Table saw odd cuts

[Kenneth Walton]

Hi,

I've got a sawstop PCS, with the stock fence. I set the angle on my blade with a digital scale to exactly zero degrees. About two months ago I aligned the blade to the miter slot (within 2 thou), and then the fence to the blade. When I rip, I'm pressing forward and right, towards the fence. I usually finish with a push stick. Forrest WWII blade.

I've been noticing that when I rip stuff, particularly thicker stuff, the cut surface isn't close to flat. Sometimes it's wood movement, I understand that, but often there's gaps between the freshly ripped parts. I try to put them back together, and usually the front and sometimes the back have a gap, like there's snipe or somethin' on the fresh cut edge.

Any ideas? should I redo my setup? Better technique? Get a new fence? Learn to live with it?!?

[Matt Day]

Does it do the same thing with an inert material like plywood or mdf?

Sounds like you've done a good alignment, but it might be a good idea to double check everything, especially if you have an easy to use alignment jig like an align-it or a super bar.

Is the fence itself flat?

And I don't trust those digital angle gauges, but that's just me. I'd prefer a plastic triangle against the blade, or super plate.

[Kenneth Walton]

I guess I don't use much plywood, except for drawer bottoms, so I'm not sure. I don't really notice issues there?

I'd imagine the fence isn't that flat. Would that make a wavy board?

[John Schweikert]

Are you using feather boards while ripping? They will keep the wood tight to the fence. Other than that, I'd say internal wood movement after ripping.

I have the 1.75 PCS with 30" fence. Everything is within .001" except I measured the last 6" of the fence to have a .005" irregularity. I haven't seen any issues even from that.

[Matt Day]

If you aren't experiencing the issue with mdf or plywood, I think you have to chalk it up to wood movement.

A fence that is not flat is going to cause a number of issues. I would put a straight edge against it to check it, or if you don't have a good one try your jointer beds.

[John Coloccia]

When you aligned the top, were you sure to align it on the exact same spot of the blade (i.e., rotate the blade as you move the indicator back and forth). That removes any sort of run out from the equation. Anyhow, assuming that's correct, then align the fence to the miter slot. It's much easier since the alignment tool runs in the slot, and you're aligning everything to the same point. I'll bet that fence isn't as aligned as you think it is.

It's also important that there be a slight amount of toe out at the end of the fence. The back of the fence should be kicked out a couple of thousandths. Theoretically, you could have it dead nuts, but you absolutely can not have it toed in. Since there's no way to actually get it perfect in the real world, it should be just very slightly skewed in the "safe" direction. I'll bet this is your problem, and the back of the blade is mangling the precision work the front of you blade is trying to do.

Incidentally, the biggest fault with the SawStops is the faces on the fence. They are atrociously bad, considering how expensive the saw is. They really should replace them with something more fitting a high end saw.

[Andrew Pitonyak]

If you measure the front (first part cut), middle, and the back (last part cut), do they all show as the same width?

What is your longest straight edge or flat surface? How straight does the cut appear to be compared to the straight edge?

I saw something similar and I think that the problem was related to how the wood fed through the cut based on inconsistent pressure of the wood against the fence, especially near the end of the cut as the wood had a tendency to sometimes exit at a slight angle rather than straight. Or in other words, SNIPE as you mentioned. Constant consistent pressure keeping the wood up against the fence helped.

If the fence is not flat (remember that long straight edge I asked about; see links below), or square then all bets are off.

http://www.leevalley.com/US/wood/page.aspx?p=50074&cat=1,240,45313
http://www.leevalley.com/US/wood/page.aspx?p=56676&cat=1,240,45313,56676
http://www.leevalley.com/US/wood/page.aspx?p=71658&cat=1,43513,51657

http://www.woodcraft.com/Product/154074/woodpeckers-serx-straight-edge-rule-36inch.aspx

I purchased a nice long straight edge (longer than 3 feet) from Woodcraft some years back and I have made good use of it.

[Prashun Patel]

I have two issues with ripping thick stock.

1) I sometimes don't push through straight. When it has to be jointed off the blade, I use a featherboard to help register against the fence.
2) Thick stock can release tension. A fix for this is to rip it wider by 1/8", let it stabilize and then kiss off the edge on a second pass.

[John Sanford]

Rather than using a push stick, use push blocks or, even better, GRR-Rippers. A push stick is a squirelly narrow/single point of contact that doesn't actually give a lot of control.

Also, another factor may be that the workpieces are rocking slightly, the result of the face against the table not being flat. The fact that the problem is worse with thicker stock is what leads my thoughts in this direction.