I found this chart useful when i first started cutting
Blade Size-Speed Chart:
# 2/0 800-1100 Speed
This blade is good for very fine detail in corners and tight curves because smaller blades will turn tighter radius cuts. Faster than 1200 will usually shorten blade life from the heat buildup causin premature breakage. Will have some fine tear out on the bottom of the work piece.
1/8" Baltic Plywood and hardwoods
1/4" Baltic Plywood and hardwoods
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# 2/0R 800-1200
This blade is used the same as the 2/0 but will eliminate the bottom tear out. When cutting less than 1/4" thick material, check that the reverse teeth are not cutting through the top of piece , leaving tear out on the top instead of the bottom. The bottom of the blade can be trimmed off to lower blade in the clamps to fix this problem, just don't lower it to where the reverse teeth do not contact the wood.
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# 2 800-1200 Speed
This blade will not cut as tight of radius as the 2/0, so not as much fine detail can be done with this blade. It has a longer blade life than the 2/0.
3/8" Baltic Plywood 3/8" Hardwoods
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#2R 800-1200 Speed
Will do the same as the 2, but with the reverse teeth the bottom tear out is eliminated.
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#5R 1000-1850 Speed
This is my favorite blade. Because of the reverse tooth there is not any bottom tear out. It will cut fast and leaves a good smooth surface ready to paint. Over 1850 speed the heat build up reduces blade life considerably.
1/8" (6 layers stacked) Baltic Plywood
1/4" ( 3 layers stacked) Baltic Plywood
3/4" (2 layers 1/2") (3 layers 1/4") Pine
1/4" to 3/4" Hardwoods ( Test cut all hardwoods because some, due to density, will leave a burn mark on the cut edge, due to the reverse tooth design of the blade)
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#5 1000-1850 Speed
When the cut edge is burned, switch to this blade to eliminate the burning. There will be bottom tear out with this blade that will need to be sanded after cutting. Will cut faster than the reverse tooth blades , so on some of the 3/4" pine it may be better to cut simple designs with this blade for speed ( sanding on a stationary belt sander after cutting).
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#9R 1200-2000 Speed
Good for cutting thicker materials. Does not have the tight turning radius of the smaller size blades.
1 1/2" Pine
Thicker hardwoods
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#9 1200-2000 Speed
Use when edge burning occurs as described for the #5 blades.
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# 12R 1400-2000 Speed
A good cutoff blade. Will cut about as fast as the bandsaw. Good for cutting off lumber and plywood's to the desired shapes and sizes. Can cut some of the 1 1/2 pine but the edges will not be as smooth as when using the smaller blades.
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This chart is given as a good starting reference point. You may want to try some of the other brands and types of blades available but this should get you started in the area of what each blade is used for.