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Cutting Aluminum Sheet/Plate
| Gone Away | 21/07/2010 00:53:44 |
| 829 forum posts 1 photos | Well .... I finished cutting out the plates with the jigsaw. I left them a fair amount oversize since the finish is a bit rough and not very straight even with a guide fence. I then considered how I'd mill the edges to finish them. The table travel is only 10" so it would need two setups for each edge. Plus I could foresee difficulty clamping as the plate would have to hang over both the front table edge and one end. After briefly considering using a router table with a milling cutter in the router and a speed control (I've seen it done), I thought "what the heck" and decided to try trimming the sides on the tablesaw after all. And it was fine - no grabbing or kickback. On some sides I took a minimal just to straighten them using one edge only of the saw blade. On other sides I needed a full cut using both blade edges. In either case, I experienced no problem and now wish I had done everything on the tablesaw from scratch. It might have been a little more difficult working with the full size sheet but I think it would have been OK. I used the blade that was already on the saw (10" 60T 1/8" kerf - nothing special) with minimal tooth penetration through the material. I cut through the plastic protective film on the sheet and used no lubricant. I "cringed" rather less than I would cutting particle board. I wore a full face shield (and sheet metal gauntlets) but there were no flying chips anyway. So, yes, it can be done and thanks again to all. Edited By Sid Herbage on 21/07/2010 00:55:58 |
| Billy Mills | 21/07/2010 01:16:10 |
| 377 forum posts | Sid, do your metal cutting jigsaw blades have a wavey form? there are plain sided blades and wavey ones which cut a wider kerf for clearance. The wavey ones do not jam as easily and will produce curves easily. ( same as hacksaw blades) Never had a problem with the protective plastic film. Some people have used candle wax as a blade lube for soft Ali which does tend to bind up more than other metals. Have used a Makita electric nibbler quite a bit to open up complicated holes in PC cases. Very handy tool that saves hours but the crescent shaped swarf is an absolute B****D as it is very sharp, but the swarf is large and better than steel dust in this application. The JN1601 nibbler is the stepped oscillating shaft in slotted cylinder type which limits the thickness to a safe value for the tool to be 1.6mm so too small for Sid's job. There is another type with a tooth and two fixed faces which will accept thicker work and is often air powered, again very useful. If you clamp a bit of angle against the job and guide the nibbler against the angle you can produce a fair straight cut instead of the drunken walk job. Nibblers can mark the surface as -especially the single tooth type- put the shearing load onto the Operator side of the sheet. Same as a jigsaw but the shear is much greater. Regards, Alan |
| Gone Away | 21/07/2010 01:52:58 |
| 829 forum posts 1 photos | Hi Alan, They are wavy but not a lot - more due to tooth set really. They are Bosch T118B see: One of the problems with using a jigsaw is that the blade itself is so flexible and not particularly well guided (at least on this jigsaw). Once it starts curving off, it's hard to control. The sheet is also somewhat difficult to clamp. Cantilevering over the edge of a bench gave me a lot of vibration of the sheet. I ended up clamping it to both jaws of a B&D Workmate (one of the original British cast aluminum (or aluminium I guess) jobs. I had to clamp the jaws first onto a piece of 1" bar at each end to take the play out of them and at that they weren't precisely level. Partly because of that, I also had some difficulty clamping a fence tightly enough to resist the side force of the jigsaw when it started to wander to one side. All in all, as I said in my previous message, I'd have been better going with the tablesaw from the start for large pieces like these. |
| Lawrie Alush-Jaggs | 21/07/2010 12:51:15 |
 118 forum posts 32 photos | Hi Sid
I wrote an article about this topic last year and submitted it to the Editor of MEW for publication. As it hasn't appeared, here it is without the pictures.
In summary, go and buy yourself a cheap electric saw and put an either put an aluminium cutting blade in it if you are going to do this on a reqular basis or if it is an occasional thing, just use the TC blade that comes with the saw.
