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  1. #16
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    You can get metal cutting tct saw blades in different pitches for saws specifically designed for these blades, is that what you referred to?
    http://www.makita.com.au/products/ca...l-cutting-saws
    I have a 14" blade that I am currently fitting to a 5hp cut off saw. I am changing the pulleys to get the speed correct and changing the vice and the gaurds to catch the swarf. The cold cut saws have more power than abrasive saws and the rpm may be different.

  2. #17
    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by Burner View Post
    I have a 14" blade that I am currently fitting to a 5hp cut off saw. I am changing the pulleys to get the speed correct and changing the vice and the gaurds to catch the swarf. The cold cut saws have more power than abrasive saws and the rpm may be different.
    Cold cut saw don't use very high powered motors. On the H&F website the smallest cold cut saw uses a 1.3HP Motor (~65 mm cut) and there are quite a few that use 2HP motors (80 mm cut) while their largest ones with ~110 mm cut are typically 3HP. 14" blade will be limited to about a 125 mm cut so that would suggest a 4HP would be more than enough.

    The cold cut saw revs are in the 20 to 100 rpm range, whereas metal cut off saws are ~4000 rpm. This means you will need a ~100:1 RPM reduction.

    5HP sounds like a 3Phase motor. It might be useful to see if you can fit a VFD to that so that you can get some variable speed control.

    I will be very interested to see how you go.

  3. #18
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    Hi Bob,

    The saw Ewan linked to is called a "cold saw" but I really dont know how they came up with that name. 1300rpm on a 305mm blade. Fast, load, cooler than a friction saw, but not cold.

    Stuart

  4. #19
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    Quote Originally Posted by nearnexus View Post
    I have cut quite a bit of steel plate, and do it easily with a hand circular saw with a friction disc in it (set blade depth to less than 10 mm).

    To get a straight cut clamp a piece of timber to the steel plate as a guide for the edge of the cutting plate, so that the disc can reference along the cutting line.

    Then progressively grind down through the plate in multiple passes.

    This ensures a straight cut and conserves the disc.

    If you try cutting straight into the plate edge it will destroy the disc pronto, and always pull off line.

    Rob
    Cutting offline is a problem that needs to be watched. I have also found this problem. I use a fence for long cuts. I found I need to keep the saw hard against the cut to prevent this.

    I have also found that if I use the saw with the wheel set to a deep cut and put a bit of pressure into the feed, the cutting changes and the sparks turn to deep orange blobs and it seems to cut much faster and with less wear on the disk. I believe it may be burning thru the metal or something like that. I can only recall this happening with 6mm plate, but this is the only thickness I have cut in any quantity other than thin stuff. I have found that this uses far less disc than shallow cuts which often cause the edge to bind up. It is also much faster.

    Dean

  5. #20
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    Quote Originally Posted by BobL View Post
    I've tried just about everything,small drilling vice, clamps, mutigrips, etc,
    Using a small drilling vice requires the vice to be tipped on its side otherwise it is too high for the wheel but for anything that fits in such a vice I usually use the bandsaw, and for things that are small I use multi grips.
    I found it you use the same principle as one would use on a WW TS to handle material that I don't need to use any thing other than my hands.
    I have on the odd occasion with awkward shapes even lightly welded a piece of steel bar onto the workpiece so that I can hold that while cutting.

    Here is an example of something I knocked up the other day where all the cutting was done with the little table saw.
    I needed a 2 arm puller to remove a plastic fan from a motor shaft. I have several 3 arm pullers but no two arm.
    I was going to use a couple of the arms from one of the 3 armed pullers but the pulling points on the fan were small holes that none of the 3 puller arms would fit through.
    The paired brown-red coated arms were first ripped lengthwise from 25 x 3 mm flatbar that was about 300 mm long so my hands were well back from the wheel while that was being done.
    The all rod like sections were cut with the mitre slide and squared off and tapped with a lathe.
    The 5 mm thick wings and arms with the hooks on them, were cut free hand

    Snip

    Before I had the table saw I had used a circular with a cut off wheel a number of times and it just didn't feel right
    • First thing is the noise, I might as well use and angle grinder
    • It's just not safe on small pieces
    • It's hard to see where you're cutting and the thin kerf wheels sometimes wander a bit so correction may be needed.
    • To get around this I used the 2.5 mm thick wheels which reduced the wheel wander, these also came is larger sizes as well.
    • Angle grinders are sort of made to handle a metal and wheel dust but I'm not sure circulars are the same.


    I suppose if you only are going to do a few cuts it would be OK.
    Nice puller. I should have made one to remove the fan on my lathe motor, but I was too impatient. I tried to cobble something up from a harmonic balancer pulley puller, which work for a bit, but not when it got further out. If I have to do it again, I will make something like your puller.

