# circular saw repairs -- help!



## allthunbs (Jun 22, 2008)

Well, I'm not faring so well in the rebuild of the Stanley Circular Saw. I've installed the new bearings and everything seems to line up properly. Circular saws have a small gear at the bottom of the armature and a large "idler" gear that connects to the blade. I put in new bearings and cleaned and regreased everything. Brushes look OK. 

I've reassembled the whole thing a multitude of times and I have no parts left over. However, when the armature is spinning on the bearings it runs perfectly. When I install the idler wheel, I get one hell of a grinding noise and the motor is pushing very hard. I turn the armature by hand and it turns almost completely around and gets stuck, stopping the armature completely. It's as if something is wrong with the gear on the base of the armature. I take it out and look at it under a magnifying glass and can find nothing wrong with it. I take the idler gear and mesh it to the armature gear all around and there appears to be no obstruction. 

This is a real puzzle. Any comments or suggestions? I'm trying to get this running. It has all of the marks of an excellent saw if I can get it running.


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## RJM (Apr 11, 2010)

allthunbs said:


> Well, I'm not faring so well in the rebuild of the Stanley Circular Saw. I've installed the new bearings and everything seems to line up properly. Circular saws have a small gear at the bottom of the armature and a large "idler" gear that connects to the blade. I put in new bearings and cleaned and regreased everything. Brushes look OK.
> 
> I've reassembled the whole thing a multitude of times and I have no parts left over. However, when the armature is spinning on the bearings it runs perfectly. When I install the idler wheel, I get one hell of a grinding noise and the motor is pushing very hard. I turn the armature by hand and it turns almost completely around and gets stuck, stopping the armature completely. It's as if something is wrong with the gear on the base of the armature. I take it out and look at it under a magnifying glass and can find nothing wrong with it. I take the idler gear and mesh it to the armature gear all around and there appears to be no obstruction.
> 
> This is a real puzzle. Any comments or suggestions? I'm trying to get this running. It has all of the marks of an excellent saw if I can get it running.


Sounds like a thrust bearing problem. Motors also produce an axial thrust. There's usually a number of various thickness washers on either end of the armature. If you've mixed these up, one end of the armature could be binding in a bearing cavity, or the armature gear could be moving into the idler gear and binding there. Also, the idler and driven gears could also be suffering from misplaced thrust washers.


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## allthunbs (Jun 22, 2008)

RJM60 said:


> Sounds like a thrust bearing problem. Motors also produce an axial thrust. There's usually a number of various thickness washers on either end of the armature. If you've mixed these up, one end of the armature could be binding in a bearing cavity, or the armature gear could be moving into the idler gear and binding there. Also, the idler and driven gears could also be suffering from misplaced thrust washers.


Hi Robert:

Thanks for the reply. I've examined the saw and there are no thrust bearings on this model. All of the loads are side loads. However, thanks for the suggestion.

Ron


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## allthunbs (Jun 22, 2008)

I think I've determined the source of my problem. I borrowed a dial indicator from my neighbour and determined that the end of the armature has a slight bend in it. The bend is 15/1000 off center. This seems to be enough to throw off the gears meshing. If you take a look at a parts blowup of most saws you'll see that the armature is held in ball bearings but the idler gear is held in bushings. (at least on the ones I've looked at.) There seems to be a bend between the bearing next to the gear and the gear end of the armature. Anyone have suggestions as to how I might straighten this out? My neighbour suggests that I file down the offending protrusion slightly, just enough to mesh properly. 

Comments? Suggestions?


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## RJM (Apr 11, 2010)

Maybe you can chuck a rod (cut off the head of a bolt) into a drill press use it as a press to straighten it out. Depends on where the bend is and if you can set the armature up on blocks.


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## allthunbs (Jun 22, 2008)

RJM60 said:


> Maybe you can chuck a rod (cut off the head of a bolt) into a drill press use it as a press to straighten it out. Depends on where the bend is and if you can set the armature up on blocks.



Hi Robert:

Interesting suggestion. I'll try it


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## AxlMyk (Jun 13, 2006)

A drill press is not meant to be used as an arbor press. You can damage/destroy the quill and pinion teeth.
.015" is a bit of a bend. You need an arbor press or machine shop to straighten it.


