# Forum Home Renovation Metalwork & Welding  Cutting thin sheets of steel.

## PlatypusGardens

.....cutting thin sheet metal wear down cutting discs faster?   :Confused:

----------


## webtubbs

Is it an illusion? You're cutting longer distances in a quicker time than thicker metal.

----------


## PlatypusGardens

> Is it an illusion? You're cutting longer distances in a quicker time than thicker metal.

  Nope

----------


## ringtail

Tend to agree PG. I think it's the angle the grinder is held regardless of metal thickness. Just a fraction off 100% square and the discs get eaten. But I have noticed cutting sheetmetal as opposed to 6 mm the discs do go faster. No firm answer but discs are cheap so..........still beats wiss snips  :Tongue:

----------


## Marc

The wearing of the disk is in direct relation to the friction. More friction more wear. If the disk is grinding against a small surface the pressure applied to the disk and therefore the friction will be much higher.
You could reproduce the condition of cutting 5mm when cutting 0.5mm by applying a lot less  pressure to the metal as an experiment and in theory you should get longer life from your disk ... of course no one does that, you just want to cut the damn thing!  :Smilie:

----------


## PlatypusGardens

I usually take it easy when cutting as it makes the discs last longer.
But yeh sometimes it's go go go. 
The difference between cutting a 3-5mm plate and, say a roof sheet is massive (in terms of how long the disc lasts)   
I get the 5" thin Pferd discs in 100 packs btw.
good value   :Smilie:

----------


## METRIX

Ha Ha Ha, only yesterday I was saying this exact thing, when cutting up some old sheet metal shelving, I think it's got to do with the wheel is rubbing on the sides of the thin metal as cutting because there's really nothing to keep the grinder straight, 
I think its the rubbing of the sheet on the wheel sides thats wearing it out quicker rather than the actual cut. 
I can cut for the same time through 5mm as it takes to cut the thin stuff, and the one cutting 5mm plate is still 90% the size, the one cutting thin sheet is 90% gone so it's not a running time thing, it's being worn somehow by the thin sheet.

----------


## Godzilla73

> .....cutting thin sheet metal wear down cutting discs faster?

  You've discovered one of the mysteries of life, the men in white coats will be along shortly...

----------


## PlatypusGardens

> Ha Ha Ha, only yesterday I was saying this exact thing, when cutting up some old sheet metal shelving, I think it's got to do with the wheel is rubbing on the sides of the thin metal as cutting because there's really nothing to keep the grinder straight, 
> I think its the rubbing of the sheet on the wheel sides thats wearing it out quicker rather than the actual cut.

  But if that was the case the disc would start to shred and fray...no?   :Unsure:    
...i'm thinking more along the lines of the thin steel edge acting as a cheese grater....

----------


## Marc

The sides of a cut can be just as sharp for 5mm then for 0.5mm, it is the business edge of the disk that suffers from pushing against a tiny surface and therefore is under 10 times the pressure for the same speed comparing both materials above. 
If you push with 0.1 k force against sheet metal 0,5 thick you should be pushing with 1 k force against the 5mm thick material. If you did, your disk would disintegrate very quickly cutting the thicker material

----------


## PlatypusGardens

Hey  :Shock:  
Who changed the thread title?

----------


## ringtail

You are merely a cog in the big forum machine PG. Don't ask questions, there's a good lad.  :Tongue:

----------


## PlatypusGardens

> You are merely a cog in the big forum machine PG.

  ....better than being a turncock I suppose....

----------


## ringtail

That's true, if I knew what a turncock was.  :Biggrin:

----------


## METRIX

> But if that was the case the disc would start to shred and fray...no?     
> ...i'm thinking more along the lines of the thin steel edge acting as a cheese grater....

  Need to ask myth busters

----------


## David.Elliott

On impulse I bought one of these. Back of my head said gimmick, but...I had a bunch of corro to cut.  https://www.youtube.com/watch?v=q8bYvBzzqTU 
The best, fastest, cleanest way to cut with the least sparks. I love it...
There should be a footplate a'la circular saw that bolts on. I can find reference to it in G but cannot buy one...That'd be a great addition.. 
My go to tool for cutting metal now...

----------


## r3nov8or

I haven't used a dual saw, but have used one of those toothed blades for an angle grinder that "cuts anything". Even going easy I've broken teeth on 2mm steel tube and once you've lost one tooth the blade struggles and sheds more and more and quickly becomes useless. Corro sheet is no problem at all though.

----------


## cyclic

> .....cutting thin sheet metal wear down cutting discs faster?

