# spindle binding (I think) on BP mill



## diamond (Dec 21, 2018)

I recently got a BP Series 1 1.5hp vary-speed.   This is my first mill and I'm a newbe. Previous owner had started a head rebuild.   I finished the rebuild with a full bearing & belt replacement.  (head rebuild kit from H&W).   New sealed spindle bearings, new bushing and all that.  The motor and vary-disk shafts were in good tolerances.   Took a big risk buying a machine torn down.  It looked good, the ways and table and all visibly looked in really good condition.  To my uneducated eye it looked lightly used.   Not so sure now.

The problem I've run into is the spindle up/down movement seems to have a very distinct spot in rotation where it binds or rubs.   Can feel this by trying to lower the quill while the mill is turning.   It is a distinct "catch" or "pulsing" (depending on how fast the mill is running) as you lower the quill.  I can also turn the spindle by hand and find a spot where raising and lowering the quill is distinctly feels harder like it's rubbing where elsewhere in the rotation it is more free.   At higher speeds it's like a strong vibration as you raise and lower the quill.  Also quite a loud noise.   

I'm wondering if the spindle shaft is actually bent and rubbing somehow in the bull gear shaft.   My next step is to pull the spindle and see if I can tell if it is bent somehow.  Maybe chuck it up in my lathe between centers and see if I can measure any bend with an indicator.   

Is this binding like this a common thing and could it be caused by anything else?   I can't really think of anything else that could cause this other than a bent spindle.   Obviously that's going to be a pretty expensive fix if it is so I thought I'd ask if there were any other thoughts.


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## Technical Ted (Dec 21, 2018)

I have only worked on two J vari-speed heads; a 1-1/2hp and a 2hp. They are basically the same inside. From what I am understanding, from what you are describing, it does sound to me like something might be bent and/or not running true.

There are YouTube videos on pulling the spindle on a Bridgeport. Sounds like a good plan to check yours for run out.

If the spindle is all the way up does the top part of the spline (where the draw bar seats) look like it's running out? Can you get an indicator on it and check it while in the head rotating it by hand? This might help show something...

Ted


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## Bob Korves (Dec 21, 2018)

Sometimes the clock spring can cause that problem.


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## JimDawson (Dec 21, 2018)

When reassembling the head it is possible to misalign the top and bottom housings and this will cause the quill shaft to bind in the bull gear spline.  There are no aligning surfaces or pins.  I think there actually is a procedure to do the alignment, but I have always done it by feel.

The pic shows the split where the misalignment can occur.


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## markba633csi (Dec 21, 2018)

You are on the right track, check the spindle between centers- If you have access to a hydraulic press you may be able to carefully straighten it.
mark


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## diamond (Dec 21, 2018)

Before I pull the spindle I think I will try that adjusting the alignment of the bull gear housing.  Super hopeful that's the issue and save me a lot of money on a new spindle!  When assembling it I did notice the bull gear housing can rotate on that joint to any position.   I tried to get it back to as close to where it was previously by looking at marks on the flange but could have easily been off.   I don't know how sensitive this alignment is.  I was even thinking, why is this adjustable?   Didn't quite make sense to me at the time.

Anyone have more thoughts on that alignment, how to do it?  Jim when you say by feel, do you mean just loosen and move it until I no longer feel any binding when rotating by hand?    Guessing so but if there's a more procedural way would like to know.

Thanks guys!!!   I so much appreciate the support on this site!

-dave


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## JimDawson (Dec 21, 2018)

markba633csi said:


> You are on the right track, check the spindle between centers- If you have access to a hydraulic press you may be able to carefully straighten it.
> mark



You're close, check the runout with the quill shaft running in it's own bearings.   Remove the quill assembly and lay it on the mill table on the center T-slot so it doesn't roll around.   Don't remove the quill shaft from the ram.  Now you can rotate the shaft and check the runout on the spline end.  The likelihood of the quill being bent below the top bearing is very small.  If anything is wrong I would expect a twist in the splines caused by a major jam rather than a bend.


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## JimDawson (Dec 21, 2018)

diamond said:


> Jim when you say by feel, do you mean just loosen and move it until I no longer feel any binding when rotating by hand?



Yup, loosen it a bit and move it around with a dead blow hammer.