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## Mike (Nov 22, 2004)

Ron, the method used for straightening a shaft is to chuck it up in a metal lathe so both ends are supported, rotate it and find the high spot with a dial indicator, heat it and then tap it back into alignment. Once it runs true you must polish off any deformations caused by the process, heat it and quench it in water or oil to restore the hardness. It might be easier to just order a replacement part, after all... time is money.


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## RJM (Apr 11, 2010)

AxlMyk said:


> A drill press is not meant to be used as an arbor press. You can damage/destroy the quill and pinion teeth.
> .015" is a bit of a bend. You need an arbor press or machine shop to straighten it.


I'm assuming that the shaft is under 1/4". I don't think it will hurt the drill press.




Mike said:


> Ron, the method used for straightening a shaft is to chuck it up in a metal lathe so both ends are supported, rotate it and find the high spot with a dial indicator, heat it and then tap it back into alignment. Once it runs true you must polish off any deformations caused by the process, heat it and quench it in water or oil to restore the hardness. It might be easier to just order a replacement part, after all... time is money.


We're talking about a circular saw armature with windings and commutators. Can't very well heat it up. I think straightening on the drill press is worth a shot over grinding the gear teeth down (which I wouldn't do). In any case, if it doesn't work, then it can replaced.

We don't always do these things to save time or money. Sometimes it's the journey itself. Actually, most of the time on this forum.


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## paduke (Mar 28, 2010)

I prize hillbilly engineering and must say rj deserves applause for the drill press suggestion.


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## allthunbs (Jun 22, 2008)

Mike said:


> Ron, the method used for straightening a shaft is to chuck it up in a metal lathe so both ends are supported, rotate it and find the high spot with a dial indicator, heat it and then tap it back into alignment. Once it runs true you must polish off any deformations caused by the process, heat it and quench it in water or oil to restore the hardness. It might be easier to just order a replacement part, after all... time is money.


Hi Mike:

Thanks for that. I have several machine shops not far from me but they're all bloody expensive. I'll try the "hillbilly" method first and see what I can accomplish with that.

There are no parts available for this. It was made in 1967 by Stanley which was bought out by Bosch who've managed to lose all of the information on the older products.


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## allthunbs (Jun 22, 2008)

RJM60 said:


> We're talking about a circular saw armature with windings and commutators. Can't very well heat it up. I think straightening on the drill press is worth a shot over grinding the gear teeth down (which I wouldn't do). In any case, if it doesn't work, then it can replaced.


Nope, parts not available. Needs to be corrected or it goes to the copper recycling yard. 



> We don't always do these things to save time or money. Sometimes it's the journey itself. Actually, most of the time on this forum.


Yup, the latter is the case. I might have to break down and buy a saw but if I can get this working properly, I will. It's a nice saw.


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## allthunbs (Jun 22, 2008)

paduke said:


> I prize hillbilly engineering and must say rj deserves applause for the drill press suggestion.


Cute. You'll note I quoted you above.

Now, if I could take the armature and place it between blocks and tap it back into alignment that way would that do the trick? _Or_, does it really have to be heated?????


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## RJM (Apr 11, 2010)

I think of myself more of a ******* ...


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## RJM (Apr 11, 2010)

allthunbs said:


> Cute. You'll note I quoted you above.
> 
> Now, if I could take the armature and place it between blocks and tap it back into alignment that way would that do the trick? _Or_, does it really have to be heated?????


You couldn't put enough heat into it (to do any good) without ruining the windings. If you can tap, press it, whateverit, and the runout comes in, it'll stay fixed. After all, it got bent without heat.


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## N'awlins77 (Feb 25, 2011)

Ron, I've had a similar situation I had to fix at a jobsite. I'm a metal cutting machine tech. This was on a small servo motor. The shaft running through the armature was about 1/4 inch in diameter and it was about 8 inches long. The armature was offset on the shaft. The bend was about 1/2" on the longer end. 

I chucked the short end (straight end) in a drill press. I then took a black marker, using my two hands to hold the marker steady, touched off the shaft near the armature where the shaft was still straight. I slowly moved the marker down towards the bend. When I felt and saw the marker vibrating, I pulled the marker away. This being the start of the bend. Then, using the marker and my two hands, I went down to the end of the shaft, slowly advancing the marker until it started to hit the wobbly end of the shaft. This marking the high spot of the bend. 

I then took the armature out of the drill press, being careful not to rub out my marks. Then I took a piece of an old leather belt, rapped it around the armature and clamped it in a vise. Snug, but not too tight. I turned the armature so that my mark on the end of the shaft, was facing me, or at the "9 o'clock" position, facing the end of the shaft. I then took a piece of pipe that just fit over the shaft, slid it up to the end of the other black mark (point of bend), and then pulled the pipe toward me. 

