So I broke it...

[Bruce Barker]

Slightly OT, but recently I changed blades on my miter saw, and "snugged" it (not "snug and a bit" as recommended above) since I am paranoid of breaking bolts.

The new blade, a Freud, completely changed the sound of the saw. Was the strangest sounding thing. Would whistle as it started much more slowly than before, then would sing as the blade spun down more slowly than before. I was thinking, how could a blade make the saw sound and run so differently!

I bet you have guessed what I did wrong by now...

[Steven DeMars]

Steven was right. I used a metal drill bit and the notch on the tip of the bit and it provided enough surface to move the bolt and spin it out. I broke the bolt using an impact wrench to get the bolt off that was on way too tight. I couldn't get it off by hand or with my 18V drill. But the impact wrench losened it up. Jut a little to strong I guess. I should have stoppped as soon as I got it to budge. I'll order the replacement bolt.

Guess I'll have to wait to try the new blade. Too bad I was anxious to check it out.

Thanks all.

I keep some left handed drill bits to do the same for right handed bolts.

[Johnny Pearce]

Backwards rotation ?????

[Bruce Barker]

No, but just as dumb. Didn't tighten the arbor bolt enough. The blade was freely spinning on the bolt. Rather sobering when you consider what would have taken place if the bolt had fallen out. Thank goodness they are reverse threaded.

[Steve Clardy]

I keep some left handed drill bits to do the same for right handed bolts.

Yep. I have a set also. Sure are handy at times.

No, but just as dumb. Didn't tighten the arbor bolt enough. The blade was freely spinning on the bolt. Rather sobering when you consider what would have taken place if the bolt had fallen out. Thank goodness they are reverse threaded.

Oops.

[Gene O. Carpenter]

The action of the threads binding against one another, DUE to the bolt head/flange coming in contact with the flange washer, is what secures that blade firmly to the shaft. Some have a type of Thrust Washer to apply holding grip to the blade and still allow slippage in case of a serious bind. When the blade and the locking washer are in position the end of the saw mandrel is ever so slightly below their outer edge, to give "take up room"!
If you turn it in the wrong direction you're creating a strain on the bolt head and quite naturally applying too much strain the head will snap off! Now the "binding action" is no more! So the bolt remnant should turn easily out..Just have to turn in the right direction!
If you try to drill or tap it out by any means you could possibly mess the shafts threads up or even swedge the bolt in tighter..Been there done that! I was into motors and mechanics before I got into amateurish woodworking..Those years of mechanicing have helped me tremendously with my WW machinery.

The easiest way would be If you have a Dremel or other rotary tool, use one of those "fine" grinding cut off wheels put on a pair of safety glasses and very carefully cut yourself a slot in the bolt. If it broke off flush you should still be able to get a deep enough slot to get a bite with a screwdriver but even if the end is slightly below the shaft's end go ahead and cut a little deeper..AGAIN, determine the correct removal direction and using a smaller screw driver turn it out. The 2 little slots will have no effect on the saw's operation..

Just remember, "if the blade is on the Right side of the saw the Arbor Bolt will be a Left hand thread and if the blade is on the Left side it will be a Right hand thread"..

[Zack Monroe]

I'm in a similar situation with the same model saw. But the bolt head didn't shear off, it's still attached. It spins but doesn't come off.

Any thoughts appreciated.

[Bill Dufour]

5/58 bolt torque is recommended about 120-180 foot pounds for max shear. I would say that is as tight as it is safe to go before thread failure. I would not go over 50% of those numbers on a bolt that should come out at some time.
For myself about double spark plug torque should be enough. Oil filter torque would be about right.
Torque is not transmitted through the bolt. It is friction between the arbor flange and the blade that transmits the torque. The bolt just keeps things aligned and touching so they do not slip.
Bill D.

[Zack Monroe]

Bill, thanks for the quick reply but I'm confused.

The bolt was overtightened while turning it CCW to take it out. Left hand thread was unknown at the time.

Something snapped but the bolt is still attached somewhere and does not pull out.

I suppose I can grind off the head, remove the blade and see what's going on underneath.

[Jerry Bruette]

Sounds like you may have stripped the threads. You've either pulled them off the bolt or out of the arbor and they're still bound up together. For your convenience I hope the bolt is stripped.

[Lamar Keeney]

My Dewalt miter saw has a left handed bolt.

[Rod Sheridan]

Drill, tap and insert a NORMAL bolt. It's left handed, no easy-out needed.

I certainly wouldn’t do that on a bolt that secures a saw blade, there’s a reason the manufacturer put a left hand bolt in.

Regards, Rod

[Steve Clardy]

I certainly wouldn’t do that on a bolt that secures a saw blade, there’s a reason the manufacturer put a left hand bolt in.

Regards, Rod

Agree. Not a good idea.

[Dave Zellers]

This is a misunderstanding. He was talking about tapping threads inside the broken bolt to aid in removing it, not changing the thread rotation of the arbor itself.