Thread: Do I need to sharpen these circular blades?

It's a bit hard to be definitive because they're not clean, but they do look pretty second hand.

They are tungsten carbide tipped and yes you do need to sharpen them

A 2D photo doesn't really help unfortunately. The teeth look blunt as burglary but that could be just the way light is reflecting.

You need to consider the following:

1: How old is that blade; how many cuts has it performed?
2: What type of cuts; rip or crosscut? You will blunt rip teeth quicker when used for cross cutting and vise-versa
3: What material has it been used on? Softwoods are easy; hardwoods not so (depending on janka rating); manufactured boards (MDF, chipboard) are very abrasive.
4: Are you getting burn marks on the timber? Sharp blades cut; blunt blades burn.

However...... the first thing I would consider though is whether the overloading has been happening gradually over a couple of weeks or so or if it has just started. If it's a recent development and happens at the slightest load then I'd be looking at a defective overload switch.

You can always clean them too; CMT amongst others make a cleaning compound that dissolves the gum and crud on the teeth. You can also soak the blades in kero, diesel or other light oil and scrub with a BRASS wire brush.

Sharpening, nope, I wouldn't.

Throw them out or nail them to the wall as an ornament, then go and buy a couple of new ones.

What they obviously need is a clean up and then maybe post a second close up like this so we can see if there's an issue - without a clean up everyone is just guessing.
If it was me and they cut OK I would just use them.

Dewalt.jpg

In the second photo, the burn line on the same radius as the bottom half of the gullet indicates to me that the gullets are loading up and not clearing while cutting. A number of things can cause that - is the burn mark on both sides of the saw blade ? or only one side?

1. dull teeth,
2. the kerf closing up in the cut - is a riving knife or splitter fitted?
3. the wood being cut, is it green or very resinous?
4. feed rate - to fast does not permit the gullets to clear - loading up the blade, increasing friction
5. saw alignment - is the fence adjusted correctly & parallel to the blade. A taper will cause the saw to bind as the wood passes through the saw.
6. damaged saw blade - warped or bent.
7. correct saw blade for the application, tooth count and is it designed for for hand held circular saw, mitre saw, or table saw?

Both blades appear to be rip blades, however deWalt also use the depth limiting stops on some of their cross cut "extreme" saw blades. - are they being used for ripping or cross cutting as well?

As for sharpening - why bother? The DeWalts are almost a throw away blade at their price point in the market even though they claim that they can be sharpened once or twice.

Do you have the saw blade product code - i.e. DT90280-QZ

• DT90280-QZ

Sorted out the overload.
Had the Festool vac on high.
Turned it down to low and no prob.
Tested it back on high and overload.
Back to low to finish my cuts.

Wow gents!
Freakin' blitz on the support.
Impressive!
Really appreciated.


If I was going to hang it on the wall.
How would I incorporate an epoxy poor?

When you saw "overload switch" are you referring to,

1. the thermal overload on the saw,
2. an over load switch on a power board,
3. or the circuit breaker on your main switch board.

My comments were directed at #1.

2.
Now I'm thinking about upgrading it to a professional PB.
The yellow and black one I already have been using in another area.
But might not work. I don't know.
Plug Boss

The other thing that can significantly affect a saw/blade performance is how much blade is engaged in the cut. Don't listen to all the American b******t about having the blade just protuding above the work, raise it at least 20mm higher than the top of the stock and give the saw motor/ blade a fighting chance.

Originally Posted by barrysumpter

2.
Now I'm thinking about upgrading it to a professional PB.
The yellow and black one I already have been using in another area.
But might no work. I don't know.

Do you switch both the saw and vacuum on at the same time?

Does it trip the overload protection on the power board at start? or after you commence a cut?

It's almost certainly a 10 amp power board, ie. not up to the job.

Yes.Plug Boss it is.