Cutting large pieces of aluminium
In issue 151 of MEW Dave Fenner talks about the difficulty he had cutting large pieces of aluminium for his metal mangle and suggested that someone might like to address the problem with an article. I am not sure that it will stretch to a full article but here is some of my experience. Some years ago a mate of mine bought a bank building when the Australian Banks were going through one of their “To serve you better” phases and shutting down loads of branches. The bank took out everything that wasn’t bolted down and left everything that was. Everything that was included all of the bits protective stuff that they put in, the shutters, heavy office panelling and the like. The idea according to one of the designers I spoke to later was that the staff should be in an area that was mortar proof. To that end the shutters are 10mm armour plate. The panels for the Manager’s office are 16 mm bullet resistant aluminium plate with a 6mm air gap and then another sheet of 6 mm bullet resistant aluminium. Needles to say I am quite well endowed with 16mm and 6 mm aluminium plate as well as huge barbecues of 10mm armour plate. I wanted to build a multi-purpose saw/router/planer bench. I had had a Triton for over twenty years and never been entirely satisfied with it. I decided on a single plate 900mm square x 16mm thick. I needed to cut it to size, square it all up and then cut a hole with a rebate in it to take a piece of 6 mm plate. This was before I had a milling machine or a lathe bigger than a Unimat SL. I made the beast and it works like a charm. The router bolts onto a plate and drops into the hole. Similarly the 9 1/4” circular saw and the 75mm Makita planer. This is what I found out about cutting large pieces of aluminium and the tools I tried. 1 Hacksaw 2 Jigsaw 3 Reciprocating saw 4 Circular saw 5 Band saw 6 Abrasive disk 7 Water saw 8 Router
Test method I tried cuttibng with each tool except the router and water saw. I don’t have any aluminium router bits at present and I also do not have a water saw. I laid a piece of 900 mm wide 16mm bullet resistant aluminium plate on a pair of saw horses and with my daughter manning the timer cut with each tool for a period of one minute. You can see the results in photo AC1 and AC2. The cuts from bottom to top are as per the list in table 2 |
118 forum posts 32 photos | Hmm
That was a paste directly from Word. This time I'll try it from Notepad..
Cutting large pieces of aluminium In issue 151 of MEW Dave Fenner talks about the difficulty he had cutting large pieces of aluminium for his metal mangle and suggested that someone might like to address the problem with an article. Test method Lubricants Hacksaw. |
| Lawrie Alush-Jaggs | 21/07/2010 12:55:39 |
118 forum posts 32 photos | Jeez. What a pain.
Let me try the next bit. This is a bit ordinary.
I'll post the next bit in another post
Different makes of blade can make a difference. Starrett fairly recently introduced some new hacksaw blades that use a different system of welding to other manufacturers. I have a stack of Sandvik Bimetal blades in various tooth numbers that I purchased many years ago. The difference between the Sandvik and the Starrett is almost but not quite like the difference in cutting brass with a carbon steel blade and a standard Bimetal blade. Reciprocating saw Bosch makes a range of blades for the reciprocating saw. Not as extensive a range as for the jigsaw but none the less rather good. Taking into account what I said about accuracy there are times when you just have to make the cut. I had a block of 200 x 100 x 100 ally that I wanted to cut in half. The jigsaw was not going to do it and neither was the sliding compound mitre saw. I didn’t have a band saw at the time so it fell to the reciprocating saw to do the job. The same shop I bought the jigsaw blades from –Total Tools- also sold reciprocating saw blades. I bought two types, the S1411DF (top in photo 6) and the S711DF (middle in photo 6). The S1411DF is a 300mm 6TPI blade designed to cut wood and aluminium sections of up to 60mm x 5mm wall. The S711DF is a 150mm x 6TPI blade which is designed to cut the above and epoxy products from 8 to 50mm. The third blade in photo 6 is a Makita P-04905 24 tooth. It is handy for stirring drinks and filling up your tool box. |
| Lawrie Alush-Jaggs | 21/07/2010 12:57:32 |
