Another question about bandsaws. I have an SIP 10" and want to be able to cut metal, mostly aluminium but some thin (2mm) steel.
New thread started.
New thread started.
Metal cutting on a wood bandsaw
- Thread starter Grandad455
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Every material has an optimum cutting speed (expressed in surface feet per minute or metres per minute).
You can look up tables of suggested values for different materials. You can compare the blade speed on your wood bandsaw with the blade speed on a metal cutting bandsaw to appreciate the difference.
The difficulty is that the optimum cutting speed for wood is an order of magnitude higher than for metal.
With care and plenty of lubrication, it might work acceptably on aluminium. It will not work well on steel.
For 2mm steel, a rule of thumb is three blade teeth in the material so it will need a much finer blade than you currently have.
There are a couple of other things to consider: cutting metal will produce hot chips/swarf. If these land on the fine wood dust of the thing you cut before the metal, firey things can result.
The lubrication is also an issue. The more you overspeed, the more you need lubrication. WD40 or isopropyl aclohol works well on aluminium, but both are liquid and will turn wood dust into wood mud or slurry. Solid (wax) lubricants work a bit better, but again do not play well with the sawdust.
People have converted wood cutting machines into metal cutting ones, but it involves installing an additional step-down pulley. If the machine has a three phase motor, it is slightly easier, but even with electronic tricks, you end up with a machine that is too slow for wood and too fast for metal.
Have a look at how a proper dual purpose machine (Startrite) configures its drive system. If there was a less complicated soution to achieving dual purpose, they would have used it.
You can look up tables of suggested values for different materials. You can compare the blade speed on your wood bandsaw with the blade speed on a metal cutting bandsaw to appreciate the difference.
The difficulty is that the optimum cutting speed for wood is an order of magnitude higher than for metal.
With care and plenty of lubrication, it might work acceptably on aluminium. It will not work well on steel.
For 2mm steel, a rule of thumb is three blade teeth in the material so it will need a much finer blade than you currently have.
There are a couple of other things to consider: cutting metal will produce hot chips/swarf. If these land on the fine wood dust of the thing you cut before the metal, firey things can result.
The lubrication is also an issue. The more you overspeed, the more you need lubrication. WD40 or isopropyl aclohol works well on aluminium, but both are liquid and will turn wood dust into wood mud or slurry. Solid (wax) lubricants work a bit better, but again do not play well with the sawdust.
People have converted wood cutting machines into metal cutting ones, but it involves installing an additional step-down pulley. If the machine has a three phase motor, it is slightly easier, but even with electronic tricks, you end up with a machine that is too slow for wood and too fast for metal.
Have a look at how a proper dual purpose machine (Startrite) configures its drive system. If there was a less complicated soution to achieving dual purpose, they would have used it.
Thanks @ChaiLatte,
The fire hazards and lubrication problems seem to indicate two separate machines. Anyone suggest an inexpensive model to dedicate to metal cutting? One that be converted to run at a slower speed.
The fire hazards and lubrication problems seem to indicate two separate machines. Anyone suggest an inexpensive model to dedicate to metal cutting? One that be converted to run at a slower speed.
Seriously : consider a handheld jigsaw.
Any model with variable speed could potentially do the job.
Taking the good Mafell one as an example, it has adjustable speed from 800 to 3,000 strokes / minute. You use these with the speed dialled right down for metal which highlights the point made above that a woodcutting saw is far to fast for metalwork.
Bimetal / High Speed Steel blades are easy to get and the saw cleans up easily.
If you don't need to cut much / thick steel it maybe the cheapest option.
Axminster sell a benchtop bandsaw with a wide variable speed range that I believe is aimed at people who want to cut a bit of thin non ferrous metal as well as wood, but it will set you back most of £2k.
Any model with variable speed could potentially do the job.
Taking the good Mafell one as an example, it has adjustable speed from 800 to 3,000 strokes / minute. You use these with the speed dialled right down for metal which highlights the point made above that a woodcutting saw is far to fast for metalwork.
Bimetal / High Speed Steel blades are easy to get and the saw cleans up easily.
If you don't need to cut much / thick steel it maybe the cheapest option.
Axminster sell a benchtop bandsaw with a wide variable speed range that I believe is aimed at people who want to cut a bit of thin non ferrous metal as well as wood, but it will set you back most of £2k.