It's a rude and crude way of doing it, and it took a couple of tries, wiping the marks off and putting it back in the drill press and mark again. But in the end I got it straight enough that it didn't make noise or make the motor run hot. At the time, the servo motor was not in stock and it would have taken 2 to 3 weeks to get one in and my customer couldn't wait, so they paid dearly for me to do this. BTW, my customer had went ahead and ordered the new one, just in case. But three weeks later, they got it in, but it was the wrong one. So since my repair job had held this long, they took a chance and returned the new one, and did not have them send another one. This was 3.5 years ago, and counting....


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## bobj3 (Jan 17, 2006)

Hi 

I don't get it 
All tools have a voice and this one telling you I'm going to die soon, use me as long as you can and than put me out of my misery and get a new one. .....after all I'm just a 30 year OLD Stanley tool ,what do you expect from me.

======


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## allthunbs (Jun 22, 2008)

N'awlins77 said:


> Ron, I've had a similar situation I had to fix at a jobsite. I'm a metal cutting machine tech. This was on a small servo motor. The shaft running through the armature was about 1/4 inch in diameter and it was about 8 inches long. The armature was offset on the shaft. The bend was about 1/2" on the longer end.
> 
> I chucked the short end (straight end) in a drill press. I then took a black marker, using my two hands to hold the marker steady, touched off the shaft near the armature where the shaft was still straight. I slowly moved the marker down towards the bend. When I felt and saw the marker vibrating, I pulled the marker away. This being the start of the bend. Then, using the marker and my two hands, I went down to the end of the shaft, slowly advancing the marker until it started to hit the wobbly end of the shaft. This marking the high spot of the bend.
> 
> ...


All of the other suggestions are exactly what I needed. They give credibility to this suggestion and I'm thinking this one is spot on. The shaft I'm dealing with is 1/2" not 1/4" but I have a heavy vice and some other tools that can be pressed into service. Thank you all. I'll be digging into this one later today. I'll try to post results in the next day or so.


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## allthunbs (Jun 22, 2008)

bobj3 said:


> Hi
> 
> I don't get it
> All tools have a voice and this one telling you I'm going to die soon, use me as long as you can and than put me out of my misery and get a new one. .....after all I'm just a 30 year OLD Stanley tool ,what do you expect from me.
> ...


That's just it. It is a 30 year old tool that's been abused and with a little care it can give another 30 years of good service. Why destroy something for the sake of a blemish. Besides, now I know the correct way to straighten a rod as well as a bunch of hacks to accomplish a similar result without expensive tools. Further, I learned alot about metals and saws and gears and what makes a good saw. But what's most important is that I'm getting a good quality working saw for $15 and a little effort. The alternative is no saw. I don't have the $150 for a new one.

Thanks to each of you, Lee, Robert, Bill and, Mike for your assistance. This sort of information should have a permanent home on the forum. The problem is, how does one index a topic like this???


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## bobj3 (Jan 17, 2006)

Hi Ron

In the states that's 10 dollar power saw at most pawn shops, the bottom of the barrel saw..I have sold my share of them or to say gave many away...as a door prize thing..(take one it's free ) 

========



allthunbs said:


> That's just it. It is a 30 year old tool that's been abused and with a little care it can give another 30 years of good service. Why destroy something for the sake of a blemish. Besides, now I know the correct way to straighten a rod as well as a bunch of hacks to accomplish a similar result without expensive tools. Further, I learned alot about metals and saws and gears and what makes a good saw. But what's most important is that I'm getting a good quality working saw for $15 and a little effort. The alternative is no saw. I don't have the $150 for a new one.
> 
> Thanks to each of you, Lee, Robert, Bill and, Mike for your assistance. This sort of information should have a permanent home on the forum. The problem is, how does one index a topic like this???


