How to cut aluminum w/miter saw?

bulkhead · 2005-12-20 06:23

I have a miter saw, and I'd like to cut angled aluminum with it. The aluminum ranges from 1/16" to 1/8" thick, basically what can be purchased at Home Depot or Lowes. I've done some research, but I'm still not clear on what type of blade I need. I don't really want to spend a lot of money ordering a nice blade online, since I will probably only occasionally make some cuts (its not for daily, industrial usage). What should I look for when purchasing a blade? Number of teeth? Material? (

I've looked, and it seems that www.sears.com has the best/lowest price selection on miter saw blades. There is a Sears, Home Depot, and Lowes near me, so a blade from any of those would be ok. It would be great if someone could recommend a blade, or just provide some general info or experience on this. The saw I have is craftsman brand, and accepts a 10" blade (if that matters).

Thanks.

300c_Pilot · 2005-12-20 08:34

Cutting metal with a wood miter saw (toothed blade) is dangerous because it is high rpm where a metal saw is low rpm. Only use a rated abrasive blade. A metal shop can set you up.

steve_b · 2005-12-20 11:53

Carbide blades are good for steel...but aluminum is softer and doesn't give a clean cut.

Like 300c_Pilot said, if you can't slow your blade down, then use a hacksaw or a metal bandsaw.

We picked up a metal cutting blade for our table saw, and we do cut aluminum on it, but we aren't after accurate cuts, and we tend to have to 'clean up' the cut ends quite a bit!

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Steve

"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."

SN96 · 2005-12-20 13:38

A fine pitch carbide blade feed at a slow rate can give a fairly clean cut. I have used a compound miter to cut aluminum square tubing with 1.5 mm thick walls with no problems. As a side note: the faster I feed the blade through the material, the "rougher" the cut was.

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Mike

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C.Moher · 2005-12-20 19:20

Finally...a question I can answer...

The rule of thumb is that you must always have 3 teeth in contact with your material. Otherwise, you run the risk of ripping the teeth off your blade. Use an abrasive disk for material that thin. If you do go with a fine toothed blade, angle it in such a way that you have maximum material in contact with the blade...ie with anglular material place the two edges down so it looks like an upwards pointing arrow ^. Previous posts are correct about cutting speed. Mitre saws run at high rpm so your blade will tend to overheat on metals. You should be ok with aluminum with a rest in between cuts. You won't have any of these problems using an abrasion disk. Irregardless keep it edges down to avoid chatter (excessive vibration).········ vice jaw[noparse][[/noparse]^]vice jaw

Charlie Moher

Journeyman Machinist

bulkhead · 2005-12-20 20:46

Ok, thanks for all the replies. I don't really want to purchase the saw and blades for cutting metal, because I only need to cut aluminum which is much softer and thinner than what most people cut with metal-cutting saws. A rougher finish on the cut is fine, I could just grind or file it down. I mainly want to use the miter for quick, straight 90 and 45 angle cuts, which I now have to make by hand using a hacksaw and then filing off material until the angle is right.

SN96, what type of blade did you use to cut that? How many teeth do you mean by "fine pitch"?

So, if I understand it correctly, I should use a blade with MANY teeth so that at least 3 may be in contact with the thinner aluminum material? I found a 10" blade with 200 teeth (it says its a finishing blade for plywood) and several blades with between 80 and 100 teeth-why is there such a large jump, from 100 to 200 teeth? Would a blade with that number of teeth work for aluminum?

If I get an abrasive blade, will my miter saw be too fast to use it? It doesn't have variable speed. Are there other precautions I must take if I use an abrasive blade on a wood miter saw (I will be cutting aluminum only)?

C.Moher, thanks for the tips on how to place the aluminum on the saw, I'll keep those in mind.

One last question-How do I use lubrication during the cutting? What's the difference between using stick wax and a fluid like WD-40? Do I lubricate it differently if I use a toothed blade or abrasive blade?

Thanks.

Robert Kubichek · 2005-12-20 21:01

bulkhead said...
Ok, thanks for all the replies. I don't really want to purchase the saw and blades for cutting metal, because I only need to cut aluminum which is much softer and thinner than what most people cut with metal-cutting saws. A rougher finish on the cut is fine, I could just grind or file it down. I mainly want to use the miter for quick, straight 90 and 45 angle cuts, which I now have to make by hand using a hacksaw and then filing off material until the angle is right.

SN96, what type of blade did you use to cut that? How many teeth do you mean by "fine pitch"?

So, if I understand it correctly, I should use a blade with MANY teeth so that at least 3 may be in contact with the thinner aluminum material? I found a 10" blade with 200 teeth (it says its a finishing blade for plywood) and several blades with between 80 and 100 teeth-why is there such a large jump, from 100 to 200 teeth? Would a blade with that number of teeth work for aluminum?

If I get an abrasive blade, will my miter saw be too fast to use it? It doesn't have variable speed. Are there other precautions I must take if I use an abrasive blade on a wood miter saw (I will be cutting aluminum only)?

