Deburring Glass Tube

I'm making some canisters that have a glass piece in them. It is a
tube 200mm in dia, 5mm thick, and 350mm long. The tolerances on the
tube are quite wide, it can be up to 1mm out of round, although the
wall thickness is probably within 0.2mm.
I have a custom made toolpost grinder for parting them off in the
lathe which after some trial and error seems to work well, and I now
have a good process. I can part one off in about 7 minutes.
Currently I'm using a linisher to take off the sharp edge, and prevent
the glass from chipping, however this gives a poor finish, and will
sometimes chip the edge. Deburring in the lathe will not work,
because the piece is out of round.
Any suggestions on a better way to debur the edges? I'm only trying
to achieve a 0.5mm chamfer.
Cheers, Dom.
Oh, I'm need to debur the inside and outside edges.
Reply to
Dom
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Fire polishing ???? I did some old bottles years ago with an old phonograph turntable and a torch ..
Take care ...Tom in Belle Vernon PA
Reply to
garigue
Maybe look at one of the small units used by some glass workers such as
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. You can get many different plated diamond heads for these so you should be able to find something to suit your needs. There are makers other than Inland also, Glastar IIRC. You can also get custom items plated to suit you needs, I turned up blanks and had them plated by Asahi Diamond in the UK to suit my requirements.
Reply to
David Billington
Tom, what sort of flame did you use? I have tried using my oxy- acetylene, but the glass cracked, and threatened to explode! Will the type of glass make a difference?
Reply to
Dom
Archived from an old post:
1. I set up my workmate with the jaws open to about the radius of the jar I wanted to cut. 2. Laid the jar in the jaws so that it could rotate. 3. Set up a tungsten tipped tile cutter to the centre of the jar and C-clamp in place so that the cutter is pressing on the jar.
4. End stop the jar using a clamp and a block of wood. 5. Score the jar by rotating it by hand against the cutter. 6. Turning the jar slowly in the lathe I gradually applied heat from a small hobby gas torch to the score line increasing the heat slowly until ping! the end fell off. 7. Then I dressed off the end with wet and dry.
Good luck,
Grant Erwin
Reply to
Grant Erwin
The type of glass makes a significant difference. Common soda glass has a COE which is significant and you are not likely to be successful unless the glass is quite thin, like < 1mm, or you warm the whole piece carefully. A common process in production wine glass making is to blow the piece, score the bowl, then crack off the upper section with a flame which then fire polishes the rim leaving the finished edge, the thin section allows this to work. Borosilicate glass has a much lower COE so the internal stresses built up due to heating are much lower and so thicker sections can be heated locally without breakage.
Reply to
David Billington
Tom, what sort of flame did you use? I have tried using my oxy- acetylene, but the glass cracked, and threatened to explode! Will the type of glass make a difference?
Hello there Dom ...... I was making some drinking glasses from old bottles ....so type of glass I guess is run-of-the-mill ... the directions if I remember were to use a crocus paper to smooth the edge after making the cut ...I wasn't quite satisfied with the surface so I figured I try firepolishing .....I ran into the cracking problem but I was able to get a good edge if I was careful in initially heating the piece .... but in looking at the fellow who asked the question .... the wall thickness and diameter are pretty "hefty" . Again this was about 35 years ago or so ...it seems I remember using an old toaster oven at first ..... all I say is for sure is that the wife said get rid of those crappy glasses ......so that was the end of glasses from bottles and even an incompleted chandelier project....
Take care ...Tom
Reply to
garigue
I have done this three ways: 1.) Put a piece of wet-or-dry sandpaper on a flat surface, like a piece of plate glass, and slide the end of the tubing back and forth. 2.) Same as 1.), except use an abrasive paste, like valve lapping compound, instead of sandpaper. 3.) Hold the edge of the tubing against a belt sander, with a water drip to keep things wet. If you don't use water, the glass will chip. I have made scoops out of wine goblets this way.
Reply to
Leo Lichtman
Hello Erwin ...boy you guys are jogging my memory ....I used a glass cutter to scribe a line on the bottle circumference on a wooden jig I made .... Then I used a bent rod with a weight on it that went into the bottle which then was tapped about the scribed line from inside the bottle ..... this resulted is some nice separation and in some cases a handful of glass shards ...gloves of course .... then I tried using a string soaked in alcohol tied at the scribe line ...lit it then ping ...nice separation ..... seemingly I got the string flame system from an old Pop Mechanics ....
Take care Erwin ..... Tom in Belle Vernon Pa
Reply to
garigue
Tom, what sort of flame did you use? I have tried using my oxy- acetylene, but the glass cracked, and threatened to explode! Will the type of glass make a difference?
Sorry Dom .... need to improve my comprehension ..... used propane but it took some time ....
Take care ..... Tom in Belle Vernon PA
Reply to
garigue
IIRC from ~60 years back, the method was to wrap a cord once and a half around the bottle, then pull it back and forth to heat the glass. After about five minutes, dunk the bottle into cold water. SNAP! Gerry :-)} London, Canada
Reply to
Gerald Miller
Thanks all for your good suggestions! This has given me some new ideas to try.
Cheers Dom.
Reply to
Dom
"garigue" wrote: (clip) then I tried using a string soaked in alcohol tied
^^^^^^^^^^^^^^^^^^^^^^^^^^ The burning string method does not require a scribe line.
This can also be done with a piece of resistance wire stretched around the bottle. Again, no need for a scribed line.
Reply to
Leo Lichtman
There was a recent thread on this group relating to making your own triode vacuum tubes. The French video shows lots of glass work, including the use of a VERY soft fluffy flame to preheat the freshly cut glass before using a hot flame to smooth out the edge. You might look back a few days and find the thread.
Reminded me of my old chemistry class in highschool and college. Doing your own glass work was one of the first things we were taught in lab.
Paul
Reply to
co_farmer
I've used a wet carborundum stone to bevel the edges of rear view mirror blanks before installing them in the housings. Done by hand, no heat. A diamond hone plate with water should work, too.
Stan
Reply to
stans4
I used a Harbor Freight diamond disc (dust and plating on a small thin steel disc, set of 4 with an 1/8" arbor for $5, IIIRC) in a Dremel tool to shorten a piece of glass tubing (specific type unknown).
The disc with the Dremel was a little slow, and made a small cloud of dust while it was cutting, but it cut the tube without too much trouble, and then I used silicon carbide sandpaper (referred to as "wet or dry" by the other responders), which is the almost-black wet-sanding paper used in automotive (and other) paint refinishing processes.
The SC paper allowed me to form a very smooth, slightly radiused edge on the end of the tube, but as you probably already realize, the glass had a frosted look. The tube's purpose was to mate with a tapered silicone seal which enters the end of the tube, so I wanted the opening to be radiused and smooth, so it wouldn't be cutting into the silicone.
This was a solder collector tube for a Pace desoldering handpiece, BTW.
Note: there were a lot of eBay sellers offering different sorts of glass tubing, but just try to get them to give you ID and OD sizes.. they probably can't/won't, at least in my experience.
WB ......... metalworking projects
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Reply to
Wild_Bill
Talk about memories. :-) A friend and I made a bunch of film developing tanks to fit the Nikor reels out of a particular beer bottle that way about 54 years ago (I think it was 1954). ...lew...
Reply to
Lew Hartswick
wet/dry sandpaper, used wet.
abrasive stone, available at stained glass shops. looks like
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regards, charlie
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Reply to
charlie

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