Got a Craftsman 5 1/2 in circular saw that just started to make a grinding noise. Upon examining the blade, I noticed that it binds when I hand turn it on the shaft. I assume that this binding is associated with the grinding noise. I've had the saw for 15 yrs. and have had no problems. Checked obvious things like a loose or bent blade but all seems fine. I'm thinking maybe bad bearings??? Any suggestions?

I've had this same circular saw since new (the 80's). There is not a spindle lock. The bolt turns clock-wise to tighten. I usually hold the blade with a gloved hand and snug up the bolt. It will tighten when in use. When removing the blade, one can place a block of wood between two teeth to lock it in place.

Remember that on a circular saw, the bolts are typically left-handed thread so it is the opposite of a typical bolt. This is because the blade spins to the right so if a normal bolt was used it would loosen as the saw operates.

For any saw blade or grinding wheel, the rule is this. Pushing against the points of the teeth should be the direction that tightens the nut. So you must loosen it in the same direction that the blade spins. For example, if your saw blade is on the right side of your saw, then the blade spins counterclockwise, and the wood pushes against blade clockwise - so you turn it counterclockwise to loosen it (which is in the same direction that the blade spins.). If the blade is on the left side of the saw, you loosen it clockwise. Good luck, Al K

This bolt is what called left handed thread so you need to turn it in the oppisite driction as a normal right handed bolt. righty tighty and lefty losey well its rigthty losey. A t this point you need to get this bolt out or the saw it junk you can try slideing something under the bolt something thin and try to get back force on it as you turn the bolt in the correct dericition and see if it will thread out if it dose then you will have to get a left handed tap the size of the bolt hole and retap the hole and also get a new bolt.The tap will cost 30 dollars or so well good luck

without knowing the model number I can only assume that it is a circular saw and the blade is on the right hand side and then the bolt should be a standard thread. Hold the spindle lock in and turn the bolt counter clockwise to loosen. If other than it would probably be a left hand thread and do just the opposite. Let me know and if so please provide the model number so I can look at a breakdown for the tool.

Is this a brushless motor?

1. Unplug the saw.
2. Locate the blade lock button used to lock the motor shaft when changing a blade. For your saw, this button is usually located on the left side of the blade guard somewhere around the motor housing.
3. Push the button while rotating the blade until the button engages and the blade will no longer turn.
4. Use the wrench that came with the saw (or another wrench) to loosen and remove the blade bolt. For your saw the bolt should have standard right hand threads which means you loosen the bolt by turning it counter clock-wise.
5. Remove the old blade and replace it with a new blade of the same mounting type. Some blades have a round through hole and some blades have a diamond through hole.
6. Re-install the blade bolt and tighten clock-wise while holding the blade lock button down.

Is there anything jammed between the blade and the body/guard of the saw?

there is a spindle lock button between the handle and the blade housing, rotate the blade by hand while pushing in on the lock buttonwhen it goes in all the way the blade will be locked in position so you can loosen the bolt with a wrench

some saws don't have a blade brake , i always take a pair of vise grips and adjust to grip blade tightly and hold or bind against housing then remove bolts works well for me