    Drilling vice. It was for a bandsaw that this was used by Tubalcain. I understand your thoughts. It was just a suggestion.

    Circular saw not feeling right.

    They are noisy. I don't have a spare table saw. You do. Great use for it. How would it handle 2400 x 1200 sheets? I have cut some of these in 3mm checker plate for the wheel tracks on a car trailer. Maybe I was wrong in my previous post. An angle grinder does not have the same control. I will not use a 9 inch angle grinder for cutting, but I will use my circular saw because it has a base plate and can have a fence for a guide. Hugely safer, believe me.

    Small pieces. I agree. I use a 5 inch angle grinder and vice.

    I have used engineers chalk and not had a problem seeing where I am going. I also use a fence. Thin kerf wandering? not tried one yet. Maybe I will need to stay with the thicker wheels. I will try different ones tho.

    Circular saws are not made to handle these dusts, but it is a spare saw. I also have a Triton 9 inch which is looked after. Cutting metal wipes the warranty, but this saw has cut huge amounts and is still going strong. I doubt your table saw is designed for it either.

    One warning. Do not touch the guard after a heavy cut. It will burn the heck out of your skin. It gets extremely hot.

    Cheers

    Dean

  6. #21
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    Quote Originally Posted by Chief Tiff View Post
    Aren't there now thin kerf reverse rake TCT circular saw blades specifically designed for use in circular saws to cut sheet metal? There are also some bloody good recip saw blades out there; we use them regularly for cutting steel up to 3/4" thick beacuse they're much safer than cutting discs.
    I have not had a lot of success in the past using a recip saw. Maybe I need to persist with them. I would not have considered cutting 3/4 thick steel. I bought mine to cut the nails holding the floor beams to the stumps of my house so I could level it. It was the only thing except a hacksaw that would fit in there. I was not about to use a hacksaw in that cramped position. Just bought a pack of three Bosch Li-Ion tools which included a recip saw. I have used it on chipboard. Maybe I should try it on metal.

    One of the things I have found difficult to cut is corrugated iron. (Sheets and Tanks) I have heard about using a recip saw and clamping it with timber on both sides to prevent it moving. Another thing to try.

    Dean

  7. #22
    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by Oldneweng View Post
    They are noisy. I don't have a spare table saw. You do. Great use for it. How would it handle 2400 x 1200 sheets?
    The little TS is backed up to and almost level with a 2.1m long bench so I use the bench as an out feed table for long cuts but the problem is I only have about a 1200 mm clearance in front of the saw.
    The top of the TS is too narrow for anything wider than about a 1200 mm of material.
    Physical handling a piece of sheet metal larger that that become unmanageable for most people and especially in the space I have available.
    For DIYers it's probably also better to move a tool over large sheets of metal than the other way around.

    ][QUOTEI have cut some of these in 3mm checker plate for the wheel tracks on a car trailer. Maybe I was wrong in my previous post. An angle grinder does not have the same control. I will not use a 9 inch angle grinder for cutting, but I will use my circular saw because it has a base plate and can have a fence for a guide. Hugely safer, believe me.[/QUOTE]
    Just about anything is safer than an angle grinder - After the humble ladder it's the most common tool that is involved with reported DIY injuries.

    Circular saws are not made to handle these dusts, but it is a spare saw. I also have a Triton 9 inch which is looked after. Cutting metal wipes the warranty, but this saw has cut huge amounts and is still going strong. I doubt your table saw is designed for it either.
    Sure but unlike a circular it has a belt and pulley so the motor is well away from the bulk of the metal dust. I do clean it out about once a year - blow out all the metal dust etc.

    I understand what you mean about using power tools that are surplus to requirement for other purposes. I was recently been given an old Hitachi circular that needed a bit of TLC and will probably use that for any long sheet metal cuts and use nearnexus' method of cutting.

    One of the things I have found difficult to cut is corrugated iron. (Sheets and Tanks) I have heard about using a recip saw and clamping it with timber on both sides to prevent it moving. Another thing to try.
    A quality pair of power shears does wonders on corrugated iron and similar material like Trim Deck, fast accurate and very safe. The one material that I found shears struggles with is rip cuts on mini orb where the stuff is so stiff that it's hard to generate enough clearance for the shearing action to progress. Abrasive wheels should not really be used on zinc alum or galv materials as the metal grit will stick to the coating and it will rust and make a mess. Abrasive wheels also leave a terrible edge on the corrugated that is difficult to remove - provided you don't repeatedly stop and start a cut (thereby generating tiny hooks) the shears leave a slightly corrugated or rippled edge but it's much smoother than an abrasive wheel and you can run you hand along the edge without cutting yourself

  8. #23
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    Quote Originally Posted by BobL View Post
    The little TS is backed up to and almost level with a 2.1m long bench so I use the bench as an out feed table for long cuts but the problem is I only have about a 1200 mm clearance in front of the saw.
    The top of the TS is too narrow for anything wider than about a 1200 mm of material.
    Physical handling a piece of sheet metal larger that that become unmanageable for most people and especially in the space I have available.
    For DIYers it's probably also better to move a tool over large sheets of metal than the other way around.

