Circular saw blade

[hcset]

I have a Ryobi Circular saw with 150mm 18 teeth saw blade. It does cross cut on a 30mm thick plywood at 45 degree angle just fine. I read somewhere where blades with more teeth will give a cleaner finish cut.  So I bought a Ozito with 36 teeth blade as Ozito is the only brand I could find that makes 150mm blade. But whenever I put on the Ozito blade, I couldn't finish cutting the plywood at 45 degree angle. The motor and blade always stop halfway. I checked the blade wasn't loose. And when I changed the blade back to Ryobi then it worked fine. Does anyone know what could be the problem? It's not brand compatibility issue, is it? 

And it sounded like the circular saw worked harder with Ozito blade when I was cutting the plywood straight and also left burnt marks.

Henry 

[ProjectPete · Accepted solution]

I'd say it's a simple case of the Ozito blade being poorer quality than the Ryobi @hcset .

- Overall composition/quality is lower than your Ryobi blade.

- The coating (or lack of) on the blade is likely causing extra friction.

- The kerf may be thicker than the Ryobi blade, causing the saw to struggle (power wise) to cut through the ply.

- The teeth are likely not as sharp and lasting as the Ryobi blade.

You're correct though re extra teeth creating a cleaner cut. However brand and blade composition is still a key factor.

I use Diablo blades and can even use a 40T on my mitre saw which will cut better/finer/cleaner than a 60T Craftright blade.

[hcset]

Thanks for the insight @ProjectPete.

[MitchellMc]

Welcome to the Bunnings Workshop community @hcset. It's great to have you join us and many thanks for your question.

It's fantastic to see you've already received a helpful reply from @ProjectPete.

Can I please ask if it is the 18v battery-powered Ryobi circular saw you are using? If so, what amp hour battery are you using?

As you increase teeth on a saw blade you get a finer cut but you also reduce the rate at which you can feed material. This isn't particularly evident with 240v equipment but can be with battery-powered units. I have the Ryobi battery-powered saw and experience the cutting in and out on the 18 teeth blade. This is because my blade is blunt and in need of replacing. It's cutting in and out because the motor is straining to cut.

I've been recently made aware that the AH of a battery can actually affect the performance of the unit and not just runtime. So if you're running a 1.5AH battery it might have something to do with the following. When cutting 30mm thick plywood at 45 degrees (which is significantly thicker than 30mm) could be right on the cusp of your motor cutting out. The addition of the higher tooth count might have just pushed it over the edge especially if you are trying to feed at the same rate as your 18 tooth blade.

The user manual for that machine lists the cutting capacity at 45 degrees as 32 mm. So if you are cutting a 30mm board at 45 degrees that is going to be over the maximum cutting capacity.

I believe the issue is that you are right on the edge of whether the saw is capable of cutting in that fashion and you might have found the limit to its ability when swapping blades to the higher tooth count. @ProjectPete has made a good point also that the Ozito blade could quite possibly be a more budget variety.

Please let me know if you need further information or had any questions.

Mitchell

[hcset]

Thanks Mitchell.

If I remember correctly, I was using 18v 5Ah at that time. I know I was pushing circular saw to the cutting limit but I tested on a 30mm offcut and it worked fine so I decided to go ahead with the plywood. The only difference is that the test was on a much shorter piece, 30mm vs 600mm the plywood :).

Anyway, I managed to finish the cut using the Ryobi blade but I am just curious what's the issue so I know what not to do in the future.

Henry

[kml]

Hi Mitchell,

I too am seeking an alternative 150mm Blade for finer cuts.  The Ozito 150mm blade was instock at my local Bunnings store, however this was the only replacement blade that could be purchased & the only alternative option to the 18 tooth blade that comes with the Ryobi 150mm Circular Saw.

What would be your recommended alternative blades? or what blades do you have to suit & for use with your Ryobi 150mm battery powered saw?

much appreciated, cheers

Kim

[MitchellMc]

Welcome to the Bunnings Workshop community Kim (@kml). It's marvellous to have you join us, and many thanks for your question about purchasing a saw blade.

Due to 150mm circular saws being far less popular than the standard 180mm circular saws, there are only a limited number of options available blade-wise. Ryobi only supplies the 18-tooth blades, and I've checked with our other blade manufacturers like Diablo, and there is nothing in a higher tooth count that they produce for a 150mm saw. They do have the Diablo 150mm 20T General Purpose Cordless Circular Saw Blade, but its arbour size of 20mm is far too large, even with a bushing.

What sort of finer cuts were you looking to do, and what sort of issue were you experiencing with the 18-tooth blade?

Please let me know if you have any questions.

Mitchell