Here you can see the original and modified head springs merged together. This gives me all the geometry I need to create the fixtures and cnc code to create the modified spring.

Here is the solid model of the modified head spring.

Here is an actual modified head spring after both machining operations.

This is the fixture design which holds all 10 heads to be modified at the same time for the first operation. This is easy to accomplish by making everything symmetrical and then using a linear component pattern to create the model.

In the cam, I only program the first location then use a macro to step and repeat the code to create all 10 individual locations. I think cycle time on the fixture was like 20 minutes or so.

Actual machined fixture

Solid model of the fixture with components installed.

Parts installed on the fixture awaiting machining.

Cycle time less than 5 minutes….hardly worth the effort of creating the fixture, but it needed to be done!

Just for size comparison so you get a feel for the actual size!

Bottom of fixture with chamfered threaded holes.

Up close and personal with the locating features (0.0565” and 0.009” tall) All edges chamfered so there are no burrs to cause registration problems!

Fixture 2 solid model

Fixture 2 actual machined part

Solid model of fixture with heads assembled onto fixture.

Here you can see the first 5 finished parts still on the fixture with the hold down caps removed. I used the FDM 3d Printer to build the hold down “Hats” just to test the idea. After printing them, they seemed like they would be strong enough to hold the stainless down for machining so I tried it and saved myself the trouble of machining them from aluminum!

In this 3d model, you can see the generous fillet I added to the fdm hat to increase the strength out near the edge. This relief was necessary because the 0.050” end mill only has an 0.085” length of cut then necks up to the 1/8” shank so I needed to clear the shank.

I was real careful and used some cutter comp to sneak up on the exact fit I wanted between the locating pin and the holes in the head spring! There is no perceptible play in this setup.

The head is clamped underneath the hat and the excess has been trimmed away with the cutter. You can see the actual 3d printed fillet in this view.

Here is a nice shot of the thin wall left between the existing slot and the new slot.  I wasn’t sure I would get this intact but the hat clamp did its job. At the thinnest section, it’s about 0.003” or so.

The  tenth part is still in the fixture for future reference but I have 10 good parts from this setup from the 10 original parts I was given to modify!