# Apprentice lathe problem - grinding, chirping?



## Hakchuma (Apr 21, 2014)

Hello,

My lathe is making a strange noise during rotation in two places. I have noticed that my skew does not cut as smooth as it normally does just after it has rotated past the grinding noise. I am wondering if it is a flat spot on a bearing or something? I have inspected the belt and the belt looks fine.

it doesn't sound like it is coming from the upper portion of the head stock. It sounds like it is coming from down below in the motor but, when I take the motor off and rotate it I can't hear it anymore. 

I made a video to help explain it a little better. I am not all that mechanically inclined and this is just a hobby for me so I am a little lost on this one.

Any suggestions or ideas of what the problem is? 

http://youtu.be/MfwRw-_hyxY


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## Bill Boehme (Feb 9, 2014)

The roughness part is easy to answer. You have the wood mounted in face grain orientation. You said that you are using a skew, but it would be much better to be using a bowl gouge. You didn't say what you are making and we might be able to give you some pointers in that regard. The roughness that you discovered isn't related to the sound -- it is the result of the difference between side gain and end grain. It also indicates that you may not be using the skew correctly or that it is dull. Like I said, a bowl gouge would be a better choice here, but in either case, a sharp tool properly used should result in less end grain tear out.

When you removed the belt and rotated the motor, did you also try rotating the spindle to see if the noise was there? Here are some steps to systematically isolate the problem.


Remove the chuck, but leave the wood mounted in it. Rotate the chuck around in your hand and shake it and try wiggling the wood. Sometimes there may be something loose in the chuck or the wood may have warped and one jaw is not solidly gripping the wood.
Remove the belt and inspect it for problems
While the belt is off rotate the motor shaft and also the spindle while listening for noise. Since the sound always occurs at the same spindle position, it would have to be the spindle since the motor and spindle are probably not turning at a one to one speed.
Inspect the pulleys o the motor shaft and on the spindle to make sure that they are not loose. If they are, tighten the setscrew. Bearing sound doesn't occur once per revolution so you can quit worrying about that -- besides, if a bearing is making noise then it is already bad and there is no need to worry that it may go bad if you continue to run the lathe. Changing bearings is no big deal on that lathe anyway.


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## Bill Boehme (Feb 9, 2014)

One other thing to check whether you hear the same sound when the belt is in all of the pulley positions or just one. It probably doesn't matter, but just something else to observe.


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## Hakchuma (Apr 21, 2014)

*Thanks*

Thanks. I disassembled the motor just to take a look and I could not hear any of the noise when I put it back together, shockingly. I haven't tested a cut yet.

When you say use a bowl gouge, I thought the skew was for making a real fine cut? could you please explain to me because I really don't know the first thing about any of this and I have been learning VIA youtube.

When would I want to use a skew vs. a bowl gouge and why? I am going to true up another piece of wood and look at my results for the skew and the bowl gouge in the mean time.

Thank you! So much! for your help sir.


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## Maylar (Sep 3, 2013)

A skew is a spindle turning tool, and spindles have the grain parallel to the lathe bed. You have the blank mounted with the grain running perpendicular to the bed, as is often done with bowls. The roughness you are getting is on the end grain. Your skew needs to be razor sharp, but you'd probably get better results with a bowl gouge and a shear cut.


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## Hakchuma (Apr 21, 2014)

*I think I might know*

I think I might know what is going on concerning the noise my lathe is making. I pulled the bushing out and each bushing has some large chips broken off of them. I have also noticed that maybe a few bad catches has contributed to those chips? I can get the motor running real quite but once I put a little too much pressure on a piece of wood, or if I have a bad catch it almost seems as though the main shaft goes out of wak' until I pull it apart and re-seat everything and put it back together. 

I am wondering how difficult it will be to find bushings for this particular motor? I am guessing it is not very wise to keep running a motor when the bushing are not smooth at all? And, could possibly damage the brass thing (I don't know what it is called yet) that they ride on/close to?


