circular-sawscrewsstuck
I need to change the blade on my Dewalt DCS391 circular saw for the first time. The blade clamping screw is for an hex key left-hand threads, but I can't unfreeze it no matter how much lever of pressure I put on it, I'm starting to eat the screw head.
I'm following instructions from the manual with no luck.
Suggestions?
If you're sure it's the shaft that's loose, and not a misalignment in the blade attachment, then it's most likely one of the bearings supporting the shaft that's bad. Check for play in the bearing flange (Component 36). If that's solid, then check the bearing sleeve (component 13). Unfortunately if it's the armature that's damaged (component 3), then you're better off buying a new saw.
Does the old blade have a diamond shaped hole? My 77 is a few miles away, but my recollection is that it uses that configuration. Some new blades won't have it at all (and thus are not suitable), others will have a round hole and a pre-cut diamond hole that punches out to engage the diamond shape on the saw clamps.
Here's the manual, which suggests both the "left hand thread" and diamond arbor as correct recollections on my part:
http://mdm.boschwebservices.com/files/SHD77M-02-73%20Manual%20r113863v5.pdf
Here is a blade which appears to have the diamond hole possiblity, but not yet knocked-out.
Here is one with the hole cleared to the diamond shape:
Note that the worm drive saw, while you prefer the feel/heft of it, can be rather more dangerous than a direct drive saw if it's jammed and kicks back. Most people treat them with a healthy dose of respect - or learn to eventually.
Best Answer
Following up on how I've resolved this and what was the issue. At the time of this post I've tried everything that was suggested and the clamping screw did not bulge at all. However, I did not had access to was pneumatic tools in my shop at home, so I went to a local tool store and they dislodged the clamping screw for me.
They explained to me my mistake and why I had such a hard time removing it. The issue was that I've inverted the washers (r, s) and they were not in the correct position.
Here's a picture of the circular saw once it was correctly assembled with the r and s washers in the correct position.