Chop Saw

[CenterSparks]

Hi

Im an apprentice, today i was jusung a chopsaw to cut some unistrut brackets and the blade blunted to nearly useless. I was just wondering if this was down to me or just the blade, is it possible i made it blunt with bad technique. I start the blade spinning before cutting, should i keep it spinning while lifting the blade back up? Sometimes it makes horrible screeching or strange noises if the metal falls and catches the blade on the way up, would this blunt it? I just want to know any tips or techniques.

Cheers

 

[monkeyelectric]

When cutting don't force it just let it cut at its own pace, i normally cut all the way through the piece then let the power off

 

[CenterSparks]

Okay thanks, Do you stop it spinning while you lift it up or before? Or after its clear, basically Is it possible im blunting it when pulling back up?

 

[derek]

May I ask what sort of blade you are using?

 

[grantr37]

You got earplugs and a set of safety Goggles??? ? and Gloves? the wearing out of the blade depends on the hardness of the metal and if it's Uni Strut with Holes in it or if it's Solid Uni strut without holes........you need to keep the blade spinning until you lift the saw back up......use the clamp on the bottom of the saw to hold the Uni Strut you are cutting, don't let the Blade get smaller than about 4 inches of blade left as the speed of rotation increases as the blade gets smaller as there is less diameter to rotate....going over the max RPM can make it shatter and shoot out....
make sure nobody is using the side of the cutting disk as a file for filing strut or screwed rod either as this will damage the blade and make it dangerous...

Cutting Uni Strut I like to put the flat back of it on the bottom, start the saw up to full speed then slowly lower it down until cut through then move it back up before letting go of the button.....watch out as the metal can get very hot....unplug the saw before undoing and removing the metal that you have cut and then use a flat file to rub off the metal shavings sticking out of the cut part....


you would be better off getting a headphone style pair of ear defenders for using the chopsaw....

A small fire extinguisher nearby is handy if you are working inside a building, hot works and all that...




A point to mention.....if you are being asked to use a solid metal blade with teeth on it similar to a wood saw I would ask for a Grinder style abrasive wheel blade, the metal blades are very bad and I think that they are also dangerous, and a lot louder....
The sales people at the tool sales companies will always try to sell the next best thing that they want to shift, and they have been selling these blades, I don't like them at all.....

 

[CenterSparks]

Thanks for the tips, It is a multi purpose blade for wood and metal. The saw has no clamp so you have to hold the strut in with your hand. I have Safety glasses.

I was just wondering if my technique was what blunted the blade.

Cheers for the help!

 

[derek]

Use an angle grinder/abrasive disc! Multipurpose blades are rubbish.

 

[AP Electrical]

Make sure work piece is supported throughout its length, I.e you don't have 12 ft hanging of the end of bench when cutting....

 

[grantr37]

multipurpose blades are dangerous.....and you should not be holding the strut in with your hands, there should be a clamp, maybe somebody can make some kind of a guide/clamp for you or supply you with a new saw.....
a blade spinning at that kind of speed can have your hand off in 1/2 a second, and if it goes wrong it can break and go through you...

 

[Adam W]

Again I'd use an abrasive wheel - it hasn't got teeth so you can grind it down to pretty much nothing and it'll still cut unistrut.
The chopsaw should have a clamp to reduce the risk of the work flying up and hitting you in the face.
I generally line up the blade, raise it, then lower it to cut the unistrut with the blade spinning.

Once last word of advice particularly for this time of year - don't wear a fleece when you're cutting metal on a chopsaw.

 

[Deleted member 26818]

I really can't understand why people are suggesting that abrasive discs are better than a toothed blade?
About the only drawback I can think of with a toothed blade is the cost.
Discs give a rougher cut, wear out, can be more easily damaged, can become contaminated, are a fire risk, are more prone to shattering, require frequent replacement....

 

[Stuuk1]

I really can't understand why people are suggesting that abrasive discs are better than a toothed blade?
About the only drawback I can think of with a toothed blade is the cost.
Discs give a rougher cut, wear out, can be more easily damaged, can become contaminated, are a fire risk, are more prone to shattering, require frequent replacement....

Couldn't agree more, the abrasive wheels are a nightmare! Smoke and sparks everywhere and depending what type of industry/site you are working on you will then be required to obtain a hot works permit each day...

Stick with the wheel with shiny teeth!

Are you sure that the blade was installed correctly? There is an arrow showing the correct direction... If you put it in the opposite way and then cut metal it will instantly rip 90% of the teeth off which sounds like you may have done.

Make sure you also wear ear defenders with your goggles, I suffer occasionally from tinnitus caused only by chop saws when I was an apprentice and thought I was invincible.

When I worked on sites I actually resorted to wearing ear plugs all day long, you can still hear everything perfectly fine but they cut out the tinny noise of yourself and others cutting metal.

Find a video on YouTube of how to correctly put ear plugs in, I never knew there was a correct way, but when someone showed me it is unbelievable the difference it makes!

 

[telectrix]

Find a video on YouTube of how to correctly put ear plugs in, I never knew there was a correct way, but when someone showed me it is unbelievable the difference it makes![/QUOTE]


wow, so that's the correct way. all these years i've been sticking them up my nose.

 

[monkeyelectric]

Just one thing, how the hell do you get them back out? A pair of needle nose?

 

[shanky887614]

went to use pipe fitters chopsaw recently and it had a blade the same size as an angle grinder disk in it.

ah well only wanted to cut 10 pieces of shallow strut so back to trusty hacksaw

will bring chopsaw up 3 floors from van next time i need to chop some.