Multiple German manufacturers e.g. Bosch, Wilpu only recommend their 24 TPI (or 1mm tooth pitch) only up to 2.2 or 3 mm of metal, leaving their coarser 14 TPI (2mm tooth pitch) for up to 6mm metal. I've cut 6 to 8mm bars (axes for doors and window handles) with a 24 TPI blade and had no issues... the blade didn't seem to lose any sharpness and the cut was a matter of seconds every time I used it. So what am I missing here by not using their recommended/coarser blade?

  • I would guess that the finer blades don't clear tailings efficiently in thicker materials. It's possible not all of the teeth clear the kerf on thicker materials. – Matthew Gauthier Aug 17 '17 at 1:42
  • As @Ecnerwal said : The more TPI of teeth - the more the material in those teeth - the blade will no longer cut. Also depending on the blade material construction it might be hazardous to have a loaded blade.. – Ken Aug 17 '17 at 4:36

As far as I recall, the usual recommendation is to have roughly 3 teeth in the material. That gets it cut and moved out quickly, without grabbing excessively. The finer blade does not have room to store 6-8mm worth of shavings (i.e. in the tooth gullets until the blade comes out the far side) so it does not cut as well as is ideal, since it is "packed full" before it can dump chips.

  • I agree with 3 teeth in contact but I was taught that was a minimum to prevent shearing the teeth. – Ed Beal Aug 17 '17 at 2:29
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    @EdBeal yes, that is why, but if you only keep finer blades on hand, they can't sell you other sizes! No seriously it's for speed. – Harper - Reinstate Monica Aug 17 '17 at 18:55
  • Heh. Good one. This is interesting information. I had never heard of this recommendation but it sure makes sense. I would think it helps with controllability also. – SDsolar Aug 17 '17 at 21:05

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