The two gantry braces shown here are used to stiffen the gantry and to provide a means for connecting the stepper motor and the bearing block.

Since the gantry overhangs the carriage 1/4" on each side a pocket has been milled out so the braces can connect directly to the Y extrusion and gantry.

 

Gantry Brace Assembly

Left Brace

The left brace holds the bearing block, which is assembled before attaching to the gantry.

The brace can be slid into place via the 8 1/4 x 1"carriage bolts. 

Once in place the 8 1/4" x 1" bolts are used to secure the brace to the gantry.

An exploded view showing the bearing block and various hardware components.

Note that unlike the Y bearing blocks these are installed on the outside of the brace.

 

Right Brace

The right brace holds the motor which can be installed ahead of time.

The brace can be slid into place via the 8 1/4 x 1"carriage bolts. 

Once in place the 8 1/4" x 1" bolts are used to secure the brace to the gantry.

An exploded view showing the motor and various hardware components.

 

ACME Screw Installation

The screw is slid in through the bearing block.

The inside thrust bearing and clamp collar are added to the screw.

Important!!!

A 3/8" to 1/2" spacer needs to be added between the collar and the thrust bearing. This is to make sure the collar protrudes enough so that we have access to the clamp screw.

The screw is then screwed into the ACME nut.

Once through the nut its inserted into the helical coupler.

The inside collar is pressed tightly against the spacer and thrust bearing and tightened.

The outside thrust bearing and collar are added. The collar is pressed firmlly against the thrust bearing and bearing block and tightened.

 

Conclusion

Both the X and Y drives have been added, its time to start looking at the Z axis.