This will be the chessboard base, 20” x 20” cut from 24” x 24” stock (1.125” thick), scrap piece that I picked up, not cheap, but cheaper than new. Final thickness will be ≈0.75”.
This is the bottom of the board. Operations completed – cutting to rough size, edge finish pass, rough facing and fly cutter finish.
Pending for bottom – drilling and counter bore for cap screws to hold the stainless and brass squares on the top side, chamfer.
Fixturing: Bolted to base plate on 0.75" spacers. Hand drilled 4 - 17/64" holes and then counterbored each individually while having 3 tightened to base plate at all times.
Parted off the excess stock:
End Mill: 0.5" 2 Flute (Needed the 1.5" flute to cut all the way through stock)
DOC: 0.25 (5 passes)
WOC: 0.5" (Slot cut on 2 sides)
RPM: 8000
Feed Rate: 15 IPM
MRR: 1.88
Three machinist jacks with slight preload support the excess stock
Finish pass 4th photo
Very nice work ! I guess this is an example that perhaps the baseplate as supplied with the machine is a bit small, it would be nice to be able to have hold downs outside the work envelope for those larger pieces. I was thinking of imbedding some threaded inserts outside the envelope to allow for hold downs … will need to decide that when my machine arrives next week.
As far the base plate, this piece is slightly larger. The bolts I used to secure the piece are 3 rows in from the left and 2 rows in from the right on the 2" x 2" - 1/4-20 grid on the base plate. I chose these positions because they will not interfere with any other operations and be canceled when complete. I used the machinist jacks just support the parted off section so it wouldn’t sag or vibrate on the final pass. It worked out fine, don’t think a larger base plate or additional inserts would have been helpful in this instance.
You may have noticed that the surface has some discoloration. I blew the piece off with compressed air, but did not wipe it down before leaving it overnight. The flood coolant stained the machined surfaces. Couldn’t clean it off chemically. The only things that worked, without getting too aggressive, were steel wool (fine) and polishing compound, but they introduce their own scratches into the machined surface. At least this is the bottom of the board. Although I do have staining on the finished edge that I will have to address.
You give me the content I need while I scratch my head waiting to hear back about what the heck is going on with the Canadian logistics for transport. Should have had my machine by now.
What a great project…can you walk us through one of the upcoming operations, like a shot of your CAD model, then your CAM model followed by a screen shot of your Gcode, then setting your G54 and setting the tool offsets for the cutter that will be used.
Finished the base today. Don’t have much to share this time, I was fighting my own inexperience and mistakes most of the time. Got the top faced off, fly cut and chamfered. Tried to get the outside 2" the best with the fly cutter, the rest of the non-sense in the middle will be covered.
