# Spindle woes pt. 2.



## Izzy (Sep 27, 2018)

So my spindle woes continue with my Bridgeport  I dunno if they're supposed to be this loud as I've never ran a series 2 before so I've take some videos to hopefully help out. The video shows the machine powering up and winding down. Now I don't know if these other problems are related but I think they might be. The cutter had a wobble to it which I noticed by eye and I put an indicator on it an measured .003" the video shows this as well. And with the spindle just free spinning the load meter reads around 80-85% and goes down to about 60-65% when I take a cut. First video is the start up and wind down second is the cutter wobble. Also in high gear the lowest rpm it will go is about 1000 which leaves a 600rpm gap from the top of low gear. Not sure how to go about fixing that either.


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## Izzy (Sep 28, 2018)

Anyone out there?


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## derf (Sep 28, 2018)

The runout is probably on the shell mill cutter body itself, not necessarily the spindle. No doubt you have it in low range, and most of that noise is coming from the back gear.


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## Izzy (Sep 29, 2018)

Fair enough, being a sandvik I figured it would be pretty good. 
It sounds the same at any speed either high gear or low gear....


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## Kroll (Sep 29, 2018)

I was told that alot of the noise comes from worn bushing that is on the reeves pulleys.This is for a series 1 so this may not apply to yours,I just order two pairs.Maybe take a collet and mill cutter and see if your still out .003,take what I say with a grain of salt,I'm a newbie and clueless.But also maybe check out some Youtubes for spindle noise and run out.I been watching several of the H&W Bridgeport videos they been lot of help.


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## Izzy (Sep 29, 2018)

Yea there's lots of info on the series 1 not so much the series 2 lol I'll try this with a brand new endmill and collet and report back


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## Izzy (Oct 2, 2018)

Well I got a chance to check it with a brand new 1/2" sandvik endmill and I had .002" I had an old co-worker from the mold makers I used to work for check it out he thinks something isnt right either. Anything I can do to test or check for bad bearings for sure?


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## BaronJ (Oct 2, 2018)

Hi Izzy,

Just found this thread !
The noise is normal for a varispeed head.
The 2 thou runout is probably dirt in the taper, give it a good wipe with a paper towel, or a ding on the collet.
Also you shouldn't use a dial gauge against a running spindle, it damages the tip of the gauge feeler.


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## Izzy (Oct 2, 2018)

I'm not too worried about the tips I have tons of them lol well I'm glad to hear it sounds fine. Any ideas on what would cause me to loose my speeds? The slowest it spins in high gear is 1000 it should be around 4-500


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## BaronJ (Oct 2, 2018)

Hi Izzy,  Could just be belt slip, its only a pair of cones that move as you alter the belt tension with the speed control.


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## Izzy (Oct 2, 2018)

Is there anything I can do about it? Belt dressing on the belt? Or maybe wd-40 where the cone rides up and down on the shaft?


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## Kroll (Oct 2, 2018)

Izzy do you know if you have delrin bushings on both of the cone pulleys the ones that slides up/down on shaft?I was told that these are the main problems with Bridgeport but mine is the Series 1 so I don't know if series 2 has these plastic bushings.Maybe this is the problem why the belt is somewhat loss and slips.


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## Izzy (Oct 7, 2018)

Is that on the motor side? The motor was freshly rebuilt and I'm pretty sure I remember seeing bronze bushings on the pulleys for the motor. It does seem to get quieter in the low speeds now that I've played with it a bit.


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## Cadillac (Oct 8, 2018)

If you can get access to the variable pulley I would try checking for play on the shaft to pulley. If the bushing is worn it will cause the pulley to chatter and wobble giving a lot of noise. As for your speeds that is determined by the variable pulley. If the bushing is shot it will not have the movement that’s designed. Also you drive belt could be stretched causing you to not get those lower speeds. 
 To check your spindle get rid of the collet and put your indicator on the inside of the spindle. Check it in two areas preferably one on taper and one on the straight part. That will give you true spindle runout. 
 9out of 10 times your noise is gonna be from the variable pulley.


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## Kroll (Oct 8, 2018)

Pulley thats at the front and slides up/down mine has two black bushings that is glued in place with epoxy.The other pulley that has the spring on it and also slides up/down has a different type of bushing but looks to be plastic or some kind of fiber,but its also epoxy in place which is what I am working on now.The pic shows the pulley and old parts.Yours could be different than mine which all this is a new experience for me which is another reason why following along.The book is for a Series 1 I know yours is different series # but maybe this help


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## Izzy (Oct 8, 2018)

@Kroll I'm somewhat in the same boat I know how to operate a machine better than I know how to rebuild one! Haha. So to access the pulley your talking about you have to remove the top half of the head casting correct? I don't see any other way of accessing it.


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## derf (Oct 8, 2018)

If your RPM is higher than it normally should be, that means the belt is shot.....and is also the source of the noise.


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## Izzy (Oct 8, 2018)

The belt looks like it's in good shape tho, is there any measurement or test I can do to verify the belt being no good? It honestly looks like it's in really good shape...


