Motor Bearing Failure in Craftsman 1975 Radial Arm Saw

[scoots]

I realize that a radial arm saw is kind of a strech for the topics on this site but I am going to ask pardon because it's a vintage unit, and there may be people who can advise me on a bearing failure...for obvious reasons I am loath to throw the unit away.

The subject is a Sears/Craftsman radial arm saw from about 1975, Model No 113.23100. While cross cutting a piece of .75x6 pine stock, (First cut of the day) the motor made grinding noises. I unpluged the machine, elevated the blade and removed the cover guard (to prevent rubbing)and found that the blade revolves freely for about 270 degrees. For the last 90 degrees, the blade "drags" on something and there's a gravel sound.

I am assuming that one of the perminently sealed bearings has failed. I called Sears, and surprizingly I was told that the bearing number 63503 is still widely available, and if needed, I could call the manufacturer, Emerson Electric at 314.553.2000.

My quesions are these: Does my diagosis sound correct? If not, what else can it be? Is anybody familiar with this motor bearing? Is this something I can do my self (my shop is set up for woodworking, not a machine shop)? Should I remove the motor and have it serviced at a motor shop?

Thanks for the input...

 

[vacosaurus]

I think if the blade drags on something I would take the blade off and turn the motor with out the blade and see if the motor drags. If the motor still drags I would see if there was side play on shaft that would allow motor armature to drag inside on the field laminates. if so you probably have a bad bearing. I would first look for something obvious on exterior of motor that would make the draging sound before opening motor. Also if it is something internal I would try to get an exploded parts breakdown diagram off the internet or from the sears part store they could eMail it to you and it would help guide you on disassembley. Good Luck Bill,

 

[cfz2882]

I have fixed quite a few of those over the years-they can be a little tricky to do a bearing change because besides the usual through bolts,emerson used epoxy to hold the end bells aligned-apparently a jig was used at the factory to hold everything aligned until the epoxy cured.Usually,if the epoxy cracks right,can be reassembled with a little new epoxy applied-did get one a couple years ago that emerson forgot to epoxy:made in 1974,it had been used very little as the rotor was dragging-used 4 strips of thin ,rigid plastic to hold the rotor centered in the stator bore until the epoxy I applied cured-then pulled the plastic strips out through the front vents-motor finally right after being faulty for 40 yrs...

 

[tolivac]

Does the saw have a mechanical brake to stop the blade "coasting" after it has been turned off?The brakes can cause dragging problems.At the tool repair place I used to work for we turned away the Sears saws-parts were hard and expensive to get.Radial saws are quickly declining in popularity becuase of miter saws and slide miter saws-they work sort of like radial saws-but for crosscuts and miters only.The miter saws can't be set for ripping as radial saws can.The mechanical brakes can cause problems like what you have.If you don't mind blade coasting-you can remove the brake.When Sears saws were brought into the place I worked for for repairs-we often just ordered a new motor for the machine-again from Emerson Tool.Before Home Depot closed-Emerson tool was making radial saws for HD.If you like a radial saw-see if you can get a new one thru HD.At this time new motors for Sears machines may NLA.Since Sears is going thru problems-a new machine from Rockwell,or HD may make more sense.Rockwell Radial saws are marketed to commercial users-you may get a 10" one from the commercial dealer to use at home.Just specify a tool with a 120/240V single phase motor.It will be expensive but the machine is top quality--and you can get parts for it if it needs service.Those are the only makers of radial saws today-most tool companies are abandoning them becuase of liability reasons.Radial saws have a higher accident rate than other tools.The ral funny thing----DeWalt tools-they were the ORIGINATORS of the radial arm saw--they no longer make them!!!FUNKY!!!Another thing--shop used tool dealers and try to get a DeWalt-a better machine than the Sears one.But parts could be a problem.

 

[kb0nes]

Generally a ball bearing failure won't cause the drag and noise you note through just part of a revolution. If the bearing is bad it will usually just make noise uniformly around the full revolution.

I suspect the RPM activated brake has a problem. Or maybe there is just something that has got into the motor.

I have a mid-60's Craftsman radial arm saw that does suffer from noisy bearings. Mine just growls when its spun up. I talked with a local motor service shop a while back and they told me they would do bearings for ~$100. I suspect I could do the bearings but free time is minimal so I'd probably pay someone. I have a good chop saw now so the RA saw hasn't run in years.

If the brake is broken, I'd likely disable/remove it. The one in my saw does precious little only slightly shortening the coast down. Parts are probably impossible to get as mentioned abive. In high school we had an add on electronic motor reversing brake on the radial arm saw. It would stop the blade in a fraction of a second eliminating the worry of re-positioning work near a still spinning blade.

 

[scoots]

Thanks for the help

I want to thank everyone who responded to this problem. I will look into the break first. Sorry for the late reply, I hurt my knee and have not had access to my computing for a while now.

 

[davetranter]

Dragging/grinding motor

Perhaps aleady been done, but may I suggest giving it a thorough blow out with an air line, if you have access to one?? It sounds like it may have 'inhaled' something through the ventilation holes.

All best

Dave T

P.S. Don't ya LOVE my U.K. spelling?? ;-)

 

[tolivac]

Yes, Dave-that is a thought blow it out with an air hose-woodworking power tool motors often get caked with sawdust inside-most new woodworking tool motors are sealed-fan on the outside of the motor.With these -you have to blow out the motor fan and cooling fins with the air blower gun.The caked sawdust can mess up the brake and motor centrifical start switch in open frame motors.If you are lucky-the blowgun cure can work.Its worth a first try.If it does work-saves you from having to take apart the motor.