I'm not punching cleanly...

[bricol]

There is absolutely no way you've got the necessary precision for the required clearance between individual punch and die with that set up for a clean, burr free, cut, never mind for all those together.

I'm not near the info I need at the moment, but when I get into work, if I remember, I will have a rummage for the supplier of punch and dies of very similar size that I used on a machine I designed a few years ago that is bashing out a few hundred thousand holes per set before the punch and die need re-grinding. Their website has all the info you need for clearances etc - and if I remember correctly, the price per punch/die was small enough for it simply not to be worth making your own.

 

[Gareth J]

What's the outcome for? Considering you have the setup now and know how to dress the ends of the punches, if precision isn't paramount and you only want a dozen or so, maybe just deburring the burrs that occur will be sufficient?

 

[oldbikedavey]

There is absolutely no way you've got the necessary precision for the required clearance between individual punch and die with that set up for a clean, burr free, cut, never mind for all those together.

I'm not near the info I need at the moment, but when I get into work, if I remember, I will have a rummage for the supplier of punch and dies of very similar size that I used on a machine I designed a few years ago that is bashing out a few hundred thousand holes per set before the punch and die need re-grinding. Their website has all the info you need for clearances etc - and if I remember correctly, the price per punch/die was small enough for it simply not to be worth making your own.

The Roper - Whitney website is a mine of information on the subject of punching holes through things.....

 

[bricol]

Dayton Progress in Kenilworth.

Website has info on clearances - goes without saying, you need a robust, precise, guiding system for the punch and die to avoid all the issues you are having, never mind the reduced punch & die life.

I used their punches and die-buttons in a system that was punching holes in 300 products a minute - die life was in excess of 200,000 operations on average - which is still crap, but a whole lot better than the original one-shot punch systems designed in the US that managed one or two operations - literally, one or two holes created from a punch/die set before needing regrinding!

My punch moved into the die just over 1mm, that was enough to punch clean and push the slug far enough into the die-button to be ejected out the bottom - and important consideration for automatic operation. Lubrication was important to tool life too. We tried angled punch tips to reduce force, but ended up back with a flat tip.

Used a 0.187" punch through 1mm material.

A punch and die set cost around 20 quid looking at my notes from 2016 - and yes, I can hear the "I can make it for 50p . . ." but they were simply fit and use, saving much more than the extra £19.50.

Subsequent operation them drove a forming tool through the hole to form a "chimney" for a later insertion of another component. Vision systems in the machine inspecting the size, shape of the hole, its position, for any burrs etc.

I think you would be better off aligning one punch and die properly, and creating something to relocate your component in the positions you require the holes, as I'm guessing the precision of hole locations will be rather less than the positional accuracy required for the arrangement of punch & dies that you cannot hope to create with a rule, center-punch and a pillar drill.

 

[jsf55]

If it's a large amount of these to be done it would be worth investing in a die set
No connection and others out there

Die Sets - Standard & Bespoke, Pressfit Or Demountable Pillars & Bushes

Die Sets - Wide range manufactured inhouse to customer requirements, using the highest quality materials. Bespoke service with a price & delivery advantage throughout the UK

www.berger-tools.co.uk

 

[iNf]

After re-reading what you wrote I think that the issue is you may have mixed up 'silver steel' with high speed steel 'HSS'
As stated above silver steel is easily machined then you harden it by heating to cherry red then dunking in water.
If you're using hss you're not going to machine it in the lathe. You usually shape it by grinding. See @pete above technique will also work with hss albeit a bit slower.
Do you have a link to what you bought?

 

[Erie Fred]

I didnt mean underneath. A lot of press tools have a sprung plate that is on the top die and holds the work before the punches hit it. It stops the folding up of the workpiece.

For such thin material, you could slip a bit of rubber hose over each of the punches (because they're currently "too long" anyway).

Known as a stripper.
It holds done the blank, and then strips off the piece from the punch.
urethane tube is a common one, but plain old rubber hose works.

 

[Erie Fred]

Rule of thumb I recall for punch/die clearance is 10% of the material thickness.
So the OP needs to up his game on accuracy a wee bit.

 

[Kram]

If you're using hss you're not going to machine it in the lathe.

You certainly can! CBN inserts make it quite easy, ( chinese ones are good enough and cheap) does not even stress the lathe, just to be mindful not to leave hard swarf on the ways. Sharp edged carbide will also do it but need sharpening often.

I wont suggest its as good as grinding, tho probably quicker but not everyone has a decent grinding setup.

