Introduction: Improvised Tap and Dye From Salvaged Bolt and Nut.

About: i have spent my life finding alternative ways to get every task done in spite many challenges. most of my projects are as we call how we do things Fabrecobled (to make (fabricate) something from whatever layin…

Sometimes you find yourself needing a tap or die that is not in your collection. Time, cost and distance are the main reasons that have prevented me from just getting the right tools as needed. So this is a technique that provides a suitable tap and or die for plastics and soft metals, haven't had much luck with steel except for cleaning or chasing treads.



You will need.
If making a tap only.
A bolt of the desired size and pitch.
Hack saw, a rotary with cutting disc will work to.
Vise or other holding method.

For tap and or die
Nut and bolt of desired size and pitch
Drill and suitably sized drill bit

Step 1: Figure Out Where the Thread Starts.

We need to find where the thread starts.
Follow the thread around until the thread is at its complete profile, this is usually across the bolt or nut from the starting point.
Mark both. (See picture 1, 2)

Step 2: Cutting the Cutting Flutes. Clamps and Coolant, Use More.

If just making a tap. Clamp your marked bolt up so you can cut across it with your hack saw, creating the cutting edge and a space for chips to go.
It may be useful to file a bit of taper on the bolt, and for smaller bolt made taps filing more space ahead of the cutting edge minimizes compression of plastic ahead of cutting, creating a better cut.(See picture 1)

SHOP TIP: cutting a slot in a bolt then cutting the head off to length is a effective way to make quick set screws, turn with flat head screwdriver. (See picture 2)

For a tap and die set.

1. Align the thread alignment marks and clamp the whole thing together so the threads align and the bolt and nut faces are flush. (See picture 3, 4, 5)

I used a shim that was previously used as a glue spreader to prop the bolt head in the right position before vigorously clamping every thing down to my board and horse bench top.

2. Liberally apply cutting fluid

Drill sizing: I'm making my set from 9/16-12 nut and bolt so the OD is 9/16 inch and the tap drill you would use is 31/64 inch. The flutes should be deeper then the thread is thick but not to much because the nut side wall will limit size. I recommend using a drill that is about 2X the thread thickness 1/8 inch in this case.

3. Start drilling a hole parallel to the bolt shaft at the intersection of the threads (it may be necessary to center punch the thread to prevent drill walking (happened on the lower hole)), drill threw one thread (you will feel it break threw) then drill the same on the other side. (starting at the top allows the oil to run down to the other hole for use)

4. Repeat steps 2 and 3 until flutes of satisfactory length are created. (See picture 6)

Step 3: Clean Up and Use.

  1. Screw together and unscrew the tap and die many times to remove any burrs from the cutting edge/ threads.
  2. Clean all the filings and oil from the set.
  3. Congratulations you improvised a tap and die set. now use it.

To use

Find the parts that need threaded / chased and use like you would a normal tap and die.

I was chasing 3D printed threads (I printed this thread because I had no funds for tools but had a suitably sized nut and bolt in my Salvaged bolt collection)

Clamps are the Amps (amputees) best friend in the shop you can see I clamped the tap and die down then used my hand to work the parts (that are meant to be twisted) on and of the tool incrementally until satisfactory results were achieved. Plastic shavings can be seen on the tools in pictures 3 and 4.

The tool I'm working on is a tool handle I have been dreaming of for years and finally prototype. It accepts 1/4 inch drive bits and saws all blades (the PLA doesn't have the grip to hold up to aggressive sawing (printing in a different material may help?) The white stuff in picture 5 is lithium grease I removed and replaced this with crayon wax later. The saw blade barely fits in the chuck. (I forgot to account for printer tolerance) printed on Makerbot Z18

Should I post the print files for the handle to thingiverse and this instructable? Favorite and or comment if you think I should.

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