06-26-2012, 04:55 PM
I got most of the trigger finished tonight. It took longer than expected because I decided to make some changes on the model to make it easier to machine. The sear was the hardest part just because it was so darn small and hard to see. This part was a good application for carbide tooling just because the end mills required were so small and long and the material was tool steel. I don't use carbide much, but it was handy for this application. Next is the backside of the trigger and possibly rounding off the front so it feels better on the finger (another thing I changed on the model).
After mounting the trigger to the sub-plate, the first two cuts were made on the front of the trigger.
Next came the back side of the sear (on the right) and the flat that the trigger return spring pushes on.
The sear tapers 10º to .030" which matches the half cock notch in the hammer.
The newly added curve on the front of the trigger was milled to a 3/8" radius with a form tool mounted in a fly cutter. It was ground on a 5/16" tool bit and mounted in a fly cutter, then the part was spun on the rotary table against the spinning form tool to generate the curve.
The radius on the back side was milled to size with a 3/32" carbide end mill.
The machining is complete and it's ready for hand finishing.
After mounting the trigger to the sub-plate, the first two cuts were made on the front of the trigger.
Next came the back side of the sear (on the right) and the flat that the trigger return spring pushes on.
The sear tapers 10º to .030" which matches the half cock notch in the hammer.
The newly added curve on the front of the trigger was milled to a 3/8" radius with a form tool mounted in a fly cutter. It was ground on a 5/16" tool bit and mounted in a fly cutter, then the part was spun on the rotary table against the spinning form tool to generate the curve.
The radius on the back side was milled to size with a 3/32" carbide end mill.
The machining is complete and it's ready for hand finishing.