Hoffman Mechatronics
Bridgeport Mill J1 Rebuild
4.6.2 Feed Driving Gear Assembly Inspection
Inspect all of the gear teeth to ensure that they are not worn, and that there are no teeth missing.
If you find excessive wear, or absent teeth, replace the offending part. You will want to inspect
the roller bearing at the end of the Cluster Gear Input Shaft for dirt, rust, or jerky movement.
Gravity tends to deposit dirt in this bearing, and most times it is safer to replace than hope it
doesn’t fail in the future. You will also want to inspect the sliding gear assembly to ensure that it
moves freely on the shaft.
4.6.3 Feed Driving Gear Assembly Reassembly
Assembly follows the reverse order of disassembly except that you must adjust the pinion gear
that makes contact with the overload clutch ring gears. This adjustment is made by adjusting the
height of the pinion gear during reassembly. The goal during reassembly is to ensure that the
pinion gear does not bind on the overload clutch assembly ring gears, but is also not so loose that
the teeth chatter excessively. Experiment with tapping this shaft downwards until the gears no
longer move smoothly, and then backing the shaft up until the gears once again move smoothly.
Once you are happy with the setting, you can secure the height of the shaft by securing it with
the grub screws.
4.7 Feed Reverse Gear Assembly RIR
The Feed Reverse Gear Assembly is responsible for providing you with the ability to reverse the
Quill Feed direction, as well as providing a hand wheel for micro adjustments to the quill height.
4.7.1 Feed Reverse Gear Assembly Removal
When removing the Feed Reverse Gear components you have to be careful. There is a small ball
bearing, 3/16 to be exact that acts as a detent ball for the Feed Reverse Selector Shaft. There is
also a very small spring that is applying pressure to the detent ball. Figure 24 below shows this
ball bearing, the spring, and the retaining cup that holds everything in place. Before removing the
Hand wheel Clutch you will want to remove these items and place them into a baggie.
Mounting Hole for
Reverse Feed Detent
Ball Assembly
Hand wheel clutch
3/16” Detent Ball
Figure 24 - Reverse Feed Gear Assembly
BPJ1RBLD_002
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January 31, 201111