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## Izzy (Oct 8, 2018)

I definitely want to be sure the belt is no good before ordering a new one. I just looked up the price and I'm looking at about 400bucks for a belt after Canadian exchange rate and shipping gets added on


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## Kroll (Oct 8, 2018)

You know a person hates to take anything apart when the mind has a big ? in it.You will have to remove the motor which at that time you be able to see if the pulley wiggles that has the bushings in it.If it does I believe that it be a safe bet that the other bushings for the vari pulley will also be bad.But you may also discover even bigger problem.Say if it is the pulley on the motor is loose and wiggles then there's chance that the motor shaft may also be damage if the problem has been going on far to long.But lets be optimistic and say that only the plastic bushings are bad.But like others it could also be bearings which I had to replace one and it was 30.00.Anyway I went to H&W website which sells parts for these BP which some parts are price far while others will test a person pacemaker.So while there I look up what I think is your mill and it looks like you also have plastic bushings.So take a look at H&W Series II 4hp see if this looks like your mill vari parts.


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## Izzy (Oct 8, 2018)

I don't believe it to be anything to do with the motor assembly like I said it was freshly rebuilt by a motor shop before I got the mill running and I've only had it running for a month or so. I remember the bushing for the pulley on the motor being bronze though so it could only be the bushings for the pulleys in the head that would be plastic. I'll take a look in the H&W site I didn't think they had series 2 parts they're hard to come by.


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## Izzy (Oct 8, 2018)

Looks like they have what I need and for 100bucks cheaper than what I found! Still an expensive belt tho... I've got the machine tied up on a job right now but I'll have to dig into it a bit try to find the problem but as of now symptoms are pointing to the belt and bushings...


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## Janderso (Oct 8, 2018)

Wow, my old step pulley is very quiet. I have heard the variable-cone heads are noisy. In fact, I was watching a Youtube video, this guy turned his mill on and you could hardly hear him talking.
Belt and bushings are less than a spindle overhaul.
Good luck.


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## derf (Oct 8, 2018)

As the belt wears, the width diminishes, causing it to ride deeper in the pulleys. Typically the sharp outside edge will break down also. This will not only speed the spindle up, it will ride the shaft instead of the sheaves when it bottoms out. That will cause clatter. 
 It is best inspected off the machine.


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## Izzy (Oct 9, 2018)

So I looked inside the head the other day with a flash light and the bottom cover off. The edges of the belt still seem sharp to me. Also I can confirm the bushings on the motor pulleys are bronze! I can also confirm that the belt is not riding on the shaft I can see a clear contact patch from the belt on the pulley and it stops before the shaft. The pulleys in the head have bushings that are made of Babbitt, or tin or something of the like they where silver/greyish in color. I could shake the pulley by hand tho so I'm gonna go ahead and say thats where most of the noise is coming from. I ran the machine with the cover off and cranked the speed up and down while watching the belt and pulleys it looks like the moving in pulley in the head is getting stuck in it's travel at some point. Finally I lubricated the moving pulleys with a little spindle oil and sprayed some belt dressing on the belt. This quieted it down a bit but I'll have to address the bushings in the head at some point it's still noisy at high speeds.


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## Kroll (Oct 10, 2018)

Good deal you found a problem and bronze bushing are not expensive.And come in many different sizes which McMaster has a lot different sizes.But making these repairs may last you rest of your life so its a good investment.


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## Izzy (Oct 10, 2018)

It's absolutely going to get repaired just a matter of when! They don't make series 2 anymore but I love the thing it's a beast! Chrome hand scraped box ways, variable power feed on everything, spindle load meter, 4hp motor, 11x59 table. I have plans to do a full tear down and rebuild/restore some time in the future but untill then I just need to keep in running somewhat smoothly.


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## derf (Oct 11, 2018)

If you want to eliminate all that noise and aggravation for good, go with a vfd and solid pulleys and use a poly V belt. This reduces all the rotating mass and yields 25% less friction and drag in the drive train. Wind up speed is 3 times faster.


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## Izzy (Oct 11, 2018)

Unfortunately vfd isn't an option for me for a few reasons. The biggest one being they don't make a 4hp vfd that goes from 220 single phase to 440 3 phase and if they do it's gonna cost 3x what I've got into the entire mill including tooling and labor costs! Don't get me wrong I think that's a great idea, and I'd probably run with it if I had a regular ole series 1 but its just not practical for me in my current situation.
I think for now I'll just finish up the mill work that has to be done then tear into it and order some bushings and belts. I indicated the inside of the spindle and had 0 measureable run out which made me feel much better about my spindle bearings and I feel much more confident in saying it's the bushing for the driven vari-disc that are causeing the noise.
Also the run out I was getting seems to be coming from the collet. I measure 0 run out everywhere till I put the collet in then I start getting some woble.
The spindle load meter I'm starting to think may be a separate issue possibly just a bad load meter.


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## warrjon (Nov 6, 2018)

I  have King rich KRV3000 and BP clone with 4J head, and my head makes that noise and it's worse in back gear. My belt is brand new as I replaced it when I got the machine. I was suspecting bearings because a friend of mine has the smaller KRV2000 and his machine is quiet.

BTW my mill is 5hp and I run it from an eBay VFD, I did have to modify the wiring in the motor to bring out the star connection so it's now wired for 240V 3ph


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## Dynahoe Dave (Nov 8, 2018)

Another option - Get a 5KVA 240-480 transformer.  And a 480V VFD.   Used transformers on ebay, around $200.


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