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## diamond (Dec 21, 2018)

Ah makes sense about any bend being above the bearings.  The spindle is much thicker below the splines.   

This is great, I have some easy things to try this weekend that don't involve tearing down the entire head.  There is hope.  LOL   I'll update y'all with what I find.

-dave


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## diamond (Dec 22, 2018)

Pulled the spindle measured runout following Jim's suggestion to just lay it on the bearings.   Measured ~.001 runout on the spindle just above the top bearing.   Move 6" up the splines, towards the top of the spindle, and it's ~.007 runout.   So there is definitely some bend in the spindle above the bearings.   I don't know what the tolerances are for the spindle spline fit in the bull gear splines but I assume it's pretty tight.   Having any backlash in the fit would be a bad thing I'm guessing.  So unfortunately it is looking like a bent spindle is one of my issues.   I'm guessing this is binding and the cause of the "pulsing" feeling as it rotates and I raise & lower the quill.

I think I have a second issue in the drive but I'm not sure yet what it is.   After I pulled the spindle I ran it to see if the noise went a way.  It is reasonably quiet in neutral however when high range is engaged that loud "growl" is still very much there and a fair amount of vibration.   I know vary speed heads are noisy but this still doesn't seem right.   The rebuild has all new bearings & bushings but I did not replace the bull gear shaft or the vary disk shaft.   The clutch cogs looked ok to me and they mesh up without any play but maybe I missed something in there.   

So I pulled the motor and upper belt housing and I did discover the new grease I put in the bull gear housing is getting forced up  through the hole in the cover and into the belt housing.  I think I over filled it.  H&W kit said to use two tubes of grease, so I did.   I may have to tear it down further and remove some of that grease.   It's getting on the timing belt and that's probably not a good thing.   Might be causing other issues.  I'm almost wondering if it could even be pushing up the aluminum cover causing it to rub on something.

Oh well, I'm getting pretty good at tearing down a BP Series 1 head.   lol


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## JimDawson (Dec 22, 2018)

My head also has all new bearings, but there is still a growl in the area of the small drive gear (large timing belt pulley) shaft.  I need to tear mine down again and locate the problem.  I have vibration also, but I know the motor shaft is bent so pretty sure all of it is coming from there.


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## Cadillac (Dec 22, 2018)

Not saying Jim is wrong about testing the spindle. If you have v blocks it would be more accurate to check on them with those directly on spindle. Preferably on a known flat surface. When your measuring do you see a “lobe” in the shaft measurement?Or is it .007 difference? To much grease can do damage as much as no grease too. I would try to isolate problems by taking belts off and spinning each Assy. Could be multiple things seeing it was disassembled prior to sale.


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## Technical Ted (Dec 22, 2018)

I don't know what the tolerance for run out is for the spindle splined shaft. Do you have a press for straightening it? If it were me, I would call H&W Machinery Repair https://www.machinerypartsdepot.com/ and ask them for their opinion. They have helped many owners out and take pride in doing so. Especially if you bought the rebuild kit there. It would be important to have an accurate measurement for run out before talking to them though... Or, they might even suggest a way to check it. 

Two full tubes of grease is too much. It takes closer t 1-1/2 tubes. From Ilion's book, with the shift lever in hi, the grease should come about 1/2 way up the gear teeth. No grease on top of the bull gear. The pinion gear cavity should be full. 

The noise could be coming from the clutch not meshing correctly in Hi gear. Does it make the same noise in low? If not, this is probably the issue. You can adjust the clutch mesh. See this other post: https://www.hobby-machinist.com/threads/bridgeport-j-head-noise.73218/#post-614788 This adjustment was discussed pretty well in that thread. 

You could also put the spindle between centers on a lathe to check for run out. If you rotate it between centers and the bearing races run out, you know you have an issue.

Ted


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## ddickey (Dec 22, 2018)

Are we talking quill or spindle. I'm assuming quill?


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## Technical Ted (Dec 22, 2018)

ddickey said:


> Are we talking quill or spindle. I'm assuming quill?



That is a good question. When I read his original post, I "understood" him to mean that the binding was happening only in certain areas of spindle rotation. This lead me to agree that he might have a bent spindle, not a quill problem.

Maybe I'm wrong??? Diamond please explain better what it actually is.

