I have a Chinese 6040 router (with an Ethernet Smoothstepper and a G540) which I have been using successfully for plastic and Aluminium.
I am a complete newbie at this, although I'm very pleased with the results I am getting so far!
I want to do some two sided milling of 6mm aluminium, and I have some questions about making and using a suitable jig.
My plan is:
Make the fixture:
1. Use 6mm x 100mm x 100mm aluminium for the fixture plate -- this will be large enough to mount the stock I'm using.
2. Mount the fixture plate on my t-slot bed using the rather basic clamps the machine came with.
3. Machine two (or four?) sides of the fixture plate square with the axes of the CNC machine. (as a reference so that I can later remove and reattach the fixture)
4. Drill holes for dowels at appropriate places for the stock size I'm planning to use.
5. Insert dowel pins like these: Dowel Pins Hardened Ground 3mm X 10mm 10 PK Steel | eBay (steel into Aluminium -- will that be OK?)
Prepare the stock:
6. On another part of the bed drill the same hole pattern into the stock. (my parts are always cut from the center of the stock, so I don't need to worry about its edges or absolute alignment.
7. Slip the stock over the dowels -- hold down with clamps or double sided tape.
Machine the job:
8. Machine the first side
9. Flip the stock -- I'll ensure the centerline of the part is equidistant between the dowel pins.
10. Machine the second side
Remounting the fixture: (at some point I'll remove the fixture for some reason and need to reattach it)
Aligning:
11. Clamp the fixture as closely aligned as I can by eye/setsquare
12. Mount my dial gauge in my spindle chuck and sweep it along the machined edge, tapping the fixture until it is square with the motion of the axis. I only need to do that for one axis, as the other is perpendicular.
13. Find zero?
Questions:
1. Should I be using a mixture of dowels (for location) and threaded rod (to hold down the stock)?
2. Can I use a plastic spoil board between the fixture and the stock?
3. What's the best way to find a zero point in step 13 above?
Looking forward to comments, suggestions and corrections of terminology!
Thanks,
Tom