What about the good old hacksaw, requires more effort but for the odd few an easy solution. Next consider the angle grinder with a thin cutting disk, these made by Norton are ok
Norton Extra Thin 0.8mm Metal Cutting Disc
recently cut some 8mm thick 60mm wide steel plate with them, but invest in a nice heavy pair of leather welders gloves.
Norton Extra Thin 0.8mm Metal Cutting Disc
recently cut some 8mm thick 60mm wide steel plate with them, but invest in a nice heavy pair of leather welders gloves.
Myfordman
AKA 9Fingers
In order to cut steel, not only do you need the correct blade but also to drop the blade speed by about a factor 15:1
This is too much for a single pulley drive and too much for an inverter drive as well. If your saw is three phase then the combination of a pulley belt drive and and inverter makes this feasible.
You can see how I did mine about 13 years ago here Modifications to a Startrite bandsaw
This is too much for a single pulley drive and too much for an inverter drive as well. If your saw is three phase then the combination of a pulley belt drive and and inverter makes this feasible.
You can see how I did mine about 13 years ago here Modifications to a Startrite bandsaw
clogs
just can't decide
I would buy another SLOW speed band saw just for that job....
jigsaws are ok if u have a vari speed machine set on slow.........
decent blades last a good while...except on st/steel......
u will def need decent safety glasses....those shards are lethal....I use glasses and a face shield together......
plus for straight line work and or slow courves go the grinder route......
the thin grinder blades from Lidil's are very good.....they last better than a lot of branded goods......
if u do buy the thin blades from somewhere else buy those for St/steel, they last almost twice as long.....
would need to check but the last blades I bought from Lidil said made in Germany.......
Bought from a local tools store those thin blades are 5 times as much as those from Lidil....
when they have em in my wife has an order to clear the shelf......
jigsaws are ok if u have a vari speed machine set on slow.........
decent blades last a good while...except on st/steel......
u will def need decent safety glasses....those shards are lethal....I use glasses and a face shield together......
plus for straight line work and or slow courves go the grinder route......
the thin grinder blades from Lidil's are very good.....they last better than a lot of branded goods......
if u do buy the thin blades from somewhere else buy those for St/steel, they last almost twice as long.....
would need to check but the last blades I bought from Lidil said made in Germany.......
Bought from a local tools store those thin blades are 5 times as much as those from Lidil....
when they have em in my wife has an order to clear the shelf......
Just to add to that good advice, the jigsaw in combination with some sort of straight edge guide will be better than the bandsaw.
You can drown the part in your chosen lubricant and a quick wipe of the jigsaw base cleans it up when you are done.
You do not need to go looking for exotic blades either. The correct type of Bosch blade from the range carried by Toolstation will do very well.
As above, turn the speed down low and switch off the penduum action.
You can get away with quite thin material if you double-sided tape it to a piece of sacrificial 3mm ply. The fine saw blade cutting into the ply calms it down a bit and makes the experience less exciting than trying the metal on its own.
For some things, you can mount the jigsaw upside down on a large flat piece of wood (old kitchen cupboard door is good) with the blade projecting through a hole, and use it like a filing machine. That allows you to nibble away at internal curves in metal.
I think you need to keep metal and wood cutting away from each other, cleaning sawdust from a bandsaw is one thing but metal chips is going to be a lot worse. Having just had to make some metal brackets I have spent ages cleaning up the swarf and getting my woodworking bench back to clean and it is easy to get bits of metal embedded into wood.
AES
Established Member
To add to the posts above, most of which are spot on, you can also look at a LONG sticky thread about cutting metals of various types and thicknesses which is right at the top of the General Metalworking Section.
It lists just about all the affordable (to the hobbyist) metal-cutting "tools and gadgets" from hand tools like hack saws up to band saws designed specifically for cutting metal (they're a MUCH different animal to band saws for cutting wood, for the reasons - and many others - outlined by other posters above).
There are MANY tools much more suited to the occasional cutting of metals - hack saw (NOT hard work if you know what you're doing and use the right blade/s, see article); angle grinder with cut off disc; coping/jewellers/fret saw with suitable blade/s (for thin sheet); "nibbler" attachment for hand-held electric drill (also mainly for thin sheet); "tin snips" (various types - also mainly for thin sheet but often distorts the edge, again see article above); and if available, the "Goscut" tool (again see that sticky).
