Stack dado problem

[Brent Gamble]

Been lurking for a while, this is my first post. Here's the problem. Just bought a stack dado set (Freud 8" pro dado). Used it this past weekend to cut some dado's and rabbetts for a bookcase. Got the cuts made just fine....but, took me around 20 minutes to get the sucker on the saw and around another 20 or so to get it off. The blades and chippers are so tight on the arbor of my Delta contractor tablesaw that they have to be coaxed, wiggled etc. to get them on and off. I've had this saw for 5 yrs and have used all kinds of blades on it and never had a problem. Is this normal, or did I get a bad set? Oh, and before someone asks, I was putting the blades, chippers and shims on one at a time.

[Dan Barr]

sounds like a bad set to me. send it back.

i'm guessing that it doesnt take 5 minutes for you to put your normal rip or crosscut blade on the saw. it seems that the hole in the dado blades is smaller than the hole in any of your other blades. i would measure the holes and compare. you could also measure your arbor on the tablesaw.

either way, sounds like the dado set is the problem. holes are too small. send it back.

ciao,

dan

[Ellen Benkin]

Freud has a no questions asked replacement policy. Good idea to check the size of the holes with another blade, though.

[Mark Grotenhuis]

Your dado blades should be snug on your arbor, but not so snug its hard to get them on. I have the same dado set you do and I've found that my dado blades do fit more tightly on the arbor than my standard rip blade, but it never takes me more than a few seconds to push them on and off by hand. If you have to use force to coax them on I'd be worried about ruining your arbor. Get a caliper and measure your arbor and your dado holes to find which one is out of specifications. I'm with Dan, sounds like the dado blades have too small of a hole.

[Charles McCracken]

Brent,

In my experience, Delta seems to maintain one of the best tolerances on arbor diameter. Freud tolerance on the bore is 0.6250" +.0007/-0.0000. Combine these tolerances with the fact that the plates of the dado components are thicker than standard saw blades and any variance from going straight on will cause a bind. If the dado components will turn easily on the arbor once installed (with the power disconnected, of course) then the fit is correct and you will be able to cut dadoes with very flat bottoms. If the fit was loose enough that the components slid on easily the result would be that they would not locate properly and the dadoes would be uneven. You can lightly buff the bores with fine emery cloth to make it easier but be very cautious of getting them too large and/or out of round.

[Cliff Rohrabacher]

The blades and chippers are so tight on the arbor of my Delta contractor tablesaw that they have to be coaxed, wiggled etc. to get them on and off.

You must have got the best set they made that year.

The snugness is a good thing. It means that you have a very close fit. If it were an interference fit you'd not be able to get 'em on without an arbor press. If it were a sloppy fit you'd have a non-flat bottom cut and the problem of imbalance might arise.

Is this normal

It is on all the pricey Austrian saws. My Hammer saw arbor is a really snug fit to the blade and the Hammer Dado is really snug. No room for error. It prevents the blade from cutting more on one half of the rotation and from being out of of balance too.


The one thing I'd do is to take a smooth curved slip stone and put a tiny chamfer on the edges of the bores (tiny as in almost invisible like .005" or less). That'd make sure you aren't riding on a burr the factory left on.

[Jim Becker]

A good blade will always be snug on the arbor and this is particularly true to a dado set when you want flat bottoms and precision over some width of cut. That said, it should not be so tight that you can't get the things off and on with reasonable effort. I assure you, my blades are snug on my Minimax saw like on Cliff's Hammer. But I can get them on and off without using a crowbar...

[Bill Wyko]

I have the same set with the same issue. I just take my time and change one blade at a time. Maby try some topcoat on the shaft.

[Duncan Potter]

Same set, same saw, similar issue. Very tight fit, I have to wiggle them on and off. Can always get them by hand, though, no banging or prying required. They seem to be loosening up a very slight bit.

I always though it was a good thing, although a time waster.

[John Lucas]

Brent,
Sorry for the problem. Before you send them back, take a look at this. The blades in good dado sets are necessarily thin so that you can put them on in various combinations. One problem that arises is that the thickness of the steel at the arbor (hole) is so thin that it can slide into the threads. If you take just one chipper and try it, you will see that this is true. What this means is that in order to stack multiple blades/chippers you will have to carefully put the blade/chipper on the arbor and be sure that it gets all the way to the prior blade/chipper and is not resting in the gullet of the thread. Same goes for removing. One or more of the chippers will fall into the gullet and will need coaxing to remove.
Take a close look and see how this is. If you understand this, your set might work just fine. I have a similar set (CMT Pro) and same problem...but easily overcome.

[Jim Cunningham]

I have the same set. On my Grizz 10" arbor the blades and the chippers fit fine. Start putting on the shims and it is a real pain. They don't want to go on or off. They, being so thin, get caught in the arbor threads and can present a real problem.

[Howard Acheson]

Good dado blade sets have arbor holes that are intentionally tight. If there is anything but minimal play, the blades and chippers would not cut in concentric paths and the dado bottoms would not be flat.

That said, you can use some 150 Wet&Dry sandpaper and lightly sand the inside of the hole on each blade and chipper. Keep trying the blade on the arbor and stop just when it takes a minimal amount of wiggling to get it on and off.

[Frank Drew]

I'm with Charles and Howie... a little light work with some abrasive will do the trick. After all, they do go on, just too tightly, so very little needs to come off. Unless you're totally hamfisted and forget what your doing, it's unlikely that you'd take off so much that you'd get a noticeably irregular cut.

[Peter Quinn]

Just for comparison, I've used that set and a forrest on PM66, and I've used that freud set with a 1" arbor on an SCMI. They are always snug, no wiggle room, but no fighting either. Takes about 30 seconds to stack or unstack the dado, smooth as butter.

I think some arbors have square threads more like ACME threads that facilitates blade change. I've never experienced this shim issue I hear many talk about either. Are the arbor threads not square like acme or jack threads?

[John VanDivier]

Brent,
Sorry for the problem. Before you send them back, take a look at this. The blades in good dado sets are necessarily thin so that you can put them on in various combinations. One problem that arises is that the thickness of the steel at the arbor (hole) is so thin that it can slide into the threads. If you take just one chipper and try it, you will see that this is true. What this means is that in order to stack multiple blades/chippers you will have to carefully put the blade/chipper on the arbor and be sure that it gets all the way to the prior blade/chipper and is not resting in the gullet of the thread. Same goes for removing. One or more of the chippers will fall into the gullet and will need coaxing to remove.
Take a close look and see how this is. If you understand this, your set might work just fine. I have a similar set (CMT Pro) and same problem...but easily overcome.

I have the Freud set and had a similiar problem when I first started using it. What I discovered was that although the blades fit very tightly to the arbor the major problem was with the shims. Basically you must install each blade, chipper and shim separately and make sure each one is pushed completely onto the arbor. Removing requires the same procedure. What happens is that the thin shims drop down into the threads blocking the installation of any of the following components if not pushed completely onto the arbor. It takes a bit of time but I want there to be a nice tight fit of the blades and chippers because that is what determines how nice and flat the bottom of the dado/rabbet is. John