How can I cut 0.8mm thick stainless steel sheet more accurately by hand?

[Dave SParticipant @daves59043]

With Jewellers saws blades, especially for the smaller sizes, just looking at them wrong causes them to snap

I have used both Super Pike and Platinum King (and also Valorbe) blades, and I (a somewhat experienced operator) get better results in Stainless (and Titanium) with Platinum King blades. This will of course be down to various conditions such as the actual alloy, the saw frame, the operator etc. FWIW the Super Pike blades seem 95% as good as Valorbe ones for less than 95% of the price.

On a 'real' hacksaw I use full hard blades – I found that bimetallic ones seemed to stretch and loose tension, with the result that the cut tended to wander more. Yes they are more likely to break if you 'twist' the frame during the cut, but you shouldn't be doing that anyway….

Hacksaws get their 'set' from the wave. I think this is mostly because the teeth are small, so setting individual teeth like on a woodsaw is impractical. I have had a big, course power hacksaw blade with individually set teeth, but most are wavy. Jewellers saw blades, at least in the finer sizes don't have an set that I've noticed.

Most junior hacksaw blades seem to be a bit rubbish – they are very soft, and the spring frame and soft blade inevitably leads to wandering cuts. The handles on most junior hacksaws don't help their either.

Dave

[jaCK HobsonParticipant @jackhobson50760]

My experience is that you have to chase accuracy gains in every department you can think of… and then discover other areas you missed.

It starts with marking out. A thin scribed line is probably best (beats pencil or printed templates glued to the material). Thinner the better.

You have to be able to see the line so you know where to aim for. So high contrast using layout blue, careful lighting, and magnification.

You need to see the line and where the tool (saw) is cutting – so really firm work holding so it doesn't vibrate. Good positioning. Clamping. Blow or brush the swarf off the line.

Start slow – speed comes with practice.

Give yourself time/space to adjust. It is difficult to adjust part-way through a stroke. The less you cut in one stroke, the smaller the maximum error before you readjust. So smaller saw teeth, less pressure.

Long strokes help get the best life from your blade, but might not help with accuracy at first. But it is good to practice long strokes.

Develop a nice feeling of the cutting action. Each stroke should be considered. lighter pressure means less blade deflection.

Constantly re-check you are sawing vertical. Relax the grip and posture. Learn to feel when the saw is upright.

Enjoy the process rather than focusing on the end goal.

If your mind isn't 'in it' then take a break.

There is more to consider but I suspect all that is on another level than the advice wished for i.e. there is no one, quick-win or secret to accurate sawing. The simplest advice is 'practice' but probably worth saying 'mindful practice'.

Edited By jaCK Hobson on 02/11/2021 14:00:48

[File HandleParticipant @filehandle]

Although i use fret and piercing saws to cut on the pull stroke I have always used coping and junior hacksaws cutting on the push stroke. will now have to try them the other way around to see if it makes a difference. Just tried a search and there is no definitive answer. But Paul Sellers argues that a coping saw should be push, he probably has a bit more experience with using one than me.

[old martParticipant @oldmart]

I,m with SOD on this, scribe the exact line, cut as near to it as possible and finish by grinding or filing. It is slow, but gives time to get it perfect.

[Dave HalfordParticipant @davehalford22513]

Posted by Keith Wyles on 02/11/2021 14:44:17:

Although i use fret and piercing saws to cut on the pull stroke I have always used coping and junior hacksaws cutting on the push stroke. will now have to try them the other way around to see if it makes a difference. Just tried a search and there is no definitive answer. But Paul Sellers argues that a coping saw should be push, he probably has a bit more experience with using one than me.

I found pulling coping saws meant the blade was less likely to break and doesn't catch.

[David NobleParticipant @davidnoble71990]

Just in case you hadn't thought of this and, if I'm correct in thinking that you are more concerned with the end product rather than learning how to use the tools, have you though of approaching a local sheet metal shop and asking them to guillotine the strips? This would be much quicker, more accurate and the cost would be minimal.

David

[Nigel Graham 2Participant @nigelgraham2]

For cutting any thin sheet and plate I always try to mount the material horizontally, e.g. by clamping it to the bench edge, foldiong bench, length of timber held in the vice, etc. according to task.

The allows slanting the saw to put a good number of teeth in contact all the time (steadily tilt it carefully vertical for the last little bit when cutting into a corner.)

A lot of the secret of cutting sheet material is access. If you can place yourself with respect to the work so the action is comfortable, it is far easier to obtain good results; but as others say driving the saw still boils down to experience and not rushing!

With enough practice it is possible to saw closely enough to the line for the edge to need little more than some gentle filing to clean up – though I think I'm rather out of practice!

[Perko7Participant @perko7]

I was always told that to cut thin sheets easily they should be clamped to something more solid and both cut at the same time. A waste piece of thin plywood or mdf was usually the object of choice. It made cutting much slower but permitted greater accuracy.

[Michael GilliganParticipant @michaelgilligan61133]

These recent suggestions seem very logical to someone who has a decent solid workbench but, if I understand his previous posts correctly, John’s facilities are necessarily more flexible [in both senses of that word].

MichaelG.

[Dave SParticipant @daves59043]

A jewellers bench peg will clamp onto any decent table, and is the correct thing to use to support thin metal when cutting it with a jewellers saw

Dave

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Dave S on 04/11/2021 11:55:26:

A jewellers bench peg will clamp onto any decent table, and is the correct thing to use to support thin metal when cutting it with a jewellers saw

Dave

.

Yes, I know that, Dave 

But folks seem to be suggesting using a heavy backer, and a hacksaw.

MichaelG.

