Woodmonkey":2ij5ai9b said:
The axcalibur blades are the same kerf thickness.
Ah but you have to be careful - it's not that simple...
... I was caught out. The other dimension that matters, and is rarely stated online, is the thickness of the saw plate (the metal disc that carries all the teeth for anyone not used to all this).
Axminster to their credit (and my chagrin) do state that their 160mm blades are unsuitable for plunge saws. I thought, "they're really inexpensive and I have a rough job to do,
and they have a narrower kerf than the Makita ones, so they should be fine."
Not so. The teeth stick out either side of the plate, obviously. Even if they cut a significantly thin kerf (1.7mm versus 2.2mm, IIRC) If the plate is really thin, they stick out more to the sides.
Now here's the rub, literally: the blade's has one side of the saw plate is clamped tightly to the arbour on the spindle, and that is a fixed horizontal distance from the rubber strip. Thus the position of the "inner" edge of the kerf, right next to the rubber, is determined by the tooth projection from the saw plate surface
and nothing else.
In the case of the Axminster blades, the teeth stick out too far, sideways from the saw plate. So, although the kerf is quite a bit less than the proper blades, you will end up re-cutting the rubber strip, meaning you have to replace it if you go back to the proper blades at a later date (and you still want the best possible results).
I recommend not discovering this when you use your new 3m rail for the first time (DAMHIK).
To change the subject very slightly, the "proper" blades for Makita and Festool are different again: Makita ones are officially 165mm diameter, whereas Festool ones are 160mm. It's complicated further because Makita make blades to fit Festool (160mm), and these are branded
identically, apart from one small number on the blade and the pack.
I've puzzled over this too. It's annoying because it throws off the depth scale on the Makita (if using a "festool" blade, you have to add 2.5mm to the depth you want and set the scale to that), but I think there's a reason other than diameter as such which is why Festool chose the size they have:
Old-style circular saw blades will ring like a bell, because they're made of springy metal and they're highly symmetrical. This means they're extremely noisy in use, but it also means the cut will be rough: The rim behaves like a cymbal hit by a drumstick, and vibrates sideways. If you want a really good clean kerf you need to damp this as much as possible.
So Festool's blades are small diameter and thick, so that the resonance is high frequency and small amplitude, and the choice works well. They are still big enough to cut to depth in most normal kitchen worktops. I think Makita thought they might squeeze slightly more depth of cut from the system, without roughening the kerf too much (plus the possibility of purchasers having to buy really uncommon blades from Makita!).
To get a really good finish you really do need that thick saw plate, and it will probably be better with 160mm blades (very, very slightly). And I need to get round to making a depth conversion table and sticking it on my saw!
And finally, the inexpensive rip blade I got to do one quick job, was a failure: it cut the rubber strip, it cut the rubber strip roughly (because it vibrated), and it produced long stringy sawdust which the extraction system really didn't like at all (it didn't clog, but nearly did). So I have learned a lot from my experiment!
Ho hum, life is never simple.
