Hoffman Mechatronics
Bridgeport Mill J1 Rebuild
Figure 41 - Table Nearly Ready for Removal
With all of these components removed, the table should be free to slide off of the mill. The only
exceptions could be any way oiling, or flood fluid return plumbing that may be connected. Please
ensure that all peripherals are removed prior to sliding the table off. The table weighs
approximately 200 pounds, and has a precision surface, and ways. You do not want to damage
any of these surfaces, so take care to lift the table with an appropriate lift, and set it on a surface
that will not mar the ways. I tend to fasten chains to the bearing retainer holes and use an engine
lift to slide the table off. As I tend to do much of my work alone I find an engine lift invaluable.
6.3.2 Table Inspection
Many people have asked me how I inspected my table, and what I was looking for. First and
foremost we want to inspect the ways for any excessive wear. At machinery rebuilding facilities
this is done with the use of specially built granite or cast standards. These standards are
manufactured to the correct angle and dimension of the ways and used with surface plate dye
will help to show inconsistencies in the surface.
I placed my table upside down on a granite surface plate first and used a dial indicator to
categorize the way surfaces to determine the extent of wear on the way surfaces. I then turned the
table over, blocked it up and used the same dial indicator to measure the surface. If your table
surface or ways are extremely bad, I would recommend a machine rebuilding service. While you
are able to acquire all of the tools required to true the table, saddle, knee and pedestal; you will
find that it quickly becomes cost prohibitive to purchase all of this equipment for a single use.
The ways on my table were acceptable for the types of work I was going to be performing, but
the table surface had been abused over its lifetime. Fortunately for me I found a machine shop
capable of resurfacing my table. They elevated the table onto custom made parallels that were
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January 31, 201111
