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  1. #1
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    Default Metal Cutting Drop Saw

    https://youtu.be/FmZ6eNj-IzQ?t=93 Shows a drop saw cutting a 50mm steel bar and I think it might be one of these https://www.totaltools.com.au/123846...RoCAg0QAvD_BwE

    Has anyone used one?
    CHRIS

  2. #2
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    I imagine that the saw itself is irrelevant, it is the saw blade that is critical. It is a TC toothed blade, and the chief difficulty would be in having a silver soldered joint that could handle the heat produced by the cutting action. Likewise the constant interrupted cutting action would require a specific grade that is better able to handle that cutting condition.

    Eye protection would appear to be even more critical that when using a friction saw due to the chips being more mobile that a glowing spark. A chute to direct and capture the majority of the chips would be a must in my viewing of that video.

    As to whether the saw is the one shown in the advert, I cannot say.

    Thanks for the video

    Quentin

  3. #3
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    Quote Originally Posted by Cueball View Post
    I imagine that the saw itself is irrelevant, it is the saw blade that is critical. It is a TC toothed blade, and the chief difficulty would be in having a silver soldered joint that could handle the heat produced by the cutting action. Likewise the constant interrupted cutting action would require a specific grade that is better able to handle that cutting condition.

    Eye protection would appear to be even more critical that when using a friction saw due to the chips being more mobile that a glowing spark. A chute to direct and capture the majority of the chips would be a must in my viewing of that video.

    As to whether the saw is the one shown in the advert, I cannot say.

    Thanks for the video

    Quentin
    Thanks for the reply but I don't want to put a metal blade on my primary mitre saw and I suspect the blade speed might be too high anyway though I haven't checked on that. The Diablo blade here has a 3000 RPM upper limit for instance. https://www.bunnings.com.au/diablo-2...blade_p6370886

    I doubt that a silver soldered brazing method would be used, more likely a fusion welding process I would think. The saw in the link has a top blade speed of 2500 RPM which is lower than a normal mitre saw AFAIK. I just checked and my saw has a top blade speed of 3800 RPM and I think that would be fairly normal.
    CHRIS

  4. #4
    BobL is offline Member: Blue and white apron brigade
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    I doubt they are the same saw
    I've seen those saw cut loads of thin walled steel tubing (its the one thing they do well) but the total tools one is rated for a max of 6mm thick steel and even then like most manufacturers claims I reckon repeated long term cutting at that thickness will compromise the life of the blade.
    A 2500 RPM blade speed motor means too slow for wood, and too fast for many repeated cuts on solid steel so in short order a new blade will be needed - good for the blade suppliers, not so good for the user. If you are in business of course you maybe can pass the charge onto customers.

    The saws that run at 1400 rpm will get longer blade life but if you want decent blade like the only way to do this in solid steel is to use a real cold cut saw which runs run at much lower speeds still.

    Anyone that asks me about these I recommend a small metal cutting bandsaw, no noise, can cut much larger steel stock, can set it running and go do something else.

  5. #5
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    No thanks, metal bandsaws take way too long to do anything, I had one and sold it for that reason.
    CHRIS

  6. #6
    BobL is offline Member: Blue and white apron brigade
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    I doubt they are the same saw or maybe they are but if so it won't work like that for too long.
    I've seen those saw cut loads of thin walled steel tubing (its the one thing they do well) but the total tools one is rated for a max of 6mm thick steel and even then like most manufacturers claims I reckon repeated long term cutting at that thickness will compromise the life of the blade.
    A 2500 RPM motor means too slow for wood, and too fast for many repeated cuts on solid steel so a new blade will be needed - good for the blade suppliers, not so good for the user.
    Steel

    Anyone that asks me about these I recommend a small metal cutting bandsaw, no noise, can cut much larger steel stock, can set it running and go do something else.

  7. #7
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    I have used some of the ferrous cutting saws, mostly the little Triton one. The blade geometry etc is critical, as Quentin suggests, but so is the rigidity of the saw frame. I first encountered the blade geometry about 20 years ago and understand that it was originally developed successfully by Australian Saw Co in Melbourne, and now used and produced around the world.
    As can be imagined, the saw blade generates a fair degree of reaction when cutting, and this must be resisted by the frame of the saw, and effective clamping of the work. Personally, I would have reservations about using what is effectively a SCMS with only moderate clamping capability for cutting steel, particularly solids that size, on a regular basis as the user effectively has to provide the reaction forces to counter the blade teeth entering the work.
    Evolution were one of the first to release dedicated metal cutting drop saws in the 14inch range some time ago, but I don't know if they still market those models in OZ. The version shown in the links is I suspect an attempt to put something 'multifunction' into the marketplace, and I suspect it would be OK for occasional bar cutting, but would not like to buy one specifically for cutting bar regularly. An issue to consider is the cost of replacement blades, which are easily damaged if the work moves in the clamp or the blade manages to jump in the cut. I would be extremely reluctant to attempt mitre cuts on round stock as I doubt that you could clamp the material effectively enough to prevent it slipping and spiralling through the clamps due to the axial loads imposed. This is an issue with round stock in any rotary metal cutting saw, but is generally controlled with an adequate vice to keep the metal in position.
    I used to be an engineer, I'm not an engineer any more, but on the really good days I can remember when I was.

