before i started building this band so i ordered some bandsaw blades specifically this one and this
one and both of those blades chatter quite a lot with this blade the stock positively
bounces when it hits whereas this one is just more of a chatter but this blade that just arrived in
the mail this one cuts much smoother even though it looks not that different from the other blades
these cuts were made with this blade and this cut with this new blade these are both three
tpi blades and about the same tooth shape but the worst one is this one let's put that one in
compared to these two this one is just a disaster so i'm going to try to capture what's happening
here at 600 frames per second from this old camera but at really low resolution
it looks like the blade periodically just lunges forward into the wood and that's because it has
a rather sharp hook tooth shape to it looking at a high-res photo of these three blades this one
which has the most chatter has the most hook to it and this one the least and this one somewhere
in between and that hook can really help pull the blade into the wood faster which is why it jumps
so much every time it does that bang it jumps forward in the wood but that hook tooth shape
isn't all bad because for softer woods it can be helpful because it makes the blade cut a little
bit easier with less power and less thrust against it which can be very useful for re-sawing and for
instance when rachel was trying to use that blade to cut up some walnut in the sapwood it didn't do
the banging oh it's only in the heartwood which is a bit harder that she encountered that banging
but i wonder if there's more at play because this blade that gives me all
this trouble has got a lot more set to it so i just verified that all of these blades
have a 32 thickness to them let's check the set so here's my low-tech height gauge setup
and i'm just going to measure the tip of the tooth facing up on the table saw so that should
be the thickness of the blade plus the set in either direction because the other teeth will
hold that blade up and i'm getting the 64 thou on that tooth let's try another tooth 64
64. pretty consistent and let's just check zero is still good and the back of the blade is reached
33 above the table here and now the 3 16 inch blade the set on that one is getting uh 52 53
and only 50 on this one oh no 52. and finally that troublesome blade 61 63 62. i think that slight
inconsistency has more to do with the teeth being harder to hit because they're smaller
but at any rate the blades that shatter more have got about 10 thou more set to them
than the 3 16th inch blade that works much better since that quarter inch blade is hardly usable to
me the way it works right now i'm wondering can i reduce the set of that blade just slightly
all right here's my barbaric blade set reduction setup let's see if it works
i'm overlapping my presses because the vise jaws have
a texture to them so they might sometimes miss some of the teeth
well i think that made a difference but uh maybe five or six thou that's it i'll
try something even more barbaric i put the blade in backwards by flipping it inside out
and i'll try to grind away at the tips of the set of that teeth with a grinding stone
hey look i can touch the running blade because it's backwards
and maybe you're wondering how do you flip the blade inside out well this way well that
made no measurable difference so i think i need to be a bit more aggressive about the grinding
you can see the ground part on the tips of the teeth actually shining a little bit okay the set
on this blade now is a little bit less than the blade that's working really well for me
well it's still chattering but the cut is much cleaner than it was before even in the
sapwood where i wasn't getting the sort of chattering the cut has improved quite a lot
the cut radius has of course gotten worse so this is as tight as i can cut now
whereas before i was able to cut a fair bit tighter
and if i cut slow enough that it doesn't shatter that cut actually has a bit of a shine to it now
and cutting fast again much improved over what it was before and a shine to it too the reason i like
to grind the corners off the set of the blades is with a corner cutting like that it kind of makes a
jagged cut in the wood like that but if i grind that flat on both sides then that makes these
cuts flat too so that should make a smoother cut and the reason i was suspicious of the set
making it shatter worse is for the part where the tooth is set like that of course it's effectively
half the tpi than it is normally so we're going from four tpi to only every other tooth or two
tpi being set in this direction so the further they're spread effectively it reduces the tpi
i was cutting here leaving the pencil line intact but only the pencil line nothing
else the way that works is actually not entirely making a freehand cut because i'm always pushing
to the side a little bit so that the back of the blade rides against one side of my cut
and that way i can just kind of steer the cut through the wood whereas if i was cutting
straight like this any sort of wiggle in my hands would result in waviness in the cut
i also bought this blade which is a six tpi quarter inch blade and this one cuts super smooth
so the 6tpi blade cuts really smooth and it doesn't whine it doesn't chatter
only problem is with 6tpi it doesn't cut very deep very effectively and also when i'll need
to resharpen it that'll be a lot more work because that's a thousand teeth and high tpi blades need
to be a lot sharper than low tpi blades to do the same kind of cutting but being able to make really
clean cuts is very useful when i use my bandsaw as a pretend cnc machine and i was thinking recently
well if i had a cnc machine i could just run out the parts for another one of these sanders
and just build another one but then i realized that's kind of stupid because bantaming out
the parts for that sander only took half an hour which is probably less time they would take on a
real cnc if you factor setup time in and it's also only a small fraction of the time that it took to
actually build that sander anyways i might stone the sides of these blades as well at some point
because that sort of technique this is far from the first time that i've done
that you