Scroll Saw Blades:
Scrollsaw Blade Size Number
Most scroll saw blades are numbered using the "Universal" numbers,
from 0 to 12, where the smaller the number the finer the blade.
Some manufacturers of course use their own coding, so you'll have
to get a table listing TPI (teeth per inch), thickness and width,
to be able to cross reference these codes. There is no direct correlation
between the Universal number and the TPI. It can only be said, the
higher the number the lower the TPI and that they generally fit
into this range (ie. #12= 9.5 TPI, #7=11.5, TPI #5=12-15 TPI, #1&2=
20-28 TPI.
Higher number blades are always thicker and wider, so they cannot
cut as tight corners. Lower number blades are thinner and narrower,
do cut tighter corner, but break much more easily and cut slower.
If the wood burns too easily, you probably have too fine of a blade,
if the cut is too coarse you probably have too few teeth. Small
blades can burn the wood more easily if they are run too fast, so
use slower speeds with smaller blades and faster speeds with #9
to #12 blades.
Tooth Design:
Often you will find blades with a number and a letter like R, F,
or S. The letter designates the cut pattern of the teeth.
Reverse Tooth (R):
These blades usually have the bottom 5-9 teeth facing up and the
rest facing down. Make sure you install it correctly, with the majority
of the teeth facing downwards. The reverse teeth are designed to
prevent tearout on the underside of your work piece... particularly
good if you are cutting plywood. They do not cut as fast as a regular
blade. If the reverse teeth are coming through the top face of thin
pieces of wood, you can always shorten the blade from the bottom
to correct this and remount it in your scrollsaw. Remember if the
reverse teeth come through the top, you're now getting tearout on
the top instead of the bottom.
Fret Blade (F):
Generally this denotes a blade that is designed for fine internal
cutting, with higher TPI's. It makes a great cut that requires next
to no sandiing.
Skip Tooth (S):
Designed with a tooth and then a space, then a tooth and a space.
They are great blades for fast cutting, and rarely leave burn marks,
but tear out is significant and they leave a rough cut edge that
must be sanded.
..... you'll also find reference to...
Spiral Blades:
you can cut in any direction with these blades and that sounds great,
BUT I haven't met anyone that really likes them. They are hard to
control and keep on the line. They do have a special application,
when a line has been cut with a regular blade and then you wish
to make it larger and more visible. A spiral blade handles the job.
Double Tooth:
Teeth are grouped in twos and then a space, to improve on the cutting
quality of a Skip tooth blade but still allow for efficient removal
of the dust. They are made with and without reverse teeth.
PGT:
This designates a blade that uses a different technology to cut
the teeth. They are "precision ground" with no burr, from carbon
tool steel and hardened to a greater level than normal blades. For
exotic woods, of higher density, they are great. Generally they
will outlast all other blades. As far as I have seen they are always
made with reverse teeth.
Blade Type
Pin ended:
Blades have a small pin on the top and bottom to allow mounting
on the blade holder of your machine. Some cheaper machines only
handle this type of blade. They are a more rigid blade and do not
cut as tight corners. They are not available in as many blade sizes
and tooth configurations. They are beefier and do not fit through
very small holes due to the top pin design.
Plain Ended:
These blades are the standard, flat on both ends. Come in a wide
arrangement of sizes from jeweler accuracy on up. Sized in numbers
from 00- 12. Saw must have a holder to allow you to use these blades.
Most veteran scrollsawers will always use the plain ended blades,
mostly because by that time they have probably upgraded their saw
a few times, and almost all of the quick change heads are designed
for flat blades. As a novice first check to see which type of blade
your machine holds, then order a selection of sizes to try. They
will never go to waste.
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