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## Mike (Nov 22, 2004)

You will have to forgive me for my "industrial" answer. Most of the shafts I have had to straighten were 4-8" diameter. The principals are the same, just a smaller scale. Determining where the bend is will be the difficult part on an armature. If you are lucky and it is just the end of the shaft I would try drilling a tight fitting hole in a piece of hardwood about 1" square, inserting the armature and clamping it in a vice vertically. By doing this you should be able to see any wobble when the armature is turned. You should be able to carefully bend it back into shape. Apply force across the jaws of the vice so your shaft does not rotate off vertical. This should only take a tiny amount of force to straighten since the armature rotates most of the way when assembled. If the bend is very close to the end of the shaft support it in a metal V block and use a brass bar like a punch with a heavy hammer to try tapping it back into alignment. The point was raised that heat was not involved in the bending process but it seems likely for the bend to occur the saw was in heavy use and the shaft did heat up. Perhaps you hit a knot that briefly increased the torque in a "spike" which caused the shaft to distort? What ever the cause, once metal is bent trying to straighten it will weaken the metal unless it is heated first. The idea of heating and then quenching would add back lost case hardness (which does not sound possible in your situation.) I think a visit to craigslist.org for a used saw would save you a lot of time.


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## allthunbs (Jun 22, 2008)

Mike said:


> You will have to forgive me for my "industrial" answer. Most of the shafts I have had to straighten were 4-8" diameter. The principals are the same, just a smaller scale. Determining where the bend is will be the difficult part on an armature. If you are lucky and it is just the end of the shaft I would try drilling a tight fitting hole in a piece of hardwood about 1" square, inserting the armature and clamping it in a vice vertically. By doing this you should be able to see any wobble when the armature is turned. You should be able to carefully bend it back into shape. Apply force across the jaws of the vice so your shaft does not rotate off vertical. This should only take a tiny amount of force to straighten since the armature rotates most of the way when assembled. If the bend is very close to the end of the shaft support it in a metal V block and use a brass bar like a punch with a heavy hammer to try tapping it back into alignment. The point was raised that heat was not involved in the bending process but it seems likely for the bend to occur the saw was in heavy use and the shaft did heat up. Perhaps you hit a knot that briefly increased the torque in a "spike" which caused the shaft to distort? What ever the cause, once metal is bent trying to straighten it will weaken the metal unless it is heated first. The idea of heating and then quenching would add back lost case hardness (which does not sound possible in your situation.) I think a visit to craigslist.org for a used saw would save you a lot of time.


Nuts with the "industrial" answer. I'm learning here and this is the best school I've ever attended. You don't know how much I appreciate your time and willingness to pass on your experience and knowledge. Thank you.


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## BrianS (Nov 7, 2004)

Ron, just curious how you are making out on this. And, curious as to what grease you plan on using on the gears when you get the shaft straight.

Brian


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## allthunbs (Jun 22, 2008)

BrianS said:


> Ron, just curious how you are making out on this. And, curious as to what grease you plan on using on the gears when you get the shaft straight.
> 
> Brian


I've been working the last few days so I haven't gotten back to it yet. The unit is disassembled so all I have to do is work on the armature. 

I'll be using synthetic grease. It's used for the auto racing industry so I figure it'll do for my patches. Brand name is Amsoil. I've been using it on my bikes for years. Holds forever.


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## BrianS (Nov 7, 2004)

Perfect. Thanks Ron. I dug my Dad's old B&D saw out and thought I'd take it apart to see if I could fix it. Long story.. stolen from my garage and I found it at a flea market and got it back.. not working. Probably kept it for 5yrs like that. No idea why, but now it spins up?? Got to check for broken wires or an open, but that will be later. Grease is all dried up and NONE was on the gears, just all caked in the housing. I'm sure my Dad just used wheel bearing grease on it when he took it apart for cleaning.. I've got some Moly grease, but maybe will invest in some synthetic for it.


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## allthunbs (Jun 22, 2008)

BrianS said:


> Perfect. Thanks Ron. I dug my Dad's old B&D saw out and thought I'd take it apart to see if I could fix it. Long story.. stolen from my garage and I found it at a flea market and got it back.. not working. Probably kept it for 5yrs like that. No idea why, but now it spins up?? Got to check for broken wires or an open, but that will be later. Grease is all dried up and NONE was on the gears, just all caked in the housing. I'm sure my Dad just used wheel bearing grease on it when he took it apart for cleaning.. I've got some Moly grease, but maybe will invest in some synthetic for it.


Hi Brian:

The biggest headache in repairing these tools is pulling the bearings. Major PIA! I have yet to invest in a bearing puller but may have to soon. I think my old Stanley has 9 machine screws, two bearings and two bushings. Dead simple. I use the best grease I can find and I think the synthetics do the trick nicely.

Gotta Go. Talk soon.

Ron


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