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## Bill Boehme (Feb 9, 2014)

Even though you are saying "bushings", i have a very strong hunch that you are actually referring to "brushes". If your lathe is a mini or midi with variable speed then it has a DC motor with brushes. Brushes are carbon blocks that make contact with the commutator on the armature. It is not unusual for the brushes to have a few tiny chips on the edges because they are brittle. On the other hand, if the brushes are worn down to the point where they are very short then they might be cocking in the holders and chipping very badly. If that is the case, they must be replaced or else they could damage the commutator. Brushes are fairly standard items and most motor repair shops would have them. Your lathe manufacturer would also have them.

Remove the brushes and take a picture and we can tell you if they are worn out.


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## NCPaladin (Aug 7, 2010)

The brass thing you mention may well be bronze. Many lathes had/has bronze bushings.
Have you checked the set screws in the pulleys, in particular the spindle pulley? Sometimes if loosen they can move a slight bit.
If it is "clicking" in the same spot you may also want to check your spindle lock. It may just a little bit forward (or the pulley slightly off) and only clicks at the same spot with each turn.
I had a similar problem with mine and it was the spindle pulley had moved very slightly.
Since your headstock is open at the bottom for the belt, the clicking may sound like it is coming from the motor even though it is origionating at the spindle.
Just some possibilities.
I would replace the bushings anyway if they are chipped.


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## Bill Boehme (Feb 9, 2014)

One other thought. If you are not talking about brushes, then perhaps what you are calling a bushing is really a plain bearing. Some low cost motors use plain bearings instead of ball bearings. Generally, the plain bearings are part of an assembly that has some fiber material that is oiled and there will generally be a small hole in the bearing that allows oil to go from the "reservoir" area to the space between the bearing and shaft. When it is working properly, the oil actually circulates from the reservoir to the bearing /shaft and then a slinger on the shaft returns the oil back to the fiber reservoir. I've never seen any chipping on these bearings. The usual failure mode is that the oil leaks out and the bearing goes dry. When that happens the bearing is ruined, but the worst part is that this also causes the shaft to wear and so replacing the bearing won't solve the problem., because there will not be a smooth snug fit. Without that, the oil won't circulate. For that reason, you are not likely to find replacements for that type of bearing.

The above bearings are silver in color, but as mentioned, thee are also Oilite® phosphor bronze bearings that are often used on small fan and blower motors. If that is the casse, there will be normally be an oil zerk in each end of the motor. I cant imagine chipping on these, but in any event, when they are worn out so is the motor armature.


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## Bill Boehme (Feb 9, 2014)

Hakchuma said:


> ...... And, could possibly damage the *brass thing* (I don't know what it is called yet) that they ride on/close to?


OK, after rereading your post, I now know for certain that you are talking about *brushes*. The *brass thing* is the commutator. Each segment is connected to a different set of wires on the armature and that is what keeps it rotating. Does the commutator look flat and smooth? If it has deep circular grooves worn in it then the news isn't so good. If the brushes are just worn down too short, but the haven't damaged the commutator YET, then get new brushes ASAP and do not run the motor until you do.


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## john lucas (Sep 18, 2007)

I'm confused by all of this. It sounds to me like it's something in the spindle since it happens in the same spot each time. Does it have a spindle lock or index pin. either one of those could be out of position and touch the spindle somewhere. There could also be something such as a door latch or loose switch that may be touching the headstock spindle somewhere. 
If you disconnect the drive belt and run it and the noise is gone it's not in the motor. If you can rotate the spindle by hand and the noise is there it obviously related to the spindle somewhere. If it only happens when the belt is attached to the spindle then I would suspect the spindle bearings.
Are you using the skew as a scraper laying on it's side or as a bevel rubbing tool? It should cut much cleaner as a bevel rubbing tool but would be challenging to use on a side grain piece of wood in that orientation. It's mostly for spindles. 
I have several videos that will help you understand tool usage. Go to youtube and type in John60lucas and it will bring up my videos.


