sealing polished mild steel

[SillyOldDufferModerator @sillyoldduffer]

Posted by Michael Walters on 20/12/2016 11:27:02:

…

Gold is an interesting one because it is so rare, and that it doesn't actually originate from this earth, the scientific consensus on the origin of gold at the moment is that it literally "fell to earth" and was seeded in someway, probably through space rock. So maybe the renaissance artists were onto something when they kept using gold colours to depict heaven?

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Michael W

Edited By Michael Walters on 20/12/2016 11:48:21

I sometimes feel guilty about my many contributions to subject drift on the forum but the opportunity to go from Iain's Candlesticks to the Origin of the Universe and the semiotics of Renaissance Art is too good to miss. My Armchair is red-hot this morning!

I'm not sure where the idea that only Gold comes from Outer Space comes from. My understanding is that all matter comes from Outer Space.

Various measurements consistently indicate the Universe is nearly 14 billion years old. Back then something very strange happened to create it.

The Big Bang Theory suggests that a singularity exploded. As this cooled, first sub-atomic particles, then simple atoms appeared. Gravity caused these atoms to cluster together, eventually forming stars and galaxies. When enough mass collects in one place, gravitational squeezing becomes powerful enough to start a nuclear reaction, and a star is born. Continuing nuclear reactions convert light atoms into heavy elements inside the star.

Stars do not burn for ever. In the end the nuclear reactions are insufficient to stop the star collapsing into itself and exploding, a super novae. That explosion flings heavy elements into space where these in turn coalesce into planets and other objects.

Underpinning this sequence of energy – matter – energy conversions is Einstein's famous equation, e=mc², which suggests that matter and energy are equivalent. (Now that's genius!)

Modern physics is very interested in the Big Bang, it's alternatives, and of course – another big question : what existed before the Big Bang and caused the singularity? At the moment the universe is expanding: will it eventually collapse back on itself, create another singularity, and restart the process?

In art, Joni Mitchell's 'Woodstock' picks up the idea humanity has Cosmological origins and links it to the Biblical Creation when she sings:

We are stardust
Billion year old carbon
We are golden
Caught in the devil's bargain
And we've got to get ourselves
Back to the garden

I don't think Renaissance painters used Gold to represent Heaven because they understood the Cosmos. I think they used Gold because it looks good, glows like the sun which has well known life-giving properties, and because it is very expensive. It's an earthly symbol of the wonders that heaven will deliver when we die.

The Big Bang theory does not require God to exist. Some religious groups prefer to believe in 'Intelligent Design', arguing that Intelligent Design 'Theory' is as valid as Big Bang Theory because both are unproven. This is a misunderstanding of what science means by the word "Theory". It goes well beyond the lay meaning. A scientific theory is always supported by evidence and there are many observations in nature consistent with the universe originating with a Big Bang. Although Big Bang Theory suggests that the Biblical account of creation is wrong, it does not challenge the existence of God. By definition, God is unknowable

With all that behind them, Iain's Candlesticks make a very impressive Christmas present!

Dave

[MWParticipant @mw27036]

Hi Dave,

Sorry I led you down the philosophical path this morning! I only meant it in jest because I remember reading about how Gold is quite unusual because it is so rare, and that it isn't an element commonly found in the make-up of planets that we know of. It doesn't have a clear origin or age of formation that most matter does.

An article talked about the eminent theory that scientists believe most likely that gold veins fell in the form of meorites and comets. I found it quite amusing that the best minds we have at our disposal could come up with is simply "it fell out the sky"! It isn't as daft as it sounds when they know these rocks can actually contain quite a lot inside them.

It may not be correct but in this day and age we don't like to have unknowns or anomalies lurking in our midst. So we have to explain it, even if it sounds a little shaky, we can't admit we don't know anymore, although it doesn't change that fact!

The renaissance artists link clicked in my mind because I have studied art and numerous levels and I think you're right, they did choose gold because it was expensive and looked nice. But also for it's non tarnishing nature in the ancient world was a rare thing indeed, so it felt "everlasting" just like heaven was supposed to be. I'm not really the religious practising and thinking type, but that hasn't stopped me from being interested and appreciative of culture and belief, I hope.

Michael W

Edited By Michael Walters on 21/12/2016 13:50:35

[Iain DownsParticipant @iaindowns78295]

Curiously and equal unconnected to my post, I'm given to understand that the alchemical search for turning lead into gold was actual a metaphor. Gold represented the imperishable and eternal and what the alchemists were actually looking for was eternal life. From the mundane dull and perishable (lead) to the pure, imperishable and eternal gold – everlasting life.

I suspect (though I've not heard) that it's the imperishable and untarnishable nature of gold which led to it being used in halos and the like – the eternal and holy.

And of course it's pretty.

As for it the candlestick (singular) makes an impressive Christmas present – time will tell. The stem (stick bit) is my first piece of taper turning and has worked quite well. I am unable to get other that a rough finish on the lathe at the moment, so have spent some hours with file and various grades (120 – 5000) of sandpaper to end up with a good surface (I've been telling people that I've spent hours polishing my stem and got some quite strange looks – I don't really know why).

I found some improvement in the finish when I tightened up the bearings and so I suspect that a significant project in the new year is to replace the spindle and bearings (with angular contact) and completely strip and rebuild the lathe. FIrst, though I need a decent press to remove and replace the spindle / bearings.

I shall post a picture if it doesn't embarass me too much.

Iain

[MWParticipant @mw27036]

Posted by Iain Downs on 21/12/2016 20:48:43:

As for it the candlestick (singular) makes an impressive Christmas present – time will tell. The stem (stick bit) is my first piece of taper turning and has worked quite well. I am unable to get other that a rough finish on the lathe at the moment, so have spent some hours with file and various grades (120 – 5000) of sandpaper to end up with a good surface (I've been telling people that I've spent hours polishing my stem and got some quite strange looks – I don't really know why).

I found some improvement in the finish when I tightened up the bearings and so I suspect that a significant project in the new year is to replace the spindle and bearings (with angular contact) and completely strip and rebuild the lathe. FIrst, though I need a decent press to remove and replace the spindle / bearings.

I shall post a picture if it doesn't embarass me too much.

 

Iain

Hi Iain,

Its good to hear it's coming along well. The rough finish is a signature hallmark of taper turning with the compound (or top if you're American) slide, quite often the gibs have a bit of slack in them just to make it easier to move with such a small handle.

The best way I find to go about it, is to use one hand to operate the handle and another to steady the movement of the hand wheel and to keep it revolving smoothly.

Another good idea for when you want to make accurate length tapers is to measure the length before you start cutting and witness the outside of the bar slightly and keep increasing the depth of the cut using the cross slide only, and keep doing that til barely just cuts past the mark.

Michael W

Edited By Michael Walters on 21/12/2016 21:49:31

[Iain DownsParticipant @iaindowns78295]

HI Michael.

The taper is along about 12 inches of a 14 inch steel bar and considerably longer than my topslide travel!

I've offset the tailstock as far as it will go, used the slowest speed traverse my gearing will do and a freshly ground and honed HSS tool. I ran the last few traverses at about 200 rpm (which was a little like watching paint dry) as the faster it went the rougher the finish and the more the chance of chattering.

At that speed I ended up with no chattering and a visibly grooved but even finish. I suspect that the bearings / headstock arrangement isn't all it could be (see other plaintive posts of mine) and I also think the saddle could do with a bit of tightening. However, this project started of as the intent to build a 'thing', rather than make the lathe better, so I've made do!

Iain

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