I'm on a farm, and I'm a little person learning to do big work.
I was having so much trouble controlling a direct drive circular saw due to the gyroscopic twist when starting it up, my "adopted brother" found me this wonderful worm drive Skilsaw. It's an old solid metal case, the thing weighs like three times the Ryobi direct drive, but when it's running, it doesn't feel like anything at all! I love the darned thing.
We replaced the blade for something newer, as I've got some cabinetry to tackle – but neither he nor I can get the blade to tighten down. If there's no real drag it cuts fine, but the least thing makes the blade just stop. No jerk or bounce-back, the shaft spins but the blade is obviously not tight to the shaft.
This scares me, but I really want to be able to fix ths so I can get back to cutting. Any help would be appreciated!
Edit: Thank you all for your suggestions!
I got the bolt off (yes, reverse thread) and yes, the diamond knockout is knocked out. So it's a problem with the blade thickness. I got a hefty washer on there, threaded the bolt back on, tightened the you-know-what out of it, and the difference is obvious without even running it – before, I could hold the blade with my fingers and spin the shaft with a wrench. Now I tried holding the blade with a pair of slip-joint pliers and couldn't get the bolt to budge.
I'm leaving a photo here of how it looks, and will check back in a bit – let me know if what I did is in some way dangerous or unsafe.
Note to the respondent who noted the dangers of worm drive – thank you! I already knew, and have a healthy terror of kickback. Scariest thing I ever did with a circular saw was stand on the top rung of a ladder and cut notches into roofing plywood – and that was a direct drive, and I definitely self-medicated with a bit of Tito's that night, well after I was finished. 🙂
You people rock, and if I haven't forgotten I'll post shots of the finished bed frame. Thank you all!
Best Answer
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.