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Re: Machining acrylic

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  • rabeet00
    I have little experience buying tools online, but most of the other companies I buy from do indicate stock before you attempt to buy something. LMS does, and I
    Message 1 of 14 , Feb 3, 2002
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      I have little experience buying tools online, but most of the other
      companies I buy from do indicate stock before you attempt to buy
      something.

      LMS does, and I appreciate it. McMaster doesn't per se, but I have
      ordered hundreds of things from them and have never had to wait more
      than few days before they shipped.

      Virtually all of the electronics suppliers do as well. This includes
      DigiKey, Allied, Radio Shack and others.

      So in my case, it seems odd.

      The point is moot in any case as one can always call them on the
      phone, where I am sure they will let you know. I think I will try
      that route with Grizzly next time.

      Ed

      --- In GrizHFMinimill@y..., "jjfear" <jjfear@i...> wrote:
      > I don't know of any company that does this. Every time I have
      ordered
      > anything from Grizzly or several other premium companise. I have
      been
      > notified by email immediatly that the item is not in stick. My
      guess
      > is that opening their inventory to access on the net would be
      > expensive, and probably dangerous from a security standpoint. I
      > wouldn't want my competetors to know what I had or didn't have in
      > stock. A simple bot could log that info.
      >
      > My main complaint is that they do not revise their closeout items on
      > their web site when they've, in fact, been sold out. Otherwise, it
      > seems normal.
      >
    • nplaks
      I very recently joined the minimill group and have just completed going through the 432 messages that have been posted. One point appeared in several postings
      Message 2 of 14 , Feb 7, 2002
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        I very recently joined the minimill group and have just completed
        going through the 432 messages that have been posted.

        One point appeared in several postings concerning the machining of
        acrylic materials. This was the possible use of a device called a
        cold gun for cooling the material.

        Unless one has a huge supply of air available to operate the cooling
        gun, it is probably not a practical device. Two of the companies
        that market similar devices are EXAIR and VORTEC, whose web pages are:

        http://www.exair.com/spotcooling_products/cg_page.htm

        http://www.vortec.com/

        For a very small unit the air requirements are 8 SCFM at 100 psig.
        Somewhat larger units require 15 SCFM at 100 psig. To deliver these
        quantities of air compressors of 5 to 10 HP would probably be
        required. This suggests that these devices would most probably be
        useful in a large shop environment, which has surplus quantities of
        air available.

        For information, I do have a griz minimill, a 7x10 HF minilathe, and
        a Taig lathe. I have been a member of the Minilathe group since mid
        1999. I am considering buying an additional lathe, a 7x12 from
        Homier. One of the wise members of the Minilathe discussion group
        (not me) says that one can not have enough lathes.

        Norman Plaks
        Raleigh, NC
      • Barry Young
        You mean we don t all have a 200 gallon 5 HP compressor? Barry Young ... http://www.exair.com/spotcooling_products/cg_page.htm ...
        Message 3 of 14 , Feb 9, 2002
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          You mean we don't all have a 200 gallon 5 HP
          compressor?

          Barry Young


          --- nplaks <nplaks@...> wrote:
          > I very recently joined the minimill group and have
          > just completed
          > going through the 432 messages that have been
          > posted.
          >
          > One point appeared in several postings concerning
          > the machining of
          > acrylic materials. This was the possible use of a
          > device called a
          > cold gun for cooling the material.
          >
          > Unless one has a huge supply of air available to
          > operate the cooling
          > gun, it is probably not a practical device. Two of
          > the companies
          > that market similar devices are EXAIR and VORTEC,
          > whose web pages are:
          >
          >
          http://www.exair.com/spotcooling_products/cg_page.htm
          >
          > http://www.vortec.com/
          >
          > For a very small unit the air requirements are 8
          > SCFM at 100 psig.
          > Somewhat larger units require 15 SCFM at 100 psig.
          > To deliver these
          > quantities of air compressors of 5 to 10 HP would
          > probably be
          > required. This suggests that these devices would
          > most probably be
          > useful in a large shop environment, which has
          > surplus quantities of
          > air available.
          >
          > For information, I do have a griz minimill, a 7x10
          > HF minilathe, and
          > a Taig lathe. I have been a member of the Minilathe
          > group since mid
          > 1999. I am considering buying an additional lathe,
          > a 7x12 from
          > Homier. One of the wise members of the Minilathe
          > discussion group
          > (not me) says that one can not have enough lathes.
          >
          > Norman Plaks
          > Raleigh, NC
          >
          >
          >
          > To unsubscribe from this group, send an email to:
          > GrizHFMinimill-unsubscribe@yahoogroups.com
          >
          >
          >
          > Your use of Yahoo! Groups is subject to
          > http://docs.yahoo.com/info/terms/
          >
          >


