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Re: Tool Advice: Cutting Aluminum
I'm interested to learn about cold saws. I notice that they turn very slowly, around 60 rpm. How long do they take to cut through something like an 80/20 1" extrusion? Are the cheaper ($1,100) ones okay or do you need to spend more than that? Do you still pull down on the blade or does it do that feeding automatically? Are there any special skills we'd need to teach the students?
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Re: Tool Advice: Cutting Aluminum
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A cold saw does spin very slow, which makes it slightly less intimidating (maybe a plus for a hesitant student). -Assuming you are cutting properly, the speed is on par with horizontal band saws. -I can't speak for the cheaper ones, maybe someone else here has some experience with those. -Yes you still pull down on the blade. -As far as skill required, a cold saw is a very simple tool to use. Very similar in setup and procedure as a miter saw without the the loud noise and fast blade rotation. -Brando |
Re: Tool Advice: Cutting Aluminum
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Re: Tool Advice: Cutting Aluminum
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-Brando |
Re: Tool Advice: Cutting Aluminum
Dale,
At Skunkworks we use both types of Miter Saw and find the non-sliding one can hold better tolerance. It is a screamer though... so be prepared for eveyrone in the shop to have ear protection... (I am sure you already know this) On occasion we also cut to length on a bandsaw or use a hacksaw... and then take it for the final cut on the miter saw. We have a standing tradition of a "cut monitor" in our shop. This monitor is an adult mentor that supervises the use of the big cutting tools. (Table Saw, Chop Saws, Mill, Lathe..) This gives two sets of eyes on a cutting operation and the cut monitor's main job is to make sure that proper clamping technique and other safe methods are being used... Students normally don't use the chop saws ... and never use the table saw... For plate and such we use a waterjet... For pieces that need better precision... (I certainly envy the person above that stated they could hold .005" on a miter saw...) We cut big and finish on a big disc sander... that cleans up the saw tooth marks and with a sturdy table... can be very precise... |
Re: Tool Advice: Cutting Aluminum
Thanks Bob,
Team 1540 has a long tradition of being completely student built so I need a general purpose aluminum cutting tool that is fairly safe and that doesn't need 100% supervision. Often times I'm the only mechanical mentor in the lab so I can't monitor every cut. We've used a 12" miter saw for six years but I worry about the safety aspects of that tool as has been discussed. As good as our training is, I can't be sure every single cut is set up perfectly and that the feed rate is perfect. Our lab is one big 1500 sq ft open space so noise is also a consideration. Our miter saw can easily hit 110db and truly is annoying. Right now I'm leaning toward a cold saw or horz bandsaw. We have a vertical band saw, belt & disc sanders, and a table saw as well. I'm the only one we allow to use the table saw, however, so it only gets used when no other tool will do. |
Re: Tool Advice: Cutting Aluminum
The $1100 cold saws will do just fine. They may not be quite as precision as the more expensive ones, but mostly the differences are cosmetic. As with many of the lower-priced tools, the castings are a bit rough, but the bearing surfaces are fine, the blades are the same, motor torque and speed are the same, etc.
Cold saws run very slowly, since they are on a massive gear-head drive. The slow speed means monstrous amount of torque which translates into cutting force. Also, they have many very sharp hardened teeth. I have not had good experience having them resharpened. But the cost of a new blade isn't much different from a 96 tooth carbide-tipped blade that you would use on a miter box saw. In my experience, cold saws cut stock like 8020 much faster than a bandsaw and give a much better finish on the cut. What's more, they cut cold roll steel about as fast as they cut aluminum. Cold saws come with a vise that holds the stock tightly. Some hold the stock on both sides of the blade, some only clamp one side; both work well. You have to pull down on the handle which rocks the saw over onto the stock. The head is spring loaded to help control the motion and assist in returning the head to the upright position. There is a clam-shell blade guard which opens as the saw comes down, helping to keep fingers in their proper place attached to hands. I've never had a cold saw buck, grab, or throw parts. They are very comfortable tools to use. And remember, they are cheaper than a trip to the emergency room! This, after all, is the correct way to judge the true cost of a tool such as this. Dr. Bob |
Re: Tool Advice: Cutting Aluminum
The cutting speed was indeed one of my questions. At least our vertical bandsaw would take a long time to get though 80/20 extrusion. If the cold saw is faster that would make my choice easy. Both are roughly the same price.
I don't have 220VAC available so I was looking at this saw from Grizzly or the Jet version. Any experience out there with these? Both end up being around $1,000 delivered. For those with 220VAC available there's a nicer option from Grizzly for basically the same price. |
Re: Tool Advice: Cutting Aluminum
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Re: Tool Advice: Cutting Aluminum
Ours is a 18 TPI generic bimetal blade. Our bandsaw is one of those less expensive JET wood/metal units. It's running on it's slow speed but I don't recall what that is. All I know is it can take 45 seconds or so to get through a 1" 80/20 section. Maybe a different blade is in order?
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Re: Tool Advice: Cutting Aluminum
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-Brando |
Re: Tool Advice: Cutting Aluminum
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We have what is quite frankly a terrible quality vertical bandsaw, but with good Starrett bimetal 10-14 variable tooth blades it rips through solids in the 1" range. The problem is keeping the blade in good condition. It's very easy to dull or strip the teeth with improper usage. |
Re: Tool Advice: Cutting Aluminum
A new blade is certainly in our future, then. Any advice on how to prevent it from getting damaged besides not making turns too tight?
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Re: Tool Advice: Cutting Aluminum
There are 3 common causes of dull blades in my experience.
Cutting steel on a bandsaw that has a blade speed appropriate for wood/aluminum/plastic Cutting thick stock with a fine toothed blade Cutting thin stock with a very coarse blade. You can get a stick of wax like lubricant that you touch to the blade prior to usage that helps blade life a bit as well. |
Re: Tool Advice: Cutting Aluminum
Either the Jet or Grizzly cold saws should do fine. Mine is a Grizzly, but the 10 in. version, floor mounted, 220 v. single phase.
I think either would work fine (they may both be made in the same factory). What counts is the blade. At 9 in. you should do fine, and this one is bench mounted, though you can find a nice metal stand for it if you want to have it stand alone in your shop. My bandsaw blades come from my local saw sharpening shop. They are specifically made for cutting metal, though I run them at slow speed on my home-made 14 bandsaw. They cut aluminum fine, but my saw runs too fast to cut steel. If I try, it eats up the blades. I have a slower speed option on my bandsaw, but rarely use it since I have to reconfigure the belts. Look for a local saw shop to make up your bandsaw blades (they cut from stock, weld and anneal the joint to any length you want). Dr. Bob |
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