BPort J Head Noise

I am the proud new owner of a Bridgeport Series 1 with a step pulley J head. I just got it up and running and had a question for any BPort owners out there. When running the head in any speed except back gear the head makes a small thump- thump noise. I think I have tracked it down to looseness between the spindle and quill (if I hold the front pulley stationary I can rotate the drawbar back and forth about 15 degrees which causes the same noise I hear when running. How much looseness is normal? what are the possible causes? I bought the machine from a dealer who was supposed to have checked the machine over before selling it to me. Please give me your advice so I can go intelligently discuss this issue with the dealer.

Loosen the 3 nuts that hold the upper half to the lower half of the head while it is running in lowest speed of direct drive.
There will be a little play and will help the upper half to align with the spindle axis of rotation.
No noise in backgear you said?
Let me know how you do.
Paul

Hi Paul,

I tryed your suggestion of loosening the three bolts, there was no change in the noise. The noise is a very slight thump -thump only in direct drive. I am not sure exactly how the clutch mechanism engages between the spindle and the front pulley but if I hold the pulley stationary I can rotate the spindle back and forth 10 to 15 degrees. I imagine some amount of play is normal but is this amount OK. Could this be the source of the noise since when in back gear this would be disengaged?.

Thanks for your help!

Smike740

Sounds like worn clutches. The clutches are face type clutches with the "teeth" ground at a 7 degree taper. As they wear, they drop further into each other until they bottom out. At that point they are shot. Try removing the cam ring and reinstalling the pins. This will allow the clutches to engage the maximum amount. If some of the play disappears, I would say that the cluthes are shot. If all of the play disappears then something is wrong. Maybe someone had it apart and didn't assemble it correctly. 15 degrees of slop is a lot. Good luck. Bill

Sounds like the timing belt to me. There is a "cogged" belt below the motor and step pully housing. This is what runs the spindle in high gear. If you don't have any play in back gear, I would look into this. It's been a long time since I've had a BP head apart so I,m just going from memory.

Resurrecting old post...

I've also tried these suggestions and my slop did not go away.

Anyone have a source for new clutches?

Thanks much for any help.

TominDallas

Try this link

http://www.matacoinc.net/

also http://www.hqtinc.com

good luck,

tom