Help with Bridgeport Mill noise

iusedtoberich

AzB Silver Member
Silver Member
I finally got my Bridgeport mill wired up this weekend. The head makes a very loud noise, and I was hoping someone here might recognize the sound and have a good idea of specifically what part needs to be replaced/repaired. There is a short sound clip at the end of this thread you can download to hear the sound. It is actually quite a bit louder, but my microphone is not great.

Mill specifics: 2J vari-speed head, 2 HP motor, early 1980's production, appears to be in very good condition otherwise.

Some observations I have made: The noise is about the same in high and in low gear. It is definitely not a noise coming from the spindle like a bearing, because when in low speed and gear (60 rpm), the frequency of the noise is MUCH higher than the spindle speed. The noise does get slightly louder when changing the vari-speed drive to a higher speed (within the same speed range).

I believe this is a common problem. When I bought the mill, I had the guy power up several mills so I could swap this head for a better one, and they all made about the same noise.

I have bought and read the maintenance manual for this machine. The only reference about noise it mentions is something about an adjustment of a small part that controls the clutch and is by the high/low/neutral lever. It looks like I have to take the head partially apart to get to this.

I have seen some kits on ebay that replace the plastic bushing (part 59 in link below) for the reeve's drive pulleys (the cone shaped pulleys). They claim this could be a cause for noise and vibration. I don't know if this is the problem my machine has or not.

I figure I will have to take the head apart, but I was hoping someone here might have a good idea of what area to look at. I'm also going to post this in a metalworking forum where there are probably more people with rebuilding experience.

Here is a link to an exploded view of the head. If you think you know where the problem could be, please refer to the drawing numbers they use so we can communicate effectively. You have to click on "Bridgeport Replacement Parts" then "Variable Speed Top Housing Assembly"


Thanks,

Nick
 

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iusedtoberich said:
I finally got my Bridgeport mill wired up this weekend. The head makes a very loud noise, and I was hoping someone here might recognize the sound and have a good idea of specifically what part needs to be replaced/repaired.

Hey Nick, I'd suggest posting this to rec.crafts.metalworking . There are a lot of very helpful people there, and you will likely get some good input.

Dave
 
iusedtoberich said:
I finally got my Bridgeport mill wired up this weekend. The head makes a very loud noise, and I was hoping someone here might recognize the sound and have a good idea of specifically what part needs to be replaced/repaired. There is a short sound clip at the end of this thread you can download to hear the sound. It is actually quite a bit louder, but my microphone is not great.

Mill specifics: 2J vari-speed head, 2 HP motor, early 1980's production, appears to be in very good condition otherwise.

Some observations I have made: The noise is about the same in high and in low gear. It is definitely not a noise coming from the spindle like a bearing, because when in low speed and gear (60 rpm), the frequency of the noise is MUCH higher than the spindle speed. The noise does get slightly louder when changing the vari-speed drive to a higher speed (within the same speed range).

I believe this is a common problem. When I bought the mill, I had the guy power up several mills so I could swap this head for a better one, and they all made about the same noise.

I have bought and read the maintenance manual for this machine. The only reference about noise it mentions is something about an adjustment of a small part that controls the clutch and is by the high/low/neutral lever. It looks like I have to take the head partially apart to get to this.

I have seen some kits on ebay that replace the plastic bushing (part 59 in link below) for the reeve's drive pulleys (the cone shaped pulleys). They claim this could be a cause for noise and vibration. I don't know if this is the problem my machine has or not.

I figure I will have to take the head apart, but I was hoping someone here might have a good idea of what area to look at. I'm also going to post this in a metalworking forum where there are probably more people with rebuilding experience.

Here is a link to an exploded view of the head. If you think you know where the problem could be, please refer to the drawing numbers they use so we can communicate effectively. You have to click on "Bridgeport Replacement Parts" then "Variable Speed Top Housing Assembly"


Thanks,

Nick

Sounds like the belt.Take the cover off so that you can see if it flops around when you turn the machine on. I have two of those machines. If you need any more help email me or call me (352) 551-7171.
 
Dave: Thanks for the link. I searched their archives and got lots of good information.

Murray: I don't see any cover on my machine that would allow me to see the belt. Either I'm completely missing something, or you are thinking of a step-pulley head. I have the vari-speed head.

Sheldon: A link type belt won't work here. This machine uses a Reeves drive to achieve infinitely adjustable variable speed by changing the diameter of the motor and drive pulleys. Below is a picture of this mechanism so you can see how the pulleys effectively change diameter.

I did some more tinkering with the machine, and I have determined it is not any issues with the back gears or the clutch that engages them. I will pull the motor this weekend and check that separately. I suspect it is the delrin bushings that the cone pulleys slide on. This is what the problem has been in the past on rec.crafts.metalworking.

Thanks for everyone's input,
Nick
 

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iusedtoberich said:
Murray: I don't see any cover on my machine that would allow me to see the belt. Either I'm completely missing something, or you are thinking of a step-pulley head. I have the vari-speed head.

Thanks for everyone's input,
Nick

Mine is variable speed. You inspect the belt by taking off the cover that says "Bridgeport". It might be something more than the belt but that is a good place to start.
 
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Is yours the Series 2 CNC version? Mine is different, and does not have any large openings. There is a small 1/2 inch opening in the front that I could peek through to see the belt. It looks ok while its running, but its hard to tell because the only part of the belt I can see is the part right in the front of the pulley. I'm going to pull the motor tomorrow. Run it not attached to the belt to rule out the motor, then I'll check the belt. Thanks for the help.
 

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