Self-Lowering Dado Blade

[LeftyTom]

I have a Sears dado blade mounted in ye old Craftsman bench top table saw. The cutters and chippers are evenly spaced. Everything seems tight.

The saw is screwed to 3/4" plywood, with a 2"x4" screwed in the middle of the bottom of the plywood. The whole shebang is clamped in a "workmate" type table.

After cutting a tenon on a 2"x6" SYP, you can see where the handle on the height adjustment has moved.

Am I feeding the work too fast? The motor doesn't sound like it is under any major load.

Or has the Craftsman saw seen it end as a useful dedicated dado machine?

 

[dick541]

I think it is time to look for a better saw.
dick

 

[Travis Porter]

I had a similar problem with my planer many years ago. Called the manufacturer and they had never heard of such a thing, and they had only one suggestion. Put a fresh set of sharpened blades in it. I happened to have a set, and it worked. May be the same thing. Blades could be dull causing excessive vibration. Does it have a blade height lock? If not that, like Dick said, may be time for a better saw.

 

[McRabbet]

The Height adjustment lock is slipping. The dado blade may be dull, but you can tell that by the quality of the cut. If the edges are ragged and torn, then it should be sharpened. I am not familiar with the height adjustment and its locking, but many saws use a cam-style friction lever that binds the rotating shaft behing the adjustment wheel. If it is worn to the point where it does not tighten, you may be able to give it new life by taking it apart and adding a flat washer to add more thickness to the clamping set on the shaft. Just a guess on my part -- I'd need to know the saw model and look at an exploded parts diagram to be sure.

 

[Bas]

Here's an idea....may not help, but it's easy to try. When setting the height of the dado blade, set it a fraction too low, then bring it up. As opposed to lowering the blade to the right height. That may eliminate the "slop" you're having. Not a fix, but may extend the useful life of the saw.

I find this technique useful with lots of adjustments - the guides for my band saw, setting knives on the jointer etc.

 

[LeftyTom]

Rob, this saw has no height adj lock, just a hand wheel (yes, that is generous, when applied to this saw).

Bas, the blade lowers itself during the cut. I turn the saw on, left it run without making a cut, and the height doesn't change.

Oh well, never had that problem using a saw blade. I will put a blade on it, Make sure it works OK, and drop it off (with the owner's manual) at the Rescue Mission store in Winston-Salem.