Why is Bridgeport cam ring loose in low position?

icecats · Jan 5, 2023

Hi,
I am reassembling a j-head Bridgeport and noticed that the cam ring is loose when turned to the low position. This appears to be because the step pulley does not fully lower onto the splined gear hub (the springs in the pulley are compressed). The cam ring is tight and seems to function properly when off the machine.
I inspected the splined gear hub and noticed sharp edges in the dog. The edges are very uniform so I'm wondering if this is machined on the original part (normal) or the result of wear?
Photos and video are here:

https://imgur.com/a/wCl9S5o

.
Thoughts?
Thanks!

Ralph_P · 2023-01-18T05:26:16-0600

Have you tried releasing the brake?

spaeth · 2023-01-18T07:02:23-0600

Not sure what you are referring to as the cam ring. But the lever that shifts between high and low range is adjustable. As I remember there are two different types of the engagement lever setup, depending on the age of the head. The later one has a tiny setscrew that when loosened would allow the lever to be adjusted to take up the slack. The other one has a little sliding part with a hole that sets the position of the lever and it can be moved up or down. The issue could be the pin or hole or both are worn and need replaced. There are some video's on you tube that address the Bridgeport back gear setup.
spaeth

Richard King · 2023-01-18T07:22:28-0600

spaeth said:
Not sure what you are referring to as the cam ring. But the lever that shifts between high and low range is adjustable. As I remember there are two different types of the engagement lever setup, depending on the age of the head. The later one has a tiny setscrew that when loosened would allow the lever to be adjusted to take up the slack. The other one has a little sliding part with a hole that sets the position of the lever and it can be moved up or down. The issue could be the pin or hole or both are worn and need replaced. There are some video's on you tube that address the Bridgeport back gear setup.
spaeth

Those coupling keys are suppose to be tapered a little so the deeper you move it it gets tighter. When they are worn they rattle when they are adjusted lower or deeper. Once they are loose you have to replace them or listen to the rattle.

spaeth · 2023-01-18T09:51:17-0600

My error, the cam ring is not used on the variable speed heads. I thought you were referring to the lever on the right which shifts between high neutral low. Richard's comment prompted me to look at the parts list and see that my post was about the wrong model head.
Right church, wrong pew. Glad you got it to quite down.
spaeth

rons · 2023-01-18T14:13:30-0600

icecats said:
Hi,
I am reassembling a j-head Bridgeport and noticed that the cam ring is loose when turned to the low position. This appears to be because the step pulley does not fully lower onto the splined gear hub (the springs in the pulley are compressed). The cam ring is tight and seems to function properly when off the machine.
I inspected the splined gear hub and noticed sharp edges in the dog. The edges are very uniform so I'm wondering if this is machined on the original part (normal) or the result of wear?

A cam ring move from low to high speed and the pulley assembly does not lower. It plops down immediately under power.
Whether that is healthy I don't know.

Richard King · 2023-01-18T15:59:25-0600

Call this guy. He used to work at Bridgeport factory and can rebuild a head blindfolded.http://www.besmermachinery.com/ or H&M Parts Depot. Both are excellent and sell parts and service..

rons · 2023-01-18T19:54:17-0600

From recent experience. The two set screws that keep the cam ring in place. Remove them from their thread holes.
You will find another two holes at about 90 degrees. I found that the heights of the two sets of holes are not in perfect
alignment. Use one set and the height of the cam ring is too low. Causes noise in back gear and the cam ring handle has
to be pushed up to remove the noise. Use the second set of thread holes and the height is just right.

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