Cutting curves in 1mm thick copper sheet

[David JuppParticipant @davidjupp51506]

Posted by Neil Wyatt on 06/02/2015 17:54:17:

Bet you could get it laser cut for peanuts.

Wouldn't brass be better than copper for this job anyway?

Neil

Only by a company with good gear (though the thickness might be on your side) – the high thermal conductivity makes laser cutting of copper tricky.

[JasonBModerator @jasonb]

I think brian already has the copper and just wants to cut what he has.

Brian, this is the type of handsaw being suggested which is known as a piercing saw or jewlers saw and it can cut very intricate shapes. As the man says you will snap blades as you get the hang of things but they are not that expensive.

Infact a junior hacksaw with a fresh blade that still has plenty of "set" can be made to go round gentle curves quite easily. Now if they only still made abrafiles.

If you want to go with a power tool then a jigsaw with fine metal cutting blade will work but again you would be well advised to practice on some scrap first

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Peter Bond on 06/02/2015 18:10:49:

Nah, I'd still pierce it

.

Peter … I don't want to hi-jack Brian's thread, so I will keep this brief:

Do you work with the pin at bench level, and the saw in your lap [as on the video] ?

Personally, I find it easier to have the work considerably higher … but this may well be driven by the demands of my eyesight.

I would be grateful for your brief thoughts [either here, or by message].

MichaelG.

[JasonBModerator @jasonb]

Brian as I mentioned above a junior hacksaw which I think I have already seen on one of your photos with a new blade will cut curves. This is 1.5" radius OK its 1.2mm brass but same principal will apply to copper, bit wonky part way round as I was trying to video it but can't upload to youtube at teh moment, will try again later.

So save your money and use what you have

[Danny M2ZParticipant @dannym2z]

Posted by Brian John on 06/02/2015 13:03:19:

I find tin snips useless as they distort the metal too much.

I am not sure that a hacksaw can cut curves like that ?

An Abrafile (round) saw blade in a fretsaw frame would be perfect for that job.

Problem is that they seem to have ceased production but are available on *bay.

* Danny M *

[Brian JohnParticipant @brianjohn93961]

If using a piercing saw to cut this copper should I use 32 or 48 teeth per inch ?

NOTE : They are available on ebay from the UK but not at my large local hardware store !

Edited By Brian John on 07/02/2015 04:02:19

[JasonBModerator @jasonb]

If you go by the advice to have 3 teeth in contact then you are going to be looking a 8/0 blades which would be about 2.8 teeth in contact and 70tpi. The 48tpi should do at about 2 teeth in contact and less likely to clog on soft copper.

J

 

Edited By JasonB on 07/02/2015 08:03:20

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Brian John on 07/02/2015 04:00:18:

If using a piercing saw to cut this copper should I use 32 or 48 teeth per inch ?

.

Brian,

Of these, 48 is the much better choice for you.

As I mentioned before; the ideal is at least 3 teeth to the thickness of the material,

Just to clarify the reasoning; this gives

• one tooth 'just entered'
• one tooth 'near the middle"
• one tooth 'just about to exit'

This supports the teeth nicely, and you are much less likely to break the blade.

[Sketch it out, and you will see what I mean]

With practice, you will be able to use coarser blades; because your sawing action will be steadier

• one tooth 'just entered'
• one tooth 'just about to exit"

.

MichaelG.

[Peter BondParticipant @peterbond14804]

Posted by Michael Gilligan on 06/02/2015 19:31:30:

Do you work with the pin at bench level, and the saw in your lap [as on the video] ?

I like the bench pin as high as possible – clavicle level if I can. My Optivisor has a short focal length, which helps.

Having said that, my bench is not quite that high and I use a Benchmate a lot (and a microscope), so it ends up being a compromise – when piercing, I drop the chair down as low as possible and sometimes use a height adjusting plate. Always watching on ergonomics… As soon as I sort some space I'll build a bench just for stone setting.

On TPI and blades – http://riograndeblog.com/2011/02/jewelers-saws-and-blades-demystified/ is quite good. I don't think I'd suggest 8/0 for learning piercing with; they're very, very fine and easy to break. 2/0 will do what's needed with reasonable resilience, speed and finish.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Peter Bond on 07/02/2015 08:17:20:

Posted by Michael Gilligan on 06/02/2015 19:31:30:

Do you work with the pin at bench level, and the saw in your lap [as on the video] ?

I like the bench pin as high as possible – clavicle level if I can.

.

Thanks Peter … We are like-minded.

I have my 'pin' screwed to the top of a wooden post that I clamp in the big bench vice.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by JasonB on 07/02/2015 08:02:56:

If you go by the advice to have 3 teeth in contact then you are going to be looking at … 70tpi.

.

Not really, Jason … Hopefully my bullet points clarified that.

It's a bit like counting fence posts vs fence panels, if you see what I mean.

MichaelG.

[JasonBModerator @jasonb]

Can you explain that Michael?

As I see it the 8/0 has 28teeth per 10mm or 2.8 teeth per 1mm so 1/2.8 = 0.38mm apart.

As per your bullets that would give one just entering at 0.12mm from the edge, one in the middle at 0.5mm and one just about to ecit at 0.88mm. There will be a point where only two are in contact unless the blade has 33 or more teeth per 10mm.

48tpi has the teeth 0.53mm apart so at best you will only ever have 2 teeth in contact and at some points only one

J

[Ian S CParticipant @iansc]

When using the Piercing saw, have a bit of candle with you, and rub that down the blade to lubricate it, copper is a sticky sort of metal to cut (it's soft). To increase the number of teeth in contact with the metal, tilt the saw a few degree foreward.

Ian S C

[Michael GilliganParticipant @michaelgilligan61133]

Posted by JasonB on 07/02/2015 10:15:32:

Can you explain that Michael? …

48tpi has the teeth 0.53mm apart so at best you will only ever have 2 teeth in contact and at some points only one.

.

Jason,

Agreed, 48tpi is very slightly too coarse to get 3 teeth in contact; but it's the better of the two that Brian has found.

I think you may have missed my point about 'fence posts' … For the sake of illustration, draw a blade with 51tpi and see how it fits against 1mm material.

If you prove me wrong, I shall hide in the corner !!

MichaelG.

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