Any rule-of-thumb for replacing 4.5" cutoff wheels?

[i7win7]

i7win7 - what is your tractor pulling in your avatar? Is that a dirt pan? Do you have a bigger picture?

RB-6R

Hoelscher Commercial Products - RB Scraper

Hoelscher is a Bushton, Kansas hay baling equipment and earth moving equipment manufacturer.

www.hoelscherinc.com

 

[amhicks21]

Ive used many hundreds of cutoffs over the years with only very few incidents. When possible I run em right down to nothing. The problem with cutting roofing is the metal will start to vibrate and will destroy the disc in seconds if you let the blade get in too deep or bind. The other problem with thin metal is it gets hot quick and expands and pinches the side of the disk. You can mostly avoid this by keeping the blade very shallow and do whatever possible to keep the blade from pinching. Maybe try rotating the guard into a position that acts as a depth gauge and only let the blade come 1/4" through the bottom and, as everyone knows but it always bears repeating let the disk do the work and only guide it along without pushing.

 

[California]

FWIW, Project Farm did a comparison of cutoff blades. DeWalt took 2.5 times longer than the majority of them.

See the 7:29 point in this video.

There are other conclusions a few seconds either side of that point.

I ordered a pack of Makita blades yesterday after studying the video. He showed that these aren't consumed as fast, while taking the same time to cut as most others.

Back when I was a carpenter it was common practice to mount a Skilsaw blade backward to cut sheet metal.

 

[ArlyA]

I love my 4.5 Porter cable grinder, but I'd not use it for cutting tin. And like others have pointed out, cheap wheels are just that. Cheap!

 

[PILOON]

Back when I was a carpenter it was common practice to mount a Skilsaw blade backward to cut sheet metal.

Sort of like what I posted earlier.
A friction blade is very similar to a regular saw blade but without teeth, just all the slits.
Rare to find but sure does a great job.

 

[rangerfredbob]

I bought some new Milwaukee tin snips for doing the siding on my shop, like a hot knife through butter... I used those over an electric double cut shear I had borrowed and an air nibbler... If the metal is just currogated and not the one rib per 9" like I have they would be a pain though...

 

[aviator411]

Manufacturers of steel roofing, paneling, siding do not approve of cutting their panels with any kind of saw blade or abrasive disc due to heat produced degrading finish and accelerating rust process. Power or manual shears only if you possibly can. Not always an easy option.

 

[nknelsen]

I've read of them shattering and I'm apprehensive of getting shards in my body even though I wear PPE.
But presently the roofing metal I'm cutting is eating about 1 Dewalt DW8062 wheel per panel width.

I find that the cutting wheels generate too much heat when cutting and that will affect the paint and possibly cause corrosion later on. When I did my metal roof it was suggested that I not use a grinder for that reason.

I used a Dewalt Sawzall with a 6"metal blade that worked very well for cutting. On my average size house I think I cut it all with 2 or 3 blades. Much safer too in my opinion.

 

[Bullwinkle123]

Don't buy harbor freight cutting wheels...stick with diablo or dewalt.

I happen to like my HF cutting wheels. They're cost effective and have a thin kerf that I prefer when cutting.

That said, I suppose the thinner disks are even more likely to shatter, though I haven't had any shatter. Always something to worry about with any brand.

 

[v908]

Project Farm did a great evaluation. You might want to consider his testing/results:

 

[macklong]

Not sure if any of you have heard of this but i use a 4" twin cut saw. it's resembles a 4" angle grinder but it is not the same and can not be used as a twin cut saw. one blade turns one direction the other turns the other, it uses carbide tip blades and they last a very long time. I first was a bit skeptical but decided to make the plunge and now i am so glade I did. After getting it I thought i would put this to a test on stainless steel about an 1/8" thick, wow what a job it did went through it like butter. I am still using the same blades and it has been a good ten years now. ( not in business just DIY stuff) It makes very small chips so i wear gloves and face shield and it does make a lot of noise and some sparking so be careful on where you do your cutting. It cuts metal roofing fast and almost no burs left on the metal. I have learned through trial an era that if you clamp a board to the metal roofing that it does not flex and makes it easier to make a clean straight cut.

 

[BeezFun]

I rented this shear when I installed pro rib on my buildings, best thing I've ever seen for cutting across roofing with raised contours. Only problem is it's specific to the brand roofing you're using.

 

[ArlyA]

Great find! But what would you do to cut just one pannel off?? Or those shears aren't available to rent where you reside??

 

[ArlyA]

Project Farm did a great evaluation. You might want to consider his testing/results:

This guys test of blades and grinding wheels rocks!

 

[v908]

This guys test of blades and grinding wheels rocks!

Yeah, it's worthwhile to go back through his videos to see all the stuff he tests. Generally very thorough and informative.

 

[Man from Crooked River]

I am a carpenter who has installed a lot of metal to buildings. I never use Zip Cut blades unless absolutely necessary, they cause sparks that will ignite fires, they wear out, they burn the paint on the metal and they can explode. I know a guy who was using a ZipCut that exploded. Schapnel went thru his glove and cut a vein in his wrist. Not a pretty sight and major 1/2 hr rush to the hospital.
I use a 7 1/4" -metal cutting- carbide blade in a circular saw, or tin nibbler connected to an air hose. I made up a track for the saw to run in for straight cuts, just measure, clamp down the track and cut. And maybe a little filing of the cut.
Also if I need to cut numerous sheets, to the same size. I can cut 4 or 5 sheets at the same time. And carbide blade lasts quite awhile. I can do two to three major projects on one blade. Cheaper that buying abrasive blades, over the long run
You still need PPE, hearing protection (its noisy), gloves with high gauntlet (the cuttings are hot) and preferably a face shield

 

[zozomike]

Having done a good bit of metal roofing, the best ( and I think safest) cuts were with a steel circular saw blade, mounted backwards, will cut all day long. Not talking a specialty metal cutting blade, just a cheap steel 7 inch. MOUNTED BACKWARDS. Do not ever try that mounted forwards.

 

[Bengineer]

i recently used an Irwin 7-1/4", 68T metal cutting blade on a skilsaw to cut roofing panels. It cut the panels like butter and left a very smooth edge.

 

[Industrial Toys]

You don't know if companies like dewalt have different sources for different markets. And whether they outsource their supply. Say put out a tender for a million cutoff wheels. Next batch, might be from somewhere else entirely

 

[California]

You don't know if companies like dewalt have different sources for different markets. And whether they outsource their supply. Say put out a tender for a million cutoff wheels. Next batch, might be from somewhere else entirely

Very likely. Project Farm in the video linked above, measured the DeWalt blade at 67% thicker than advertised. No wonder it was the slowest.