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Re: Benches and stools page

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  • guydemontange
    ... the ... they re ... Now where did I leave that sturgeon? ;)
    Message 1 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
      > > 1430s. Anybody have any earlier sources?
      > Stools are way older than that. When they become fossilized,
      > 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 2 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?

      • 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 3 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.


          > regards
          > Brusi
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