# Problems w/ Craftsman 320.27666



## jimidee (Apr 3, 2014)

I bought this plunge router a little over a year ago and because of some health issues never used in until recently (now outside of the warranty by 2 months). It started fine back then and I let it run free with no load for a while to break it in. But after sitting in my heated garage for a while it now seems like it is trying to run in soft mode when the switch is thrown, but it only turns a little bit and then stops while humming. Of course, I turn it off and try again. If I jack the switch a few times before it stops turning completely, sometimes it does start up and run full speed...but not often.

I pulled the brushes and the top cover and checked the switch with my multimeter and it seems fine. The brushes and armature seem OK so I am guessing this problem may be in the variable speed module that also controls the soft start feature, but I am not able to test that for more reasons than I don't know how. I hate to buy the module for $40 (on an $80 router) and have it not be the problem.:nono:

Any ideas about what could be wrong would be greatly appreciated. I have projects lined up and this is frustrating!


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## JOAT (Apr 9, 2010)

jimidee said:


> It started fine back then and I let it run free with no load for a while to break it in.


Break it in? Never heard of that one before. That in the owner's manual, or you come up with it on your own?


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## Nickp (Dec 4, 2012)

jimidee said:


> I bought this plunge router a little over a year ago and because of some health issues never used in until recently (now outside of the warranty by 2 months). It started fine back then and I let it run free with no load for a while to break it in. But after sitting in my heated garage for a while it now seems like it is trying to run in soft mode when the switch is thrown, but it only turns a little bit and then stops while humming. Of course, I turn it off and try again. If I jack the switch a few times before it stops turning completely, sometimes it does start up and run full speed...but not often.
> 
> I pulled the brushes and the top cover and checked the switch with my multimeter and it seems fine. The brushes and armature seem OK so I am guessing this problem may be in the variable speed module that also controls the soft start feature, but I am not able to test that for more reasons than I don't know how. I hate to buy the module for $40 (on an $80 router) and have it not be the problem.:nono:
> 
> Any ideas about what could be wrong would be greatly appreciated. I have projects lined up and this is frustrating!



Couple of things come to mind... the variable speed control (probably a rheostat of sorts) under the knob... or the speed control at the end of the shaft...?

I would continue to look for mechanical first... dirt, rust, moisture, etc. Maybe a sensor rather than electronic...


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## jimidee (Apr 3, 2014)

JOAT said:


> Break it in? Never heard of that one before. That in the owner's manual, or you come up with it on your own?


Nothing in the owner's manual, but anything mechanical with rapidly moving parts (25,000 RPMs) _and_ brushes have a break-in, also known as run-in or running in. It is the procedure of conditioning a new piece of equipment by giving it an initial period of running, usually under light load, but sometimes under heavy load or normal load. It is generally a process of moving parts wearing against each other to produce the last small bit of size and shape adjustment that will settle them into a stable relationship for the rest of their working life.

Mainly I just wanted to hear it run and test the various speeds...call me fickle! :laugh: But upon inspection of the brushes recently I could tell that the brushes had partially conformed to the armature's curve with just that run-in. Didn't help much if it doesn't run now though, huh?


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## jimidee (Apr 3, 2014)

Nickp said:


> Couple of things come to mind... the variable speed control (probably a rheostat of sorts) under the knob... or the speed control at the end of the shaft...?
> 
> I would continue to look for mechanical first... dirt, rust, moisture, etc. Maybe a sensor rather than electronic...


Thanks Nick, I will remove the speed control module and look for any of those things. The schematic diagram does not indicate that it has a separate sensor (or at least it does not have a part no.) but it could be part of the module. The shaft turns smoothly and effortlessly by hand.

Any other ideas are appreciated.


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## Nickp (Dec 4, 2012)

jimidee said:


> Thanks Nick, I will remove the speed control module and look for any of those things. The schematic diagram does not indicate that it has a separate sensor (or at least it does not have a part no.) but it could be part of the module. The shaft turns smoothly and effortlessly by hand.
> 
> Any other ideas are appreciated.


I suspect it might be...when this kind of stuff happens to me (regardless of equipment) I generally look for that piece of dirt or rust or whatever that prevents sensing. What makes me think more along these lines is you mentioning that it sat for a while...build up of moisture/dry/moisture could fog a sensor (unless it is electromagnetic, of course).


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## Cherryville Chuck (Sep 28, 2010)

I'm not sure if any routers have sensors unless it would be part of a solid state feedback circuit? If the module only has one wire in and one wire out I would consider removing it and shunting across. That would tell you if its the control or something else. Since you have a meter I would check to see if there is any resistance across the control with it in the highest speed setting. If there is then get professional advice before trying that. Also check to see if the resistance changes as you adjust the control. If it changes then I would think that at the highest setting there should be no resistance.


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## jimidee (Apr 3, 2014)

Cherryville Chuck said:


> I'm not sure if any routers have sensors unless it would be part of a solid state feedback circuit? If the module only has one wire in and one wire out I would consider removing it and shunting across. That would tell you if its the control or something else. Since you have a meter I would check to see if there is any resistance across the control with it in the highest speed setting. If there is then get professional advice before trying that. Also check to see if the resistance changes as you adjust the control. If it changes then I would think that at the highest setting there should be no resistance.


The module actually has 6 wires connected to it and a little circuit board is visible. I don't have nor could I find a schematic for it. It also has the 6 speed roller switch (rheostat) attached. The module would cost me $40 and Sears has a minimum $45 charge just to look at it if I sent it in, and I could have bought a new one for $70...dohhh! 

So, I decided instead of taking the chance to buy the Dewalt fixed base/plunge combo for $200 + $20 for a 3 year extended warranty instead. I needed a good router now, even though I have two older 1 HP Craftsman fixed base routers. The difference in using these old routers and a modern one is like driving my old 64 Mustang and a new Corvette.:laugh: 

I will keep the Craftsman to play around with and will still look for any physical problems that could be causing it. Then I may sell it on ebay for parts.


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## Cherryville Chuck (Sep 28, 2010)

Jim I always wonder in a situation like that if I will be replacing one weak part with another one. The new router is probably the wisest decision. 

I like to check to see if a tool has a good reputation by googling the make and model number and adding the word "reviews". I've seen some models of Sears routers with lots of bad reviews and all of them with a common problem and some Sears routers get very good reviews.


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## DaninVan (Jan 1, 2012)

Jim; problem aside, it seems that the subject of the brush to armature 'curvature' has come up before. If I remember correctly, the general consensus was that the new brushes came with pre-curved faces, to match the armature, right out of the box. If that was the case, then the mfg. certainly agrees with you re the importance of a proper wear fit.


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## jimidee (Apr 3, 2014)

DaninVan said:


> Jim; problem aside, it seems that the subject of the brush to armature 'curvature' has come up before. If I remember correctly, the general consensus was that the new brushes came with pre-curved faces, to match the armature, right out of the box. If that was the case, then the mfg. certainly agrees with you re the importance of a proper wear fit.


When I pulled the brushes on this Craftsman router, they were slightly pre-curved but not enough to actually match the armature. Maybe they are a generic brush that could be used with several armature curvatures, I don't know...but I can say that I could definitely tell where the armature was hitting and where it was not. A proper wear fit could only be obtained in this case with time running the motor.

Thanks for your comment!


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## Jay Johnson (Feb 2, 2018)

*Changing Bit*

I am trying to change bits. The collet/nut spins loose but the 3 parts that are holding the shank in place do not loosen. I tried pliers to twist the bit but no luck. Any suggestions


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## Stick486 (Jan 4, 2013)

..


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## Stick486 (Jan 4, 2013)

Jay Johnson said:


> I am trying to change bits. The collet/nut spins loose but the 3 parts that are holding the shank in place do not loosen. I tried pliers to twist the bit but no luck. Any suggestions


...


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## mindbent (Feb 12, 2018)

You said that it runs slow for a minute then stops and makes a humming noise, correct? Sounds like it could be shorting out. Try cleaning the com and the brushes to see if that helps.


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## mikehubbell (Dec 25, 2019)

Craftman router model 320.27669. Haven't used in a while, went to use, started up and ran a couple of seconds then turned off and the red light up top by the digital display came on. shut it off and tryed again about 5 time and the same thing happens. just will not stay running.


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