Thanks,
Ted


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## diamond (Dec 22, 2018)

Technical Ted said:


> That is a good question. When I read his original post, I "understood" him to mean that the binding was happening only in certain areas of spindle rotation. This lead me to agree that he might have a bent spindle, not a quill problem.
> 
> Maybe I'm wrong??? Diamond please explain better what it actually is.
> 
> ...



Thanks Ted.  Yeah it's the spindle.   I tore it down and confirmed today it's got some bend to it.  Just laid it on the bearings and there was .007 of runout 6" above the top bearing.   As I reassembled the machine I checked the fit with the top belt housing off & the spindle in the quill and the splines sticking up through the bull gear.   Got the same measurement.  



High side & low side.  180 deg apart.

With it open that way I could definitely feel a place in the rotation where the spindle splines get a real tight fit in splines in the bull gear shaft.  Turn it 180 and it actually has a bit of play.   So I'm pretty darn certain this is causing some of my issues.  My neighbor has an automotive shop and several sizes of hydraulic presses.   I may get the guts up to try straightening it but yeah, I do think I'll wait and call Barry at H&W after the holiday before I do anything more.  They are good folks.

-dave


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## diamond (Dec 22, 2018)

Technical Ted said:


> Two full tubes of grease is too much. It takes closer t 1-1/2 tubes. From Ilion's book, with the shift lever in hi, the grease should come about 1/2 way up the gear teeth. No grease on top of the bull gear. The pinion gear cavity should be full.
> Ted


Yeah I WAY over filled it.  During my tear down today this is what it looked like when I pulled the cover.



I discovered when would switch it to low, all that grease I stuffed under the bull gear would get squeezed up on top of the bull gear and then when I shifted it back to high it was packing against the cover and I was getting resistance.  It actually pressed the aluminum cover plate up into the timing pulley and was rubbing!   

I scooped out a bunch of grease and cleaned everything up.   That really did help things out.  I do have the book and did the 1/2 way up the bull gear on high thing but I had also squirted a bunch of the grease under the bull gear in attempt to fill as much of the cavity under it as I could.   I didn't understand not to use the whole two tubes that came with the kit.   Turns out that was not the right way to do it.  Of course there was no where for that extra grease to go.  LOL   Ted you're right, it was a good 1/2 a tube of grease I scooped out.

I ran it again with the spindle out and it was pretty quiet.  Back in and the noise is there.  If I can resolve the bent spindle shaft issue I should be in good shape.


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## ddickey (Dec 22, 2018)

Aren't spindles relatively cheap?


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## diamond (Dec 22, 2018)

ddickey said:


> Aren't spindles relatively cheap?


I guess it depends on relative to what.  A new R8 spindle from H&W will set me back about half what I paid for the whole machine.  lol


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## Technical Ted (Dec 23, 2018)

diamond said:


> ... I do think I'll wait and call Barry at H&W after the holiday before I do anything more.  They are good folks.
> 
> -dave



That's a wise thing to do. Please share with us what he suggests and keep us posted on your progress.

On straightening the spindle: If you're considering scrapping it out and replacing it, I don't see what you have to lose by trying to straighten the one you have (speak with Barry first). Be careful of the bearings! You'll need to have a way setup, hopefully near the press, where you can check your results after each tiny tweak... it will be very easy to over bend it. You'll need to identify the hi spot, mark it, apply a tiny bit of pressure to it and then check it with your indicator. Here's a video I remember seeing where a shaft is straightened. Not exactly like doing the same thing to a BP spindle, but you'll get the idea if you've never done this type of thing before.






Don't press on the spindle bearings! If you do end up getting a different spindle it might be tough getting the spindle bearing off the bent spindle without damaging them. Again, this is where H&W can help out. I think you posted you put brand new spindle bearing on the one you have and it would be a waste not to be able to use them on a potential replacement ($$$$$$). 

Good luck,
Ted


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## diamond (Dec 23, 2018)

Thanks Ted.  Yep, brand new sealed thrust & top bearings from H&W.   I'm kicking myself for not chucking up the spindle in my lathe and measuring it before I put them on.  I even thought about it but convinced myself I didn't need to.  

