Cut variations in my stacked dado.

[Dell Moore]

I was wondering if anyone had any idea why I would be having problems with my stacked dado. For some reason I am getting variable depth cuts in my wood when I pass it over the blades, so of the variation are around 1/16th to almost 1/8th in variation. I have never experience this before.

If you've seen this before, please let me know.

Dell

[Jamie Buxton]

DAMHIKT, but that sort of thing can happen if you run a chipper backwards....

[Matt Day]

I don't see how the depth of cut could vary and it be a result of the blade, since the blade spins and cuts to a certain fixed height. Is your stock flat and are you applying even downward pressure as it passes through the blade?

[Rod Sheridan]

Mat is correct, since the height of the cutter above the table is constant, your material must not be flat.

I find that with sheet goods, a power feeder is ideal since it forces the material down onto the table with enough force to flex the sheet stock.

Regards, Rod.

[Dell Moore]

Jamie, I did double check the cutters to make sure I didn't put anything in reversed. It was the first thing I though of.

Ron, I wish I could set up a downward pressure system, but I don't really how it would be feasible.

I could have sworn my stock was flat, but that may very well have been the problem. I'll experiment some more.

Thanks,

Dell

[Julian Wong]

Ron, I wish I could set up a downward pressure system, but I don't really how it would be feasible.



First wax your tabletop really good.
Second, get a pair of safety boots.
Third, stand on the wood that needs a dado
Fourth, get an assistant to push the wood though with you standing on top.
:D:D:D:D

[glenn bradley]

On material that is not flat (like sheet goods or large panels) a router is a better option for dados. A small base (6" or less) will follow the contours of the board and give you a more consistent depth of cut.

Another solution I have seen is to make a sort of ZCI with a hump on it (this scares me) that the material rides over to solve this problem. I prefer the router when my stack is not a good choice.

[David Christopher]

Dell, if your blades are not sharp it will push the material away from the blade and make varying depths of cut.......sometimes you can run the piece threw twice and it will fix the problem

[John Harden]

How old is your saw and how many hours does it have on it? I'm wondering if you might have an arbor bearing going bad. You might not notice it with a standard blade installed but put all the weight and mass of a stacked dado on there and it may be wobbling.

Just a thought.

Put a dial indicator on there and give the arbor a spin by hand to see what the runout is. Obviously, remove the blade first. Should be less than .001"

Regards,

John

[Alan Schwabacher]

If the blade height is not locked, the cut depth can drift down. It's less common, but it can also drift up. To rule this out, check to see that the blade height is the same after the cut as before.

[george wilson]

READ THIS POST: It is easy to make a wooden throatplate that will make an even depth dado across a hollow board. Just make the throat plate flush with the saw top on both ends,but bandsaw a smooth "hill" in the center of the throat plate. the board will contact the top of the hill as it is pushed across. The hill needs to be perhaps 3/16" high in the center. The highest point on the hill should be centered with the highest cut that the dado makes.

As a hollow board is pushed over this hill,it will maintain contact with the board,making the dado a constant depth. Don't get carried away with how high you make the hill,or the boards will be tilted upwards too much,and the dado will become angled in the vertical plane.

[Cliff Rohrabacher]

Warped wood can be dadoed to a consistent depth very easily:

Make an insert for the table saw opening that has a little bulge in it that is at least as high as the wood's warpage causes it to lift off the table. The center of the little bulge should be the TDC of the dado.
You can make it from wood or epoxy putty or whatever you have to hand.
Then set the dado height from the top of that bulge

[george wilson]

Cliff,that is exactly what I just said,except in fewer words. I always just use solid wood,and bring the dado set on maximum width up through the plate.

[Howard Acheson]

Be sure you are setting the depth of cut by cranking the blade "up". If you have to reduce the hight, go past where you want and adjust "up".

There is some slack, play or "lash" in the gear raising and lowering mechanism gears. When raising up gravity ensure that the blade stays at it's lowest point as you raise it.

Another trick is to tighen the locking knob until you can feel some dray as you crank the handle. This greatly reduces the lash in the gears.

[Dell Moore]

How old is your saw and how many hours does it have on it? I'm wondering if you might have an arbor bearing going bad. You might not notice it with a standard blade installed but put all the weight and mass of a stacked dado on there and it may be wobbling.

Just a thought.

Put a dial indicator on there and give the arbor a spin by hand to see what the runout is. Obviously, remove the blade first. Should be less than .001"

Regards,

John


John, you nailed it. It is the arbor. I did a little experimenting and realize it was only one blade that was causing the problem. The folks a Freud clued me in to the probkem. This saw is the Ridgid TS3650, and I am really hoping the replacement will be under warrenty.

Wish me luck...

Dell

[glenn bradley]

Just make the throat plate flush with the saw top on both ends,but bandsaw a smooth "hill" in the center of the throat plate.

George is describing the humped ZCI I mentioned. I knew I had seen that somewhere. I couldn't find it and was starting to think I imagined it ;-)

[Matthew Dunne]

This saw is the Ridgid TS3650, and I am really hoping the replacement will be under warrenty.


Hey Dell,
I have that same saw. It's my understanding that earlier production models of the 3650 had an arbor which created problems with a dado blade.

There's a lot of info about this on the ridgid user forum.

I believe Ridgid was very responsive in replacing the defective units. Give them a call.