Author Topic: Hacksaw blades for aluminium  (Read 24458 times)

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Offline akisTopic starter

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Hacksaw blades for aluminium
« on: July 07, 2014, 02:20:17 pm »
I am cutting some aluminium heatsinks at home, I have cut one using an ancient mini hacksaw (6") and a rusty blade... Not really a clean cut. What is the best TPI blade to get? I am buying a normal size hacksaw this time 12". Thanks
 

Offline Richard Crowley

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Offline fluxcapacitor

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Re: Hacksaw blades for aluminium
« Reply #2 on: July 07, 2014, 02:28:39 pm »
A fairly course blade will be ok .If you are filing down afterwards rub a bit of chalk on it`ll stop the file clogging up. I use a dremel with a cutting disk ,it goes through aluminium like butter .
 

Offline akisTopic starter

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Re: Hacksaw blades for aluminium
« Reply #3 on: July 07, 2014, 02:36:38 pm »
I just did that. I used my Dremel at around 12K-15K revs, and the cutting disk, on the aluminium heatsink. First, there is aluminium filings/powder flying all over the place, the dremel rotates clockwise, so held with the right hand and away means a lot of debris flying off to the left and into your face. Secondly it did cut the heatsink but there is no accuracy, as you are holding the extension bit with one hand. That is why I gave up on the Dremel and went back to the hacksaw to finish the cut.
 

Offline TerraHertz

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Re: Hacksaw blades for aluminium
« Reply #4 on: July 07, 2014, 03:17:16 pm »
Just so you know, the best tool to cut aluminum is a woodworking drop saw, with a relatively fine pitch and still sharp blade. If the blade has never been warped, and you clamp the metal piece and use the saw's feed slides, moving the cut forward slowly, you can get a really clean cut face that looks like it was milled.

I guess you don't have access to one of those?

Of course, best done somewhere the millions of tiny metal shavings aren't a disaster, can be cleaned up easily.

Lacking a dropsaw, use the coarsest new hacksaw blade that still puts at least 2 teeth across the cut. Squirting some kerosene into the cut, and also when you are filing, makes it go much better.
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Offline DmitryL

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Re: Hacksaw blades for aluminium
« Reply #5 on: July 07, 2014, 09:32:40 pm »

Lacking a dropsaw, use the coarsest new hacksaw blade that still puts at least 2 teeth across the cut. Squirting some kerosene into the cut, and also when you are filing, makes it go much better.

BTW, I found that usual soap soacked to the state of a mild paste works perfect as a lubricant for dealing with aluminium (not for other metals). I use it for taping screw in aluminium alloys and cutting it with a fret saw.
 

Offline MacAttak

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Re: Hacksaw blades for aluminium
« Reply #6 on: July 08, 2014, 03:23:37 am »
I just did that. I used my Dremel at around 12K-15K revs, and the cutting disk, on the aluminium heatsink. First, there is aluminium filings/powder flying all over the place, the dremel rotates clockwise, so held with the right hand and away means a lot of debris flying off to the left and into your face. Secondly it did cut the heatsink but there is no accuracy, as you are holding the extension bit with one hand. That is why I gave up on the Dremel and went back to the hacksaw to finish the cut.

I never could understand why a Dremel does that. Are all of the engineers there left-handed??
 

Offline robrenz

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Re: Hacksaw blades for aluminium
« Reply #7 on: July 08, 2014, 03:31:10 am »
I just did that. I used my Dremel at around 12K-15K revs, and the cutting disk, on the aluminium heatsink. First, there is aluminium filings/powder flying all over the place, the dremel rotates clockwise, so held with the right hand and away means a lot of debris flying off to the left and into your face. Secondly it did cut the heatsink but there is no accuracy, as you are holding the extension bit with one hand. That is why I gave up on the Dremel and went back to the hacksaw to finish the cut.

I never could understand why a Dremel does that. Are all of the engineers there left-handed??

How about putting the part on top of the tool instead of under the tool. Then the debris will be thrown away from you. ;)

If they made a Dremel rotate the other way you would complain that all your drills, saws, burs, etc. don't work. ;D
« Last Edit: July 08, 2014, 03:35:53 am by robrenz »
 

Offline Richard Crowley

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Re: Hacksaw blades for aluminium
« Reply #8 on: July 08, 2014, 03:32:26 am »
I never could understand why a Dremel does that. Are all of the engineers there left-handed??
Probably not. But since drills and burrs work clockwise, making a counter-clockwise rotary tool would make it pretty much useless for drilling or milling, etc.
 

Offline pickle9000

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Re: Hacksaw blades for aluminium
« Reply #9 on: July 08, 2014, 03:34:24 am »
I always use my band saw.
 

Offline David_jones

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Re: Hacksaw blades for aluminium
« Reply #10 on: July 08, 2014, 05:20:49 am »
It's good technique .Good work really helpful for me practically .  :-+
 

Offline notsob

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Re: Hacksaw blades for aluminium
« Reply #11 on: July 08, 2014, 07:38:47 am »
you can also use those 1mm ish thick metal cutting disks on your 80mm grinder and touch up later with a file
 

Offline Psi

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Re: Hacksaw blades for aluminium
« Reply #12 on: July 08, 2014, 07:48:49 am »
Im always cutting extruded aluminium cases on the dropsaw which has a general purpose fine cut wood blade.
It's cut over 100 cases and doesn't show any sign of damage.

Yeah, i know i should get a proper alu blade.
Just saying, any blade seems to work ok for cutting alu because it's so soft.

