Thread: Problem cutting mitres on tablesaw

presumably the first cut is made without the benefit of a stop block, but the second cut does employ one. Is it possible that the one without the stop block drifts along the fence a tiny amount as the cut progresses.

My version of your jig has non-slip faces on the fences - so the workpiece stays put. Just the non-slip Tape for stair treads bought in a 2 dollar shop.

Cheers
Arron

My mitre sled and and cross cut sled both have clamps fitted to hold the piece because I found I was getting some creep because I couldn't hold the wood securely. Might be your problem.

From a close look at the third pic with the stabiliser on the sawblade, it looks like the different cut marks occur at the pointy end where the workpiece is off the base board and unsupported, and looks like it might be shaped by the back of the blade.

Anybody else got any ideas on the possible causes and solutions please?

Will give it a go with a toggle clamp holding down the front of the workpiece.

I think you are correct, the back of the blade rubbing on the pointy end. A possible quick fix is to raise the blade to full height so hopefully the pointy end doesnt reach the teeth before the full cut has been made.

Thanks Kuffy. Initially I thought the blade must be out of parallel to the table slots, haven't checked it for a few years, then I realised that this odd cut happens whether the workpiece is held against the left fence or the right fence.

Something funny going on.

Is the blade too thin? thus flexing

Originally Posted by Kuffy

I think you are correct, the back of the blade rubbing on the pointy end. A possible quick fix is to raise the blade to full height so hopefully the pointy end doesnt reach the teeth before the full cut has been made.

Definitely worth trying. Use only the front part of the blade; the back part amounts to a second cut.

Cheers,
Joe

Are you passing the piece completely pass the the blade or stopping once the cut is complete?

Looks like you're stopping once the cut is thru, I would also look at clamping the piece as close as possible to the cut as well.

Originally Posted by Sawdust Maker

Is the blade too thin? thus flexing

This was my first thought. Easy enough to use a thicker blade to do a few test cuts. I have a thin kerf blade, but noticed that it didn't give as good a finish on thicker cuts than a standard kerf blade. Also, creep is often a problem, but a bit subtle, you probably won't feel it happening at all. A strip of 240 grit abrasive glued to the fence certainly had positive effects on my jig.

Alan...

Hope someone gets to the bottom of it. I had same thing and posted a few months back. Clamps, Sandpaper, nothing helped. I'm going to bite the bullet and run my 1/8 40 tooth FTB blade thru the jig and test it if nothing else changes. If I have to then build a new sled, so be it. Will wait and follow the post first

Could it be arbor runout?

Put a couple of hold down toggle clamps on the sled, but am now limited to 45mm wide workpieces. The pieces where the problem arose were 80mm wide, and had a fair bit of overhang.

Changed the blade, in view of the possibility of flex, and used a 3.2mm thick kerf with 80 teeth. But I do have a 150mm wide stabilisier plate agaisnt the blade, so I doubt there is a flexing problem, but will give it a go.

Will cut and test a 45mm wide piece tomorrow. With 45mm wide workpieces there is no overhang.

Too hot and humid in the shed the past couple of days 38 degC and 80% humidity inside the shed

Originally Posted by Bendigo Bob

Hope someone gets to the bottom of it. I had same thing and posted a few months back. Clamps, Sandpaper, nothing helped. I'm going to bite the bullet and run my 1/8 40 tooth FTB blade thru the jig and test it if nothing else changes. If I have to then build a new sled, so be it. Will wait and follow the post first

Sitting here laughing my head off: the first time I read that, my brain deciphered it as "If I have to then build a new shed ...."
Now that seemed a bit radical.

Once you have pushed your sled through and made the cut, do you bring the piece back through the blade or turn off the saw and then bring it back? I ask this because I have seen a similar 'scarring' on the pointed ends of the mitres because of the motion pulling back the sled causes a very slight movement sideways due to the rails of the sled not being 100% fit to the mitre slots.

With your sled it might be worthwhile moving the mitre fence section back in relation to the front edge of the sled and add a rail across the front which is higher than the blade at max cut height. It will add more rigidity so the motion of pushing the sled and pulling it back with cause no movement whatsoever.

Might be worth testing it by running two pieces. Run one through and pull it back with the saw running and then run one through,turn the saw off a pull the sled back. I hope I have made sense.