Track saw technique?

[Eric The Viking]

That pic doesn't look very nice, in particular the tearing you're getting on top. It looks as though the rubber strip has been cut in too far by the other blade, and that it isn't sitting snugly down on the material. The rubber should meet the wood everywhere along the cut.

If you replace the blade, whatever you get needs to be exactly the same spec. That means same kerf, same tooth rake, same plate thickness (kerf and plate thickness are really important), and same diameter. You can vary the tooth count, obviously.

I think I can see where you might have paused or stuck slightly going over the joint in the track. That's either because:

- The joining pieces aren't aligning the track correctly,
- The track is dished or otherwise bent (mine are very slightly dished and it can be a pain),
- The two rail extrusions aren't identical (my 3m rail is a very,very slightly different shape to the shorter rails, which are several years older: I assume the die had become worn, and it means they don't ever join nicely),
- You've got the "sloppiness adjusters" (saw on rail) done up too tight.

At least those would be the reasons on my saw! It also looks like it doesn't have the tiny amount of toe-in that's helpful (you shouldn't see a complete arc, as the back of the blade shouldn't touch the cut surface), but I've no idea how to set that, and it's best left alone if there are no instructions for doing it.

HTH,

E.

 

[Chris152]

Thanks again Eric - I thought it was a pretty good cut compared to what I'd been getting before! But at least it's straight and no snipe or burning. I was concerned about the mess along the top, too, but put it down to the blade that came with the saw - the whole thing including tracks only cost £100, so I'm guessing the blade's not the best and it's 24t. But I really don't know as I've not tried other saws/ blades.

The track sits more flat on the wood as the saw crosses it - in the first photo it as resting after the wood so pulling the track down. I hadn't moved the wood (but had run my finger along that top edge and most of the bits fell off) so replaced the track and saw so you could see how it'd look as the saw passes the centre:

not perfect but much better than the last photo? The two darker areas are in the wood, they're not the traces of the saw - though I can indeed see where the rear of the blade has passed, as you say. Toe in... Also, you can see the track doesn't align perfectly, again as you suggest - though it does seem to run smoothly across the join. But running my finger along the rubber strip it does feel pretty flush with the wood, but I guess a small gap has now allowed the splintering that's there? When I get a new blade I'll move/ replace the strip if it's the same. Oh, and the sloppiness adjusters could well be too tight now - I tightened them as much as possible (without causing drag) when trying to stop the old blade wandering.

Thanks again, really appreciate your comments.

 

[Chris152]

Thanks for the blade thoughts Matt and Skipdiver - in the end I decided to spend a bit more and got the Makita 48T, it cuts a treat, almost polished.
And thanks to all for your advice. C