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7470RE: [PPLetterpress] Re: die cutting jacket

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  • wa0dfw@copper.net
    Feb 1, 2007
    • 0 Attachment
      I don't know why you have a problem logging in...you use your email
      address and password.

      Anyway, here is the whole thing from that site, unedited.

      Mo




      Date: Fri, 2 Aug 2002 13:10:01 -0600
      Reply-To: Letterpress Discussion List <LETPRESS@...>
      Sender: Letterpress Discussion List <LETPRESS@...>
      From: Leonard W Molberg <mail-to-mo@...>
      Subject: Die cutting - a short primer - it's not that difficult!
      Content-Type: text/plain; charset=us-ascii

      I'm surprised at some of you who haven't tried it. It is really quite
      a
      simple process, though, like printing, can have it's challenging
      moments.

      It's really nothing more than a straight knife edged rule which, if
      serrated, would be a perfing rule. I assume you all perf occasionally.
      Use a perfing rule against the side of another rule and you've the
      simplest, cheapest and sometimes best perfing setup.

      Die cutting is similar, you just do it, more often than not, in other
      than a straight line. If you want to just slit something just use a
      piece
      of cutting rule like a perfing rule.

      You need three things - a letterpress, a steel rule die (usually made
      by
      a die making specialist) and a die cutting plate or jacket. It can be
      done on a cylinder, but I'll stick with platen presses here (I do
      almost
      all my die cutting on Kluges)

      A simple piece of stainless steel sheet, about 20-22 gage, will slip
      under the tympan inplace of the pressboard. If your platen is set
      fairly
      high you will probably want to order the die with .918 rule, but .937
      seems to be more standard for die cutters for some unknown (at least
      to
      me) reason. A piece of mild steel sheet will work, even cut from the
      bottom of a galley, but the die seems to raise a 'burr' on it which
      fights you when pulling the piece out. Stainless doesn't seem to do
      that
      for some reason. You might be able to get a piece from a local sheet
      metal shop, cut to your platen size.

      For narrow dies, you can tape down the side of a perf or cutting or
      scoring rule to cut against with good results.

      If you decide to spend more ( a LOT more!) money, you can oder a
      hardened
      and ground steel die cutting plate for your platen, but for simple
      jobs
      the cheaper plate is quite adequate. If you're careful about your
      impression and makeready, you will not "emboss" the plate and it can
      be
      reused hundreds of times. Even if you slightly impress it, it probably
      won't keep you from reusing it. I've seen some in pretty bad shape and
      still serving well. If you get careless, well...it's just like getting
      careless any other way. Bring up the platen packing underneath until
      the
      die just cuts properly, level the platen with the platen screws if
      necessary, then if any piece of the die rule doesn't want to quite
      cut,
      makeready under the bottom of the die with "lick and stick" gummed
      stock
      or tape or whatever you wish, just like bringing up a low spot of your
      type from under the type, rather than trying to makeready under the
      tympan.

      You can also have combination cut/score dies made, but it gets more
      complicated, as you have to consider the stock thickness and order the
      score rules appropriately high. On cylinder presses, the dies need to
      have higher rules in one direction than the other, so it pays to start
      simple.

      You can put the plate under the tympan, bring up your packing until it
      just "clicks" through the tympan, then cut a margin around the die
      area
      (preferably after setting your gage pins) then tape around it with
      Scotch
      tape just outside the die area. If your clearance is too tight, fasten
      the plate down on top and double sticky tape home made gage pins of 6
      pt
      slugs to the plate. I do this all the time, the Scotch double sticky
      tape
      is thin enough that it doesn't cause problems and it stays put even
      with
      the press at higher speeds. You can double sticky tape a "tongue"
      made of
      2 pt lead to the top of the slug. If you nick that kind of gage pin or
      tongue, you probably won't damage the rule in the die.

      Lock up the die just as you would any other job and, of course, remove
      the rollers from the press before you die cut.

      If you have a real problem getting the sheet out of the press without
      it
      coming apart, you can "nick" the rules slightly to provide a very thin
      bridge to hold the sheet together, but when hand feeding it should
      not be
      a big problem.

      You'll figure out things as you go, but it's really a fairly simple
      operation, especially things like circles, windows in covers, and
      other
      simpler shapes. You can even cut your own rules for rectangular or
      square
      holes and lock them up just as you would any other form. If your lead
      and
      slug cutter is good and sharp, you can cut rule on the back side
      without
      hurting the cutter, then you can slighly bevel the ends on a bench
      grinder to get a tight corner. Then, if you wish to keep the setup you
      can cut wood and glue around the rules, using your chase and quoins to
      clamp them while glueing. I have several home made dies made this way.

      You will need "corking" or ejection rubber around the rules to keep
      the
      sheets from sticking on the cutting rule, especially in corners or
      holes
      or whatever. You can use half inch thick weather stripping rubber
      with a
      sticky back with good success, though die makers have many special
      types
      of "corking" available to suit the application.

      Rolodex cards are easy to die cut with a good die, but harder to get
      out
      of the sheet due to the little slots in the bottom wanting to hang
      on. I
      have my rolodex dies made with a rule clear across the bottom, then
      the
      small pieces come out over a home made "striping" die with a home made
      punch and hammer. I just finished a 43,000 run of 2-up door hangars
      and
      have a simple stripping die made of a piece of die board (plywood or
      anything else) with two holes slightly larger than the punched hole,
      set
      up in a spare chase with a few reglets sticking up at approximately
      the
      gage pin locations. This allows me to punch out a whole stack of
      holes. I
      try to keep the die set up to allow the piece to come out whole, then
      break out the die cut places in stacks.

      Be inventive. I'll try to answer questions if you have any, as would
      probably a hundred other list members.

      Mo
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