    ][QUOTEI have cut some of these in 3mm checker plate for the wheel tracks on a car trailer. Maybe I was wrong in my previous post. An angle grinder does not have the same control. I will not use a 9 inch angle grinder for cutting, but I will use my circular saw because it has a base plate and can have a fence for a guide. Hugely safer, believe me.
    Just about anything is safer than an angle grinder - After the humble ladder it's the most common tool that is involved with reported DIY injuries.

    Sure but unlike a circular it has a belt and pulley so the motor is well away from the bulk of the metal dust. I do clean it out about once a year - blow out all the metal dust etc.

    I understand what you mean about using power tools that are surplus to requirement for other purposes. I was recently been given an old Hitachi circular that needed a bit of TLC and will probably use that for any long sheet metal cuts and use nearnexus' method of cutting.


    A quality pair of power shears does wonders on corrugated iron and similar material like Trim Deck, fast accurate and very safe. The one material that I found shears struggles with is rip cuts on mini orb where the stuff is so stiff that it's hard to generate enough clearance for the shearing action to progress. Abrasive wheels should not really be used on zinc alum or galv materials as the metal grit will stick to the coating and it will rust and make a mess. Abrasive wheels also leave a terrible edge on the corrugated that is difficult to remove - provided you don't repeatedly stop and start a cut (thereby generating tiny hooks) the shears leave a slightly corrugated or rippled edge but it's much smoother than an abrasive wheel and you can run you hand along the edge without cutting yourself[/QUOTE]

    I think the bearings on my saw are pretty well protected from ingress. I have never seen any indication of this happening. Maybe I should strip it and check.

    Re corrugated iron, I wish I could afford/justify a good set of shears. I have tried an air nibbler but this is fiddly and leaves a lot of sharp bits behind. I have normally done it over a trailer so I can collect all the bits. I have also used a circular saw with a tungsten tipped blade. This works but you need good protection from the bits and no way to collect them. You would not want to use a good blade for this job.

    Dean

  9. #24
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    For cutting thin sheet I'm a convert to plasma cutters. I need to use a guide as free hand I'm a bit wobbly but the cut is fast, effortless and has only the slightest amount of clean up required afterwards - usually can be welded without needing any. Mine is a 25A unit but while able to cut up to 8mm for practical purposes runs out of puff after around 5mm.

    Michael

  10. #25
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    Quote Originally Posted by Michael G View Post
    For cutting thin sheet I'm a convert to plasma cutters. I need to use a guide as free hand I'm a bit wobbly but the cut is fast, effortless and has only the slightest amount of clean up required afterwards - usually can be welded without needing any. Mine is a 25A unit but while able to cut up to 8mm for practical purposes runs out of puff after around 5mm.

    Michael
    Agree. I've got a cheap Chinese 50A model and it's cut all the steel for a 12m steel sailboat plus a lot of stainless. I regularly used to do 3000mm long cuts in 4mm plate. Practical limit is 10mm in A36, it will do 12mm but the cut is bad. In 316 the limit is about 8mm if you want a decent cut, 10mm if you just want a severance cut. Cuts 6mm stainless beautifully.

    It eats tips so I buy a lot. I'm progressively upgrading my air supply with better filters, water traps etc and I expect that to help consumable life.

    I think I've tried every single suggestion here over the years but these days I only use 4. Angle grinder with thin cutoff disk, metal cutting band saw, plasma cutter for stuff up to 10mm, oxy-LPG cutting torch for thicker steel. I have a GMC metal cutting circular saw which worked fine for cutting 4mm plate until the blade got blunt - it now lives in a cupboard taking up valuable space. Lovely clean cuts though.

    Thinking of buying one of these which would cover 99% of my needs.

    http://www.ebay.com.au/itm/271350969...84.m1438.l2649

    PDW

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  12. #27
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    Ueee is offline Blacksmith, Cabinetmaker, Machinist, Messmaker
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    Hi Bill,
    I'm 99% sure that that is Robs (Nearnexus) site. Some good info on there if you have the time to browse it all.

    Ew
    1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.

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