@Thedog having ‘played’ with a number of saw manufacturers blades, it seems to me, that there are poor, good blades and excellent blades, but these are never cheap blades.
MDF is very abrasive and will dull a poor blade very quickly.
I have compared say Freud blades with say CMT (industrial range), Omas, Swedex and well, the difference is stark. In fact the last Freud blade I bought , which is typical of their blades, I through in the recycling bin. After an incredibly short time it was blunt. Where as, one of the of the other brands I mentioned will literally cut thousands of linear feet. Why is this important? Well, for most who don’t use their circular saws ever day, the deterioration of the sharpness of a blade Is often difficult to judge, and the temptation is to just keep going as long as saw dust is being produced. A dull blade is one of the main causes of serious injury.
A high quality blade will not only stay sharp longer (higher quality carbide) but will also be suitable for multiple resharpening……more carbide on each tooth. Equally they are usually significantly quieter in operation. This is I believe due to the plates being flat so that the teeth cut in one line, ie doing less work……as well as the noise reduction bits the add to the blades. So, a Swedex blade on my saw (SCM Si15) produces a cut that is almost indiscernible from the finish produced by my PT (Sedgwick CP). You have to look really hard to see which is sawn and which is planed. Again, a descent secondhand Swedex blade still holders value, where as the cheaper ones are just throw away. So, in summary, a larger outlay initially but I truly believe a safer, quieter and long term more cost effect solution.
A great reference is the Swedex catalogue, the first few pages where it goes through circular saw features and what you need to look for.
http://www.swedex.com/wp-content/uploads/2019/10/POR40827_v1_Swedex-katalog-GB_optimerad1.pdf
The other major factor affecting blades is how they are sharpened. The difference between a properly sharpened blade and not is night and day. I tried a fair few circular saw sharpening services only to find them extremely lacking. I finally came across one that is superb. I recommend him to everyone we sell a machine to. He’s a superb shop, and knows his stuff having invested in the latest machines. His web site is a little crude. He also sells saw blades. Take a look at the video of how he sharpens circular saw blades, bottom of the page.
https://priestnersaws.co.uk/
One thing I hear of which is IMO ridiculous is people attempting to sharpen their own circular saw blades without the knowledge of how it should be done. An accident waiting to happen!
