Author Topic: Turning glass on the lathe?  (Read 784 times)

Offline AdeV

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Turning glass on the lathe?
« on: March 10, 2017, 05:08:40 AM »
A few months back, I bought an antique barometer/thermometer on eBay. The glass on the barometer is cracked terminally (I knew this when I bought it). It appears to be a fairly simple flat piece of glass, with a bevelled edge, and a small hole in the centre to admit the "last reading" needle to be positioned via a thumbscrew. As the cracks run right through this hole, the glass can't be saved.

So.. my question is... if I were to, say, glue a piece of glass to some kind of backing - a piece of metal or MDF say, could I mount it in the lathe and use a stone to grind the bevel onto the edge, and some kind of drill (I'm thinking the kind of drill you use on ceramic tiles) to make the centre hole?

Or am I asking for a world of pain and hospitalisation just considering this...?

Any suggestions/alternative methods (preferably that don't involve money changing hands, as I don't have a lot spare just now) welcome.
Cheers!
Ade.
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Offline awemawson

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Re: Turning glass on the lathe?
« Reply #1 on: March 10, 2017, 05:19:08 AM »
Ade, I know you say money is short, but I've been really surprised how cheaply glass places do these things. Bevelling the edge is a standard procedure for them using slightly flexible rubber with embedded abrasives, and is often done on mirrors, and hole drilling again is their bread and butter.

If you go the lathe route any vibration spells disaster and where is the abrasive and glass going to end up - yes all over your Edgwick  :hammer:

(much cheaper though to have had it done when you were in China recently  :lol: )

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Offline Pete W.

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Re: Turning glass on the lathe?
« Reply #2 on: March 10, 2017, 05:47:20 AM »
Hi there, Ade and Andrew,

Ade, you might find the glass you need ready-made at Meadows & Passmore or at H. S. Walsh.  They both have web-sites but I haven't done a full browse.

(Usual disclaimer.) 
Best regards,

Pete W.

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Offline vintageandclassicrepairs

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Re: Turning glass on the lathe?
« Reply #3 on: March 10, 2017, 06:40:34 PM »
Hi All,
Years ago I was shown a trick to "drill" glass, later I used it to drill a hole in a toughened glass panel on an electric oven/grill, being Spanish  there was no heat control on the grill element ??

Basically you use copper tube and valve grinding paste in place of a drill bit, you need a guide to get it started
Its amazing how quickly it cuts through
I have heard of sharpening masonry bits to drill glass??
I had to resort to sharpening a masonry bit to drill out some leaf spring eyes

Enough rambling
John

Offline Doc

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Re: Turning glass on the lathe?
« Reply #4 on: March 10, 2017, 09:47:39 PM »
 I have drilled holes in glass by using a copper dia the size hole you want and diamond grit take it slow and easy and let the grit basically grind a hole through. I've also cutt glass tube in the lathe glass tube lightly clamped in a 5c collet ant then take a diamond file and turn the tube about 1000 rpm and use file to cut.
George

Offline John Stevenson

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Re: Turning glass on the lathe?
« Reply #5 on: March 11, 2017, 03:21:32 AM »
Does it have to be glass ?
I have made quite a few oil sight glasses, all engraved up with levels etc out of acrylic on the laser. Just a thought.
John Stevenson

Offline AdeV

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Re: Turning glass on the lathe?
« Reply #6 on: March 12, 2017, 05:06:38 PM »
Thanks for all the replies  :thumbup:

I guess the answer, then, is "you can... but it may be more hassle than it's worth"... taken under advisement :) The barometer is about 100 years old, so I'd prefer it to have "real" glass - plus, real glass makes that satisfying clunk when you tap it, I find Acrylic/Perspex just doesn't sound right when tapped. Plus it flexes...

Here is a photo, which unfortunately doesn't really show the true extent of the breakage... it looks much worse "in the flesh":


Anyway... as I'm back off to China at the end of the month, I might well have a look around to see if I can't find a glassmaker who can do it cheap out there ;) Although somehow, not putting a piece of genuine English glass in it seems a bit, well, unfair somehow...
Cheers!
Ade.
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Location: Wallasey, Merseyside. A long way from anywhere.
Or: Zhengzhou, China. An even longer way from anywhere...
Skype: adev73

Offline Joules

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Re: Turning glass on the lathe?
« Reply #7 on: March 12, 2017, 05:42:33 PM »
Look up glass slumping.  You make a mould heat the glass in a kiln and let it relax into the mould.
Just get doing and make swarf, you can decide what its going to be later.   :thumbup: