Anyone tried this yet?
http://www.harborfreight.com/7-1-4-quarter-inch-metal-cutting-circular-saw-8897.html
Looks like it might fit my light duty needs.
Carter
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Dec. 26, 2011 11:28 a.m. erohslc HalfDork
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Dec. 26, 2011 11:58 a.m. ditchdigger Dork
I know electricians that use those for EMT conduit. For rigid conduit they still pull out the portaband.
Just get a Freud Diablo metal cutting blade for a regular circular saw and power through stuff as thick as 1/4"
Here is an example on 3/16" http://www.youtube.com/watch?v=92KA-LgNBUM
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Dec. 26, 2011 12:29 p.m. evildky Dork
for clarification, I believe to be considdered a "cold saw" it has to be liquid cooled
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Dec. 26, 2011 1:01 p.m. Dr. Hess SuperDork
I've cut enough 304 stainless for 2 car frames using a $100 miter saw with metal cutting blades from Lowes or home depot.
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Dec. 26, 2011 10:21 p.m. erohslc HalfDork
In reply to evildky: I'd suggest that in current parlance, any saw that uses cutting blade technology (whether liguid coolant/lubricant is applied to the cut zone or not) rather than abrasive technology qualifies as a 'cold saw'.
Use an abrasive disk saw to cut through 1/2" rebar,and the striking thermal difference will quickly become apparent. ;)For others that have used 'normal' high RPM saws with metal cutting blades, have you calculated the actual toolface cutting speed (SFPM) that the blade tips see?
A 7-1/4 " blade spinning at 4000 RPM yields nearly 7,600 SFPM (!!!!!!!!)
References say recommended SFPM for steel with carbide tooling is up to 600 SFPM.I'm not saying in any way that posted experiences are bogus, just wondering what kind of blade life or tradeoffs to expect.
I know that when I goof up the SFPM calculations for my mill, the cutting results are usually not what I expect.
The hallmark of most commercial coldsaws seems to be gearing that allows the blade to run at low RPM, but with very high torque, to enable the blade tips to function like a cutting tool in a lathe or mill.
The HF unit claims max RPM of 3500, which seemed way too fast. From the exploded diagram in the downloaded product manual, there is no speed reduction gearset.
That's one reason I posted, to see if anyone has realworld experience to share.
Quoted RPM are no-load I'm sure. Maybe in service, the motor is designed to deliver torque when RPM drops due to loading, without overheating.
Carter
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Dec. 27, 2011 7:17 a.m. Dr. Hess SuperDork
The metal cutting "blades" are about five bucks or so and are abrasive, like a big "cut off tool" disk. And to answer your question, no, I didn't calculate the speed at the edge of the blade. I don't care. I just want my stainless parted exactly where I want and with minimal effort on my part. Used it yesterday to cut some 2" square 1/8" wall tubing.
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Dec. 27, 2011 9:25 a.m. Trans_Maro Dork
Dry cut saws use the abrasive blades and rung high RPM.
Cold saw uses carbide tipped blades and low RPM.
If you use a cold saw blade at high rpm, you'll have saw teeth everwhere. The heat tends to loosen the brazing on the carbide inserts, it wears them much faster as well since there is a greater chance of fracturing the carbide.
Shawn
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Dec. 27, 2011 4:01 p.m. erohslc HalfDork
The HF unit definitely uses brazed carbide teeth on a ferrous metal blade, not abrasive.
Hess, I understand that you don't care; results trump theory.
I have an abrasive cutoff saw.
But I'm after different results, that require 'cold saw' cuts.
Anyone have real world results with the HF unit to share?
Carter
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Dec. 27, 2011 9:45 p.m. patgizz SuperDork
i have a brand name one, probably the one HF sent to their factory to copy.
it works awesome. i have cut 2x4 framerail tube, 1/4" thick angle iron, 1/8" diamondplate, and round roll cage tubes. the blades are about $30 for good ones, not sure about HF ones. it makes clean quick cuts that do not build heat like abrasive wheels do.
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Jan. 1, 2012 7:44 p.m. erohslc HalfDork
Thanks PG, do you know what RPM it runs?
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Jan. 1, 2012 9:40 p.m. patgizz SuperDork
3500