  8. #8
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    Metal blades are cheap these days fortunately and Diablo do several different types. I first saw metal cut with a saw blade on what was a bench type saw about 50 years ago when I was a teenager and I was gob smacked that it could be done at all as all I had seen then was horizontal bandsaws and they are hatefully slow. On further investigation Evolution do slow speed saws that are straight chop saws which I might look into further. I went down this path about six months ago looking for a saw that had a lower blade speed for this purpose and could not find one then.
    CHRIS

  9. #9
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    My small Triton uses 71/4inch blades and runs at about 1300RPM from memory, its in storage about 20ft up in pallet racking and inaccessible at the moment so memory is all I can contribute. I know however that the blades I use for it are speed rated to be suitable for a 71/4 circ saw. Mainly use the Triton for cutting tube to 3mm wall, but have cut some round bar to 1in and flats/angles as well. Main thing with any is to control the spread of hot swarf coming off the blade, it can be mean to power cords and any other thermoplastics around.
    I used to be an engineer, I'm not an engineer any more, but on the really good days I can remember when I was.

  10. #10
    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by Chris Parks View Post
    No thanks, metal bandsaws take way too long to do anything, I had one and sold it for that reason.
    I thought that too but I got around that, plus accrued the benefits by just reorganising my work plan. While it's cutting I go do something else so there's no time overall lost. When It finishes it turns itself off and it sits there patiently waiting for the next cut. No dust, no noise , or watching out where the sparks are going.

    I doubt that a silver soldered brazing method would be used, more likely a fusion welding process I would think. The saw in the link has a top blade speed of 2500 RPM which is lower than a normal mitre saw AFAIK.
    Fusion welds only work when the metals are similar. TC teeth are a sintered mix of ceramic type materials while the blades are metallic ie some kind of steel alloy so they have be brazed.

    One thing they don't mention is try and cut the wrong bit of steel and the teeth will be toast. When this happens on a small BS the cost is about $10 for a new blade but it will be a lot more to replace an Evolution type blade. The other thing they do poorly at is stainless which requires a different blade whereas a small BS will do most stainless quite easily.

  11. #11
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    I agree with Bob. Go do something else if the cut is taking too long. But in reality, how often are you cutting large pieces of solid that take a long time to cut? Most of my cuts are done in under 30 seconds.

    Before I bought a horiz bandsaw I used a TCT aluminium cutting blade on a drop saw to cut Al. It was aggressive, noisy, and it showered the workshop with hot metal chips. I imagine the same thing cutting steel would be awful. On short pieces there was no effective way to secure the stock. I got rid of it after a piece of solid Al came loose from the clamps and was picked up by the blade.It destroyed the blade and the workpiece.

    How much metal cutting are you doing? What type of metal? I believe you are predominantly a woodworker, so I can't imagine your metal cutting needs are extreme.
    Chris

  12. #12
    BobL is offline Member: Blue and white apron brigade
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    [QUOTE=jack620;1951419] Before I bought a horiz bandsaw I used a TCT aluminium cutting blade on a drop saw to cut Al. It was aggressive, noisy, and it showered the workshop with hot metal chips. I imagine the same thing cutting steel would be awful. On short pieces there was no effective way to secure the stock. I got rid of it after a piece of solid Al came loose from the clamps and was picked up by the blade.It destroyed the blade and the workpiece.QUOTE]

    I have a 96 tooth multipurpose TS blade that is some 12 years old and use it a lot on Al and is the standard blade I keep on my on my TS..
    It has never been sharpened but still cuts almost like new.
    The hot metal Al chips are a non-issue if you have good dust extraction. The few chips that are not collected usually end up flying out the back of the table
    Just earlier this week I was cutting up some 20 mm thick AL plate with it and as usual it produced an excellent finish.
    Only as the pieces got smaller and I needed to make some awkward angled cuts did I move these to my WW BS.
    But I would not dream of using it on a regular basis on steel.

  13. #13
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    I did use the blade on my TS a few times. It was much more pleasant than the drop saw. I stopped doing it though because I was worried about getting metal chips into the rise/fall and tilt mechanisms. The rise/fall jammed on me once and required the machine to be disassembled.
    Chris

  14. #14
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    The benefit to using the mitre saw opposed to the band saw would be the ease to change angles, I might give this a go someday. The saw they are using in the video just looks like your regular run of the mill woodworking saw to me just with a suitable blade fitted to cut metal.

  15. #15
    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by jack620 View Post
    I did use the blade on my TS a few times. It was much more pleasant than the drop saw. I stopped doing it though because I was worried about getting metal chips into the rise/fall and tilt mechanisms. The rise/fall jammed on me once and required the machine to be disassembled.
    Sure, but again it's a question of good dust extraction. Like I said I've been cutting Al on mine for 12 years and no probs. Even for the first 4 years when I had mediocre dust extraction I don't recall having a problem.

    The one problem I had was not with the multipurpose blade but with another high count tooth WW blade that looked very similar to the multipurpose blade.
    The multipurpose blade has negative raked teeth where as the other blade had positive raked teeth
    I glanced at the blade in the TS and thought it was the multipurpose blade and when I tried to cut some 1/2" thick Al . . . .
    TsBladep.jpg

    The teeth went flying around the shed like bullets and a couple went straight through the 1mm thick Al dust collector hopper under the saw. The unbalanced blade then started to shake and I ran for the shed for where the breaker box was located and turned off the shed power.

    Positively raked teeth will dig into the work material and help the blade self feed but on stiff like Al it can literally tear the teeth off . A natively raked tooth pushes the material away from itself and scrapes the material away so it doesn't di in.

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