(However, be very careful grinding alu, because it's so soft it tends to clog up grinding disks/wheels and throw them out of balance. Wheels have been known to shatter when grinding alu with very dangerous results)

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Offline akisTopic starter

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Re: Hacksaw blades for aluminium
« Reply #13 on: July 08, 2014, 08:24:49 am »


How about putting the part on top of the tool instead of under the tool. Then the debris will be thrown away from you. ;)

If they made a Dremel rotate the other way you would complain that all your drills, saws, burs, etc. don't work. ;D

Then I cannot see what I am cutting. It's like asking me to place a loaf of bread over the knife while cutting a slice off.
 

Offline akisTopic starter

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Re: Hacksaw blades for aluminium
« Reply #14 on: July 08, 2014, 08:27:43 am »
Im always cutting extruded aluminium cases on the dropsaw which has a general purpose fine cut wood blade.
It's cut over 100 cases and doesn't show any sign of damage.

Yeah, i know i should get a proper alu blade.
Just saying, any blade seems to work ok for cutting alu because it's so soft.

(However, be very careful grinding alu, because it's so soft it tends to clog up grinding disks/wheels and throw them out of balance. Wheels have been known to shatter when grinding alu with very dangerous results)

Here we call it chop saw I think. I have one, but I would need a special blade, the one on it now is only for wood with perpendicularly placed teeth.  And even then, the heatsinks are too small to be secured properly into such a large tool. I fear on first contact the heatsink is going to fly off.
 

Offline akisTopic starter

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Re: Hacksaw blades for aluminium
« Reply #15 on: July 08, 2014, 08:31:25 am »
I bought a 12" hacksaw and plenty of blades. I also bought a 6" junior hacksaw with better grip than my old "one use only".

http://www.amazon.co.uk/gp/product/B0009VX3DQ/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

http://www.amazon.co.uk/gp/product/B0001GS13G/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

As long as the blade stays true and does not veer off sideways, which is what happened yesterday using my ancient junior hacksaw...
 

Offline SeanB

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Re: Hacksaw blades for aluminium
« Reply #16 on: July 08, 2014, 05:29:57 pm »
I often cut aluminium with either a mitre saw or a circular saw. Tungsten carbide blades and gentle feeding and no issues, except for a single chipped tooth from cutting some chipboard with a hidden nail in it. Need to clean the blade after use and oil it as well, but as I do that anyway it is no big issue. On thicker items I tend to first use some cutting wax on the teeth for the initial cut.
 

Offline KJDS

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Re: Hacksaw blades for aluminium
« Reply #17 on: July 08, 2014, 05:41:04 pm »
Use an axe, just swipe through it with one big swipe. If if won't go through in one swipe, use a bigger axe. :)

Offline akisTopic starter

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Re: Hacksaw blades for aluminium
« Reply #18 on: July 08, 2014, 05:58:41 pm »
Interesting idea. But my accuracy with the 3-4 foot axe is terrible. I have been chopping wood for years now and it does not get any better.
 

Offline SeanB

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Re: Hacksaw blades for aluminium
« Reply #19 on: July 08, 2014, 06:15:36 pm »
I do not have an axe easily at hand, but the 14lb Widlariser is within easy reach. A few strokes of that and you tend to have at least 2 pieces.
 

Offline DrJoe

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Re: Hacksaw blades for aluminium
« Reply #20 on: July 08, 2014, 07:18:33 pm »
I always use my band saw.

Bandsaw is the way to go. Even a table top model will have far more uses than you can imagine. Great on plastic, aluminum, tubing, and even wood.
 

Online Monkeh

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Re: Hacksaw blades for aluminium
« Reply #21 on: July 08, 2014, 07:44:09 pm »
Im always cutting extruded aluminium cases on the dropsaw which has a general purpose fine cut wood blade.
It's cut over 100 cases and doesn't show any sign of damage.

Yeah, i know i should get a proper alu blade.
Just saying, any blade seems to work ok for cutting alu because it's so soft.

(However, be very careful grinding alu, because it's so soft it tends to clog up grinding disks/wheels and throw them out of balance. Wheels have been known to shatter when grinding alu with very dangerous results)

Here we call it chop saw I think. I have one, but I would need a special blade, the one on it now is only for wood with perpendicularly placed teeth.  And even then, the heatsinks are too small to be secured properly into such a large tool. I fear on first contact the heatsink is going to fly off.

It won't go flying anywhere if you hold it (if it's big enough to do that safely!). A normal fine wood blade won't have a problem with alu.
 

Offline Paul Moir

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Re: Hacksaw blades for aluminium
« Reply #22 on: July 08, 2014, 11:16:36 pm »
If cutting with a circular saw of some sort, make sure you wear ear defenders & safety glasses.  It's very loud and angry aluminium bees fly everywhere.  Also if you use a wood cutting blade, select one that has little or no rake to prevent the work getting pulled into the saw.  The blades made for cutting aluminium have a bit of a negative rake so they don't suck in at all.  Naturally it will need to be carbide tipped saw blade.
It leaves a very nice finish and is extremely quick.  But if it's a small job then a hack saw works great with less mess. 

 

Offline Psi

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Re: Hacksaw blades for aluminium
« Reply #23 on: July 09, 2014, 10:31:29 am »
It's very loud and angry aluminium bees fly everywhere. 

haha, yeah, it does kick out chunks of alu everwhere
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Offline krivx

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Re: Hacksaw blades for aluminium
« Reply #24 on: July 09, 2014, 10:36:35 am »
If you use fine abrasive cutting (like a high-speed dremel) be careful with the dust. Apart from screwing with your lungs it can clog in the wheel if you cut enough of it. If you get enough of it in the air apparently you can cause dust explosions but that's probably not an issue for a hobbyist cutting small amounts.
 


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