Freud SD608 Dado has uneven cut width

[David Genrich]

I just purchased the Freud SD608 Dial-A-Width dado. When making some test cuts, I noticed that the width of the dado is 0.747" at the entry point, 0.692" in the middle, and 0.694" at the end. This leaves a noticeable gap, especially at the entry point.

I have taken photos and placed them at the following URL:
http://picasaweb.google.com/woodshaper/FreudSD608CutWidth


Is there something I am doing wrong? Is this normal for a SD608 Dado? Or is my set defective?

Thanks,
David Genrich

[Howard Acheson]

I bet your board is slipping against the miter gauge. Try clamping it to the miter gauge. If that fixes the problem, then do what many pros do--use carpet tape and attach some 120 grit sandpaper to your miter gauge fence. This will keep any board from sliding along the face of the gauge.

Also, dados will quickly show up any alignment problems. Be sure your regular saw blade is perfectly parallel to the miter slot. If it is off, you will produce a wider dado than it is set for.

[glenn bradley]

As the dado is spinning almost 3500 times a minute; even if the blade was inconsistent you would probably get a straight cut as long as your material was controlled. From the measurements you're getting it looks like the material is "loose" at the beginning of the cut and reacting to the contact with the blade. If you're using a miter gauge to control your material it should fit the miter slot tightly, have a large fence to control the material, etc.

Once you confirm a good miter slot fit and a solid gauge head, you might try clamping you material to the gauge head and test some cuts. I am still surprised at occasional deviations in cuts I get even though I think I've got a good grip on the wood. Here's a pic of my "beater" gauge that I have tuned. I use an Incra for critical stuff.

[David Genrich]

I thought it might be a problem with slippage of the blade. I tightend up the arbor nut and I made sure I was holding the wood tight against the milter gauge. I recently tuned my saw, milter guage, and fence, so I don't think that is the problem.

[Greg Funk]

How are you supporting the piece when you are dadoing? Is it possible the piece is moving as it goes through the cut? You might try running a test cut on a longer piece of wood using the fence. Or use the fence in addition to the miter gauge.

Greg

[David Genrich]

I made another cut using the fence and the milter guage together. The cut was even along the lenght of the cut. I repeated the test - same clean cut.

So, looks like a dado sled using both miter gauges for stablity might help?

Thanks,
David Genrich

[Greg Funk]

I made another cut using the fence and the milter guage together. The cut was even along the lenght of the cut. I repeated the test - same clean cut.

So, looks like a dado sled using both miter gauges for stablity might help?

Thanks,
David Genrich
Your miter gauge might still be OK but if there is any vibration in the saw it is often difficult to hold the wood tight enough so it doesn't move. A dedicated sled would help as it makes it easier to stabilize the wood.

Greg

[Jim Becker]

Umm...the obvious question is if the "Dial a width" feature is slipping...that's the only thing I can think of that would cause the width of the cut to change over the length of the cut.

[Gary Keedwell]

I made another cut using the fence and the milter guage together. The cut was even along the lenght of the cut. I repeated the test - same clean cut.

So, looks like a dado sled using both miter gauges for stablity might help?

Thanks,
David Genrich

I see it alot....and alot of woodworkers do it....but I just don't like using the miter gage and the fence at the same time. Too much of a chance of pinching the wood against the blade and maybe a kick-back possible? IMHO PS. Since the cut is biggest in the beginning, I would say you have a stability problem. Clamping, sandpaper on miter fence, sturdier grip etc. should solve problem.
Gary K.

[Greg Funk]

I see it alot....and alot of woodworkers do it....but I just don't like using the miter gage and the fence at the same time. Too much of a chance of pinching the wood against the blade and maybe a kick-back possible? IMHO PS.
I don't see how it can really kick back since there the wood is supported by the miter gauge. I always use the fence when dadoing with a miter guage and have never felt uncomfortable. It is also easy to keep pressure on the piece close to the fence since the blade is not coming through.

Greg

[Tom Veatch]

I see it alot....and alot of woodworkers do it....but I just don't like using the miter gage and the fence at the same time. Too much of a chance of pinching the wood against the blade and maybe a kick-back possible?
Definitely a potential for kickback when making a through cut because of the blade/fence pinch of the cutoff piece. Not a problem with a cut like a dado that doesn't cut completely through the thickness of the work.


Since the cut is biggest in the beginning, I would say you have a stability problem. Clamping, sandpaper on miter fence, sturdier grip etc. should solve problem.I agree. As stated by a previous poster, and at first blush, it seems as if the only thing that could cause variation in width would be variation in the width of the blade, but if the work shifts during the cut, even with a stacked dado set that cannot vary in width, the width of the cut will still increase.

To visualize how this can happen, think of making a cove cut with a table saw (see here (http://dknudson.unixcab.org/covecut.html) for example). In that case, the cut is much greater than the width of the blade. When the work shifts during the cut, the action, in somewhat smaller scale, is identical to making that cove cut.

[David Genrich]

I don't have any adhesive sandpaper at the moment to try that on my miter gauge. I did try holding the piece very tight against the miter with the same issue. I also found that there is some slop in the miter gauge.

I tested the dado cut with only the table saw fence - no problem there.

So, it does appear to be a stability problem within my milter gauge.

Thanks everyone,
David Genrich

[Tom Veatch]

I don't have any adhesive sandpaper at the moment to try that on my miter gauge. I did try holding the piece very tight against the miter with the same issue. I also found that there is some slop in the miter gauge.

I tested the dado cut with only the table saw fence - no problem there.

So, it does appear to be a stability problem within my milter gauge.

Thanks everyone,
David Genrich

I'm going to go out on a limb and guess that you have also encountered some difficulty cutting dead-on miter joints with "some slop in the miter gauge".

[Greg Funk]

I also found that there is some slop in the miter gauge.

So, it does appear to be a stability problem within my milter gauge.

Thanks everyone,
David Genrich

A perfect excuse to buy an Incra miter gauge...

[David Genrich]

I have the Incra Miter Gauge 3000. Problem seems to be that I have the GlideLOCK washers tightened as much as they can go, and the bar still can move around some.

-David