CNC router – upgrades

Although the V-slot gantry plates provide a simple solution for an initial prototype, a problem with them is the placement of the bolts. Because I wanted to use the existing holes in the THK linear actuators some of the bolts fall behind the actuators and as the gantry plates are only 3 mm thick there is no room to countersink them. So the linear actuator rests at the bolt heads.

The Y-axis linear actuator can only be placed on top of the screw heads
The Y-axis linear actuator can only be placed on top of the screw heads

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For the connection between the z-axis and Kress bracket this was even more problematic because this uses M8 bolts with large heads.

Z-axis bolt heads cannot be countersunk
Z-axis bolt heads cannot be countersunk

Also I noticed that the gantry plates bend very easily because they’re only 3mm thick and have a lot of holes.

Gantry plates bend
Gantry plates bend

Therefore one of the first things I used the first prototype of the router for is milling new customized aluminum connection plates.
15 mm thick ones for the z-axis so that the M8 bolts can be countersunk, 6 mm ones for the x- and y-axis connections.

 

Z-plate design in Estlcam
Z-plate design in Estlcam

 

G-code imported in Mach-3
G-code imported in Mach-3

 

Milling the countersink holes for the M8 bolts of the Z-axis plate
Milling the countersink holes for the M8 bolts of the Z-axis plate

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Kress bracket mounted to the new Z-axis plate
Kress bracket mounted to the new Z-axis plate

 

Milling the Y-axis mount plates
Milling the Y-axis mount plates

Despite the limitations of the first prototype I was pleased with the accuracy: the 15 mm plate that connects to the double table of the z-axis actuator has 8 holes and all bolts fit perfectly.

For fun I tested the text engraving function of the Estlcam software and put my initials in the front Y-axis connection plate. Although I didn’t have an optimal mill bit for engraving in aluminum the result didn’t look too bad.

Y-axis connection plate with initials engraved
Y-axis connection plate with initials engraved

The custom design of the new plates makes it possible to place the bolts that connect it to the V-slot rails left and right of the linear actuator instead of behind it so that it’s easier to position it with even more precision.

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