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Cutting sheet aluminum on tablesaw

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  • Cutting sheet aluminum on tablesaw

    I read several times about cutting aluminum sheet/plate on the tablesaw with a carbide blade. Now, is this a good idea? Is it safe?

    At the speeds a table saw runs, swinging a 10" carbide tipped saw blade. If this is done then what's the safe way to do it.
    What the thickest plate you would cut, how many teeth on the blade, any particular brand of blade?
    I'm thinking kickback would be nasty.

    Kevin

  • #2
    Brunneng, I do it all the time. Just finished two custom radar masts with all the fixens for lights, horns, antenna's and tangs. 4 inch sched.40 alum pipe, .25 alum. plate with a small bit of .5 plate as well. The carpenters go nuts when they see me do it until they realise I have my own blade on the saw.Most of the time I use a 7.25 in. Dewalt thin kerf finnish carbide blade altho most any carbide blade will work.I also have a 12 in.dewalt blade for heaver stuff but rarely use it. You don't need any wd-40 or the like as long as your saw is dialed in and you take it slow.Kick-back has never been a problem with me but I always wear gloves,complete face shield, long sleve shirt and safty glasses. I saw a carbide tooth embed itself in a workers hand once from a skill saw so I never take a chance.Make damn sure the saw guards are in place!!!! Good luck Dave

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    • #3
      Kevin - Is this a good idea? Well not compared to pulling out the plasma cutter or press shear but if you don't have one then...well yes it's doable. As a mater of fact it's pretty common in a lot of trades. I've seen table saws dedicated to this purpose for sale at Boeing Surplus and at other tooling and pattern shops. I have done this operation myself on occasion. It is realativly safe with proper precautions but it is realativly more dangerous (and less presise than other operations in the wood or metal shop because you're dealing with higher cutting forces on a workpiece that is not clamped down. It can be a mess because of the chips so be prepared for a lot of clean up. A lot of heat coupled with fine chips can lead to an aluminum fire so be careful the chips aren't forming into a concentrated pile. Also make sure the area is clear of wood dust, clean the cabinet out compleatly and disconect the dust collection if so equiped. As long as the heat's not building up there's no great risk of fire but take precautions. The blade should be a moderatly high pitch (60 teeth for a 10") with modereate rake. A triple chip blade seems to work well but a combo blade is fine. The blade should be sharp to reduce heat and HP requirements but don't use a blade you're planning on doing precision cuts with again. A blade with an anti-kickback tooth design is a good idea since it will limit overfeading the material and damaging a tooth. Inspect the blade first to make sure there are no chiped teeth, If one's going to fly off the higher loads are going to make it fly off now. Kickback can be reduced by raising the blade higher than normal so that cutting forces or directed more into the table than back twords the operator. Be sure the gaurd and splitter are in place with more blade exposed. The higher blade will also reduce the number of teeth in the cut and again reduce load. Have someone else there with you in case the blade does jam to shut off the machine. It's no fun wrestling an angry saw with one hand and reaching for the kill switch with the other. (wich has now shrunk to half its size and moved just out of reach when you realy need it)

      The accuracy of the cut will be no better (and possibly worse) than that for cutting wood (+/-1/32")so expect to do some clean up with a file. As far as thickness of stock, limit yourself to aluminum plate (1/8" to 1/2") for alluminum sheet you can find a finer piched blade but consider using a band saw or reciprocating saw.

      If you have a band saw available with the capacity you need consider making the rough cut with it and bringing to final dimension with a 1/2" router running on a fence.

      This is very do-able but it's not like ripping a 2x4 either. Think the process through first and test a small piece first. AND DON"T WEAR GLOVES AROUND THE TABLE SAW!

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      • #4
        One more thing (applies for all sawing opperations): Don't stand so that you're sighting down blade as it's running. That's the path that a loose tooth or chip is going to take if it comes off.

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        • #5
          Thanks guys,

          I do have a small metal bandsaw and the first thing I wanted to do was to cut some .5 al plate to size for a table to use on it to cut the rest of the metal on the bandsaw. So size isn't that important for this one.

          Wish I had a plasma cutter or shear.

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          • #6
            I have cut aluminum on a tablesaw many times and so long as you pick a good quality high tooth blade with a slow feed you should be okay cut it like you would any hard wood. Watch out to clean up well afterwards as it leaves tiny fragments which must be cleaned away if you go back to cutting wood.As far as kickback is concerned the main reason for kickback is either careless feeding,or when the sawblade is cutting, and the stock being cut is twisted or moved during cut,or not applied to the blade when flat on the table, or that when cutting say twisted ,wet, or damp, timber with a saw without a riving knife and the damp or twisted timber which does not sit on the table properly closes behind the blade after the initial cut is commenced throwing it back at you.
            To more fully understand how or why it does this you should understand how a blade functions.If you look at a stationary blade from the side ie crouch down at the side of your saw with the machine preferably off, raise the blade to full height to look at it during this excercise and look at it carefully, draw an imaginary line down the centre of the blade top to bottom,I E seperating it front from rear you will see that , the first half of the blade I e the half of the blade towards the front of the saw when spinning ,(Assuming as the blade is spinning in the correct direction) IE towards you as you stand at the front of the saw (actually you should always stand to the side a little in case of kickback) will push down the stock in the direction of the table as the blade is revolving in this direction. When the stock passes the halfway point of this imaginary line towards the back half of the blade you will notice a sudden change as the tendancy of the blade will be not to push the stock down but to lift it up in the direction it is going.So long as the blade is not hindered i e does not make contact with this rear portion as it is revolving helped by a riving knife being in position which should be just slightly thinner that the kerf of the blade in use,kickback should not be a problem as the kerf will produce a slot big enough to clear this part of the blade before it passes this point.Obviously as said the chances of kickback are greatly increased if the stock wanders or twists during cutting so a fence is very important and it should be fed slowely being pushed slightly towards the fence to avoid twisting or moving during the cut.
            Also I would not advise anyone to try to cut very small pieces on the tablesaw in aluminum.Better to cut sheet stock as I did I cut 3/8th stock with a ten inch blade with about 68 teeth tungsten or more actually you can buy blades specially designed for this .When setting upjust leave just a little of the blade exposed above the thickness of the material about a few millimetres below the gullet of the blade,I E so that the only part of the blade showing during the cut is the tips and gullet below the cutting teeth plus a little more say a few millimetres,dont raise the blade any more than this as it is unsafe. This should also reduce the likelyhood of lift.I hope this is clear.If you feel nervous about it leave it alone and use a small jigsaw /sabre saw with a fine metal blade.Alistair
            Please excuse my typing as I have a form of parkinsons disease

