Removing circular saw blade

[SandburRanch]

Most sidewinder (right-side blade) saws unscrews lefty-loosey. Unplug the saw, swing the blade guard up, rest the teeth on a chunk of lumber, fit a box-end wrench the right size on the bolt/nut with other end to the left, and hit the open end with a small hammer. Impact gun does the same.
Might be a washer missing is why it's so tight? Does the motor run faster than the blade? Worm drive (left blade) righty-loosey.
Jim

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I recently removed a couple of problematic lawn mower jack shaft nuts via impact in like manner but I prefer a 2x4 about 2 ft. long. Something else very important for safety is a cereal box top shim. You see, if you shim the wrench on tight it is less likely to fly off and do damage and bodily harm.

 

[George2615]

When I prevent a circular saw blade from rotating on an old Craftsman circular saw and then rotate the mounting bolt holding the blade on the shaft (in EITHER direction) to remove the blade, I can see on the backside of the blade that the motor shaft is turning with the mounting bolt. I therefore can't remove the blade. There is NO lock button or anything else I can find to keep the motor shaft from turning. (For that matter, there is also no mechanism for keeping the blade from rotating and I have to insert a screwdriver in a hole in the blade until it butts up against the saw housing to keep the blade from rotating. Even when doing that to keep the blade from rotating, the motor shaft STILL rotates along with rotation of the moutning bolt. (BTW its a Craftsman 7 1/4" saw, 2 1/8HP, 10 amp, Model 315.108320 and has "A0125" on it.) I can't find a manual at Sears either.

Thanks for any help.

Bob

If you can't get an impact gun in there, continue your trick inserting the screwdriver in the hole and letting it but up. Put your wrench on the bolt (or nut) and hit the end of the wrench with a hammer. The shock will usually loosen the bolt (or nut) holding the blade. I've had to do this many times changing a table or circular saw blade and they have always come off this way for me.

 

[David Devuono]

Since the motor shaft is turning with the blade held steady, no amount of further locking the already stationary blade with help. You need an impact gun as mentioned. I only have one craftsman tool and I found out the wrong way that it had a reverse thread bolt. Not sure if yours is the same, but might want to determine that before you hit it with the impact wrench/

 

[BHD]

most all saw bolts or nuts are self bighting,, turn or loosen toward the rotation of the blade, turn in the direction the teeth point, on a table saw lock the blade, or jam it, and turn the nut toward the front of the saw, it should be the same on the skil type saw, as well, regardless the side the motor is on. (turn the saw over so the plate is up and turn the bolt/nut in the direction of the blade rotation or to the front of the saw to loosen),

there are a number of you tube videos on how to take the blade off of skil type saws,

but I would say you need an impact as well, if you can adjust the impact start out on a low setting and try, (some times it does not hurt to try the opposite direction as some times that will break it loose, but starting slow is better than breaking some thing).

in the video below note how it loosens in the same direction as the blade would cut,
YouTube - How to Use & Maintain Power Saws : How to Change Circular Saw Blade

 

[bcarwell]

Thanks all for the quick and helpful responses.
Some didn't quite grasp the problem when suggesting methods of holding the blade still (by inserting a screwdriver through the hole in the blade guard and lodging it against the blade teeth, clamping the blade in a vise, or putting pressure on the blade with a block of wood, etc.). I can hold the blade still. The problem is when I turn the mounting bolt the motor shaft extending through the blade turns along with the bolt WHILE the blade is immobile. Some asked how the saw could work. It DOES. The reason is it takes some force to rotate the bolt, e.g. the blade is not that loose on the shaft. I hadn't thought of using the inert mass of the motor/shaft to advantage by using an impact wrench or the redneck version of smacking the wrench with a hammer. I'm going out to try it (and hope I've got the right direction, after applying some liquid wrench). And thanks for the website on the Sears manual. They have one for $3.70 if all else fails.

Bob

 

[k0ua]

This reminds me that several years ago I was disassembling a vacuum cleaner and wanted to take the fan blades off. It had a nice hex bolt holding the fan blades on, and absolutley no way to prevent the blade/motor armature from turning while applying torque to the hex bolt. I looked at it for a while before getting the impact, but I was not sure there was enough mass in the aluminum fan blades and the lightweight armature. But when you think about how fast the impact spins up to high speed I guess it is possible. End result, one burst with the impact and the fan blades were off.. Went back on the same way.
Impact will solve your problem too.

James K0UA

 

[JoelD]

I've run into the same thing with shock absorber nuts and bolts. I'll use a socket wrench and she'll spin around all day and I can't get a grab on the bolt.

One whack with the impact and they spin right off.

This sort of thing is one of the most useful aspects of an impact wrench.

I also use when trying to get flywheel nuts off of small engines.

Joel

 

[bcarwell]

THANKS AGAIN TO ALL !! Reporting back: the redneck impact wrench (e.g. box wrench and a hammer) and a little WD worked like a champ. That's all it was and I was able to get the nut free since with an impact and the inertia of the motor the nut (finally) started turning before the motor shaft. And you unscrew the nut, as suggested, in the same direction that the blade rotates, which is logical since blade rotation during normal operation will cause the nut to rotate in the opposite direction tightening.

Bob

 

[PapaPerk]

THANKS AGAIN TO ALL !! Reporting back: the redneck impact wrench (e.g. box wrench and a hammer) and a little WD worked like a champ. That's all it was and I was able to get the nut free since with an impact and the inertia of the motor the nut (finally) started turning before the motor shaft. And you unscrew the nut, as suggested, in the same direction that the blade rotates, which is logical since blade rotation during normal operation will cause the nut to rotate in the opposite direction tightening.

Bob

Hooray! Glad you got it apart! The ol' equation force = (mass * acceleration) works again!

 

[Snaker]

This issue can be common to any arbor type equipment such as saws, angle grinders, bench grinders, etc. Some have a shaft lock and some don't. Your situation of a tight nut and loose blade can be caused by two things. 1) The nut backed off and seized or more likely, 2) You had improper "stacking" of hardware. It sounds like the nut ran out of threads before the hardware stack cinched down on the blade. Part of this is due to the common mix and match of different brands of equipment and blades. Sometimes there can be a slight difference. Most modern arbor type equipment come with a cup spacer to reach the blade and keep the nut out from the end of the threads. You need that for sure and may need aditional spacers or washers under the nut. I have had occasion where the cup spacer hit the arbor shoulder before gripping the blade and needed a spacer washer behind the blade.