Denny Graham
Aluminum
- Joined
- Sep 1, 2004
- Location
- Sandwich, IL
I've got an old 50's round ram Bridgeport with a J-head, small table
and knee that I've been using for about 30 years. About a decade or so
back, I got a bargain on a 2hp variable speed Bridgeport with the
intention of restoring it for use in my home shop one day, which would
give me much more travel then my old round ram mill.
So....this past winter I started work on the new mill. Had the motor
rewound for 220v 3ph (was hard wired for 440v 3ph). New Bijur pump,
metering units and plumbing. Fixed or made a couple dozen more things
that were missing, bent and nicked up from abuse by the previous owner.
Now here it is, summer and I'm just now getting time to actually make
some chips and see what other problems are going to pop up.
I'm well aware that 1/2 the machinists are of the belief that the
collet alignment screw is not necessary in a Bridgeport mill and the
other 1/2 believe that Bridgeport puts them in every machine they've
made for a reason. I fall in the second group and mine was missing it,
so I ordered a screw 'set', installed and adjusted it yesterday before
I even tried installing a collet in the mill.
Well, the first thing that I noticed was that the collets seated all
the way up flush into the spindle before the draw bar was threaded
into them. This seemed odd because in the old J-head on my round ram
the collets would initially stick out about 1/8" or so before they
were drawn up.
When I tried to tighten up the collet in the new mill the thread
bottoms out before it is drawn up tight. The first thing that came to
mind was that something was wrong with the draw bar. But I've got
three, one from my J-head, one that came with the mill and a spare that
I picked up somewhere along the line. All three are the same length
from the thread to the contact shoulder at the top. Next I thought that
the taper in the spindle may have been damaged along the way, from a
spinning collet due to the lack of the alignment screw and not being
tightened up correctly.
But the taper feels perfectly smooth, as it should be and appears never
to have been damaged.
So, I'm at a loss as to what's going on here. Over the years I've
worked on many Bridgport's and can't recall ever having a collet seated
all the way up flush with the nose of the spindle before it engaged
the draw bar and never had one that wouldn't draw up the tooling
tight in a good R-8 collet.
Any ideas??????
Denny Graham
Sandwich, IL
and knee that I've been using for about 30 years. About a decade or so
back, I got a bargain on a 2hp variable speed Bridgeport with the
intention of restoring it for use in my home shop one day, which would
give me much more travel then my old round ram mill.
So....this past winter I started work on the new mill. Had the motor
rewound for 220v 3ph (was hard wired for 440v 3ph). New Bijur pump,
metering units and plumbing. Fixed or made a couple dozen more things
that were missing, bent and nicked up from abuse by the previous owner.
Now here it is, summer and I'm just now getting time to actually make
some chips and see what other problems are going to pop up.
I'm well aware that 1/2 the machinists are of the belief that the
collet alignment screw is not necessary in a Bridgeport mill and the
other 1/2 believe that Bridgeport puts them in every machine they've
made for a reason. I fall in the second group and mine was missing it,
so I ordered a screw 'set', installed and adjusted it yesterday before
I even tried installing a collet in the mill.
Well, the first thing that I noticed was that the collets seated all
the way up flush into the spindle before the draw bar was threaded
into them. This seemed odd because in the old J-head on my round ram
the collets would initially stick out about 1/8" or so before they
were drawn up.
When I tried to tighten up the collet in the new mill the thread
bottoms out before it is drawn up tight. The first thing that came to
mind was that something was wrong with the draw bar. But I've got
three, one from my J-head, one that came with the mill and a spare that
I picked up somewhere along the line. All three are the same length
from the thread to the contact shoulder at the top. Next I thought that
the taper in the spindle may have been damaged along the way, from a
spinning collet due to the lack of the alignment screw and not being
tightened up correctly.
But the taper feels perfectly smooth, as it should be and appears never
to have been damaged.
So, I'm at a loss as to what's going on here. Over the years I've
worked on many Bridgport's and can't recall ever having a collet seated
all the way up flush with the nose of the spindle before it engaged
the draw bar and never had one that wouldn't draw up the tooling
tight in a good R-8 collet.
Any ideas??????
Denny Graham
Sandwich, IL