Metal Circular Saw Blade – Damaged Teeth

[Robert Bowen-CattryParticipant @robertbowen-cattry70600]

Good morning all,

I was recently gifted a very nice Dewalt chop saw which came with a metal cutting blade. Unfortunately some of the teeth (which I assume are carbide) were chipped when the previous owner used it to cut stainless steel.

Are these blades repairable (is it even worth it) or should I bite the bullet and buy a new one?

Many thanks,

 

B

[JasonBModerator @jasonb]

Most saw doctors can braze on replacement tips but at about £5 each it may just be better to get a new blade if too many need replacing as you will also have to pat 25-30p per tooth sharpening.

[noel shelleyParticipant @noelshelley55608]

I would just get a new one the cost of repair and sharpening will not worth it. When using a chop saw bring the blade down slowly to start the cut and feed slowly, DO NOT force the blade, allow it to cut at it’s own speed. De Walt, Was the machine intended to cut steel, or just aluminium and wood ? Good luck. Noel.

[Chris GunnParticipant @chrisgunn36534]

Robert, a lot depends on what you intend to saw, If you are sawing angles and box sections the wide spacing of the tips leads to breakage. I have a cold saw using an HSS blade, with finer tooth pitch, and this can cope with most sections.

[Andy StopfordParticipant @andystopford50521]

The Evolution blades are pretty good – they’ll cut metal and wood (they last well with MDF too).

They’ll cut quite heavy steel sections, but I’ve also used them to mitre cut extremely thin walled steel tube for curtain poles, which is difficult to cut with any other sort of saw because it kinks so easily.

[Robert Bowen-CattryParticipant @robertbowen-cattry70600]

Thanks chaps. 🙂

It also came with an abrasive disk which I have been using for now, and will get a new metal blade at some point.

 

[Nigel Graham 2Participant @nigelgraham2]

Andy –

It might help to hold such tubes in a simple split wooden clamp (like a split journal), but such material is always awkward, and an abrasive cutting disc might be the better tool.

[Nigel Graham 2]

On Nigel Graham 2 Said:

Andy –

It might help to hold such tubes in a simple split wooden clamp (like a split journal), but such material is always awkward, and an abrasive cutting disc might be the better tool.

I needed to cut precise mitres to fit the them in bay windows and I don’t have one of those mitre stands for my angle grinder (the thin cutting discs do a good job of cutting these tubes, but there’s no way you can do it accurately freehand).

[Robert Bowen-Cattry]

On Robert Bowen-Cattry Said:

It also came with an abrasive disk which I have been using for now

Please post the model number. There is no saw made by DeWalt or anyone else that is suitable for both a toothed blade and an abrasive disk.

If it turns out that the toothed blade was being used incorrectly, that might save you wasting money on a replacement.

[Pete RimmerParticipant @peterimmer30576]

We use a Makita cold cut circular saw at work it eats metal but when the blades go off they go off quickly, the teeth break up and the blade is scrap. They aren’t too expensive though and can do a fair bit of work before they need replacing.

The teeth are not sharpened dead flat on the face so I would say that even if your saw has only slightly dulled teeth then sharpening is going to be of limited value. If teeth are broken it needs sending to the bin.

[FulmenParticipant @fulmen]

I’ve had carbide saw blades resharpened. Didn’t pay for it myself (a friend tossed them in with other tools) so I don’t know how much it cost. But he never complained about the price so I guess it wasn’t that bad. 2 out of 3 could be saved, I even think they brazed in a few teeth. The one that had to be scrapped was due to wobble.

[JasonBModerator @jasonb]

No need to send it to the bin if a tooth or two is missing. Being a woodworker I’ve sent dozens of such blades to the saw doctors over the years and they come back with the missing teeth replaced and the whole lot sharpened. Can usually get 3-4 uses out of a site blade but only 2 or three out of table saw blades depending on the grind be they straight across flat top rip blades or high tip angle finishing blades.

The talk of HSS cold cut blades is fine but the saws they are meant for run slower than the ones that take TCT blades so don’t mix them up as just like a slitting saw you will soon blunt an HSS one if run too fast.

[FulmenParticipant @fulmen]

Yeah, you can’t go mixing blades like that. IIRC the blades I used had a cutting speed of 1200m/min! That’s insane compared to what I usually do in the mill or lathe, and I wouldn’t subject HSS to that even in wood.

[JasonBModerator @jasonb]

Yep, 10″ coldcut may run at about 50rpm, My 250mm Dewalt SCMS is 4300rpm

[Mark EasingwoodParticipant @markeasingwood33578]

Like Jason I have had (Wood) blades re-tipped when being re-sharpened, but it is only worth doing if it’s only a few teeth. All the Saw sharpening places will do it.

It’s the peripheral speed of saw blades that is important, bigger diameter = slower speed, just like the traction engine driven racksaw benches.

I have hit Metal Jacketed Bullets, Shrapnel, and nails etc. when sawing up timber at work in the past, dosen’t happen much these days tho’, maybe the sawmills have better metal detectors, and all the softwoods seem to be Scandinavian, the Russian softwoods stopped when the USSR broke up.

Mark.

[Robert Bowen-CattryParticipant @robertbowen-cattry70600]

Please post the model number. There is no saw made by DeWalt or anyone else that is suitable for both a toothed blade and an abrasive disk.

If it turns out that the toothed blade was being used incorrectly, that might save you wasting money on a replacement.

It’s a Dewalt D28700. The blade is also Dewalt, I will try and post a pic up when I get a chance.

[Robert Bowen-Cattry]

On Robert Bowen-Cattry Said:

It’s a Dewalt D28700.

There’s ya problem lady.

https://www.toolstop.co.uk/dewalt-d28700-355mm-abrasive-chop-saw-110v-p2425/

“No Load Speed 3800 rpm”

https://www.dewalt.co.uk/product/dw872-gb/2200w-355mm-tct-chop-saw-soft-start

“No Load Speed (RPM) 1300”

Homework exercise: work out the surface speed of the blade for both machines in metres per minute and discuss.

[FulmenParticipant @fulmen]

I agree, that one is intended for abrasives only.

[Robert Bowen-CattryParticipant @robertbowen-cattry70600]

Fair enough, will stick with the abrasive disk. Saves me buying the much more expensive carbide blade.

As I said at the start of the thread, the previous owner had given me the saw with both the blades (including the one he had broken trying to cut stainless).

[Robert Bowen-CattryParticipant @robertbowen-cattry70600]

Good morning all.

This is the blade that I was given with the saw. I’ve marked the damaged teeth.

It seems pointless getting it repaired as I can’t use it with the saw for metal.

[JasonBModerator @jasonb]

Even if you could use it at £5 per tooth replacement plus a regrind it would cost more than a new blade

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