Piercing saw blades - grades and TPI ?

Hi all.
Getting generally confused about tooth pitch on Piercing saw blades -
suppliers generally give grades such as 3,2,1,0 and then 1/0 to 6/0 -
getting finer (assumedly higher TPI) as you go along the sequence -
but don't indicate how these map to TPIs - I'm after a fine(ish)
blade to use when crossing out wheels and the like in 1/16" brass and
working on approx 3 teeth per thickness, I guess I need 48TPI or
so.....
Does anyone know where to find a mapping of the saw grades to TPI ?
Alternatively, suggestions on which grade is suitable for my task at
hand would be gratefully recevied....
Thanks,
Youra.
x-post alt.horology and uk.rec.models.engineering as knowledgeable
people hang out in both places.....
Reply to
Youra
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Best bet is to find a retailer and have a look in person.
Second best, would be to order a couple dozen blades, getting a dozen each of the coarsest, the midrange, and the finer blades.
FWIW, for your application, I would start at the coarse end of the scale. The blades will hold up longer under the ministrations of someone learning to use a jewellers saw. The teeth will be plenty fine at thecoarse end of the selection. The coarse ones I have are somewhere near 50-60 tpi, or a bit finer.
The fine blades are really fine, and quite sensitive to side loads.
IIRC. I paid about $7 a dozen for good blades, at a retail supplier not known for being very frugally priced.
Cheers Trevor Jones
Reply to
Trevor Jones
I have been using a no.2 or size 2 Herkules brand saw blades for years on clock work, cutting out parts and crossing wheels etc, the blades are packed in a plastic tube which protects and keeps them clean.
they are about 50tpi, I think the no.1 blades are 54tpi.
the blades go from very coarse at 8 to very fine at 8/0
so its 8,7,6,5,4,3,2,1,1/0,2/0,3/0,4/0,5/0,6/0,7/0,8/0
I do have a good range of blade sizes but find the #2 blades best for general work, you are best to buy the sizes you need rather than buy a whole range, because you simply will not use them, buy the blades by the gross(144) is the cheapest way, any smaller amount the price goes up, Ofrei sells a gross of #2 Herkules blades for under $20
mount the blade with the teeth facing towards the handle so it cuts on the downstroke, keep a tight tension on the blade it should make a nice 'ping' when plucked like a guitar string, support the work on a wood bench pin, good brass like used in clocks doesn't really need a lubricant, but if cutting other metals like copper, steel, aluminium use some beeswax or a good cutting lube.
these blades are brittle, some brands more so than others, so don't be surprised when you will break a dozen of them before you get used to the feel of the blade cutting, eg, if you are cutting steel the blades will wear out faster and get slower in the cut and will tend to wander to one side more, a fresh blade will cut straight and clean.
the blade breakage is one of the reasons I suggest you buy the blades by the gross.
in tensioning the blade in the frame, fit the blade in the top clamp after making sure it is facing the right way, then place the frame top against the bench edge then lean in with the handle held to your upper chest so that you spring the frame in 8-10mm then clamp the other end of the blade in the frame.
if the saw frame is adjustable then move it so it is say 10mm longer than the blade when the blade is fitted into the top clamp.
and a note on those adjustable saw frames, I don't bother to reuse a broken blade by shortening the frame, it is a waste of time, the blade will break much easier on the tooth part, plus the fact you have to shorten your stroke to adjust for the short blade so it upsets your sawing rhythm, I rarely break blades now, tend to wear them out first :)
Reply to
dAz
Thanks to all - Google is indeed my friend - funny I'd missed that one....
I'll order a selection starting at #2 and a couple finer and see how I get on.
Breakage has indeed been a bit of an issue for me - guess I'll just have to learn the slow way..... :-)
Thanks again,
Youra.
Reply to
Youra
yes it is just practise, always try and keep the saw upright while sawing don't allow it to twist side to side.
use a good quality saw frame with quick release clamps, you want it with at least a 3" throat for general work and later one with a 5"+ throat for those odd shaped parts we need to cut out on occasions
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the only reason I like an adjustable frame is because some blade brands are slightly different in length.
and you will need a bench pin or make one
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dAz
Reply to
dAz
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I find that good support for the piece being sawn is a major part of success. I use a clamp on table like a fretsaw one ( but stronger) with only slim slot for the blade so as to support the line of cut as closely as possible.
Reply to
Neil Ellwood

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