CNC 3018-Pro: Table Riser

With the 3018-Pro used for drag engraving on CDs and hard drive platters, there’s no need for all the clearance below the Z-axis carriage required for the OEM motor and ER11 collet chuck. A chunk of laminate countertop and a hunk of Celotex foam insulation produce a nicely flat surface 47 mm above the platform:

CNC 3018 Table Riser
CNC 3018 Table Riser

It’s surprisingly flat:

Table Flatness Measurement - 2019-08-30
Table Flatness Measurement – 2019-08-30

Those are millimeters of clearance between the gray plastic clamp around the diamond drag tool holder (about which, more later) and my trusty bench block, measured at 50 mm intervals across the platform. The lower figures appeared after tightening the upper-left screw by a little over 1/6 turn = 0.2 mm, making the entire platform flat & aligned within ±0.1 mm.

Yeah, not bad for a scrap countertop!

The four M6 socket head cap screws pass through the stack into T-nuts in the platform:

CNC 3018 Table Riser - screw clearance
CNC 3018 Table Riser – screw clearance

The countertop was thick enough to allow countersinking the screws slightly below the surface:

CNC 3018 Table Riser - screw countersink
CNC 3018 Table Riser – screw countersink

I transfer-punched the screw clearance hole locations into the Celotex and drilled it with an ordinary twist drill. It wasn’t pretty, but nobody will ever notice.

Two sheets, maybe 1 mm thick, of closed-cell foam below the Celotext provide enough squish to align the top surface without straining anything. The screws are firmly tight, so they shouldn’t work their way loose under minimal engraving loads.

Taping the CDs to the surface works well for now, although a simpler version of the fixture may be in order.