I'm not punching cleanly...

[Beanwood]

I am responding to the direct question of the OP, quoted below in case you missed it:

"Does anyone sell pre-cut/ground silver steel?"

To be sure, the dowel pins only answer half the question (pre-cut) but it is a start and might provide inspiration for someone else to chip in with something that fully answers the question.

---

A lot of useful information is here:

punch and die design-1.pptx

The document discusses the design of punches and dies used in sheet metal cutting operations. It covers topics such as the cutting action in a die, stresses during cutting, clearance between the punch and die, factors that affect minimum hole size, and blanking die design. Key points include...

www.slideshare.net

..and it's appreciated. I did briefly think about dowel pins, but quickly discounted them.

I DID however think about buying 8 more pieces of silver steel, and using the already prepared ends as punches, (Discarding the middle sections until I can practice and get the ends square myself.)

 

[Beanwood]

You havn‘t got anything to hold the plate flat whilst punching. Surely you would need a pressured plate when doing that many holes?

The tin lids being punched are thin (Well under 1mm) so I'm happy it's supported well enough (Probably)

 

[Screwdriver]

The tin lids being punched are thin (Well under 1mm) so I'm happy it's supported well enough (Probably)

Hang on did I miss a step? Are you not using a die??

If not, there's your problem. At the very least you want a softwood backing (the holes will sort themselves out) or relatively soft silicone/rubber matting.

 

[Beanwood]

Hang on did I miss a step? Are you not using a die??

If not, there's your problem. At the very least you want a softwood backing (the holes will sort themselves out) or relatively soft silicone/rubber matting.

Yes, I'm using a die - it's that circular plate with 24 holes in it .

 

[DanZac]

Additionally to the points above, its hard to see properly from the picture, but it looks like there's quite a countersink / deep deburr on some of the holes on your die?

I'm no expert but I'd have thought that you need a smooth surface and a close fit on the punches otherwise the punched material will deflect into the deburr / countersink before it starts to punch through?

 

[iNf]

I might be missing something here, but if you have a lathe why don't you face off the ends of the cut bar?
Are you using already hardened silver steel?

 

[Beanwood]

Additionally to the points above, its hard to see properly from the picture, but it looks like there's quite a countersink / deep deburr on some of the holes on your die?

I'm no expert but I'd have thought that you need a smooth surface and a close fit on the punches otherwise the punched material will deflect into the deburr / countersink before it starts to punch through?

There is supposed to be the slighest difference in holes to punch - but it's something like the hole being 0.1mm over the punch size. But the hole being too small actually demonstrates the problems I'm having - as the metal won't fracture at the correct point, but will just get stretched to breaking point.

I'd like to think the picture is deceptive re deburring - but now I'm not completely sure. Once I get the punch ends square and sharp, I may just take the lightest skim off of the die to ensure there is no countersink on the holes.

 

[Beanwood]

I might be missing something here, but if you have a lathe why don't you face off the ends of the cut bar?
Are you using already hardened silver steel?

No, you're missing nothing unfortuately. I'm waiting for some collets (And collet chuck) to arrive so I can do exactly that. I tried gripping the silver steel in the 3 chuck - but it won't grip sufficiently.
I tried to use a piece of aluminium turned down, with a suitable size centre hole - and I couldn't make that work either....
Perhaps I'll just go back to watching TV instead of playing with metal work

 

[iNf]

Either your 3 jaw chuck is completely knackered or is the steel hardened?
Regarding the aluminium bar, drill hole same diameter as the rod take out of chuck and hacksaw a slot length way along right through to the hole, (a split collet) place the rod in the hole and insert in the chuck with the slot in between 2 of the jaws it should grip enough to face off the ends

 

[DanZac]

Perhaps I'll just go back to watching TV instead of playing with metal work

Whatever you do. Don't do that.

Keep going, it's all a learning experience, and you'll get it right if you keep at it.

 

[Pete.]

Definitely keep going.

For cheapo punches you could look at buying a box of 5mm drill bits and cut them off just below the spiral. Should still be in the hardened zone.

 

[500e]

Punch and die need to be a polished finish all the burrs removed, both on the die and the punch, the gouges in the die will help cause tearing rather than cutting.
Reade @Pete. #15 post squaring up the punches is not to difficult. the clearance on that thickness metal in minimal almost nothing.
Watching TV is depressing dont do it your satisfaction factor will be much higher when you get it right
The punch holder looks good and getting all the holes in the die in alignment was the hard bit

 

[Kram]

How did you drill the two dies, such that they are exactly aligned? I know if I drilled two circles like that, none of the holes would line up , no where close enough for a die.

If you need help I can cut off some hardened pins. Got quite a bit of silver steel here.

I'd perhaps look at lathe HSS toolbits as they are probably best you can get for this purpose, just carefully cut them with grinder without getting them too hot.

I note the pins stick out your die a reasonable distance if your only cutting holes in thin sheet. I would shorten quite a bit.

You may well be right - didn't realise I could use a hacksaw wrongly - but it literally just skids on the silver steel, and won't cut it
Pick any size you like from 3mm 4mm or 5mm - I have the same issue with each.

Silver steel is usually sold in the annealed state, which turns and saws beautifully. If yours is already hardened then it will need to be cut by grinding and with care not to over temper it unless tou want to reharden/temper afterwards, which wont be difficult at that size
How many parts do you intend to stamp with these dies?

 

[ukracer]

But HOW do I get the silver steel dead square and sharp edged - it's only 4 ot 5 mm???

In a lathe.... just noticed you have one.
If your 3 jaw won't grip it you need to sort it. It's probably bellmouthed.

 

[500e]

Presume he drilled the holder then made a center punch to mark the die.
Or maybe welded both together and drilled through.
@Beanwood
Read @Pete. #15 & @iNf #29
You have got yourself in a brain loop read the post look at the pictures it is not difficult.
We all get these blocks till someone says do it this way "Simples" but clean the die face get rid of All the burs gouges, cut the pins down in length.
Never done multiple punching or in thin sheet (we punch 10mm + on an iron worker) , someone here will have, maybe getting all the punches level will help in thin metal as it will tend to hold sheet tighter.
How do you strip the punched item being that thin

 

[Erie Fred]

Lining them up in the fly press (Interlocked), and locking them in place before liting the press arm.

There is clearance between punch & die.
how did you center it ?

 

[Screwdriver]

Didn't see the die plate earlier and was confused by the "supported well enough" comment. They are supported perfectly!

What would be useful I suggest is a sliding guide to ensure perfect registration. Assuming you have drilled those holes to perfection near as dammit, I'd suggest bolting something around the outside of the punch and die to keep them aligned. Might be overkill depending how many you're doing but as has been said, the punch/die clearance needs to be minimal and the edges as sharp as possible.

A good way to quickly and easily sharpen up or dress the punches would be a glass plate with emery - so long as they're set to the same height/projection from the punch holder. If they can be set so that they're only just sticking out, I'd still dress them first in a lathe though. Also when punching, you really only need them to protrude just a bit more than the thickness pf the workpiece.

If you want to really go overboard, you could fit a few springs over the punches or scattered around the plate to aid with removal. Soft urethane also works well as a stripper... Must be a nightmare stripping the punched item off once those punches go so far through the workpiece.

 

[Screwdriver]

...though I just note you are using a fly press when for some reason I thought you said you were using a drill press!

With a fly press, the die plate will bend and distort if it is not really well supported.

 

[Ton-up]

The tin lids being punched are thin (Well under 1mm) so I'm happy it's supported well enough (Probably)

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.

 

[Screwdriver]

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).