Wonky sawblade?

[billmayo]

I find that I have to use blade stablizers on the cheaper thin kref 5/8" ID 10" saw blades.

[foxtrapper]

I'm a little baffled by a kerf that is wider at the base than at the top, particularly if the blade is wobbling.

I'd chuck up another blade in the same arbor to see if the blade itself is wobbling, or if the arbor is unsqaure. If both blades wobble, I'd pull the arbor and inspect it closely. Maybe it's something simple like dirt or a burr keeping the blade from settling square. If the arbor is not true, you'll be unlikely able to straighten it.

[dusty]

If watching/testing the saw blade doesn't confirm the problem, I'd chuck a long drill bit and watch it. If it wobbles too, then I would suspect the main shaft within the headstock but I really doubt the problem is there.

My money is on the arbor and/or blade.

I'd really like to see this suspect kerf though.

[pennview]

"My money is on the arbor and/or blade."

I'd agree while looking at the problem from a few thousand miles away, but who knows as this possibility was been deemed not possible in post #5.

[jm51]

I've ordered an SD card so pics soon. Of course my original card will turn up within 2 days of the new one arriving.

I forgot to allow for the shoulder of the blade which goes to about 1" from the teeth. So this made the blade look not flat when laid on a piece of ply.

It might well be the arbor. I marked the teeth furthest from the headstock then repositioned the blade on the arbor and got a different 'furthest point'. No bad dings or suchlike on the arbor but there is a touch of surface rust on the threads. Could this be the problem? (Long drill bit in Jacobs chuck = good, no wobble.)

Early tests were done at slow speed A and it does look like an oscillation. I upped the speed to P and the cut was better, less of a wedge shaped kerf. At speed S it was better still but ~0.25mm wider at the bottom than the top. The faster the speed, the less it looks like an oscillation, just a thicker blade lol.

fwiw, blade height was set to ~ 1 full tooth over minimum.

[JPG]

You are keeping the 'shoulder' below the table top when cutting!:rolleyes:

Have you looked closely at the blade hole and the area around it that contacts the arbor?

P.S. Your speed A / speed P description sounds like wobble.

[jm51]

Submerged 'shoulder', teeth barely above the top of the 1/2" ply.

I think (hope?) it's fixed. I put a dremel/wire brush over the mating surfaces and threads of the arbor. It's still 'out' when hand turning (sanding disk = hand wheel) and using the main table as a reference* but under power the cuts are way way better and top and bottom are of the same width. (Within the limits of my digital caliper.)

Pre dremel: Speed P kerf top/bottom = 0.079"/0.082" and speed S kerf = 0.082"/0.088".

Post dremel speed Q = 0.071"/0.070"

Thanks everyone for the help, I'd never have suspected the arbor at all.

*Position main table, turn lock, watch table move a couple of thou to the right.

[dusty]

Submerged 'shoulder', teeth barely above the top of the 1/2" ply.

I think (hope?) it's fixed. I put a dremel/wire brush over the mating surfaces and threads of the arbor. It's still 'out' when hand turning (sanding disk = hand wheel) and using the main table as a reference* but under power the cuts are way way better and top and bottom are of the same width. (Within the limits of my digital caliper.)

Pre dremel: Speed P kerf top/bottom = 0.079"/0.082" and speed S kerf = 0.082"/0.088".

Post dremel speed Q = 0.071"/0.070"

Thanks everyone for the help, I'd never have suspected the arbor at all.

*Position main table, turn lock, watch table move a couple of thou to the right.

Good news! I am glad to hear that you got this resolved. I am also thankful that this was not a design or manufacturing problem. Solving this sort of problem is relatively easy though this sort of problem shall be eternal.

Your asterisked comment (highlighted) is inherent with the Mark 5/V. This can be avoided only with "heavy iron" and sometimes not then.