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RE: :: Re: [medievalsawdust] Another basic question

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  • Schuster, Robert L.
    And make the holes for the rivets oversized, so there is room for movement. Otherwise it s likely to warp when the humidity changes. --nice piece of advise
    Message 1 of 9 , Jun 27, 2003
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      And make the holes for the rivets oversized, so there
      is room for movement.  Otherwise it's likely to warp when the humidity changes.

       --nice piece of advise there Colin
      i hadn't considered this.
       
      Halvgrimr
       
    • vinlandar
      This is sounding more and more reasonable the longer I think about it. Humidity will, it would seem to me, affect that wood a lot more than it will affect the
      Message 2 of 9 , Jun 27, 2003
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        This is sounding more and more reasonable the longer I think about
        it. Humidity will, it would seem to me, affect that wood a lot more
        than it will affect the metal strapping on the back.Maybe I -should-
        give it room for contrasting expansion and not glue the strapping to
        the boards but rivet them with slightly oversized holes.

        -Thanks!
        -Charlie


        --- In medievalsawdust@yahoogroups.com, "Schuster, Robert L."
        <Schusterrl@u...> wrote:
        > And make the holes for the rivets oversized, so there
        > is room for movement. Otherwise it's likely to warp when the
        humidity changes.
        >
        > --nice piece of advise there Colin
        > i hadn't considered this.
        >
        > Halvgrimr
      • Tim Bray
        I ve put up another of my quick-and-dirty overviews of one type of furniture, this time for those late Gothic benches and stools:
        Message 3 of 9 , Jun 27, 2003
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          I've put up another of my quick-and-dirty overviews of one type of
          furniture, this time for those late Gothic benches and stools:
          http://www.albionworks.net/Stools/STOOLS.htm

          Give it a look and tell me what you think. Critical reviews gratefully
          accepted!

          Also, I'm interested in figuring out when these things first appeared. The
          earliest one that I know of is from a Van Eyck of the 1430s. Anybody have
          any earlier sources?

          Cheers,
          Colin


          Albion Works
          Furniture and Accessories
          For the Medievalist!
          www.albionworks.net
          www.albionworks.com
        • Bruce S. R. Lee
          Be very careful with burning any coating off metal parts - be they bolts, nuts or pipe. These days you have to be a metallurgist to tell exactly what s in
          Message 4 of 9 , Jun 28, 2003
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            Be very careful with 'burning' any coating off metal parts - be they bolts,
            nuts or pipe. These days you have to be a metallurgist to tell exactly
            what's in the metal coating - some hardware has cadmium plating, and even
            zinc (real gal) is not too good for you in the long run, and for
            'zincalume' plating there is the theory about aluminum & Alzheimers....;-(

            Better to give it a good grinding first to get the plating off the exposed
            bits before heating to give it a 'patina'. If you REALLY have to burn
            something, do it way, way outside on a day with a stiff breeze & keep an
            eye out for the EPA.

            regards
            Brusi
          • James W. Pratt, Jr.
            OOPS you are correct!! I have been a farm blacksmith for too long where the forge, anvil, and tree are all within two steps and upwind is always on one side
            Message 5 of 9 , Jun 28, 2003
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              OOPS you are correct!! I have been a farm blacksmith for too long where the
              forge, anvil, and tree are all within two steps and upwind is always on one
              side of the forge.

              James Cunningham

              > Better to give it a good grinding first to get the plating off the exposed
              > bits before heating to give it a 'patina'. If you REALLY have to burn
              > something, do it way, way outside on a day with a stiff breeze & keep an
              > eye out for the EPA.
              >
              > regards
              > Brusi
              >
              >
              >
              >
              > To unsubscribe from this group, send an email to:
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              >
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              >
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            • Joseph Hayes
              ... Stools are way older than that. When they become fossilized, they re called coprolites. Ulrich ...sorry I have ADHD and couldn t help myself...
              Message 6 of 9 , Jun 30, 2003
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                > Also, I'm interested in figuring out when these things first
                > appeared. The earliest one that I know of is from a Van Eyck of the
                > 1430s. Anybody have any earlier sources?

                Stools are way older than that. When they become fossilized, they're
                called "coprolites."

                Ulrich
                ...sorry I have ADHD and couldn't help myself...


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              • guydemontange
                ... the ... they re ... Now where did I leave that sturgeon? ;)
                Message 7 of 9 , Jul 1, 2003
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                  --- In medievalsawdust@yahoogroups.com, Joseph Hayes <von_landstuhl@y.
                  ..> wrote:
                  >
                  > > Also, I'm interested in figuring out when these things first
                  > > appeared. The earliest one that I know of is from a Van Eyck of
                  the
                  > > 1430s. Anybody have any earlier sources?
                  >
                  > Stools are way older than that. When they become fossilized,
                  they're
                  > called "coprolites."
                  >
                  > Ulrich
                  > ...sorry I have ADHD and couldn't help myself...

