Bridgeport - diagnose and repair noisy spindle

[Arbutus]

This is a 9x36 Bridgeport clone, made in Taiwan with the Mehanite castings, I have owned it since new and it's seen light work for about 25 years. It is well made and sufficiently accurate for my home shop work. Until recently however, when the spindle bearings now make a rattling noise when in high speed mode. Also I can move the tip of a tool +/- 1mm laterally and the slop in the spindle is quite obvious. I have a video of the problem, but uploading that to this site is not happening.

As far as I can tell, the quill sleeve is sound, and there is no additional play with the quill fully lowered.

What would be involved in replacing the old bearings? I have a 20 Ton press to squeeze them in, but extracting the bearings is going to be a nasty job. Has anyone done this? Are any special tools needed? Can anyone recommend a Canadian source for parts for these machines?

Advice appreciated!

 

[Susquatch]

There is a video on H&W machinery that shows how to do it. I'll find it and edit this post. Lots of good content on that site.

I don't normally post videos, but these are good ones. I used many of these H&W videos to rebuild or repair my Bridgeport Varidrive and Hartford Bridgeport Clone

 

[Xyphota]

I’m on mobile so I can’t be fussed to link the videos, but if you look up H&W Machinery Repair on youtube, you’ll find they have 3-5 videos showing how to disassemble and reassemble all the parts in the head including the spindle bearings.

To get the spindle out you’ll need to get the power downfeed mechanism out of the way so you’ll essentially be doing a full tear down, I think the spindle is the very last part/sub-assy. to be removed lol.

I tore my head apart last year and I don’t think any specialty tools were really required above pin spanners and snap ring pliers etc.


I’m curious about your play though; even if the bearings were completely worn out I don’t think you’d get that much play. The ball bearings would have to have completely disintegrated I would think? Assuming you lubricate them regularly, maybe you should be checking for a blocked lubrication port or something?

 

[Susquatch]

Can anyone recommend a Canadian source for parts for these machines?

There are several Canadian parts suppliers. They have been posted on here before. If anybody can find them on the forum it would be @YYCHM .

 

[Arbutus]

I’m on mobile so I can’t be fussed to link the videos, but if you look up H&W Machinery Repair on youtube, you’ll find they have 3-5 videos showing how to disassemble and reassemble all the parts in the head including the spindle bearings.

To get the spindle out you’ll need to get the power downfeed mechanism out of the way so you’ll essentially be doing a full tear down, I think the spindle is the very last part/sub-assy. to be removed lol.

I tore my head apart last year and I don’t think any specialty tools were really required above pin spanners and snap ring pliers etc.


I’m curious about your play though; even if the bearings were completely worn out I don’t think you’d get that much play. The ball bearings would have to have completely disintegrated I would think? Assuming you lubricate them regularly, maybe you should be checking for a blocked lubrication port or something?

Lube is an issue for sure, and may be the reason it's not behaving. There is a grease nipple at the upper end to lube the gearbox, but there is no other oiling point on this machine. I pour heavy oil down the spline at the top, which eventually dribbles out after wetting everything.

The play is odd, and I agree the bearings would have to be pretty bad to see that much movement. I have a video, but cant find a way to upload it.

What I hear is a clicky-rattling sound, proportional to spindle speed. There may be something else going on inside the spindle assembly (loose screw?) but the slop is undeniable, and the surface finish - for example face milling with a 2" tool leaves random scoring and scratches on the work.

Thanks for the video links guys!

 

[Susquatch]

H&W also sell bearing kits. It's a US source but I've never had a problem with delivery.

Yours is a pulley drive like my Hartford. I had a racket in my spindle too. It turned out to be the castle nut drive system. I have a thread on here about it.

New to me Hartford Mill

Just acquired a new to me Hartford Mill. I do not have access to 3ph power - only 110/220 so I can't actually run the machine yet. Here is a quick link to the original thread about finding a good mill. https://canadianhobbymetalworkers.com/threads/where-to-get-good-used-mill.3372/ Here is a...

canadianhobbymetalworkers.com

You cannot upload videos to the forum. You can only upload them elsewhere (dropbox, YouTube, etc) and link to them here.

 

[Susquatch]

As I recall, you could tell if it was the castle drive because it was quiet in low speed (which has the castle drive disconnected) and only rattled in high speed.

 

[Susquatch]

Just read your first post again.

Rattling only in high-speed implicates the castle drive system. However, if your spindle is loose, that could cause the same castle drive system to rattle but for different reasons.

With the spindle play you have, I'd say new bearings are gunna be needed. Mine is rock solid.

Mine has the mehanite too. It was a bitch drilling mounts for my DRO!

 

[Former Member]

Two solutions.....

Replace the bearings.
Replace the head.

Both are extremely valid options.

I would likely consider the latter as te first choice, cost being the highest

 

[Arbutus]

I'll take a good look at the top end, but what you say about the drive belt interference makes sense. . Yeah, sorry I meant tension.

 

[Arbutus]

There isnt any sign of interference at the top end. The slop at the spindle sleeve is between #132 spindle sleeve and #127 Spindle. And as I listen more carefully, it could be the slop that is causing the noise.

So... WHY is there slop between the sleeve and the spindle? These parts are expected to be in close fit. And I don't push the machine at all. Odd.

Question - would mechanically clamping the parts together cause any issues that are not immediately obvious? Perhaps a collar or three 4mm screws threaded into #132?