 

[Beanwood]

Wow - what a load of stuf to take in. Thanks all.
Firstly - I fully acknowledge my pin cutting is less than optimal. Admittedly, I'm embarassed to se @Pete. can do in about a minute what to me appears impossible - but I'll get somewhat closer than I have now.
Stripper plate - yes I have been using one, with minimal clearance. I hadn't connected it properly, which I thnk probably accounts for a few of the marks on th epunch pins. (I wish I'd thought to photgraph and blow them up to see where I was going wrong, before I showed you lot!!
I think that a few of the die holes now look as if they're a tiny bit damaged.
Talking of die holes - I think the size is about right - 4mm drill for the 4mm Silver Steel (Not HSS) so given any slight drift on my pillar drill will equate to about 4.1mm - which once I get everythng else sorted out I'm happy to look at again.
I completely agree - I'm not in the league of matching professionally made punch and die here - but for context - I spoke to my local small engineering company for a smaller and simpler punch/die - 8 holes of 4mm in a 15mm circle give or take - and he was sure it would be well into 4 figures for them to produce. The product I'm making will sell for about £2, with over £1 of materials - and if I sell 500 a year to start with, I'll be pleased. As you can imagine £2k for a press is 4 years of profit - that's not a business plan I can work with.

Where do i go from here? Well - back to the workshop obviously.

It won't be until the weekend - I'll get a new cutting disc (Last one is worn down now) but with that, my bench grinder, belt sander, and my collet set for the lathe due to arrive tomorrow, I'm hopeful I can get a cleaner cut on the ends.

I've never been a precision engineer - so this is going to test me - but heck - I'm confident in achieving this. I shall be digging out the microscope to look at them more closely before I release them to you all for critique again.

 

[ukracer]

Have you thought about using a circular part of a dual.sander. adding a jig or two way vice.


might take you a few discs to get the pins level. But.........i am sure you could rig something up.

 

[Beanwood]

Little update for you all.
It's taken some work on the 50grit disc sander, some polishing off te burrs on 120 grit, and a final rub on a bit of leather to achieve something half tidy.
I still need to address the stripper plate (It doesn't yet have springs to push it off cleanly, so I'm distorting the holes when I remove it) but I feel a whole (Hole?) lot closer than I was last week.
But it appears fairly consistent now.

 

[Beanwood]

New problem
I have switched back to tin lids from aluminium. Punch holes are still not quite perfect but they are getting better. But what would cause the two tags to remain? Is it likely to be an enlarged hole, or slightly out of alignment pin?

 

[Pete.]

That is still too much punch clearance.

Why not just set up one punch and do them individually? It would require such a trivial setup it seems like a no-brainer.

 

[Erie Fred]

New problem
I have switched back to tin lids from aluminium. Punch holes are still not quite perfect but they are getting better. But what would cause the two tags to remain? Is it likely to be an enlarged hole, or slightly out of alignment pin? View attachment 434373

Alignment of what "Pin" to what ?
Punch & Die.
Not the stripper plate.

 

[Beanwood]

Alignment of what "Pin" to what ?
Punch & Die.
Not the stripper plate.

Yes- two of the 18 pins in the punch are not producing a clean cut. I suspect it’s an alignment issue of the punch and die but I don’t know if the tag is on the‘tight” or “loose” side. It was cutting ok until I had to take the die out of the press.

 

[bricol]

Sorry, but I can't see a single cleanly punched hole in that last picture.
Unless of course you are trying for the uneven distortion, poor cut, burrs etc on every hole.

 

[Beanwood]

Sorry, but I can't see a single cleanly punched hole in that last picture.
Unless of course you are trying for the uneven distortion, poor cut, burrs etc on every hole.

No that’s not the look I’m going for.
Give me an idea if you’re able please of how to improve it without spending thousands (as I know you do) on creating a punch and die.

 

[Erie Fred]

While I have not aligned a ;punch & die in a die set, my toolmaker friends do this all the time.

They tell me to lay the die set on it's side, push the set together so the punches are in the die holes, and shine a light
from the punch side.
The clearance will be quite visible, as well as how centered it is.

That's how they do it.

 

[DanZac]

But what would cause the two tags to remain? Is it likely to be an enlarged hole, or slightly out of alignment pin?

Give me an idea if you’re able please of how to improve it without spending thousands (as I know you do) on creating a punch and die.

As @Pete. said, your punch/die clearance is too large. From your pictures it looks like the clearance is sufficient for the material to fit between the punch and die allowing it to bend down into the die hole and not be cut off. Which is also why the other holes are burred over.

Have a look at the clearance calculators on line to see what your clearance should be.

Personally I'd agree with the other suggestions to start with a single hole punch which should be easy to make to the correct tolerances, and move your material for each hole. A simple jig will allow repeatability.