Saturday, March 15, 2014

Tap Handle (Threading)

I didn't have a handle for my larger taps, so I built one using a two piece design, here is the original sketch written on a discarded bench grinder housing because I was too lazy to get paper.
two piece tap handle design
A better sketch with dimensions:
The goal was to make a tap handle which will hold my entire range of larger taps, here is a 1"-20 tap on the left compared with a 5/8".  In order to do this I had to mill the square halves small enough to fit the smallest but also leave enough space for the biggest taps.
a 1" tap and 5/8" tap

First step, since I'm using 5/8" round stock, I milled the top flat.
milling a flat on 5/8" round stock
Using the dial indicator stand to help get an accurate depth dimension.
Using a dial indicator to check quill depth of cut
Then milling the relief slot for the next cutter.
milling a relief slot
Milling the square half with a 45° cutter.
using a 45° end mill to mill a square half
Drilling a hole with #7 drill for a #10-32 bolt to go through.
drilling a #7 hole
Drilling and tapping the other hole #10-32.
tapping a hole to #10-32
Afterwards, the reverse side of the non threaded hole was counter bored.
counter bored hole with socket head cap screw
Then the other half was made.  I drilled and tapped the ends 1/2"-13 for optional extension handles.
home made tap handle assembled
Here is how the square part of the tap sits.
tap handle view of square
I made the extension handles out of 1" aluminum, drilled and tapped the end to 1/2"-13 as well and put a set screw.  This was done so I can just insert a piece of threaded rod, circumventing the need to cut external threads.
tap handle knurled extension handle
Milling flats on the pieces of 1/2"-13 threaded rod so the set screw will secure it to the handle.
milling flats on threaded rod
tap handle extension with threaded rod
The tap handle fully assembled with the extension handles.
home made tap handle with extension handles
With the 1" tap.
tap handle holding 1" tap
With a smaller tap and without the extension handles.  I made them removable for ease of storage, or in case lack of clearance or if I don't need as much leverage.
tap handle holding a smaller tap
Everyone loves close-ups of knurls.
knurl detail
The extra leverage made easy work of tapping in the lathe.
tapping in the lathe with home made tap handle
Now I have a tap handle for every occasion.  The one in the middle is just a piece of aluminum with a square hole filed in it and securing bolt, only good for one size (3/8").  The T handle one on the right is for smaller taps.
an assortment of tap handles for various sizes
I used a similar two piece design when I built my die stock a while back.
home made die stock
home made die stock render

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