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            • #7
              No, I'm comfortable with using the saw (been using it for 20 years) just never on metal. I'm familiar with the technology/safety procedures, etc... I know you don't know that about me however... and you never know about who else will read this.

              I figured you'd cut it similar to expensive high density plywood. Minimal exposure of blade above material to limit blade rub and tearout of surface from the rising back teeth.

              Believe me, I respect the power of a tablesaw. I've seen 2x4's thrown through a wall when ripped down the middle.

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              • #8
                brunneng:I'm a woodtick by trade but have cut alum sheet on my table saw on occasion.For a few cuts any carbide blade will work--be absolutley sure you have control of the work piece and use a slow feed.
                Dave:I understand your theory about raising the blade to force the cut towards the table,but I feel this creates more surface area on the blade to launch a kickback.I cut with the tip of the tooth barely above the surface.
                Alistar:I agree on not cutting short pieces.My motto is "Short pieces make short fingers"
                Kick back is a nasty thing on the table saw.My most memorable one was a 26" piece of 2x6 to the nose.Between the unique pain and handfulls of blood I had to figure out if my nose was still on the front of my head.All I ended up with was an embossed woodgrain bruise.
                And yes,carbide teeth do come off some times---I caught one with my safety glasses once.
                Rich

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                • #9
                  Always on aluminum run the blade all the way up!Never with the minimum exposed,with the blade up the sawteeth arc down to the table on a high angle there by reducing kickback and lift up if you are worried about the top of the blade being exposed cover it with a gaurd suspended from the ceiling if lift up is a problem attach an ajustable hold down roller or feather board.If you make the cut at a low blade projection the force of the cut is directed at you instead of down against the table.I saw 3/4"plate routinely in this manner with no problems.It also helps to give the blade a shot of wd-40 or similar before every cut.As for kick back be sure and adjust your fence perfectly parallel to the sawblade.Also a sharp(new)blade is a must.
                  I just need one more tool,just one!

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                  • #10
                    I've cut aluminum sheet,angles and bars on both my 10in.Dewalt radial arm and tablesaw.Both do a good job. Wear ear protection and eye protection. It's really noisy and like everyone says it makes a mess. But if your saw makes smooth cuts on wood,it'll do the same with aluminum.On the radial arm,I clamped the material down. On the table saw,be sure the material doesn't slip under the fence.Try some parafine on the saw blade.

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                    • #11
                      I'm a patternmaker currently and my last job was at a very high end custom cabinet (read built in furniture). Worse case of kickback I know of (wasn't there at the time) was on a 14" Altendorf. The forman in the production half of the shop was missing a couple of fingers. Not from the blade, but when the board he was ripping kicked back it hit him in the hand taking his fingers with it on its trip across the shop where left a bloody dent in the wall.

                      Rich, while raising the blade higher above the work does increase the dangers assosiated with the exposed blade, it definetly reduces the area the blade cutting through. Think of it this way: the shortest distance through the material is perpindiculer to the surface. As the angle of the cut becomes shallower, the linier distance from the front of the cut to the back of the cut is increased. Keep in mind that I'm talking about the area were actual cutting is occuring, not the leangth of the blade in the kerf. If the blade has a decent amount of relief and the fence is adjusted parallel to the blade, lift from the rear half of the blade is negated. Additionaly, if the splitter and guard are in place the increased danger of an exposed blade is minimised since they will be covered.

                      This advice is specific to the situation in the original post. For wood cutting I place the blade so the gullets are fully exposed but no higher. Note that the risk of kickback is higher with wood which twists and binds as it is cut.

                      -Dave

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                      • #12
                        Dave:Just relating what has worked for me in the past.I'll try it your way next time though.I still say control of the work piece is paramount though----no matter what the tool.
                        Rich

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                        • #13
                          No argument there.

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                          • #14
                            I have been thinking about a rubber tire with a sprag clutch inside to eliminate kickback totally ,woodworking has a similar set of kick back rollers made out of green plastic and they seem to work pretty good.I figure a go cart tire fore and aft ought to do it and you could adjust the air pressure for hold down force,just a tought.
                            I just need one more tool,just one!

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                            • #15
                              For what kind of machine/operation?

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