Hoffman Mechatronics
Bridgeport Mill J1 Rebuild
In this section of the document I will attempt to clarify the disassembly and reassembly of the
various subassemblies that make up the J-Head. The order of disassembly allows someone to
fully disassemble and categorize their parts on a subassembly basis.
Before attempting to work on any portion of the J-Head, remove power from the machine.
4.1 J-Head R & R
The J-Head as shown in Figure 13 below is secured to the front of the Ram Adaptor using 4 large
bolts and nuts that ride in a T-Track on the Ram Adaptor. As you can see from this figure, I have
removed the motor and drive assembly before attempting to remove the J-Head. This makes the
unit more manageable and much lighter.
J-Head
Mounting Bolts
J-Head
Mounting Bolts
J-Head
Mounting Bolts
J-Head
Mounting Bolts
Figure 13 - J-Head Mounting
4.1.1 J-Head Removal
You should be sure to support the J-Head before loosening the 4 bolts that secure it to the Ram
Adaptor. The J-Head weighs in the neighborhood of 60-70 pounds and is very awkward due to
the length of the spindle shaft, and the rotation of the spindle. You may think you have a good
grip, then something will spin and this unit will go flying out of your hands. You can remove the
J-Head from the unit with the Power Head attached, but keep in mind that this makes the unit
another 50-60 pounds heavier.
BPJ1RBLD_002
19
January 31, 201111
