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Bridgeport - diagnose and repair noisy spindle

Arbutus said:
What I hear is a clicky-rattling sound,
Click to expand...
Did you take your draw bar out completely at any time? I know on my Ex-Cell-O there is a spacer under the head of the draw bar. Perhaps if you took the draw bar completely out, that spacer fell off in there, and your draw bar becomes effectively too long.
 
I'd like to think it's something like that too @thestelster. We would both agree it's hard to accept spindle play that gross without a crap load of other problems first.

But I understood that the spindle nose was moving too. Can you confirm that @Arbutus?
 
Susquatch said:
Here is the video that @Arbutus shared with me. I uploaded it to my dropbox to share with others as per his comments earlier.
. https://www.dropbox.com/scl/fi/jusi...ideo.MOV?rlkey=zxjnmu9e3pwi888hc1pzsz6v6&dl=0

This does make the spindle play more obvious as I can clearly see the drill chuck moving relative to the vise. That would never happen on my Bridgeport Clone.

Sure looks like bearings or worse to me.
Click to expand...

We need to see the video view of this image:


to see where the relative movement is occurring, maybe with a dial indicator to highlight the motion.

D :cool:
 
First off my old drafting teacher would go on a small rampage about that drawing for the head "Arbutus", it appears saving paper was important by the maker.
Anyway numbers 132, 136, 137, are spacers, 127 is the spindle, 142 is the quill, 131, 135, 138 are the bearings for the spindle, all inside the quill. The adjusting nut 129 sits on top of 130 , the locking washer. 133 and or 134 are the bottom retainers and appear to be held in place by pin /screw 139.
There is a possablity the whole quill/spindle assembly will come out the bottom of the head with removal of down feed and quill lock and pin/screw 139. A big maybe!
If the play/movement is between the spindle and the quill, a number of things could be the problem. Lack of preload on bearings -- nut 129 not tightened enough. Anyone or more of the 3 bearings with wear or packing it in. Pin/screw 139 missing,worn,loose, allowing 133/134 to move down, and wear the quill body.
If you have 2 dial indicators, mount both on the head, extend the quill and lock it, put one on the quill, put the other to the spindle, see which is moving. If all good there, move the quill one to the collet/toolholder, see if anything moves. May have to remove that nose piece, 133/134 to get on the spindle, appears not by picture. Appears spindle maybe a morse/? taper and an adaptor up sizing to spindle size.
As per" thestelster" and others, check the draw bar and any adaptors being used. A new adaptor may have a longer nose not allowing draw bar to tighten proper, a few washers could be an easy temp. fix. You should be able to get an idea of draw bar length of threads by putting collet/taper into spindle, lowering quill down to a piece of wood to hold collet/taper in place, lower draw bar into spindle, on to top of collet/taper, measure top of spindle to shoulder of draw bar, remove draw bar and measure thread length verses length from spindle to draw bar shoulder. A few times have found a new to mill tool being a different length and not pulling in proper, to say nothing of messed up threads.
Please note, I am going by pictures and drawings shown,( can't see the vid.) any of my above maybe wrong, not wrong yet today as it's still before noon.
 
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thestelster said:
Did you take your draw bar out completely at any time? I know on my Ex-Cell-O there is a spacer under the head of the draw bar. Perhaps if you took the draw bar completely out, that spacer fell off in there, and your draw bar becomes effectively too long.
Click to expand...
The R8 tooling is properly seated in the spindle with the drawbar tightened and there is no spacer needed under the drawbar nut. There is no play between the tooling and the spindle.
 
I think I found the problem. The drawbar spacer is crushed and the drawbar was not pulling the tool up enough. Sometimes it's just the simple things!!!!!

5 points to thestelster !!​

thestelster said:
Did you take your draw bar out completely at any time? I know on my Ex-Cell-O there is a spacer under the head of the draw bar. Perhaps if you took the draw bar completely out, that spacer fell off in there, and your draw bar becomes effectively too long.

Also this drawbar is a replacement because the original had damaged threads, but I never checked the length vs. the original.

Drawbar spacer.webp


You folks are awesome!
 
Bandit said:
As per" thestelster" and others, check the draw bar and any adaptors being used. A new adaptor may have a longer nose not allowing draw bar to tighten proper, a few washers could be an easy temp. fix. You should be able to get an idea of draw bar length of threads by putting collet/taper into spindle, lowering quill down to a piece of wood to hold collet/taper in place, lower draw bar into spindle, on to top of collet/taper, measure top of spindle to shoulder of draw bar, remove draw bar and measure thread length verses length from spindle to draw bar shoulder. A few times have found a new to mill tool being a different length and not pulling in proper, to say nothing of messed up threads.
Click to expand...
Yep, that was the problem.
 
Arbutus said:
The drawbar spacer is crushed and the drawbar was not pulling the tool up enough.
Click to expand...

Wow! That's AWESOME NEWS!

But we are not done with you yet....... LMAO!

How did it get crushed like that?

Did you ever measure the torque you apply to the drawbar?

Another interesting question is how is your R8 alignment pin?
 
Susquatch said:
Wow! That's AWESOME NEWS!

But we are not done with you yet....... LMAO!

How did it get crushed like that?

Did you ever measure the torque you apply to the drawbar?

Another interesting question is how is your R8 alignment pin?
Click to expand...
Well that's a good question. The spacer looks like it is bronze, about 2mm wall thickness with a crack along one side. When I said symptoms came on gradually, that would make sense as the crush became greater the drawbar exerted less force and things started to wobble. I use a 12" Kurt vice handle for the drawbar so that certainly limits the torque I can apply. I'd say the spacer was simply too weak. I replaced it with a new phosphor bronze sleeve with significantly greater thickness.

The alignment pin feels rough, but it's still there.

:) :) :)
 
Arbutus said:
The alignment pin feels rough, but it's still there.
Click to expand...

I was wondering about that back in post 15. If the drawbar felt tight (bottomed) but wasn’t pulling the collet/shank tight, that would be one of the explanations for all the mills we hear about with sheared off set screws.

Glad you found the squished bushing!

D :cool:
 
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YotaBota said:
Good catch, as I have the same machine I've been following closely.


When and how were the threads damaged?
Click to expand...
That I don't know. Probably me whacking on it to remove a tool with the threads partially engaged. The original drawbar with the rough thread was replaced about a year ago which lines up with the progressive symptoms. I noticed the excessive runout a couple of days ago, and just now when I picked up the spacer with the crack, it split in half. So basically the spacer suddenly failed, leading to the insecure fit of the R8 tooling. Anyway I'm a happy camper now. :)
 
YotaBota said:
What manual is the exploded view out of?

I'm still looking for a manual for my Sharpe 9x35 mill.
Click to expand...
it is the Precision Mathews PM-835s manual. It's pretty much identical except for the bottom of the base casting. Mine is also a Sharpe.
 
Arbutus said:
So basically the spacer suddenly failed, leading to the insecure fit of the R8 tooling. Anyway I'm a happy camper now.
Click to expand...

I'm not 100% sure that you guys have the same setup as I do, but consider making the spacer to look like this:

20231120_092111.jpg


This design holds the drawbar in center of the spindle so it doesn't rattle at low speeds and accomodates adding plain washers to arbours that have shallow threading.

Here is a thread to explain the nuances. Your mill may be a bit different but maybe this will give you some ideas. For one thing, I cannot imagine a good reason for why your spacer is bronze. I'd be making that from steel if it were mine.

Post in thread 'Collet questions' https://canadianhobbymetalworkers.com/threads/collet-questions.9239/post-132448
 
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