After cleaning up the grease problem & adjusting the head as best as I can I feel like I can run the machine as long as I keep it under 1000 rpm or so for short jobs.  Above 1200 or so the ugly growl really starts to come out and gets really loud at high rpm.  But that'll let me get some hobby project work done over the holiday & then I'll reach out to Barry.

I'll definitely update the thread.   This has been a good learning experience and maybe others can benefit from what I'm discovering.   I've sure learned a lot here!  

-dave


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## Technical Ted (Dec 23, 2018)

diamond said:


> I'll definitely update the thread.   This has been a good learning experience and maybe others can benefit from what I'm discovering.   I've sure learned a lot here!
> 
> -dave



That's why we're all here... to learn and help others.

Only you can judge if running it can potentially damage something i.e. the spindle bearings, etc.. From what you are explaining it sounds like it would run better with the quill up high in the head and it would run worse the lower the quill goes (because the worse run out would be on the end of the splined shaft. So, if you do run it, take it easy...

Ted


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## diamond (Jan 7, 2019)

Sorry for not getting back to update.   Got distracted after the holidays.  

I did make connection with Barry at H&W and was relieved to hear this is very common.   Says about half the rebuilds he does he has to do some straightening of the upper shaft.   Apparently it's quite soft.   I haven't done it yet, been distracted elsewhere, but this gives me a lot of relief I won't be buying a new spindle.   His method is to do it while in the head.  He's got all kinds of mounts for holding heads on a bench to work on.   I don't have a lot of room above my machine to work on it so I'm probably going just pull the spindle and do it on a press where I can indicate the shaft & dial it in.  He said that should be fine.

I will update again on how that turns out when I get around to doing it.


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## diamond (Feb 10, 2019)

Been very slow to update.   Here is the end to this chapter in the story.

I pulled the spindle and checked the runout of the shaft by securing the thrust bearings to the table.  



It was even more bent than I first thought.   Found the shaft was running out about .018 at the top.   The good news is it seemed to be a simple bend, not a compound bend.  Could measure about .007  just above the upper bearing but the high/low sides were consistent down the shaft.   If that makes sense.  



Barry at H&W told me the shaft is really soft metal so I got the idea that I might try this setup below to straighten it vs. using a hydraulic press.   I figured I could get more control.   With the spindle shaft suspended between two 123 blocks, I used a piece of 4x4 against the ram & raised the knee with a dial indicator to monitor correction.



I started out real gently.   Only putting about .025 deflection by raising the knee.  Then re-clamp the thrust bearings to the table and measure runout.  Didn't budge.  Then I went to .050 still nothing.   Then .075 and the runout dropped a couple thou.   Continuing with .025 increments I got to .125 and all of a sudden it was gone.  In fact I overshot it by a few thousandths so I just bumped it on the other side (about .050 deflection) and the shaft is now running less than .002 measured down the length.   It appears I didn't introduce any compound bend (which I was concerned about).

Never done this before so maybe I was being obsessive about getting it true.  Barry says he just hits it with a mallet.  lol.   My approach of using the knee & ram as a press like this might make some folks cringe.   It really didn't take much pressure on the knee elevation crank to get the shaft to move.

The good news is I put it back in and the machine is MUCH quieter now and the quill moves up and down without feeling that rubbing from the spindle shaft.   Now that the shaft vibration noise isn't so loud I could start to hear other noises at high speed.  Most notably a growl in high range coming from play in the bull gear shaft/vari-speed pulley shaft cogs.  I've played with adjusting the hi/low engagement lever stop to put a little more upward pressure in high range and that seemed to make it go away.  

I know these vary-speed heads are not known to be quiet.   The belt alone makes quite a lot of noise I'm sure.   For now I'm very happy with how it's running.   Again I don't have a lot of experience with these machines to know but to my ear it sounds very quiet at most working speeds.

Thanks again to Ted and others who provided advice.   Maybe my experience with this might help someone else out.   I didn't find much in any discussions about straightening a spindle when I researched this.

Now it's on to installing the 3-axis DRO that just arrived!   Lots of good threads on that.


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## Technical Ted (Feb 10, 2019)

Great news and that's using your head with what you have available to you to straighten the shaft! Yes, I'm sure that gave you much more control and it was good thinking. I'm sure it didn't damage anything... Yep, better than a mallet!  

Good job!
Ted


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