What a difference a piece of tape makes!

[Rorschach]

Using the table saw to cut up a panel today, nothing fancy just a piece of white MFC for a kitchen cupboard shelf. Didn't need to be super accurate but I am taking every opportunity to practice using the new saw.

Wanting to avoid chipout I put masking tape over my cut lines which worked nicely (although ultimately I found out the sharp new blade would have been fine without the tape).

What I didn't understand though was why my cuts were not coming out square despite all the care I had gone to setting up the fence on the sliding table.

I checked my combi square was actually square, it was acceptable, I checked the sliding table again, it was also good. There is a tiny bit of play in the fence, but holding work against it pulls that out so that wasn't it. Then it hit me, the tape! 1 and sometimes 2 layers of tape on the edge were pushing the work out away from the fence and skewing my cut.
I removed the tape, made a new cut and the results were vastly improved. I went from 2mm out over 300mm to less than 0.5mm. Still not perfect but much better. Shows that just the thickness of a piece of masking tape can make a big difference on a long cut.

 

[johnnyb]

That's still a way out. Is it cutting properly. When it goes into the teeth at the front do the back teeth just scratch( make a slight noise) this means the slide and the blade are suitably aligned. The angle of the fence can then be adjusted. You can use pieces of tape to get this right initially. The five cut method can be used to fine tune. Take a decent square of mdf. Cut one edge and turn that edge to the cross cut fence repeat three times.finally cut a strip of the first cut edge. Snap in half and compare the ends. The difference is four times the out of squareness.

 

[Rorschach]

Oh I know it's still not perfect, I am working on that, I also know that some of that error I can see is from the square itself not being perfect, my combi square is just use for rough work really. I was more pointing out how much of a difference something so seemingly insignificant can produce.

 

[johnnyb]

Sorry didn't mean to preach. Spelch and sawdust are two other annoyances that seem to throw stuff out. My worst thing was the weight of the chunk of wood allowing wood to drop away from the fence on the planer. Less off a problem with a taller longer fence.

 

[Rorschach]

I didn't think you were and your comments were appreciated.