Punching small slots in brass

[sparky mikeParticipant @sparkymike]

I need to punch some small slots in some 1mm.sheet brass. Slots are 1mm X 6mm.

Any ideas welcome.

Mike.

[JasonBModerator @jasonb]

I would think you need to make up a punch and die set. Punch could have the 1 x 6 end milled onto the end of some silver steel. Die milled slot if it is round ended, if rectangulat then make from 4 pieces of gauge plate. Harden and temper both.

[bernard towersParticipant @bernardtowers37738]

As Jason says and dont forget to turn the die over and mill the slot 7 x 1.5 to within a millimetre of the top to give relief for the punch and if poss relieve the punch. to make it easier to be removed from the brass strip

[Clive Brown 1Participant @clivebrown1]

As a possible time-saver, you might get away with avoiding the need for making a die by punching out the slots onto a block of lead. Perhaps success depends on how clean and neat you require the slots to be, and maybe 1mm brass is a bit too thick for this technique.

[sparky mikeParticipant @sparkymike]

Other ways I have considered is plasma/laser cutting, but not sure if they can cut to those dimensions.

Another way could be to chain drill and finish off with a fine milling cutter. The ends of the slots are not critical would not concern me if they were rounded. However I could finish the slots off with a needle file if I have one thin enough.

Have to try a test one first. I do have a set of very fine printed circuit drills, but not sure how long they would last drilling brass. I only have four slots to do at this time, so obviously not worth buying a press tool.

[BazyleParticipant @bazyle]

I suspect there is more of a problem when the slot width is so small compared to the thickness of the material. Have a look at your good old paper hole punch, you know for putting sheets into a loose leaf binder. Note how the end of the punch is not square but scalloped on the end. This produces a shearing cut rather than brute force hammer blow.

[noel shelleyParticipant @noelshelley55608]

Spark eroder ! Noel

[noel shelley]

On noel shelley Said:

Spark eroder ! Noel

👍

[JAParticipant @ja]

1mm slot cutter.

JA

[Russell EberhardtParticipant @russelleberhardt48058]

Depends on how many slots you need to cut but for a small number I wouldn’t bother making a punch.  I would mark out carefully drill just undersize and use a piercing saw blade in a fret saw frame.

https://www.cousinsuk.com/product/vallorbe-super-pike-saw-blades

Russell

[JourneymanParticipant @journeyman]

For just 4 holes  at 6mm x 1mm I would chain drill and use a needle file to clean up.

John

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