On Mon, Feb 28, 2011 at 8:35 PM, Matthew Tinker <mattinker@yahoo.com> wrote:
>
>
> Gordon,
>
> I just put it in the files section (there is a notification post that
> should take you straight there.
>
>
> Matthew TINKER
>
> CNC conversion 1944 Colchester Lathe build-up log
>
> http://www.cnczone.com/forums/showthread.php?t=35519
>
> --- On Tue, 1/3/11, Gordon Haag <mr.meker@gmail.com> wrote:
>
> From: Gordon Haag <mr.meker@gmail.com>
>
> Subject: Re: [gingery_machines] Re: New Here
> To: gingery_machines@yahoogroups.com
> Date: Tuesday, 1 March, 2011, 5:28
>
>
> I would like to see that 'Junkyard Steels' paper.
>
> On Mon, Feb 28, 2011 at 8:27 PM, Matthew <mattinker@yahoo.com> wrote:
>
> >
> >
> > Hi Dave,
> >
> > thank you for the information on extruded alloys. I know that I got the
> > idea the extrusions were close to pure Al from the net when I started
> > casting Al. This seemed to be backed up by the gumminess of the metal
> when
> > turning. I thought that the difference was that extrusions are stretched
> > after they are extruded which hardens them. I visited an aluminium
> factory
> > in the south of France where I did a course in Aluminium "joinery" making
> > windows and doors. Large hot slugs of Al were fed into the extruding
> > machine, and an enormous hydraulic ram forced the hot short Al through
> the
> > forms in lengths of 100 meters at high speed. The newly extruded profile
> was
> > then stretched which made it rigid and straight. I no longer have the doc
> > and that they gave me, but it must have had the type of alloy that they
> > used.
> >
> > How about a Junk-yard scrap non ferrous metal file to get al this kind of
> > information together?
> >
> > I have "Junkyard Steels" from anvillefire that I shall put in a file.
> >
> > Thanks again, Matthew
> >
> > --- In gingery_machines@yahoogroups.com, David Patterson <odd_kins@...>
> > wrote:
> > >
> > > I'm not sure where the myth was started that extruded aluminum is near
> > pure aluminum and is no good for casting. But:
> > > Â
> > > % of materials
> > > 6061-t6
> > > 95.8 - 98.6 aluminum
> > > .80 - 1.2 magnezium
> > > .40 - .80 silicon
> > > the rest is other materials
> > > Â
> > > 7075-t6
> > > 87.1 - 91.4 aluminum
> > > 2.10 - 2.90 magnezium
> > > 1.2 - 2.0 copper
> > > 5.1 - 6.1 zinc
> > > the rest is other materials, This material cannot be welded, as far as
> I
> > know.
> > > Â
> > > 356 sand casting alloy
> > > 90.1 - 93.3 aluminum
> > > 6.5 - 7.5 silicon
> > > <= .25 copper
> > > .20 - .45 magnezium
> > > Â
> > > 6061-t6 is used a lot in window frames. Adding copper to this alloy
> makes
> > it more like 7075, which could be bad, If you needed to weld the
> > casting.  Adding copper to 7075 you get ?????
> > > the high silicon content in 356 is to make it flow better into a mold.
> > 356 die casting alloy is slightly different. Magnezium is added to
> extruded
> > alloys to allow it to work harden.
> > > Â
> > > The problem with casting extruded alloys, people expect it to machine
> > just like the block it originally came from. Won't happen, you just took
> T6
> > material to T0 material. This needs to be brought back by heat treating,
> in
> > some fashion. The easiest way I know of is to demold within a few
> minutes
> > of pouring, the agitate in a bucket of cold water, or spray with cold
> water.
> > Again keep well away from the furnace when doing this. Thickness of the
> > casting will determan how long it takes to demold.
> > > Â
> > > Â
> > >
> > > Dave Patterson
> > > odd_kins@...
> > > http://home.comcast.net/~oddkins/foundry_home.html
> > >
> > > --- On Mon, 2/28/11, Matthew Tinker <mattinker@...> wrote:
> > >
> > >
> > > From: Matthew Tinker <mattinker@...>
> > > Subject: Re: [gingery_machines] Re: New Here
> > > To: gingery_machines@yahoogroups.com
> > > Date: Monday, February 28, 2011, 8:05 AM
> > >
> > >
> > > Â
> > >
> > >
> > >
> > > David,
> > >
> > > A couple of things I don't agree with. The only problem with the Zinc
> > based alloys is corrosion. Unfortunately, this excellent range of alloys
> has
> > a bad press because it is frequently under- designed to minimise costs
> and
> > therefore breaks. The ZA 12 is great, 11% Al, 1% Cu, and the remaining
> 88%
> > Zn, percentages are by weight. This alloy has characteristics similar to
> > cast iron, it is an excellent structural material with good vibration
> > damping. This alloy is also very good for bearing surfaces. To cap it
> all,
> > it is a "dream to machine"!
> > >
> > > Aluminium extrusions are a good source of "pure" Al for making the ZA
> > alloys or to make a harder Al alloy, add 5% of copper. It is surprising,
> but
> > molten Al is sufficiently corrosive to dissolve the Cu without having to
> > reach it's melting point.
