Thread: Table saw not cutting in a straight line (cuts square, not straight)

I have the same saw and was starting to have a similar issue, I noticed the riving knife was slightly out of line with the blade. This was just forcing the timber slightly to one side when it reached the knife. Adjusted that as per the manual and now all good again.

George

Thanks, George...as I use a sled for all my cuts, I don't have the riving knife installed, so can't be that, in this case. Thanks for the advice, tho!

Originally Posted by zoovegroover

I've tried a number of different blades (none particularly sharp, tbh)

Cutting mitres requires a sharp blade, there's no two ways about it. The angle combined with the cutting pressure causes the blade to deflect away from the work as you push through, the pressure reduces as you exit the cut resulting in a nice curve.

Try again with a sharpened blade and see what happens.

Also....why don't you have a riving knife on there?

Hey Elan, thanks for this...yeah I'm wondering about the sharpness, coz I thought that when I was cutting thru the wood, but even taking really shallow clean up cuts caused issues...there was barely no pressure at all on the clean up cuts...it zoomed thru no problems.

Riving knife....errr...I don't have a great answer for that. I should really install it back in.

What Elanjacobs said. Also, are you sure the work isn't moving slightly on the sled or mitre fence? I used double sided tape to attach fairly fine sandpaper to them so the wood doesn't move, especially on mitres.

Originally Posted by AlexS

What Elanjacobs said. Also, are you sure the work isn't moving slightly on the sled or mitre fence? I used double sided tape to attach fairly fine sandpaper to them so the wood doesn't move, especially on mitres.

Thanks, Alex...I don't think so...I actually tried clamping the work piece to the sled coz I thought it might be that. I've been worried it's the arbor or something, but maybe it is as simple as blade sharpness...just seems surprising it would do that on shallower clean up cuts where the work piece passes thru with minimum pressure.

Dull blade, and no riving knife installed, and you have to start a thread and ask why?

Originally Posted by riverbuilder

Dull blade, and no riving knife installed, and you have to start a thread and ask why?

Hold up....are you saying riving knife affects quality of cut? Genuinely asking.

Are you passing the timber completely past the blade?

Originally Posted by AlexS

Are you passing the timber completely past the blade?

I am, yeah...I took it off my sled and tried it with a mitre gauge so I could go right past it...I'm gonna grab a new blade this AM...it's overdue, and it might be problem anyway...failing that, if it was an arbor issue, do you think it would be happening even on non-angled cuts?

I think it could be the dull blade but also if your timber is sitting on the sled and cutting miters there is a lot of blade going through your timber. When cutting bevels with the blade set, to cut at a "long cut"(exasperated by the sled), the timber will "ride up" and will give you a curved cut which will show up with your square.

Remedy.....put on a sharp blade, fit the riving knife, lift up more blade (in height) and it should get better. You will need to give more downward pressure as you feed the timber through to counter the "riding up".

Originally Posted by chambezio

I think it could be the dull blade but also if your timber is sitting on the sled and cutting miters there is a lot of blade going through your timber. When cutting bevels with the blade set, to cut at a "long cut"(exasperated by the sled), the timber will "ride up" and will give you a curved cut which will show up with your square.

Remedy.....put on a sharp blade, fit the riving knife, lift up more blade (in height) and it should get better. You will need to give more downward pressure as you feed the timber through to counter the "riding up".

Well, I put in a brand new high quality blade (CMT chrome), and the same thing is happening...It's super frustrating. I tried sled, mitre gauge, fence...loads of pressure against fence and down...cutting just past the timber, all the way thru the timber...nothing helps. Straight cuts are nice and clean, but these bevels are horrendous....I can't think of what to try next.

Hmmm....Does the timber rub on the body of saw blade as you go through? I wonder if maybe the pivot axis is not quite parallel to the table; you wouldn't notice anything with square cuts, but angled cuts would try to ride up the blade if it was a bit higher at the back.

Where in Melbourne are you? I might be able to come and have a look at it.

OK, let me toss a few things out here.

The riving knife needs to be aligned with the arbor flange. But we never do it that way because there is no tool or jig to allow us to do so.
What we do is to align the riving knife with the outside side of the blade. That is cool until the blade is changed. When the blade is changed, the thickness of the blade disk is probably different and our riving knife alignment is off.

With a narrow kerf blade the alignment is even further off AND in most cases the riving knife is too thick to pass through the kerf in the timber being cut. This makes for a very difficult cut as the riving knife is trying to split the timber and misalign the cut.

The suggestion here is to avoid narrow kerf saw blades on the table saw.
I know the arguments, saves timber, less work for the table saw.
Saves wood at about 0.8 MM per cut. (You do the math.) How wide does the timber have to be to save a few MM to get that extra piece?
Less work for the table saw motor. I've never noticed and have no clue how to measure it.