How to choose the right blade for the circular saw?

[Giovanni Rinaldi]

Hello everyone!

I need some help choosing the right blade for my circular saws, I need 7 1/4" and 6" blades.

So far I have those available:

7 1/4": 12, 16, 24, 36, 48, 60 teeth

6": 12, 24, 36 teeth

How do I choose the right one? What should I take into account? Do the wood's hardness or size matter? Is there any guide for choosing them? Could you help me choose one for ripping and one for cross cutting for each size (7 1/4 and 6", I need both saws to be equipped)?

I could give you some details about what I usually cut, but in order to not bloat this post I'll just wait for someone to ask them, I'm not too sure these details matter that much...

Many thanks in advance!

[Kevin Wolfe]

Look at HD Diablo blades. I got one for my circular saw a while back and they are heads and shoulders above the crappy Ryobi blade it came with. I would go 24t for ripping and 50-60 for crosscutting.

[Tom Walz]

There is typically a smallselection of 6” and 7 ¼” inch saw blades.

The small blades aretypically sold for rougher work.I usemy 7 ¼ inch saw for 2 x 4’s when I am building something.Iguess I would advise you to think of these as somewhere along the lines ofdemolition or remodeling saws.

The small saws are usuallyused in handheld applications.There’snot a whole lot of point in buying a really precision blade if you don’t have aprecision sawing platform.

When you get into 10 inch sawblades you start getting a really wide selection of blades.
Tom Walz
Carbide Processors

[George Bokros]

I use a Diablo 7 1/4" 60 tooth for plywood in my circular saw and love it. ~$20 each cuts a 1/16" kerf

[George Bokros]

There is typically a smallselection of 6” and 7 ¼” inch saw blades.

Tom Walz
Carbide Processors

And and even smaller selection of 8 1/2" blades

[Keith Hankins]

I have the Forrest WWII as it's a good compromise between crosscut and rip. Perfect cuts to.

[scott spencer]

Hello everyone!

I need some help choosing the right blade for my circular saws, I need 7 1/4" and 6" blades.

So far I have those available:

7 1/4": 12, 16, 24, 36, 48, 60 teeth

6": 12, 24, 36 teeth

How do I choose the right one? What should I take into account? Do the wood's hardness or size matter? Is there any guide for choosing them? Could you help me choose one for ripping and one for cross cutting for each size (7 1/4 and 6", I need both saws to be equipped)?

I could give you some details about what I usually cut, but in order to not bloat this post I'll just wait for someone to ask them, I'm not too sure these details matter that much...

Many thanks in advance!

Number of teeth should be based on the intended application along with the other design parameters of the blade. If all other parameters are equal, more teeth will equate to a cleaner cut, but with the downside of creating more friction/heat and resistance, slower feed rates, and a higher chance of burning. Fewer teeth equates to a faster more efficient cut, but typically also means a rougher cut. Depending on thickness, as a general rule of thumb, it’s recommended to have 5 to 7 teeth in the material for crosscutting and finish cuts in hard wood, and 3 to 5 teeth for ripping operations.

[Kent A Bathurst]

Number of teeth should be based on the intended application along with the other design parameters of the blade. If all other parameters are equal, more teeth will equate to a cleaner cut, but with the downside of creating more friction/heat and resistance, slower feed rates, and a higher chance of burning. Fewer teeth equates to a faster more efficient cut, but typically also means a rougher cut. Depending on thickness, as a general rule of thumb, it’s recommended to have 5 to 7 teeth in the material for crosscutting and finish cuts in hard wood, and 3 to 5 teeth for ripping operations.

Perzakly.

Crosscutting means exactly that - you are cutting across the fibers. More teeth give a cleaner cut. Including plywood.

However - when ripping, you are digging out those long strands of fiber. More teeth means the gullets are smaller, and get jammed with those long fibers before they can clear - so fewer teeth = bigger gullets.

A lot depends on the type of grind on the teeth - but that is a next-level complication.

On a 10" table saw blade, 80t is a common blade for crosscutting and ply. [80t also on a CMS - same reason].

Do the math:

10" dia x Pi - 31.4" circumference. 80 teeth / 31.4" = 2.55 TPI

7.25" x Pi = 22.77" circumference. @ 2.55 TPI that is 58 teeth, or 60.

On the ripping - The thicker the lumber, the fewer teeth on the blade - as Scott's explanation dictates. If you have too many teeth for hte thickness, then you have too many teeth in the wood. Same deal - cannot clear the fibers effectively.

I use: 40t for 4/4 + 5/4; 30t on 6/4; 20 t on 8/4. Those are for 10" blades - do the math for 7.25" equivalents.

Also - just to make it more complicated: Some species are notorious for "burning" when ripping: cherry and hard maple are two that come to mind. When ripping those, I move down one spot on the tooth count. Not as clean of a cut, but I always slap ripped edges across the jointer anyway, so it doesn't matter. And - the dadgum stuff doesn't burn - at least - not nearly as much. And the burn can easily require more off when going across the jointer than the low-tooth-count rough cut.

[Giovanni Rinaldi]

I'd like to thank everyone for all the answers, however I can only get hold of Bosch blades, and I likely won't be a good customers for you, unless you ship overseas, so please, avoid sponsorising your products.
Perzakly.I use: 40t for 4/4 + 5/4; 30t on 6/4; 20 t on 8/4. Those are for 10" blades - do the math for 7.25" equivalents.Forgive the dumb question but... What are those? Inches? You use 40 teeth for 1" and 1,25" pieces?