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        • rabeet00
          Update on acrylic: The task I have in mind is to bore round pockets into 1+ cast acrylic, and have a clean enough finish that I can wet sand the result into
          Message 4 of 14 , Feb 15, 2002
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            Update on acrylic:

            The task I have in mind is to bore round pockets into 1+" cast
            acrylic, and have a clean enough finish that I can wet sand the
            result into being nearly perfectly clear.

            So now that I have a mill, I tried the most blunt thing I could think
            of - I mounted up a 1" end mill, brand new and very sharp (cut my
            hand just mounting the thing in the holder).

            I ran the mill at low speed with the shifter on low/high torque and
            fed the mill in very slowly.

            It made very long trails of swarf. The mill did not budge, though I
            was startled at some of the sounds the cutter made. ;)

            The resulting pocket seems to be perfectly round, and has a better
            finish than I had figured for. Neither the swarf or the material got
            warm, let alone hot enough to melt it.

            Next I will try using the boring bar to make an even cleaner finish
            on the sides. If anyone knows of a tool one could use to finish up
            the bottom of the pocket on a mill (yeah I know, get a lathe) I would
            appreciate knowing about it.

            Ed
          • rabeet00
            Hrmph, so I tried a boring bar and the result is a quite different finish. That is, not nearly as nice as the end mill made. Is this feed & speed thing? Or how
            Message 5 of 14 , Feb 15, 2002
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              Hrmph, so I tried a boring bar and the result is a quite different
              finish. That is, not nearly as nice as the end mill made. Is this
              feed & speed thing? Or how shart the boring bar is(n't)?

              Sorry if I am boring (heh) you with all my questions. :)

              Ed

              > The task I have in mind is to bore round pockets into 1+" cast
              > acrylic, and have a clean enough finish that I can wet sand the
              > result into being nearly perfectly clear.
              >
              <snip>
            • nyroadrocket@nyc.rr.com
              I have not seen this Rex mill everyone is talking about. Any photo s out there? Cheers, Jordan in NYC
              Message 6 of 14 , Feb 16, 2002
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                I have not seen this Rex mill everyone is talking about. Any photo's out
                there?



                Cheers,

                Jordan in NYC
              • rabeet00
                Bill has photos of his in a folder on the Photos section of this group. I think what they are is a Taiwanese made version of the older Atlas CH-10 mini mill,
                Message 7 of 14 , Feb 16, 2002
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                  Bill has photos of his in a folder on the Photos section of this
                  group.

                  I think what they are is a Taiwanese made version of the older Atlas
                  CH-10 mini mill, the precurser to the ones sold by Grizzly, Harbor
                  Freight, etc. Here is a guy that has the Atlas:

                  http://www.billsbest.com/thatlas.html

                  It looks a lot like mine.

                  REX, then takes those and reworks them to be more true, stiffens up
                  the column and replaces the Z rack and pinion drive with a lead screw
                  and handle. He also makes all of the lead screws 10 dpi.

                  The differences between the basic CH-10 and the newer Grizzly et. al.
                  mill are the CH-10 has a belt drive, slightly different spindle
                  design, different electronics (no need to be at low speed to start
                  the spindle). The basic CH-10 also does not have the fine feed found
                  on the new ones.

                  Other differences are the column and head are aluminum while I
                  believe the Grizzly is pretty much all iron. Seems REX does other
                  custom modifications such as those to Bill's mill. I think I recall
                  Bill saying his column is iron, and his spindle is R8 vs. MT3.

                  Ed

                  > I have not seen this Rex mill everyone is talking about. Any
                  photo's out
                  > there?
                  >
                  >
                  >
                  > Cheers,
                  >
                  > Jordan in NYC
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