                  Now where did I leave that sturgeon? ;)
                • rmhowe
                  ... You know I hadn t either. That s a good point. Most wood (and plywood) expands/contracts about 1 1/2% along the grain but as much as 6-8% across the grain
                  Message 8 of 9 , Jul 6, 2003
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                    Schuster, Robert L. wrote:
                    > And make the holes for the rivets oversized, so there
                    > is room for movement. Otherwise it's likely to warp when the humidity
                    > changes.

                    > --nice piece of advise there Colin
                    > i hadn't considered this.
                    >
                    > Halvgrimr

                    You know I hadn't either. That's a good point.

                    Most wood (and plywood) expands/contracts about 1 1/2% along
                    the grain but as much as 6-8% across the grain depending
                    on species and humidity.

                    When I look at rivets for bosses or ship's roves (rivets) I am
                    frequently amazed by the huge heads on these things - meaning
                    how flat and wide they are. It seems to be (by some experience)
                    that normal mild steel won't spread that far - I'm fairly sure
                    it won't without splitting or by heating and hammering a lot.

                    In normal riveting which we do in armor making the mild steel
                    rivets we normally use should be clipped off at 1 1/2 times
                    the shank diameter of the rivet past the point where it emerges
                    through the materials. This wouldn't make the large, flat, wide
                    heads I normally associate with the shield rivets I've seen in
                    most archaeological depictions, and I don't see regular rust
                    spreading out that far beyond the edges. The size of their
                    rivet shanks was probably much larger than ours.

                    What they had was wrought iron, or iron that has had about 7
                    percent silaceous slag hammered back into it to make it workable
                    after smelting. I've never tried to rivet with this stuff with
                    a narrow crosspeen hammer but it must work much differently
                    before work hardening.

                    Maybe an air hammer might produce fast enough blows to cause
                    enough friction from metal movement producing heat and
                    preventing work hardening enough to spread the rivet head out
                    to look like the real stuff, but somehow I doubt it. I'm
                    certain that hand hammering won't. Or did they put it in
                    red hot?

                    Magnus
                  • rmhowe
                    ... Yeah but we re all been eating out of aluminum pots and pans all our lives, and consuming candy wrapped in aluminum foil as well. I don t think you can
                    Message 9 of 9 , Sep 1, 2003
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                      Bruce S. R. Lee wrote:
                      > Be very careful with 'burning' any coating off metal parts - be they bolts,
                      > nuts or pipe. These days you have to be a metallurgist to tell exactly
                      > what's in the metal coating - some hardware has cadmium plating, and even
                      > zinc (real gal) is not too good for you in the long run, and for
                      > 'zincalume' plating there is the theory about aluminum & Alzheimers....;-(

                      Yeah but we're all been eating out of aluminum pots and pans
                      all our lives, and consuming candy wrapped in aluminum foil
                      as well. I don't think you can avoid aluminum much in the
                      modern world. There are lots of soft drinks with citric
                      acid in them in aluminum cans, and for many there is BEER...

                      MajicBadger used to smelt brass in his open forge to cast it.
                      What happened to him was BrassFounders Ague. Massive headaches,
                      various other bodily syptoms for quite a while. I am told it
                      is rather like malaria at times. Eventually goes away.

                      I've seen Master Eldred cast with a cutting torch as a heater
                      and trying to stand out of the huge amounts of fumes as the
                      zinc gradually burned out of the brass. Tin/copper makes Bronze.
                      I think he may have had milder symptoms. He melted in
                      an open crucible and poured it into wooden or metal
                      sand casting flasks right on top of a block wall.
                      Still in one piece. Some folks are just lucky.

                      I recommend casting over a sand table with a splashguard
                      on your side of it. In industrial arts our casting sand
                      table was low but it was on rollers. Melted metals which
                      are hot enough can hit concrete, and spall themselves
                      and bits of the concrete off by a steam reaction from
                      liberating the water in the concrete. Happens very fast
                      I am told.

                      Cadmium is considered quite hazardous, particularly in the
                      jewelery field where it was in so many solders. I once read
                      that jewelers (and welders) have about ten years less life-
                      span. Many plating solutions were cyanide based - most
                      of the briter ones. I'm not sure if someone has licked
                      the silver plating without cyanide successfully yet.
                      This is why I have three fume hoods to install in
                      my shop as well as a localized movable dust extraction
                      system with a much smaller micron bag to add to it.

                      I had tried doing bone carving, which I love, and I was
                      producing a few really good pieces. Unfortunately the
                      muscles in my arms and back won't handle it now and
                      I am going to have to switch over to electrical rotary
                      tools and pneumatic engravers. The high rpm ruby burrs
                      scare the mess out of me making dust that tiny. After
                      a particle size gets too small your cilia in the lungs
                      can't expel it as it gets below the cilia heads.

                      Two years ago I damned near died of something causing
                      pneumonia (that was not showing the symptoms I am familiar
                      with from two previous bouts of pneumonia, and two of
                      pleurisy. So I rather suspect the bone dust. Fever of 105
                      when they started treating me. Two days on anti-biotic
                      IVs in the emergency room and intensive care. Amazing
                      how quick they can cure you these days. I think the
                      bill was in the $5200 range for two days.

