problem with a low end dado blade

[Tom Fischer]

Bought a Mibro 8 " stacking dado
http://www.amazon.com/gp/product/B000HE87VI/ref=oh_details_o02_s00_i00
Using a PM 2000 3 hp

Setup the dado with both cutters plus one 1/8" chipper.
Then added two spacers.
When tightening, the nut squeezed soft. Went almost a full turn.
When removing the dado, it was jammed. Had to bang it off with a small hammer.
Both shims were slightly deformed.
And the then the arbor washer was "tight" going back on.
I had to run the saw with no blade, no nut, no washer, and "touch" the arbor with a fine stone.
Only then would the washer go back on.

Looking closely at the shims, one is now deformed, the 5/8" center hole is now out of round, and the steel has mushroomed up, causing a burr.

I've used dado sets before. Never had a problem.
What happened here?
Is this dado set defective?
I'm afraid of damaging the saw.
tia

[Richard Hutchings]

That can only mean your shim fell between the threads as you were installing the blades. Possibly your blades weren't interlocked correctly also giving the soft feel when you tightened the nut.

[Tom Fischer]

Blades were definitely aligned correctly. I thought the shim was on the unthreaded part of the arbor. Maybe not.

[Richard Hutchings]

Maybe the shim fell between the threads as the blades were slid onto the arbor and then got forced between the hole in the blade and the arbor causing the tight fit and misshaped shim.

[Clint Baxter]

[QUOTE=Tom Fischer;1931400]Bought a Mibro 8 " stacking dado
http://www.amazon.com/gp/product/B000HE87VI/ref=oh_details_o02_s00_i00
Using a PM 2000 3 hp

Setup the dado with both cutters plus one 1/8" chipper.
Then added two spacers.
When tightening, the nut squeezed soft. Went almost a full turn.
When removing the dado, it was jammed. Had to bang it off with a small hammer.
Both shims were slightly deformed.
And the then the arbor washer was "tight" going back on.

When you mention " added two spacers", are you talking about the shims? If so, they would definitely be situated on the threaded portion of the arbor shaft. As such, it seems one could have ended up catching on a thread causing your issue.

The only time I ever used shims was between the blades of the dado, for micro adjustment of the width. if you are using them as such and you want to avoid a repeat performance place them after placing the first outside cutter. You have the best chance of catching the unthreaded portion of he arbor shaft that way.

Clint

[Van Huskey]

Based on what I think happened I agree with the others that the shim got caught in the threads. I am a big fan of magnetic shims since they rarely shift one stuck to the blades.

[James Baker SD]

Based on what I think happened I agree with the others that the shim got caught in the threads. I am a big fan of magnetic shims since they rarely shift one stuck to the blades.

+1 on that.

James

[Ronald Blue]

I bought the Mibro set last year, tried it and returned them. I never had issues as you described but was dissatisfied with the quality of the dado cut. Not very smooth and some tear out on the edges. Felt like they were not very good quality.

[Michael Mayo]

I have the Mibro 8" set and it will forever sit on the shelf from now on. I used it many times but about 2 months ago I went to use it and noticed a couple of teeth were broken completely in half and chipped. I was not pleased. I have since bought an Amana Prestige Dado set and although it cost 3 times what the Mibro cost it is like night and day difference using that Dado set compared to the mibro piece of junk. I learned once again that you get what you pay for.

[Kevin W Johnson]

I noticed Lowes has this exact set on clearance for $41 and change, IIRC. I left it on the shelf, and it sounds like I made a wise descision.

[Sid Matheny]

When you have to use shims be sure to add only one blade/chipper/shim at a time to make sure everything goes on the shaft past the threads. Thin shims can get hung real easy on the threads. And +1 on Van's magnetic shims.

Sid