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## Bill Boehme (Feb 9, 2014)

john lucas said:


> I'm confused by all of this. It sounds to me like it's something in the spindle since it happens in the same spot each time. Does it have a spindle lock or index pin. either one of those could be out of position and touch the spindle somewhere. There could also be something such as a door latch or loose switch that may be touching the headstock spindle somewhere.
> If you disconnect the drive belt and run it and the noise is gone it's not in the motor. If you can rotate the spindle by hand and the noise is there it obviously related to the spindle somewhere. If it only happens when the belt is attached to the spindle then I would suspect the spindle bearings.
> Are you using the skew as a scraper laying on it's side or as a bevel rubbing tool? It should cut much cleaner as a bevel rubbing tool but would be challenging to use on a side grain piece of wood in that orientation. It's mostly for spindles.
> I have several videos that will help you understand tool usage. Go to youtube and type in John60lucas and it will bring up my videos.


I agree 100%, but the OP is fixated on the motor, so that is why I asked him to show a picture of the brushes, It is possible that they could be worn out although they normally last for many years. Most certainly, a catch has absolutely nothing to do with the brushes wearing although constantly stalling the motor can lead to arcing and pitting between the brushes and commutator. That would be an extreme situation. Constantly overloading and stalling the motor can cause winding in the armature to burn out which would be evidenced by extreme loss of power and overheating of the motor. I doubt an of that is going on here.

I also thought about the possibility that there is a frayed piece of wood ticking against the tool rest since the cuts seemed rather ragged.


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## TomC (Oct 27, 2008)

[QUOTE="Hakchuma". When would I want to use a skew vs. a bowl gouge and why? I am going to true up another piece of wood and look at my results for the skew and the bowl gouge in the mean time. Thank you! So much! for your help sir.[/QUOTE] 

I was told by a very experienced turned to never try to use a skew on a bowl blank. It looks like the way you have your blank rotating you are Turing a bowl or in the orientation of a bowl blank. I would not use a skew. Like others have said use a bowl gouge. Looks like you are getting tear out on the end grain. Use a sharp bowl gouge and take light cuts. That should help. Don't know what your noise problem is.
Tom


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## Hakchuma (Apr 21, 2014)

Thank you for all the guidance on the correct tool I should use. That was extremely helpful as I had never known that. I wonder how long it would have taken me to figure that out? dunno. just glad I know now. 

The brushes on the motor were cracked/chipped. To be honest with you all, I was so upset that my lathe already had a problem and I had already spent a whole lot of money on chucks/tools etc, I was very depressed and upset. So upset that I closed the door on the lathe room and nearly gave up for nearly a month and a half. I just simply didn't even want to deal with it I was so upset. was thinking about selling the lot and just moving on.

Well today I called craft supplies USA today just to see what they said. I described the problem and within less than a minute they told me they are going to send me a replacement lathe free of charge and a shipping label to return the old one. I was so surprised by this amount of customer service that I was dumbfounded. I'm 42 years old and never in my life had something like that happen.

So feeling pretty good about wood turning again and it only took about 5 minutes of my day.

Thank you.


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## duncsuss (Aug 21, 2009)

:thumbsup:


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## Bob Willing (Jul 4, 2008)

Hakchuma said:


> Thank you for all the guidance on the correct tool I should use. That was extremely helpful as I had never known that. I wonder how long it would have taken me to figure that out? dunno. just glad I know now.
> 
> The brushes on the motor were cracked/chipped. To be honest with you all, I was so upset that my lathe already had a problem and I had already spent a whole lot of money on chucks/tools etc, I was very depressed and upset. So upset that I closed the door on the lathe room and nearly gave up for nearly a month and a half. I just simply didn't even want to deal with it I was so upset. was thinking about selling the lot and just moving on.
> 
> ...


 You will find hands down that Craft Supply is one of the best suppliers and a concern for their customers. I placed a large order for one item over the phone and much to my surprise they sent me a post card thanking me for my order. Never had that happen before with any other supplier.


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## sawdustfactory (Jan 30, 2011)

Ive been to Craftsupply twice for classes and everyone at that company is great. From the front office people, to the warehouse guys to the instructors all the way to the president of the company. Everyone making sure you have a world class experience. I was fortunate to take my classes from Dale Nish before he passed away. We were invited both times to Dales house one evening for desert and to view his private collection of turnings, which is one of if not the largest private collection of turnings. Truly great folks all around.


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