It's your money and choice of course, but personally, unless you are going to be cutting metals REGULARLY, and in relatively large quantities and of wide variety of types & thicknesses, I consider a metal cutting band saw to be both a waste of money and of workshop space. In fact I do not have one, despite doing quite a bit of metal bashing in my shop.
HTH
Edit for P.S.
Also agree with a poster above who suggests a jig saw. Can work very well, but again, needs careful set up AND the right blade/s (sorry, see that sticky article again)!
Edit for a further P.S.
(Sorry Grandad 455, I really am getting forgetful in my old age)!
Especially bearing in mind your mention of cutting 2 mm thick sheet steel, please don't forget the "minimum of 3 teeth always in contact with the job throughout the cut" rule. (Sorry if I'm teaching "grandma to suck eggs")!
That rule especially applies with 2 mm metal (and thinner - any metal BTW - especially if you do not want any distortion/curling along the cut edge/s).
So IF you have one, another ideal tool for that job is a powered scroll saw (with the right blade/s, as ever). But no problem if you don't have a scroll saw, a hand-powered "fret/jewellers/coping saw" will do the job easily, but once again, you need the right blade! As we're talking about a thickness of only 2 mm, that clearly means a VERY fine-toothed blade if we're to obey the above (vital IME) "3 teeth rule".
But that's NO problem because over on the Scroll Sawing Section you'll find another "sticky" (it's also long, sorry) in which you'll find a lot of details on who makes what blades and where to buy them. That article is of course mainly aimed at wood working, but both powered scroll saws and "jewellers/etc" hand saws use the same blades for cutting thin sheet metal, and both tools are regularly used for that purpose by the professionals.
BTW, you need have no fears about time/difficulty taken to cut by hand if you don't have a scroll saw. The above sticky includes downloadable tables from a couple of manufacturers listing blades designed especially for cutting sheet metals of all types, including sheet steel. And with the right blade, even using "only" a hand-powered jewellers/etc saw, the job really does become a "hot knife-butter" act!
Done it myself loads of times, both manually and with the scroll saw.
Again, HTH
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Another issue with using a typical bandsaw is the tyres. These will get metal chips embedded in them, and you will never get them out. I have an old kity, this has been reduced to about half speed using different pulleys, and cuts thin aluminium and brass sheet no problem with the correct blades and lubrication, but generates a lot of swarf which can be a pig to clean up. It sits on a large commercial baking tray and has constant drop lube to the blade. The model I have doesn't have tyres so that isn't a problem. No use at all for steel, it's still far too fast, unless it's very thin. I have used it to cut 0.5mm steel sheet used in clock dials, but that really is the limit. For steel I have a Sheppach metal cutting variable speed chop bandsaw for cutting tube, channel etc accurately. As others have said use a decent jigsaw or discs for long cuts in sheet, or if it's thin I have a pneumatic sheet cutter, nibbler or shears, depending on the scale of the job. Stainless is brutal stuff on bladed cutting tools and I always use discs, and second Clogs comment about the Lidl ones, they really are very good.
AES
Established Member
@Grandad 455: I've just found out that the article about metal cutting that I've referred to above as a sticky in the General Metalworking Section isn't a sticky any longer. I've asked the Mods to re-instate it, but in the meantime, there's a link below. It IS long, sorry, but I think you may find it useful:
https://www.ukworkshop.co.uk/threads/hacksaws-how-to-choose-em-how-to-use-em-other-stuff.109936/
https://www.ukworkshop.co.uk/threads/hacksaws-how-to-choose-em-how-to-use-em-other-stuff.109936/
So, a great big thank you to all who given their time to successfully answer my question about band saws and metal cutting. Having read all the responses, I shall now stick to wood cutting with the bandsaw and use a jigsaw and disc cutter for the metal. When I get the chance, I will read the stickies on the subject as well. Sadly my free time is limited and as my workshop is too small to work in, I have to wait for dry weather and work outside, not much luck there at the moment.
Please, just a couple of small things on this. First, try not to grind such that the sparks go towards glass as they can make a mess of it. Second, the sparks and dust are mainly iron filings. When those sit on your white marble patio, after a few showers of rain, an artistic brown line or a load of brown specks appear on the floor.