                      > Better to give it a good grinding first to get the
                      > plating off the exposed
                      > bits before heating to give it a 'patina'.

                      Sounds like good advice.
                      I once got chromic acid poisoning from rewelding
                      plastic bottoms on some tanks used for cleaning
                      glass for the electronics firms. I used to make
                      a good portion of the plastic equipment (up to
                      huge size) for the industries here in NC/SC/VA.

                      Even made a gold plating table once with four
                      drop in tanks that over flowed into each other.
                      No drain, raised flanges had to fit under the
                      U shaped edges of the tanks which fit into a
                      depressed center table which I had to make a
                      lapped frame cut hollow underneath.
                      Rarely got the easy work. Wish I had more
                      pictures of things I've built like that one.

                      I should like to add never to grind aluminum and steel or
                      iron and have it fall into the same pile. If it ignites
                      it causes a very high heat thermite reaction. One man
                      wrote into a magazine saying he had been badly burned
                      on his hands. Came to find out that his son had been
                      grinding aluminum on his belt sander the day before.
                      When he ground steel and it produced the usual sparks,
                      the pile of dust was ignited. You can actually weld
                      underwater with a thermite reaction. They use it on
                      such things as welding some railroad rails and
                      ship repairs. Grinding steel and aluminum on the same
                      belt sander was quite common when we used my equipment
                      for armoring and I never really considered it dangerous.
                      I thought you had to have a magnesium strip to get enough
                      heat to ignite it. Apparently not, so it's good to note
                      above the sander. That particular one was a 1 x 42".

                      I hope most folks know not to grind metal other than
                      ferrous (steel/iron) on a grinding wheel used dry.
                      It will load the wheel up and make it useless.
                      Sanding belts don't load with metal like that.
                      Neither do ScotchBrite wheels, but I imagine few
                      peole outside the metal or jewelry industry use them.

                      > If you REALLY have to burn
                      > something, do it way, way outside on a day with a stiff breeze & keep an
                      > eye out for the EPA.

                      Why I put wheels on some items. Like the bandsaw
                      and a rolling metal table suitable for putting
                      smaller machines/grinders/sanders/etc. on.
                      To take them outdoors.
                      Some dusts are really irritating.
                      Bone, Horn, Antler - all stink when you are working
                      them. All go all over the house from the basement
                      shop. Very fine airborne dusts.

                      Saw on another list that Tandy is claiming
                      their horns are only for "decorative purposes" now.
                      Someone had written them wanting to know what the
                      strong chemical smell in the horns was now. They
                      wouldn't say. Instead they recommended another
                      horn dealer.

                      I've seen the OSHA folks walk right into all eight of
                      my former university's physical plant shops and shut
                      down half our equipment, none of which we could use
                      again until we matched up to their specifications
                      as regarded guards and blade covers. I had to refit
                      three shops worth myself. All of a sudden we got all
                      kinds of things we'd been wanting. Fortunately I knew
                      what the best things on the market at that time were
                      when the state coffers finally opened.

                      Previously the state was somewhat immune to OSHA and didn't
                      care about what happened to the employees. One turned
                      them in and they got 17 citations in one day from only
                      two job sites. They should have seen the ones we were
                      working on. Far worse than the citations.
                      Of course he got fired for "falsifying something" on his
                      job application the next day or two.

                      The rest of us all of a sudden got saddled with all
                      kinds of safety gear from special shoes to powered
                      dust hoods for the glasses wearing and fume masks
                      for the rest. No more paper filters for us. Dammit.

                      We never were able to finally get a suitable guard
                      for the big swing-saw we used to use to cut heavy
                      stuff to length. The saw blade was suspended on
                      a swinging trunnion, and you pulled the saw towards
                      you. Rather like a radial arm saw without all the
                      fancy angles. Very powerful. Almost cut through a
                      6X6. I disabled before I fixed that one, the last
                      machine. Surplused after I left with a lot of machines
                      from very many shops on campus. There were at least
                      four machine shops and the design school shop that
                      had nothing to do with us there. I don't know what
                      the vocational ed folks had. Never saw their shop.
                      I was in industrial arts - now technical education
                      with half the machines surplused to make room for
                      the computers.

                      I am seeing more and more warnings in magazines now
                      that wood dusts are carcinogenic (cancer causing).

                      This first was looked at in Japan and later the U.S.
                      and they determined that it was mostly nasal cancers
                      related to sanding and finishing. That finer particulate
                      matter again. Having worked many, many thousands of
                      board feet myself in many species ya gotta wonder.

                      I know poplar dust used to crack my nasal membranes
                      after the dust dried them out.

                      Now the medieval man who used axes, adzes, chisels,
                      and sometimes saws and boring tools rarely made such
                      a dusty mess of himself.

                      Magnus

                      >
                      > regards
                      > Brusi
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