118 forum posts 32 photos | on them so they tend to slice rather than chisel at the material. The proper lubricant to use with these blades is a sterate/paraffin wax. It is available from larger hardware stores and tradies tool suppliers in cardboard wrapped stick form. Although it looks like candle wax it is a different formulation. I am told that they are not interchangeable though when I did this test I used a $2.00 garden candle and it cut without a problem. The wax is applied to the blade before cutting and prevents aluminium chips from sticking to the face of the tooth. Incidentally, a dab of wax on a linisher belt helps minimise clogging when sanding Aluminium. For cutting sheet aluminium you can buy a Record-Irwin blade in just about any blade size to suit the most common hand held circular saws. As with all operations in this article you really do have to use correct safety gear. I am not being a nanny about this. You have to use hearing protection because a circular saw cutting aluminium howls like a banshee and will knock the top 5 kHz off your hearing double quick. You also MUST wear eye protection because the saw will spit out little bits of aluminium all over the place. Getting aluminium out of your eye is more difficult than steel swarf because it is not magnetic. For sheet work use a hand held circular saw or a table saw. For cut off work try using a mitre saw with the work clamped. In both cases the finish is superior to any of the other methods here. If you want to get the job done today then use a circular saw. If you want a contemplative monastic experience then use the 24 tooth blade in the reciprocating saw. Use feel to determine the best feed rate. Better a little slow than too fast. Band saw I really like using a wood workers bandsaw for aluminium. It is fast and fairly accurate. I use the bandsaw for rough slitting of clamps and the like then finish off with a slitting saw because it is just so much quicker. Almost any profile roughing work is performed faster on a bandsaw. The blades are nothing special, just a standard spring steel bandsaw blade. The normal three teeth rule applies as it does to the jig and reciprocating saws. At least three teeth have to be in contact with the material to avoid blade damage or damage to the work. Given the three tooth rule, the thinner the material the greater the number of teeth required. For thick material I use a ten tooth blade and for general cutting a fifteen. The blade speed is about 300 SMPM or 1000 SFPM. Cutting speed is generally less than you think. It is important to let the saw do the work and take a light cut. If you press to hard you will end up a number of problems • Uneven tension. The bottom of the blade will be under greater tension than the top allowing the top to flex and make the cut deviate. • Clogging of the gullets will cause the blade to jam and possibly break the blade or polish the rubber of the tyres which means less grip on the blade requiring greater tension which leads to • Blade breakage. Use no lubricant or you will make a mess of the tyres. Photo 8 shows a fifteen tooth 1/8” blade that will cut a minimum radius of about 3/8” in aluminium. It will cut a tighter radius but you start generating a lot of heat in the blade which just does it no good. When using a wood workers band saw for aluminium it is very important to ensure that you have it set up correctly. The blade must be tensioned fairly tight. The blade must be tracking accurately on the wheels. The guide blocks or bearings must be adjusted correctly and the top guide must be as close as possible to the work. The very best book available on setting up a band saw is Mark Duginski’s Band Saw Handbook. Abrasive disk Dave mentions trying a metal cut off wheel and finding that it clogged rather than cut. Pferd, Flexovit and several other manufacturers make aluminium abrasive cut off wheels in the normal sizes. They are of a special non loading construction. They are used in the same way as steel cut off wheels. For occasional use I think they are excellent. They have a longer life than their steel cutting counterparts. (photo 9 – courtesy Pferd. www.pferduse.com) As mentioned in the safety section, use a face mask to avoid breathing in the aluminium powder. Water saw |
| Lawrie Alush-Jaggs | 21/07/2010 12:57:51 |
118 forum posts 32 photos | If you are getting serious and need a lot of complex, thick parts cut then water saw is the way to go. A water saw squirts a thin jet of water at 50,000-60,000 PSI out of a nozzle at your work. The work is fairly relaxed about this gives up the struggle. Garnet dust can be injected into the stream to make the stream more abrasive. Water saws can cut pretty much anything from sponge cake to 125mm thick granite to hardened (63 HRC) steel. Although there are versions that allow for freehand cutting the ones you are most likely to come across are CNC. Google for your nearest operator. Router If you have a 1500 watt or greater router you can use that for cutting large chunks of aluminium. A number of manufacturers make solid carbide spiral router cutters. Two patterns are available, a spiral up cut and a spiral down cut. The up cut tends to pull the router down on to the work and the down cut