Custom work - Angel Hammer Lightening Tech index > Custom Work > Angel Hammer Lightening

I had a request for some "weight reduction" modifications on these Angel hammers. The mod is fairly straightforward, simply involves indexing the hammers on a lathe then turning a large groove in the middle to remove the unwanted mass.
Angel hammer modification diagram
The shape of this modified groove depends on who is performing the modification; in my case I chose to make a groove with 60º angled walls and a R0.06" corner radius. My reasoning for the angled walls was to allow for higher strength without adding more weight. I'm not sure if this was necessary but I figured it wouldn't hurt the final product.

I cut these parts on my SL10 lathe. The work was quick and the parts turned out good...
Angel hammer lathe turning
Angel hammer lathe turning
Angel hammer mod finished
The total weight of the modified stainless hammer is now 0.042 pounds, down from the unmodified stainless hammer weight of 0.103 pounds. I also performed the modification to one Titanium hammer, which ended up lighter at 0.024 pounds.

Below is a video that shows the complete lathe turning modifiction:

Permalink: http://www.youtube.com/watch?v=d78V-7Lh_u8

After the lathe modification, the next step is to mill away additional material from the "back" end of the hammer, but I chose to skip that process because I didn't want the hammers to rub on the inside of the marker body. Milling away the back of the hammer only reemoves 0.003 pounds from the total mass. It could be done, but it wasn't worth the additional time ($$).

CNC program:
Below is the CNC lathe code I wrote to perform the modification. The finishing cut is programmed directly, but the roughing cuts were accomplished with a Haas G71 roughing cycle, which may not work on all CNC controllers. Some controls cannot use a G71 to cut a "valley" shape, so be aware the code may not run on all machines.

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o0050 (ANGEL HAMMER TURNING)
(Machine: Haas 2axis slant bed lathe)
( T4-4 | OD TURNING INSERT - STRAIGHT HAND - 35DEG VNMT R1/32 )
(EXTEND MANDREL 1" FROM JAWS)
(Z ZERO @ FACE OF MANDREL OR LEFT SIDE OF WORKPIECE)
N100 G20 G40
( ===GROOVE ROUGHING - CANNED CYCLE=== )
N102 G0 G40 G53 X0.0 Z0.0 T0404 (home posit)
N106 G0 G40 G54 X.89 Z1.5 M8 (approach move)
N108 G50 S2000
N110 G96 S120 M3 (SFPM for stainless roughing)
N114 Z1.0155
N116 X.6215
N188 (D radial depth | U leave X diam | W leave Z)
N190 G71 P192 Q204 D.03 U.02 W.005 F.005
N192 G1 X.3647 Z.9687
N196 G2 X.3269 Z.9417 I.0098 K-.027
N198 G1 Z.1463
N200 G2 X.3647 Z.1192 I.0287
N202 G1 X.6215 Z.0725
N204 (end of profile)
N206 G0 Z1.0155
N208 X.89
N232 Z.9
( ===GROOVE FINISHING - DIRECT COORDINATE=== )
N234 G50 S3500
N236 Z1.5
N238 X.875
N240 Z1.0326
N242 X.7154
N244 G1 X.6215 Z1.0155 F.003
N246 X.3647 Z.9687
N248 G2 X.3269 Z.9417 I.0098 K-.027
N250 G1 Z.1463
N252 G2 X.3647 Z.1192 I.0287
N254 G1 X.6215 Z.0725
N256 X.7154 Z.0554 F.02
N258 G0 X.875
N260 Z1.5
N262 M9
N264 G0 G40 G53 X0.0 Z0.0 (home position)
N268 M30
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