C.Moher, thanks for the tips on how to place the aluminum on the saw, I'll keep those in mind.

One last question-How do I use lubrication during the cutting? What's the difference between using stick wax and a fluid like WD-40? Do I lubricate it differently if I use a toothed blade or abrasive blade?

Thanks.

Besides having a finer pitched carbide blade, use a piece of scrap wood on both sides of aluminum, as it makes it easier to hold/position/cut piece, and is much safer...
The tip to place the piece angle up is only good if you cut a square cut.... Any other cuts use a wood sandwich for safety...

Bob N9LVU

kogerat · 2005-12-20 22:46

Hi Bulkhead,

In a past life, I worked in a shop where we cut aluminum truck frames to either lengthen or shorten them. We used a Skill saw with a combination rip-crosscut blade and lubed it up with beeswax. The cuts had to be debured, but made good square cut if you had a steady hand. If you are cutting aluminum angle in a miter saw, I would think you shouldn't have much problem. I wouldn't use a blabe with too fine of teeth because aluminum is soft and will build up between the teeth and just create heat with littile cutting. This is also what the beeswax is for, lube·plus it·keeps aluminum from building up on blade. If you can't find beeswax, toilit seal rings used to seal toilets to the sewer pipe are·made of beeswax and are sold at most hardware stores.·I would be leary of an abrasive blades. Unless they are made for use with aluminum, the soft aluminum will lodge in the abrasive and swell with the heat generated by cutting and the blade could explode. Could be ugly. Hope this helps.

Jim K

Paul Baker · 2005-12-20 22:53

Beeswax can also be purchased in arts and craft stores that have candle making supplies. I saw a huge chunk in Micheal's just last weekend.

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C.Moher · 2005-12-20 23:59

I just read the specs and warnings for the NorZon 3X abrasion disk. It does not make any mention of any prohibition of non-ferous metals. The point about it clogging up is well taken though. But, I can't see that happening at high speed with thin metal. If it did clog up and explode, it would make a great law suit ! They are less than $10 I think and are sold at Home Depot. Sorry, I thought you had a fully indexed head and slider, if not then yes you would have to clamp it with a block of wood for angular cuts, but, avoid contact between the wood and disk.
Don't nic the disc with any sudden hits on the material or its done.

Tracy Allen · 2005-12-21 00:06

IHere is one entry in 'Norman Yarvins Usenet archive on metalworking...
yarchive.net/metal/aluminum_sawing.html

Back up a couple of levels at that URL and link to all sorts of information that the sponsor took as the "best of" answers in a few areas of interest.

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Tracy Allen
www.emesystems.com

C.Moher · 2005-12-21 00:08

Norton (Norzon), SAIT, Flexovit and 3M Green Corps
are all good makes of abrasion disk....buyer beware on cheaper brands.

C.Moher · 2005-12-21 00:36

sorry...I almost forgot...you do not use lubricants or coolant with abrasion disks.

Your cut end will be painfully hot for 10 minutes after cutting. Don't touch it !!

knightofoldcode · 2005-12-21 02:07

I don't know much about cutting aluminum, but I have cut a piece of steel with my wood miter saw. I just used the abrasive disk, clamped the metal to the chopsaw, and slowly cut the metal, I stopped the cutting for about 30 seconds for every 1 minute of cutting, just to make sure it didn't get too hot. The metal was a steel piece of metal used for rack mount devices. It was the actual rack mount rails, for a custom cabinet project for my webpage servers, and other computer servers.

The metal as mentioned above was very hot after the cut, however after 10 minutes of cooling, the cut quality was almost perfect. The saw was a 10" blade miter chop saw from Delta. About $100. The saw blade was the abrasive disc, and was around $10. Both were purchased at Lowes at different times.

I campled the steel to the bed of the chop saw for two reasons, one, it wouldn't move obviously, and make a cleaner cut, and two, even if it got hot, which it did, I wouldn't let go from the heat. [noparse]:)[/noparse]

I would assume Aluminum would be almost the same, but it'd cut faster.

I would think that a cut with a wood blade on metal, would be VERY dangerous..... I woudn't suggest it, under any circumstance.

Knight.

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StarMan · 2005-12-21 03:28

I have a DeWalt 12" miter saw that came with a 60 tooth carbide tipped blade.· I use it for wood, aluminum, and all sorts of plastics.· I've cut all sizes of aluminum from very thin pieces·to fairly large (3" x 6") cross sections.· I've never used any lubricant and the cuts always come out nice.· A little deburring is sometimes required.· I've had the saw for about four years and never changed the blade.· It still works great.

For deburring, I would suggest getting a deburring wheel that attaches to a bench grinder.· They run about $30 to $40.·

Chris I.

knightofoldcode · 2005-12-21 03:38

I've cut all kinds of plastics as well with my chop saw and had excellent results. Especially with PVC pipes. Both for Electrical and for water pipes. That works almost better than wood. [noparse];)[/noparse]

I only change my blade for plywood and metal.

Knight.

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This message transmitted with 100% recycled electrons.
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How to cut aluminum w/miter saw?

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