Hammer Build

For the past three years, we have run a program at GM Technology Center to train new build team members in shop safety and general machining procedures: Hammer Build. Each student is given a set of directions and works with either an adult or student mentor to build their very own hammer. The students start with 2 pieces of round and bar aluminum stock and must use the mill, lathe, and tap to machine and assemble their hammer.  A hammer owner will have learned how to safely use a band-saw, mill, lathe, and tap, among many other things.  After they are finished, the hammer is theirs to keep, as well as the experience they have gained.  A CAD model and the directions for our hammer can be found below.

Directions:

1. Band Saw
   1. Cut ¾ in. round stock to 5 in.
   2. Cut ¾ in. square stock to 2 in.
2. Lathe
   1. Face both ends of the (round) bar.
      1. Place bar in lathe and clamp down.
      2. Align blade at or below the center of the bar.
      3. Smooth off both ends of bar. NO NUBS!
   2. Zero the X and Y axis.
   3. Take down 1/16 in. at a time of the X axis until you take ¼ in. off the diameter. (1/8 in. off each side) Go slightly less then 3/8 in. down the handle (in the y-axis).
      1. Now move the blade in the diagonal direction into the corner you have created. This reduces stress on this part of the handle
   4. Use a centering bit.
   5. Now use a #7 or 0.187 in. bit and drill 7/16 in. into the handle.
3. Tapping
   1. Clamp the handle down with the hole upright.
   2. Get a ¼-20 tap bit.
   3. Put some tapping fluid in the hole and on the tap bit.
   4. Tap the hole by spinning the bit one revolution, then back a ¼ revolution until you feel a small cracking.

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4. Milling Machine
   1. Face both ends of 2 in. block with a large end mill in a collar.
5. Caliper
   1. First file the ends of the block so that your caliper reading will be accurate.
   2. Find the center of the block using the caliper. Use a paper and pencil for calculations if you have to. NO Calculators.
   3. Write down your measurements, this is where you will need to drill.
6. Milling Machine
   1. Center the Milling Machine.
   2. Using a ¼ in. bit in a drill chuck, drill all the way through the block.
   3. Next, Use a ½ in. bit. BE CAREFUL not to drop the bit when exchanging it.
   4. zero the z-axis.
   5. Using the ½ in. bit, drill just over 3/8 in. into the block.
7. Deburr the edges.
8. Drill Press
   1. Use a countersink bit on the other side of the 2 in. block.
   2. Make sure you drill deep enough that the screw head will sit flush with the hammer head.

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9. Grinder
   1. Use the grinder on these edges of both parts.
10. Screw Wall
    1. Find a ¼ - 20 - ½ in. countersink screw.
11. Put your hammer together!