Bridgeport Power Feed 6F not engaging properly- Any ideas?

JetMech · Apr 26, 2020

Hi Folks,

I have a 1986 Textron-vintage BP with a 6F power feed on the table.

When bought, the feed would work but wouldn't engage easily in one direction.

I opened it by removing the front plate, cleaned out the ancient oil, and wiggled the parts around. All looked good so I put it back together and added new oil.

It works in both directions, but when you move the lever over, it takes a bit for it to "catch" and start driving the table. Sometimes it will just move as it should, but often it will "grind the gears" for a second, maybe a few gear teeth worth before it drops into mesh and starts driving.

It sort of feels like a spring that pushes the gears into mesh is weak, but I'm not sure if there even is such a spring- HW lists a spring in their parts breakdown, but I'm not sure it's the issue.

Am I on the right track? What can I do to make the thing engage positively every time?

Thanks for any help you can offer!

projectnut · Apr 26, 2020

I would give the guys at H&W Machine Repair a call:

H&W Machine Repair & Rebuilding - Parts and Service for the Metalworking Industry

They specialize in anything Bridgeport. They're easy to talk to and more than happy to help. If you do need parts they're one of the few places that will have them.

I have no affiliation other than being a satisfied customer.

HWElecRepair · Apr 27, 2020

The spring behind the gear isn't necessarily there to engage the gear. If it isn't engaging properly when you put it in gear, my guess is that your switches have some oil in it and are sticking. As far as the teeth grinding, my guess would be that the driven gear has the .600 race or the cam follower isn't in the right spot in the slot on the bar... it could also be that the bar is not properly tightened and is loose and allows the clutch to slip.

Can you take the front cover off (I know you just filled the housing with oil) and post a pic of the interior for us to look at?

Jon
H&W Machine Repair

JetMech · May 4, 2020

projectnut said:
I would give the guys at H&W Machine Repair a call:

H&W Machine Repair & Rebuilding - Parts and Service for the Metalworking Industry

They specialize in anything Bridgeport. They're easy to talk to and more than happy to help. If you do need parts they're one of the few places that will have them.

I have no affiliation other than being a satisfied customer.

Well, that's some good advice- But Jon beat me to the punch!

JetMech · May 4, 2020

HWElecRepair said:
The spring behind the gear isn't necessarily there to engage the gear. If it isn't engaging properly when you put it in gear, my guess is that your switches have some oil in it and are sticking. As far as the teeth grinding, my guess would be that the driven gear has the .600 race or the cam follower isn't in the right spot in the slot on the bar... it could also be that the bar is not properly tightened and is loose and allows the clutch to slip.

Can you take the front cover off (I know you just filled the housing with oil) and post a pic of the interior for us to look at?

Jon
H&W Machine Repair

Jon,

I was advised to ask you, but you must have heard us talking about you. . .

Seriously, thank you for your time and your advice. I made a video of the issue in the hope that it makes it easier for you or others to advise me.

Here is the link to the short YT vid:

YouTube

Maybe that will enlighten you as to what I'm missing. I'm not sure, but it seems that the rightmost spring that pushes out the splined "driven clutch" part may be weak.

It is also possible that I'm expecting too much- maybe you always have to "wiggle the handle" prior to engaging the feed. I have no prior experience against which to judge, but I'd think that the thing should engage positively each time.

What do you think might be the matter?

Thanks in advance, to Jon or anyone else who'd like to suggest something.

pieterb · May 4, 2020

Hello, interesting issue. I have a similar problem but only when the speed is set to high and only in one direction. So I am already used to lower the speed, engage the lever and then change the speed again. I am interseted in the possible solutions for your problem (and maybe mine also).

greetings

HWElecRepair · May 5, 2020

Dang, had my entire comment typed out and then had a database timeout, freaking PM.

Dont think of that spring as being what pushes the driven clutch into the gear. That is a tiny spring and is not designed for that. The cam follower that sits inside of the race is what moves the driven clutch and holds it in place. The issue is that the cam follower OD is 500 thou and the raceway of your driven clutch is 600 thou. For a time, especially in 8F powerfeeds, the driven clutch ID is 515 thou, giving next to no room to jump back and forth and chatter. If you have the cam follower adjusted properly (it sits inside of a slot in the cam arm), the cam arm tight, then that will hold the gear in place and it wont be able to push back. I am working with HQT to get those driven clutches back to the proper dimension since they went back to the 600 thou race. If you need a driven clutch, you got 2 options. Get some shims, cut em in half, and get them onto the race to make up the difference or find you a proper sized one. I am down to just one, so unfortunately I cant offer mine.

If you get too strong of a spring it will not allow the power feed to disengage and go into neutral. Getting a stronger spring could help, but its just a bandaid.

@pieterB does yours only chatter or does it actually come out of gear?

Jon
H&W Machine Repair

JetMech · May 6, 2020

HWElecRepair said:
Dang, had my entire comment typed out and then had a database timeout, freaking PM.

Dont think of that spring as being what pushes the driven clutch into the gear. That is a tiny spring and is not designed for that. The cam follower that sits inside of the race is what moves the driven clutch and holds it in place. The issue is that the cam follower OD is 500 thou and the raceway of your driven clutch is 600 thou. For a time, especially in 8F powerfeeds, the driven clutch ID is 515 thou, giving next to no room to jump back and forth and chatter. If you have the cam follower adjusted properly (it sits inside of a slot in the cam arm), the cam arm tight, then that will hold the gear in place and it wont be able to push back. I am working with HQT to get those driven clutches back to the proper dimension since they went back to the 600 thou race. If you need a driven clutch, you got 2 options. Get some shims, cut em in half, and get them onto the race to make up the difference or find you a proper sized one. I am down to just one, so unfortunately I cant offer mine.

If you get too strong of a spring it will not allow the power feed to disengage and go into neutral. Getting a stronger spring could help, but its just a bandaid.

@pieterB does yours only chatter or does it actually come out of gear?

Jon
H&W Machine Repair

Jon,

Thanks again for your help. I'll take it apart this weekend and see if I can see what you're describing for me. Thank you for your patience.

pieterb · May 9, 2020

Hello Jon,

when I engage the lever, the cams inside chatter and the feed is very slow ( the cams slip), when I slow down the feedrate there is no chatter and the cams engage without a problem.
See video on youtube.

greetings

HWElecRepair · May 10, 2020

Without seeing the inside of the ger box, this sounds like its a similar issue, or the teeth on the two gears are wearing.

Jon

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