Edited By Michael Gilligan on 04/11/2021 12:06:50

[Howard LewisParticipant @howardlewis46836]

Has no one suggested shears, preferably bench shears?

The long blade of bench shears will give a cleaner and straighter cut than a saw.

If no bench shears, grip one handle of hand shears in the vice, so that it behaves as a small bench shear..

Less easy if the sheet is longer than the blade of the snips.

Ideally, a guillotine for the job.

Howard

Edited By Howard Lewis on 04/11/2021 22:25:50

[Rod RenshawParticipant @rodrenshaw28584]

Lots of good advice on using a piercing saw above. I have piercing saws and used them sometimes but I am not as well practiced as many who have given the advice.

Looking at the original question I think I would try another way. I removed the hardened jaws from my bench vice years ago and have fitted 6" lengths of mild steel 1" X 1/2" BMS in their place, and these seem to give enough grip for my small work. A little file work and/ or selective packing between jaw and vice ensure that the jaws grip well along the top edge.

I would mark out as needed, and hold the part of the sheet intended to become the workpiece between the vice jaws with the marked line along the upper surface of the jaws. Then cut along the top of the jaws with whichever hacksaw came to hand. The jaws support the thin metal very well so it cannot vibrate and the jaws guide the saw so the cut almost has to be straight. The side of the blade just rests on the jaws, which act as a guide. The jaws do get scarred and worn but are easily corrected from time to time with file or milling machine and are replaced cheaply when needed.

Rod

[Pete.Participant @pete-2]

Posted by Howard Lewis on 04/11/2021 22:25:10:

Has no one suggested shears, preferably bench shears?

The long blade of bench shears will give a cleaner and straighter cut than a saw.

If no bench shears, grip one handle of hand shears in the vice, so that it behaves as a small bench shear..

Less easy if the sheet is longer than the blade of the snips.

Ideally, a guillotine for the job.

Howard

Edited By Howard Lewis on 04/11/2021 22:25:50

Howard, I have mentioned bench shears in a previous thread about sheet metal cutting, I even demonstrated it, the OP drew up a cad model showing potential microscopic edge deformation showing this method wouldn't be suitable.

Since then the OP had the parts laser cut, the laser cut parts he had made looked like they had a rougher edge than the bench shear.

The photo below is the demo I did to show the part would remain flat, but apparently microscopic edge deformation means this is no good.

Edit to add the OPs original method mentioned the edge would be fettled for final finish, so why this microscopic deformation was a problem I don't understand. 

Edited By Pete. on 04/11/2021 23:30:28

[JasonBModerator @jasonb]

Pete, Given that the OP seems to want small pieces of metal he is more likely to want the strip you have cut off than the remaining sheet, could you cut say 10mm x 15mm and still have it flat.

From sheared plate I've had the deformed edge can go back further than the texture from a Laser cut and would need more clean up, see problems in the other threads for that.

I expect a half decent bench shear to be too big/heavy for the op so more likely to be hand held or large tin snips with one handle in a vice.

[Andy_GParticipant @andy_g]

Posted by Michael Gilligan on 04/11/2021 12:02:10:

But folks seem to be suggesting using a heavy backer, and a hacksaw.

MichaelG.

It doesn't need to be a heavy backer – 5 mm thick ply is plenty.

If the ply/metal can be clamped to 'a decent table' it will make sawing easier, but it could be held under one's knee, carpenter style if desired.

Where there's a will, there's a way…

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Andy_G on 05/11/2021 13:30:50:

.

It doesn't need to be a heavy backer – 5 mm thick ply is plenty.

[…] but it could be held under one's knee, carpenter style if desired.

.

If you say so, Andy

But my own attempts at such methods have always produced disappointing results.

In John’s circumstances, I would just get on with learning to use a piercing saw.

… It worked for me, and probably millions of others.

MichaelG.

[Pete.Participant @pete-2]

I didn't forget about the requirement of needing to put it on a shelf when not in use, mine weighs about 12kg and it's no problem putting it on a shelf when not in use , you can buy this small bench shear from a Polish seller on eBay for around £70, it weighs 6kg, I don't think anyone would struggle to put that on a shelf.

The lower blade is also positioned horizontally, so it acts as a small table which is quite useful.

[Pete.Participant @pete-2]

The circled area that was laser cut appeared to look rougher than what I got using a shear, I'm just saying a bench could create 4 straight edges in maybe 30 seconds or so, effortlessly.

Edited By Pete. on 06/11/2021 01:43:27

[not done it yetParticipant @notdoneityet]

Do we know whether the OP requires a straight cut or perhaps a curve? Large shears are good for straight cuts…

I suspect that nobody cuts with a hand saw without finishing by some other method. It seems nonsensical, these days, to make multiple straight cuts in thin sheet materials unless the item is an intricate piece of jewellery or decoration. Shear, guillotine, water-jet, laser, EDM are all better options,I would think, depending on the intricacy/requirements of the cut.

[jaCK HobsonParticipant @jackhobson50760]

Once again, these threads from OP are getting my tool taste-buds drooling. That Polish Shear of Pete's looks just the job!

Saw, shear, laser… whatever… if you need surface finish as well then a final stage of abrasive removal is likely needed – files or stones. So I don't think it matters what method is used to cut… files are probably the next thing, and if super accurate and finish is required, then diamond stones. ie.any saw is not going to give satisfactory results on its own if a high quality shear cut is not appropriate.

OP should help me on my lifetime quest and start a new thread on where to get left handed file – he gets better engagement than me

[jaCK HobsonParticipant @jackhobson50760]

That shear is closer to £90 by the time it is delivered… but still… I can't resist! Perfect compromise for me between capability and size

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