARWRENCH 5/16 x 18 NC Taper Tap - 388709N
GEARWRENCH 5/16 x 18 NC Taper Tap - 388709N

A common question asked on the Amazon Q&A section was "Hot long is the tap?". As seen in the picture above:


Length: 2 3/4 inches



GEARWRENCH 5/16 x 18 NC Taper Tap - 388709N - Packaging
GEARWRENCH 5/16 x 18 NC Taper Tap in its packaging

The packaging is a standard click to lock plastic container.



three in one household oil - vintage oil can

For all tapping and drilling I use the same ancient bottle of 3-1 Household oil (with lubrashield!). I'm pretty sure I bought this at a yard sale 20 years ago.



GEARWRENCH 5/16 x 18 NC Taper Tap - Holding oil

Here is a picture of the tap loaded up with oil (overloaded). It sounds silly but not all taps hold oil the same way. I would imagine it has to do with the finishing of the material used to make the tap.



The tap cut cleanly and retained the metal shavings in the fluted recesses. I could not hand tighten the socket head bolt in to this thread before hand, but was just about able to thread the tap in with only minimal resistance.




GEARWRENCH 5/16 x 18 NC Taper Tap - 388709N - Final

The threads cut true and after a quick spray of carburetor cleaner, the fastener threaded in perfectly with no wobble.


My Review:


Buy it if you need to cut or chase threads in aluminum. I have not tried it with steel, but I think going slow with enough lubricant should be no issue.


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