BP Series 1 - 2J Head - Brake Malfunction

middle.road

middle.road

Granite Stoopid...
H-M Supporter Gold Member
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Apr 28, 2014
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I'm not going to have the time until later tonight to do some in depth searching, and I need to save some time.
I figure to post this and rely on the H-M expertise pool to save me. :grin:

Right in the middle of a run, and the brake lever, no matter which way I throw it, it will not hold the spindle.
Break it to me gently.
Am I looking at having to tear into the Head?
Any possibility it's something in the handle linkage?
What are the chances that the brake shoes are still good?

I'm heading back out into the shop to try to get the drawbar loose and get the collet out.
And yes, the key inside is missing... *SIGH* Just when I was rolling. Thanks!


-=-EDIT-=- Cool! Who fixed it for me?
Went up to it, addressed it kindly, jiggled the lever back & forth and around, grabbed it and it stopped at the '8 O'Clock' position.
Locked and I removed the cutter and collet.
90 minutes ago it wasn't grabbing. Moving the lever clockwise it would got around to a 9:30-10:00 position, CCW it would go to a 2:00-2:30ish.
Now it's grabbing at 4&8.
What the heck? Big Arse Gremlins? I don't get it.
 
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I guess at this point I'd consider yourself lucky. I like when things take care of themselves. :encourage:

Not sure it is a good sign for the long run, it may be a precursor to failure at a later date. But, for now, consider it a fluke and move on. In the future when or if something more permanent should fail, yes, you'll have to remove the head cover and just dig into it. The brake itself is a very simple mechanism once you get to it. And getting to it really isn't all that bad once you decide to just go for it.
 
If you don't already have one it might be in your interest to download a copy of the Bridgeport Series I Manual. Here's a link to a copy on the Hardinge website:

http://hardingeus.com/usr/pdf/Knee Mills/SeriesIPartList4302Plus.pdf


The second half of the document includes pictures and parts lists of all the components. The PDF pictures will lead you in the right direction, but they aren't the best quality. Once you find the basic picture you need I would go to the H&W Machine Repair and Rebuilding website and access the same picture. Here's a link to the variable speed gear assembly on the H&W website:

http://www.machinerypartsdepot.com/store/1478157/page/553410

Note it does include the brake assembly

H&W has excellent pictures of all sections of the machine, and carries almost every part needed to repair a Series I machine.
 
Thanks for the links! I didn't get the time last night to watch any videos.
I did read over Paul's (expressline99) post and picts on his rebuild, before fading off. Should have went for a belt drive model /me thinks...

Once nice thing is that I have the original manual that came with the machine. That plus the links above at least give me plenty of information. Lucky on that for sure.
I was thinking that I should go ahead and get a belt since it still has that 'Clunk' that it came with. It has calmed down a tad but is still very prevalent.
$65 for a belt, $60 for shoe (if req'd) *ouch*. I thought I had a belt laying around from an auction lot, but never found it.

This one has me stumped. At least I managed to get through what I needed to & finished up.
Something doesn't feel right on this lever linkage, perhaps that might be where the problem lies. (Hope Springs Internal...)
Today I would like to get around to making a T-Nut for the BXA and get it on the Birmingham.
And of course, I managed to score some side work to help out the ol' budget, and really can't afford to tear it down currently.
 
Silverbullet said:
Could the brake be rubbing heating up and expanding. It's not dragging when running is it.
Click to expand...
It possibly was during it's previous life. I've slapped it back and forth to find the sweet spot before engaging the motor, because I noticed it was dragging when I first fired it up. So I've made it a habit to do that.
How much you want to bet that the previous operator laid on the brake all the time?
 
Years ago when taking classes on basic machining we used Bridgeport Series I machines. They were all the variable speed and worked very well. Our instructor was adamant that any time you removed power from the spindle the brake was to be applied. I never liked the idea thinking at the rate and number of times the brake was applied each day the shoes would wear out in a year or two.

I have a Series I with the variable speed head in my shop. I rarely if ever apply the brake when removing power from the spindle. I just let the motor coast down. It takes a little getting used to, especially when tapping. My machine was built in 1972. It was purchased by a local high school and used for shop classes until the late 1980's. It was replaced by a CNC machine and pushed into the back room for another 10 years. I purchased it in about 2000 and put it in my shop. I believe it still has the original brake shoes, and they're still at about 80%
 
I've got a sinking feeling I've got to tear into it. It was acting up all day yesterday. Sometimes it would 'grab' at around '8', other times go past that and not grab.
I've also now got what I think is a drawbar problem. Going to go start another thread on that.
 
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