[slowtwitch]

Good Stuff !!!! I recently acquired a 5 inch, 45 degree face mill. I'll give it a try....I may be installing new spindle bearings sooner than I thought ...lol

[SWATH]

Blog post:
http://www.warmachinellc.com/ar15-hi...xture-plate-2/

Fixture plate 2 machining video:

[Brian L]

You should use the round boss in the center, and then a diamond shaped pin to locate the parts rotationally. It will make it worlds easier to get the parts on and off.

[SWATH]

Interesting. I guess the idea is less contact area for friction? Do you have a link to these diamond shaped pins? I wanted to use pins instead but couldn't find any of the exact right size and the main one needed to be threaded anyway so I decided to just mill them in a steel plate.

[Brian L]

The idea is even few tenths of a thou variation in center to center distance can really muck things up for fit. So you use a round pin, or boss in your situation, and then the rotational locator would be a diamond pin with the locating portion at 90

[Brian L]

Just as a second thought, you could always diamond the smaller locating pins on your fixture, they don't even have to be diamond shaped, you can just mill flats on two sides so the pin only locates in the axis it needs to.

I've just done a lot of production work and you want your fixturing to be as easy and quick to use as possible.... like I don't know how you expect to get at the bolts for the parts in the rear? Take the fixture out of the machine? I think I would have investigated a fourth axis and used a tombstone for the parts.....

[SWATH]

Thanks Brian that's very good info. I did not know about the diamond pin theory. I guess since I already made the fixture, if it becomes an issue I can still make the small round boss a diamond shape and see how that works.

[SWATH]

Latest installment in the series. Finally some 3D profile machining using the new fixture plate!

Blog article: AR15 High Rail Gasblock CNC Machining (7): side gutting and 3D profiling | War Machine

AR15 High Rail Gasblock: (pt.7) Side gutting and 3D profiling