  Not sure what thickness you are referring to but up to say 2mm I prefer a jigsaw with metal blade to get a cleaner straighter cut.
I have too much trouble using angle grinder discs, they do wear quickly because of the thin edge of sheet you are cutting against.
If using angle grinder discs I always found it much better to run a score along the sheet and then bend and snap over a piece of timber or similar.

----------


## PlatypusGardens

> Not sure what thickness you are referring to

     

> up to say 2mm

  
about that ^     :Wink:

----------


## Marc

> On impulse I bought one of these. Back of my head said gimmick, but...I had a bunch of corro to cut.  https://www.youtube.com/watch?v=q8bYvBzzqTU 
> The best, fastest, cleanest way to cut with the least sparks. I love it...
> There should be a footplate a'la circular saw that bolts on. I can find reference to it in G but cannot buy one...That'd be a great addition.. 
> My go to tool for cutting metal now...

  Yes, seems to be a good invention. I did not buy it because of the massive kerf. And I imagine it will throw a lot of debris around 
About that video ...  :Frown:  ... 8 minutes to show a few seconds of the saw cutting steel then the rest is more bla bla ... Aaaaaaaaaaaa.

----------


## PlatypusGardens

> About that video ...  ... 8 minutes to show a few seconds of the saw cutting steel then the rest is more bla bla ... Aaaaaaaaaaaa.

  
PFrfft 
A bit rich coming from you with your 1.5 hour blacksmith videos!   :Rofl5:

----------


## Marc

ha ha .. 1.5 hours? how do you know that? 
The point is if you are going to show a saw, show the saw in action don't talk about it. May be he was saving the planet by not using electricity ...  :Smilie:  
Another negative about that dual saw is the cost of replacement blades ... about $40. 
Still thinking about it. I have power nibbler, air nibbler, power snips yet always use the grinder with 1mm disk.  :Whatonearth:  
Imagine the amount of steel bits you will be picking up from the floor if you cut something like 5 or 6mm thick!

----------


## PlatypusGardens

> I always use the grinder with 1mm disk.

  Same.
I've always got one grinder set up wit that disk in it and it gets a lot of use.   

> Imagine the amount of steel bits you will be picking up from the floor if you cut something like 5 or 6mm thick!

  I once cut a piece of aluminium with that "hacksaw" toothed disk on the grinder.
OMG what a mess.   :Shock:   
Went back to manual hacksaw after that   :Unsure:

----------


## justonething

> On impulse I bought one of these. Back of my head said gimmick, but...I had a bunch of corro to cut.  https://www.youtube.com/watch?v=q8bYvBzzqTU 
> The best, fastest, cleanest way to cut with the least sparks. I love it...
> There should be a footplate a'la circular saw that bolts on. I can find reference to it in G but cannot buy one...That'd be a great addition.. 
> My go to tool for cutting metal now...

  he should read the manual and use the lube stick with cutting metal

----------


## Marc

Found this review *I also haven't used this guy, but here, in short, is what the guys at Toolmonger said:* *(For their complete answers, search for "dual saw" at toolmonger dot com.)*  Cuts okay, with surprisingly clean edges.Incredibly noisy.When cutting metal, throws large, hot chips in two directions.Depth of cut is limited to 1" with 5" blades (so it can't cut framing lumber in one pass.)Cuts a very wide kerf (no mention of how wide though.)Jerks unpredictably in both directions.Possibly no better than a 5' angle grinder (which does pull, but only in in a predictable direction.)Possibly made by a company that got many BBB complaints under its previous name, Infusion Brands International.Doesn't come with a cutting guide, so out of the box you have to cut free hand.Accessories and blades are expensive. *Hope that helps!*

----------


## METRIX

It's like any of those tools which are not taken by the mainstream, limited use and not as good as they look on the TV.

----------


## PlatypusGardens

> It's like any of those tools which are not taken by the mainstream, limited use and not as good as they look on the TV.

  
Yeh it's funny how "Not available in any stores" often is the main selling point for these infomercial gadgets   
Some scathing reviews here -> Does Dual Saw Really Work?  
 Note that the only person saying it's good is an Aussie.     :Biggrin:

----------


## Marc

> Some scathing reviews here -> Does Dual Saw Really Work?

   Ouch

----------


## PlatypusGardens

Meh 
Dual saw.  
Tri-saw is where it's at.
No kickback either   :Biggrin:

----------


## r3nov8or

> Meh 
> Dual saw.  
> Tri-saw is where it's at.
> No kickback either

  Great for dovetails

----------

