What's new
What's new

Bridgeport M head clock spring

techymechy

Aluminum
Joined
Oct 24, 2018
Howdy,

The clock spring on my Bridgeport M head came undone. I don't thing it was ever properly tensioned. The spring is still in the head and it had the slots in it to keep it wound. How does one tension the spring?

Thanks for your help.


Dave
 

techymechy

Aluminum
Joined
Oct 24, 2018
Hi akjeff. Thanks - I saw that video. This is for the J head. I have a M head where the spring is on the LHS of the head. I'll take some pictures tomorrow.

I worked on the spring a little bit tonight and think I screwed it up. I tried to wind the spring with some needle nose pliers and a little square chunk broke out about 1" from the end of the spring. I also noticed that the spring may be moving in the head so I wonder of the spring end closest to the head castings may be broken out.

How much of these springs can I guy cut off and still have it work?

I can't see an easy way to tension the spring on a M head. Does anyone have a suggestion?

Thank for your help.
 

techymechy

Aluminum
Joined
Oct 24, 2018
I talked to H&W about how to do this and if I needed to purchase a new clock spring.

I removed my spring and it was blown out on the end that connects to the main casting. I screwed up the spring on the end that connects to the shaft that connects to the down feed handle.

The spring material shears quite nicely so I snipped the ends off. I am using a small Whitney hand punch to make the holes in the spring for the pins. Worked great.

To reinstall the spring, I was told to do this:

1. Remove the micro adjust screw, micro adjust nut and jam nut.
2. Lower quill until it just disengages from the pinion gear. Be sure to support the quill so it does not fall out.
3. Close the spring so that it fits into the housing, install the spring and connect the ends.
4. Use the quill down feed handle to wind the spring. I wasn't given any amount. This will have to be determined. Raise quill and engage pinion gear.
5. Insure that the quill is not dropping or raising and adjust the spring tension as necessary by dropping the quill and adjusting the amount of spring tension.
6. Reassemble.

I'm 1/2 way through remaking the holes in the end of my spring. H&W told me that I can remove a couple of inches from the spring and everything will be fine.

Hopefully, I'll get this done tonight to confirm that everything worked out. I thought that this should be documented somewhere.

Dave
 
Last edited:

browniesharp

Aluminum
Joined
Aug 23, 2004
Location
Somerville, NJ
I posted this over at Bridgeportmill @groups.IO forum back in Feb of this year.


Replacing Clock Spring in M head

  • Remove Motor
  • Remove drawbar
  • Loosen ½ inch bolt on pulley assembly and pull upward to remove. If difficult to remove, twist around back and forth to generate heat necessary to expand aluminum housing
  • Remove depth setting apparatus on front of mill head
  • Remove ½” cap screw from microstop.
  • Push quill upward to limit and remove the quill skirt. Note the tabs are down.
  • Remove the quill feed clutch knob and then the three screws and spring cover.
  • Gloves and a faceshield should be worn.
  • With the quill fully upward, remove the inner spring portion from the nub on the pinion shaft. Carefully remove the spring by pulling it out.
  • After many hours of vain attempts with the approaches from the internet,
  • I decide to just “Man Up” and try to wind the spring in place with just my bare hands (with leather gloves and face shield). I attached the outer end of the spring on the hook inside the housing section of the M Head. Wind the spring into the “well” clockwise forcing the spring inside the proceeding wrap with your fingers. This gets easier with each additional turn. Eventually you will get to the nub on the inside pinion shaft. Now rotate the feed lever until the nub lines up with the inner slot in the spring and with a small screwdriver force the slot of the spring over the nub. I did this whole process in probably 5 minutes in one shot. I don’t consider myself has having strong fingers or hands. At this point, view M Head Matters 5 (there is a series of YouTube videos by “Unknown Apprentice” titled “M Head Matters”) at around 20 – 24 minutes for final adjustments.

