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Marty Basso's Tap Wrench Metal Work Project

Rationale for teachers

Layout and tools

lathe operation and controls

taper turning and threading

knurling

more designs

This project should take a student 4 hours of shop time to make

SOME THOUGHTS FOR THE STUDENTS
Have you ever thought about the things you use in your everyday life? How many items do you use or wear that are handmade? How many processes that you complete each day are now done by technology? Today we have bread makers, Blenders, cell phones, pagers, etc. Are we becoming reliant on these technologies? Our dependence on these items has resulted in the loss of many skills from our cultural knowledge base. I want you to think about these things the next time you embrace technology. Ask yourself the question, how was this done 50 years ago?, 100 years ago? etc. What direction is our society taking?
This project is designed to give you practical manual skills using tools and machines. But I want you to think about the tool that you are going to create, are there other things that you could make? I want you to discover the pride you feel by making something yourself. I want you to be able to separate yourself from our reliance on technology. What role do you think technology should have in our society? What can we expect from the 21st century?

Description of project:
Students will select one of the designs provided, or make their own, and produce the tap wrench.
Students will select material necessary and cut to length
Students will proceed to layout the material according to drawing specifications
Students will begin machining processes. Extra care will be taken to ensure accuracy.

The objectives of the tap wrench project is to:

get students familiar with layout, and machining processes.

Give students an understanding of design variations possible in the production process.

Accustom students to making their own tools (rather than buying).

Get students to question technology and consumerism and their role in society today.

Get students to understand the manufacture and assembly of parts

This is one view of the assembled tap wrench with tap	Another view of the tap wrench
Here is a close up of the finished jaw parts. Note each jaw has holes that are threaded on opposite sides. Note the square hole and the rounded outside edges.	Here is a picture of all the finish parts

Handles

Handles will be cut and faced to length and center drilled both ends
End will be turned down for thread on one end
Other end will be rounded and prepared for knurl.
Students will set up lathe for knurling. Medium knurl will be selected. Speed will be set to less than 100 RPM and feed set between .010" to .020"/revolution. Students will be reminded to keep feed and pressure applied during the knurling process. Knurling tool must be set up perpendicular to the work piece.

Threading

The student will carefully reverse the piece for threading. Be careful holding the piece in the chuck to prevent marking.
Set up the threading tool so that the height in on center. The axis of the cutting tool should be perpendicular to the work piece.
The lathe quick change gearbox will be set up for 3/8" NF and the end of the handle will be threaded.
Calculate the depth of thread using the corresponding table or formula.
use the thread chasing dial to chase the threads on each consecutive cut.
check the thread using a 3/8" NF nut. The thread should not be loose. Because the thread is a fine thread, depth of cut should be watched carefully.

Jaws

The jaws will be drilled to tap drill size for 3/8 NF. I like to weld the two pieces together with a small tack weld, this helps the student locate matching holes more accurately. I find layout troublesome for some students.
Once hole is drilled the jaws can be separated and one hole on each piece will be drilled for to accept the turned 3/8" piece of the handle. Care must be taken to ensure that each hole of the jaw matches up with the corresponding hole in the other jaw. Thread will exist in only one hole of the each jaw.
The tap drill hole of each jaw can be tapped. Care must be taken when tapping to ensure accurate threads.
The wrench can be checked and assembled for fit.

Optional Heat treating of the jaws (Case Harden)

heat treat jaws, case harden to improve tool life.
polish surfaces to remove scale and assemble
I like to put some Never seize on every part that I assemble.

Milling the square hole

Once wrench is assembled to your satisfaction, check layout marks for machined square (to hold square tap end) make sure the center is accurate and layout marks to indicate where milling is to take place.
Set up jaws in milling machine chuck and check with protractor head of combination set, or other tool that will indicate accurate 45 degree angle. The protractor has a level indicator that will assist the layout of the 45 degree angle.
Mill groove to fit tap in both jaws.
Remove the jaws and file to remove burrs.
Assemble and check fit. File if necessary. V slots should line up accurately to produce square hole.
If a milling machine is not available, the student can drill a small hole and enlarge the square using a file.

Go to Marty Basso's other pages
(Technology)(Machinist)(School Work)
(Haida art)(Politics)
(Burma info )(more Burma pics)(Vietnam pictures)(Queen Charlotte Island photos)
If you have comments or suggestions, email me at:

basso@interchange.ubc.ca