tend to push it away. The up cut relies on having a very good quality accurate undistorted chuck so that the cutter does not pull out. The up cut deposits chips on top of the work. This is important if you are making a blind plunge cut. Having the swarf deposited on top of the material means that unless you have effective dust extraction you run the risk of trapping swarf under the router sole plate with the concomitant tendency to damage the surface. Down cut deposits swarf behind and below the material. This is okay if your cut has an open end or if you have completely penetrated the material. A 1500 watt router running at full speed – about 20,000 RPMs will allow you to take ½” wide cuts about ½” deep. A CNC router will take a deeper cut but it is better braced than you will be. My experience is that you can take a ½” x ½ “ cut if the router is firmly pressed against a well clamped straight edge but only for as long as you are properly balanced. If you have to reach past your safe balance point the router will take off and wreck the job and maybe you too. The actual cutting depth and feed rate is dependent on the cutter so check with the manufacturer. Be very careful NOT TO CLIMB MILL. It will take off on you and wreck everything, quite possibly including you in the carnage. An out of control router is like the Tasmanian Devil in Bugs Bunny cartoons. If you are not familiar with routers then I suggest you do not use one for this work. They can be really dangerous. You can also get solid carbide burrs that are designed for aluminium. Generally they are ¼” shank. Fitted to a die grinder they are sensational for free hand sculpting and rapid metal removal in aluminium. Be very careful. |
| Lawrie Alush-Jaggs | 21/07/2010 12:58:07 |
118 forum posts 32 photos | Material to cut: 16mm aluminium plate of no particular grade *Effectiveness is whether you can cut complex shapes and the ease with which the job is done |
| Lawrie Alush-Jaggs | 21/07/2010 12:58:26 |
118 forum posts 32 photos | Conclusion My suggestion is to estimate what other use you can get from the various tools listed here. As metal workers you probably already have angle grinders so for occasional use buying cut off wheels makes sense. This article is about thick section material and although the 100mm grinder did work it is really underpowered and too small for the job. The 230mm wheels cost just twice as much as the 100mm but cut twice as fast and because of their diameter will cut much further. |
| Stub Mandrel | 22/07/2010 21:35:13 |
 4318 forum posts 291 photos 1 articles | Hi Lawrie, I can see what you mean about accidents... you've only got a nose, one eye and half a 'tache left! Our reciprocating saw is a short cut to vibration white finger - I find the bowsaw less effort for scutting firewood! I see the new (B&D) model has a vibration absorbing pad on the handle. Gordon's earlier suggestion of a COARSE blade for the jigsaw could be a useful suggestion for many.  Neil |
| Billy Mills | 23/07/2010 00:14:25 |
| 377 forum posts | Lawrie- very interesting, your info will save a lot of time next time the card won't work. This has to be one of the better threads of late, it illustrates well how experience and differing needs lead to different techniques. Tools ARE personal. Away from the production line where we are concerned with total costs of batches and investment issues we are free to use a hacksaw, a bandsaw or whatever else we can get our hands on. Having admited to using a carbide tipped blade on Ali earlier I have some reservations. If someone reading this thread tries to cut metal on a sawbench or with a handheld circular saw without being as careful as the experienced and inteligent people above it could end in tears and blood. Yes it can be done and can work very well. The chips can come off very hard and fast. Eye protection is essential. There is a lot of inertia in a fast spinning saw blade that can grab the work and send it flying into your guts. At least check that the blade is a type suitable for the job and think about where the job goes during the cut, where your hands are, where the chips fly, what stops a kickback? How do you stop chips in your face? What stops the dog jumping up your back in the middle of the cut? What else can happen? An old blunt blade of doubtful origin is just what you don't want, it won't cut but it will kick. I am cautious because of Jeff. He was a very skilled older man who was a real craftsman- the kind of man that is very hard to find today. I hired him 27 years back. One day I found him not using a push stick on a circular saw table that is guarded so I told him to always use the stick in the future. He became upset and said that he was very experienced and was using saws before I was out of school, he had never cut his hands. I gave him a letter requiring him to always use the stick. Every time I heard him using the saw I checked that he was using the stick, sometimes when he had finished I remarked that I was pleased he was using the stick. Six months later I was called to the cutting room. There was a trail of blood leading to a rest area where Jeff was trying to stop blood gushing from his hand. You have to think it through BEFORE you try the cutting. Happy and safe cutting, Alan. |
| Gone Away | 23/07/2010 01:01:40 |
| 829 forum posts 1 photos | Posted by Alan Gray 1 on 23/07/2010 00:14:25: Yes it can be done and can work very well. The chips can come off very hard and fast. Eye protection is essential. Funnily enough I had no problems with flying chips whatsoever. They must have all gone downwards. I think perhaps two things helped that: - I had the blade height set for minimal penetration - the material I was cutting had an adhesive protective plastic film on one side which I kept on the top surface and cut through it I also stood well out of the line of the blade (then again, I also do that when cutting wood - just common sense) had the anti-kickback installed, fed the material slowly, used a full face protector and reminded myself where the off-switch was before each cut. As far as using a handheld circular saw on metal goes, my only thoughts are that personally, I wouldn't do it. . |
| Billy Mills | 23/07/2010 18:29:50 |
| 377 forum posts | Sid Depends on the saw, if you have an industrial sawbench with good dust extraction chip production will be well controlled. A chopsaw or a handheld circular saw will not have much blade guarding so chips can fly out. A coarse toothed rip saw with loads of positive rake CAN tear out a large chip if the feed is not controlled- hence the comment. Very slow feed and you will shave off foils of Ali but feed too fast and it will grab chunks with that positive rake. Ali sawblades are normally about -5 degree negative rake with lots of TCT ( say around 80) so the chips are generally smaller, have a lot less inertia to surface area so don't go so far or fast. They do cut very nicely but cost too much for the odd use at home ( B & Q £110 for a Bosch blade) Appologies for the initiated, however we have every kind of person reading our comments. I would not like to think that someone has had a bad time in attempting something without understanding what CAN happen. Regards, Alan . |
| Gone Away | 23/07/2010 21:48:05 |
| 829 forum posts 1 photos | Posted by Alan Gray 1 on 23/07/2010 18:29:50: Ali sawblades are normally about -5 degree negative rake with lots of TCT ( say around 80) so the chips are generally smaller, have a lot less inertia to surface area so don't go so far or fast. They do cut very nicely but cost too much for the odd use at home ( B & Q £110 for a Bosch blade) Ouch! I checked today . Around here (Ontario, Canada) Freud have a non-ferrous-metals blade for about $80 (say about £50) which is do-able .... especially as a gift from SWMBO. Haven't checked out Bosch yet - coincidentally I have a nephew who's a Bosch sales manager  (he used to be a sales manager at Freud but I didn't know about these blades then  )Edited By Sid Herbage on 23/07/2010 21:49:52 |
| Gorak | 23/07/2010 22:41:12 |
 13 forum posts | I have one of those 10" Freud Non-Ferrous metal blades. I mounted it in my mitre saw and used it to cut several 3" square aluminum extrusions. Freud recommends lubricating the blade with "Jig-a-loo" dry lubricant, which I did every few cuts, and the resulting cuts were very clean and smooth. One word of caution, this is not like cutting wood on a chop saw. Your stock, and the waste, need to be clamped securely to the saw table otherwise things can go bad very quickly. DAMHIKT!! Even though I've been woodworking for many, many years and am quite familiar with using power saws safely, after having done this cut a few dozen times I'm still not comfortable with it on extrusion that large and can't say that I would recommend this solution for anything other thicker/wider than 2". In fact, after my experiences with this combination of saw and blade I'm even more convinced to save up and get a dry-cut metal chop saw where the blade spins much more slowly. As for using this blade on a table saw (I assume that is the same as a "saw bench" that the Brits have been referring to), I've used it to trim 10mm 6061 plate aluminum and, other than the mess it makes, I felt quite comfortable and safe making the cuts guided by the rip fence. However, I did rough cut the plate aluminum with a jigsaw using a Starrett metal-cutting blade lubricated with Tap-Magic (only because that is what I had on hand). |
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All Forum Topics > Workshop Techniques > Cutting Aluminum Sheet/Plate