Can a table saw have smooth cuts and be off?

[Travis Conner]

Ok so I put an amana saw blade on my saw straight out of the box and it's given me sanded smooth like cuts, and I've checked it to make sure it wasn't out of square and it looks ok. That was comparing the table to the blade. I checked the blade against the fence and I'm thinking the fence might be off just a tad. Now I can rip a board and i'll notice it appears to be off maybe a 64th of an inch over 3 or 4ft. Now I know boards aren't perfectly straight so I don't know if I should just leave it or what. It cuts as smooth as can be.

[glenn bradley]

it appears to be off maybe a 64th of an inch over 3 or 4ft.

Do you mean that the board is 1/64" narrower or wider at one end or the other? Does the material remain firmly against the fence for the entire cutting path?

[Travis Conner]

Yes and yes. It might be less than a 64th I can't quite remember

[Howard Acheson]

Have you checked and adjusted the blade alignment recently?

Here is the low tech, low cost way to align a tablesaw that I learned maybe forty years ago and use to teach to my students.

Make 3/4 x 3/4 x 12" hardwood stick. Drill a hole somewhat centered in one end and insert a brass #8 x 1" round head fine thread machine screw about half way. UNPLUG THE SAW. Raise the blade completely up. Clamp this board in your miter gauge (if you determine that there is some slop in your slot to miter gauge, use a playing card to take up the slop) so the screw head just about touches the blade at the front. Now rotate the blade by hand and determine which tooth is the closest. Adjust the screw in or out until it just touches this tooth. Mark this tooth. Rotate the blade so the tooth is now at the back of the table and move the miter gauge/stick assembly to the back and see if it touches the marked tooth to the same extent. If it doesn't, adjust the trunnion (if a contractor saw) or the tabletop (if a cabinet saw) until it does.

For a contractor saw, first use a small c-clamp on the rear trunnion and cradle to keep the assembly from moving. Then loosen the two rear trunnion bolts and one front trunnion bolt. Slightly loosen the other front trunnion bolt and use a stick to tap the trunnion until the blade and screw lightly touch. The blade does not move directly around the center so you will need to repeatedly go back to the front of the blade, readjust the screw, and then again measure the back. Be sure to check after tightening the trunnion as the trunnion frequently moves when being tightened.

For cabinet saws, loosen the bolts that hold the tabletop and tap one corner until things come into alignment.

The same adjustment gauge can be used to set the fence parallel to the miter slot. Slide the miter gauge to the front of the table and move the fence over to the screw head and insert a playing card between the screw head and the fence just so you can move the card as it touches both the fence and the screw head. Now move the miter gauge to the back of the table and see if you have the same feel when you insert the card. I like my fence absolutely parallel--if you want to have a slight opening to the fence, you can easily estimate the opening by adding a thickness of paper to the card.

I always show my students with a dial gauge that their adjustments are within .001 - .002.

You can also use the same gauge to measure blade runout by using a $5.00 feeler gauge.

Finally, after you are satisfied with the above adjustments, check the position of the splitter to make sure it is exactly in line with the blade.

Bottom line, there is no need to spend more than the $0.05 for the brass screw.

[Keith Weber]

It sounds to me like a technique thing. If the distance from the front of the blade to the rip fence is set to say, 6 inches, then it should remain at 6" for your entire cut. Having it toed in or out slightly won't change that distance. If it's toed in too much, then the back of the blade could start cutting, which presents a bad kickback hazard (which is why it is often recommended to use a .002-.003" toe-out. But, even in that case, the distance from the back of the blade to the rip fence will remain the same, and the width of your cut piece should consistent.

If it toed out way too much, then the back of the blade can pull the piece being cut away from the fence, causing your problem, but only if it's enough to pull it away from your fence. You mentioned that it was flat against the fence the whole time, so if that was true, then your cut should be consistent.

So my guesses would be...

1) You're letting the wood move away from the fence slightly during your cut (not enough pressure against the fence).

2) Your fence, or blade has enough flex in it (you mentioned a new blade), that it causes the varying rip width (maybe too much pressure against the fence, causing it to flex.) This would be more common using a cheap contractor or table-top saw vs. a cabinet saw with a beefy Biesemeyer fence.

3) Your wood isn't straight, causing it to move away from the fence regardless of a firm pressure towards the fence. Edge joint first, then rip.

I would try using feather blocks to hold the wood firmly against the fence and see if that rectifies your situation.

[Mike Schuch]

I do not see how a board can be tapered after cutting it on a table saw using the table saw fence? If you push the stock all the way through the saw so it exits past the back of the blade the width of the cut piece will be the smaller of the width between the front of the blade and the fence or the rear of the blade and the fence.

If you are getting tapered cut pieces while using the fence the only posibility is you are not keeping the stock against the fence during the cut and the stock was 1/64 away from the fence at the beginning of the cut or at the end of the cut.

If the fence is off by some huge amount, lets say 2 degrees, then I would expect a lot of saw marks and even some burning on the cut piece but it should be uniform width if you held it aginst the fence during the entire cut and pushed the cut piece all the way through the saw.

The only way to make a tapered cut on a piece of stock when using the fence is to use a taper jig of some sort. It you used the miter jig or a cross cut sled and they were out of adjustment I could easily see one of them producing a taper cut.... but not the fence.

[Phil Barrett]

I agree, if the saw is cutting cleanly, the work piece was fed reasonably close to parallel to the blade. It's hard (for me anyway) to rely on hand pressure to keep the work piece against the fence for the entire duration of the cut, I use a feather board on the in-feed side of the blade to press the work piece against the fence with fairly uniform pressure. That frees me to put my main focus on feeding the work piece through the saw. I still have to keep an eye on it but it's a lot easier.

By the way, I use a magswitch feather board which is super easy to set up. Because it's so easy, I wind up using it all the time.

[Prashun Patel]

My rips have tapers sometimes. My prob's usually improper feeding.
A featherboard on the fore side helps.

I also get better results when I rip rough and kiss it to final width. I despise the waste and the dust this generates, but when sizing pieces identically for critical stuff like legs, I'll do this.

[scott spencer]

Are you putting a straight jointed reference edge against the fence?

[Justin Ludwig]

1/64" over 3-4ft? I'm a picky guy, but not that picky. I have other tools for tolerances tighter than that.

[Travis Conner]

I see. I'm thinking the boards were crooked to begin with. I cut some cedar today and it was right on.

[Bill Orbine]

Sometimes there is tension in the board. Ever see, as you rip, the board pinches on the blade or spread apart? That's about the most common problem with the width variation even though you did everything as perfectly as you can possibly manage.