> > >
> > > WARNING, if you take Zn, Zinc over 700°C, it will "smoke" ie. it
> reaches
> > it's boiling point and gives off zinc in the form of vapour, this is not
> to
> > be inhaled! Poison!
> > >
> > > If you do anything nasty to yourself, I accept no responsibility!
> > >
> > > Regards, Matthew
> > >
> > > Matthew TINKER
> > >
> > > CNC conversion 1944 Colchester Lathe build-up log
> > >
> > > http://www.cnczone.com/forums/showthread.php?t=35519
> > >
> > > --- On Mon, 28/2/11, David Frantz <websterindustro@...> wrote:
> > >
> > > From: David Frantz <websterindustro@...>
> > > Subject: Re: [gingery_machines] Re: New Here
> > > To: "gingery_machines@yahoogroups.com" <
> gingery_machines@yahoogroups.com
> > >
> > > Cc: "gingery_machines@yahoogroups.com" <
> gingery_machines@yahoogroups.com
> > >
> > > Date: Monday, 28 February, 2011, 9:32
> > >
> > > Â
> > >
> > > Extruded aluminum NO. Look for originally cast Aluminum as you will
> > already have an alloy suitable for casting.
> > >
> > > As to zinc it is suitable for many machine parts so don't loose any
> stash
> > you may have. What you should avoid is using it for structural parts of
> the
> > lathe. Especially parts where vibration or ringing might be a problem.
> > Further don't mix tools used for Aluminum, such as crucibles, with those
> > used for zinc.
> > >
> > > Zinc alloys should be much easier to cast and frankly easier to find. I
> > would not avoid using it, it is just a matter of selecting the proper
> places
> > to implement zinc parts. In some places I'd even go so far as to suggest
> > that zinc would be a better choice, for example knobs and handles which
> > could remain bare. It would avoid that nasty aluminum stain on the hands.
> > >
> > > One other way to use zinc would be to cast a frame or structure and
> then
> > fill it with epoxy concrete. For a lathe bed this would deaden the frame
> yet
> > give you metal to bolt things like the ways to. So there is more than one
> > way to skin a cat here. Adaptation is really the word here; Gingery
> designed
> > a lathe that is ideal for the material, Aluminum in this case, going to
> zinc
> > just requires a bit of thinking or design effort.
> > >
> > > David A Frantz
> > >
> > > websterindustro4at4mac.com
> > >
> > > Sent from my iPhone.
> > >
> > > On Feb 27, 2011, at 7:57 PM, james <james122964@...> wrote:
> > >
> > > > So, it would be better to use the extruded aluminum? or should I hunt
> > around for actual cast aluminum?
> > >
> > > >
> > >
> > > > I sure wish the die cast stuff would have been worth it, as it melts
> a
> > lot easier and is heavier, guess I could use it for pulleys.
> > >
> > > >
> > >
> > > > Jim
> > >
> > > >
> > >
> > > > --- In gingery_machines@yahoogroups.com, David Frantz
> > <websterindustro@> wrote:
> > >
> > > >>
> > >
> > > >> Long ago I worked in the die cast industry so I have some experience
> > with this. First die cast alloys are not the same as zinc based casting
> > alloys designed for sand casting. Second die cast alloys age
> significantly
> > of time. Third die cast alloys are sensitive to the ratios of metals
> which
> > means it is easy to get fining results if the alloy varies from the
> accepted
> > ratios much.
> > >
> > > >>
> > >
> > > >> Given that you wouldn't have any problems pouring a Zinc die cast
> > alloy. The low melting points mean that you can get by with a cheaper
> > furnace. Sources for the alloys where at one time cheap and plentiful
> > (carburetor and other auto parts). Zinc die castings can have initial
> > strengths equal to similar cast iron parts. So there are good points to
> > consider with respect to Zinc castings.
> > >
> > > >>
> > >
> > > >> The bad points are also worth considering. One in this context is
> that
> > a Zinc casting might not be as dead as a cast-iron or aluminum one. That
> is
> > you may see much more in the way of ringing and vibration transmission.
> As
> > mentioned above the alloys do age over time which might result in a need
> to
> > re scrape parts overtime. Actually all cast metals have an aging factor
> it
> > is just that some Zinc alloys can age more than others, plus this is in
> the
> > context of die casting.
> > >
> > > >>
> > >
> > > >> In the end I would NOT recommend zinc die cast alloys for most parts
> > of a lathe. I just think you would get far better results from other
> > materials for most of the structure.
> > >
> > > >>
> > >
> > > >>
> > >
> > > >> On the granite:
> > >
> > > >>
> > >
> > > >> Granite counter top material can pass as A surface plate. You should
> > check the flatness your self and make sure it is well supported to
> prevent
> > bending under use. Simply due to the thickness it ought to be a better
> > starting point for a surface plate than ceramic tile or other things that
> > are often suggested. In any event realize that a surface plate requires
> > maintenance just like every other tool.
> > >
> > > >>
> > >
> > > >>
> > >
> > > >>
> > >
> > > >> David A Frantz
> > >
> > > >> websterindustro4at4mac.com
> > >
> > > >>
> > >
> > > >
> > >
> > > >
> > >
> > > >
> > >
> > > >
> > >
> > > > ------------------------------------
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> >
> >
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> ------------------------------------
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