 

[Susquatch]

Just to be clear, the noise I had was related to alignment between the two castle gears that connect the top and bottom half of the spindle drive, and the housing. There was no belt interference that I recall. However, belt tension did affect it.

I don't understand the slop you refer to.

If you mount an indicator on the head somewhere and then put the indicator needle on a tool in the spindle do you get the play you mentioned earlier? Or is the play really only on the sleeve which makes it look like the spindle itself is wobbling but it isn't?

 

[Arbutus]

There is no lateral movement between sleeve and quill barrel, #142. The free end of the spindle is able to translate about +/- 0.5mm and moves without effort, as if the bore is enlarged/shaft is reduced.

Also the sound of the spindle hitting the inside of the bore when I push it is similar to the rattle when it's running. The rattle is much worse at higher high gear speeds too, which indicated some harmonics at work. Once a drill point is settled the noise reduces somewhat.

Hence the collar. But I cant figure out the WHY?

 

[Susquatch]

There is no lateral movement between sleeve and quill barrel, #142. The free end of the spindle is able to translate about +/- 0.5mm and moves without effort, as if the bore is enlarged/shaft is reduced.

What I'm really asking is:

Is the spindle really moving toward the sleeve or is the sleeve moving relative to the spindle?

 

[Tecnico]

This is a 9x36 Bridgeport clone, made in Taiwan with the Mehanite castings, I have owned it since new and it's seen light work for about 25 years. It is well made and sufficiently accurate for my home shop work. Until recently however, when the spindle bearings now make a rattling noise when in high speed mode. Also I can move the tip of a tool +/- 1mm laterally and the slop in the spindle is quite obvious. I have a video of the problem, but uploading that to this site is not happening.

As far as I can tell, the quill sleeve is sound, and there is no additional play with the quill fully lowered.

What would be involved in replacing the old bearings? I have a 20 Ton press to squeeze them in, but extracting the bearings is going to be a nasty job. Has anyone done this? Are any special tools needed? Can anyone recommend a Canadian source for parts for these machines?

Advice appreciated!

View attachment 40776

Just a quick question about the image above and where the arrow is pointing, are you saying that the slop is occurring right where the arrow is pointing?

Am I missing something because it looks like that location is where the R8 arbor engages in the spindle, part #227. If that’s the case then it would point to the drawbar not pulling the R8 arbor up into the spindle.

Maybe the drawbar has stretched?

Since we’ve been talking about them lately, is it possible that the dog point alignment set screw has gone astray and is messing with the engagement of the R8?

Just a little brainstorming here…


D

 

[Susquatch]

That's sorta what I'm struggling with too. I can't really tell from the photos or the description what it is that is moving.

We all know the moon travels across the sky. But it really doesn't. It's just the earth spinning.

What is moving relative to what here?

How big is the video you made @Arbutus ? Can it be txt'd or emailed? I could PM you my contact info.....

 

[Arbutus]

That's sorta what I'm struggling with too. I can't really tell from the photos or the description what it is that is moving.

We all know the moon travels across the sky. But it really doesn't. It's just the earth spinning.

What is moving relative to what here?

How big is the video you made @Arbutus ? Can it be txt'd or emailed? I could PM you my contact info.....

Video is 13 secs - 13Mb. Send me a DM with your eMail Susquatch

But to answer the other questions as clearly as I can - the R8 spindle #127 translates inside the spindle sleeve #132. Part #133, the nosepiece at the bottom of the quill, and part #132 appear to be rigid and show no relative movement. The quill #142 is a smooth, sliding fit in the head casting. The R8 tooling fits correctly into the spindle without any freedom when the drawbar is tightened.

So to fix the symptoms, I might try this well fitted, concentric support collar:

 

[Tecnico]

But to answer the other questions as clearly as I can - the R8 spindle #127 translates inside the spindle sleeve #132. Part #133, the nosepiece at the bottom of the quill, and part #132 appear to be rigid and show no relative movement. The quill #142 is a smooth, sliding fit in the head casting. The R8 tooling fits correctly into the spindle without any freedom when the drawbar is tightened.

I'm not sure we're talking about the same things so I'll try and describe it how I see it and throw in a different image of the parts.

In your reference image, part #132 is a spacer tube, maintaining separation between bearings #131 and #138, you cannot see that part unless you remove the spindle from the quill. A portion of #127, the R8 spindle is visible and protrudes partially through Part #133.

In the image below, an excerpt from a Sharp (Long Chang/First) manual, Part # 132 is labelled TM-H176 and separates bearings 6206ZZ and 7207# while Part #127, R8 Spindle is labelled TM-H166 (R8).

If the lower bearings of the spindle are loose you should see motion between #127 and # 133 or in the image below, TM-H166 (R8) and TM-H172 (R8).



Gotta go, it's late, catch up again tomorrow.

D

 

[Susquatch]

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.

I cannot speak for others here. But only speaking for myself, I am not fond of the idea of packing the head with grease as per the H&W recommendations. I think that might be good advice for machinists who are not inclined to follow the daily oiling recommendations. But I am not one of them. In the absence of a way to flush grease as it gets contaminated, I have a clear preference for daily oiling.

 

[thestelster]

That's a lot of play. I don't think it's your bearings. I would first put a couple washers as spacers on your draw bar to reduce the amount of thread engagement. I think your draw bar is bottoming out on the tooling.