I also have an additional original M head clockspring taken from a canabalized M head which appears in good condition
 

techymechy

Aluminum
Joined
Oct 24, 2018
Hi Brownie,

We basically did the same thing. I used nearly the same technique as you except you took your quill up and I took my quill down. Thanks for posting your technique too. I used my 3 Jaw chuck on my lathe to wind my spring. Here are some additions to my technique:

A couple of pointers:
1. I used a Whitney No 15 (I think) hand punch for punching the end holes in the spring material
2. I used tin snips to removed the damaged ends of the spring
3. The 3 Jaw chuck technique works great for winding the spring before inserting into the head
4. I used needle nose vice grips to wind the spring and transfer it from my lathe to the M head. The pliers were only gripped about 1/2 of the spring thickness. The other half was used for placing the spring into the casting. When I placed the spring in the round chamber on the M head, I used my hand (wearing gloves) to hold the spring in the head and push when I released the vice grips. Worked great.
5. I shortened my spring about 2". This meant I had to push the pin in a little that catches the spring on the main head casting.
6. I think I wound my spring about 2 to 2 1/2 turns then engaged the quill into the pinion gear. I would not go less than 2 1/2 turns of the down feed handle. I just barely snug my fine feed engagement knob that provides a little friction too. This works fine. Since I shortened my spring, I didn't want to wind it too tight.

I also posted this on the Bridgeport.io group as well. I searched over there but didn't find your article. Hopefully, this web site is more searchable on Google, etc.

Dave
 
Last edited:

akjeff

Aluminum
Joined
Nov 17, 2008
Location
AK
Crap, didn't catch you were working on an M head, sorry! Glad you got it sorted out.
 

techymechy

Aluminum
Joined
Oct 24, 2018
I posted this over at Bridgeportmill @groups.IO forum back in Feb of this year.


Replacing Clock Spring in M head

  • Remove Motor
  • Remove drawbar
  • Loosen ½ inch bolt on pulley assembly and pull upward to remove. If difficult to remove, twist around back and forth to generate heat necessary to expand aluminum housing
  • Remove depth setting apparatus on front of mill head
  • Remove ½” cap screw from microstop.
  • Push quill upward to limit and remove the quill skirt. Note the tabs are down.
  • Remove the quill feed clutch knob and then the three screws and spring cover.
  • Gloves and a faceshield should be worn.
  • With the quill fully upward, remove the inner spring portion from the nub on the pinion shaft. Carefully remove the spring by pulling it out.
  • After many hours of vain attempts with the approaches from the internet,
  • I decide to just “Man Up” and try to wind the spring in place with just my bare hands (with leather gloves and face shield). I attached the outer end of the spring on the hook inside the housing section of the M Head. Wind the spring into the “well” clockwise forcing the spring inside the proceeding wrap with your fingers. This gets easier with each additional turn. Eventually you will get to the nub on the inside pinion shaft. Now rotate the feed lever until the nub lines up with the inner slot in the spring and with a small screwdriver force the slot of the spring over the nub. I did this whole process in probably 5 minutes in one shot. I don’t consider myself has having strong fingers or hands. At this point, view M Head Matters 5 (there is a series of YouTube videos by “Unknown Apprentice” titled “M Head Matters”) at around 20 – 24 minutes for final adjustments.

I also have an additional original M head clockspring taken from a canabalized M head which appears in good condition
Hey Brownieshatp,

I’d be interested in purchasing your spring if you want to sell it. I PM’d you earlier. Please PM me back.
 

Shiseiji

Aluminum
Joined
Sep 15, 2014
Additional comment. I made basically a simple open end clock spring barrel from a 4" piece of plywood with a hole in the center, a hose clamp, and a hard ware store mending plate. Put the spring in the hose clamp, the mending bar on top of the spring and hose clamp, and screw the mending bar to the plywood. Use the hole in the plywood to wind the spring, tightening the hose clamp until the diameter is smaller than the well in the head. Remove the hose clamp with the spring and, after positioning the quill as above, push the spring into the well attaching it to the counter balance shaft and the spring catch.

Ron
 








 
Top