glass cutter

[messe]

Has anyone used the glass tube cutter from McMaster- Carr. Will be cutting Pyrex test tubes.
Thganks
Mike

 

[ZipSnipe]

Well Pyrex is not really a glass you can cut, maybe with a diamond wet saw. But it is under pressure, tempered as you try to score it it can break, sometimes and very rare you can cut tempered and it won't shatter for a day, but then BAM !!! it breaks out of the blue.

 

[Hopper]

Jan Ridder's website has plans on it for a glass tube cutter that some of the Stirling engine makers use. Basically a diamond cuttoff wheel in a dremel held against revolving Pyrex-type glass tube.

 

[Ogaryd]

Hi Mike,
I have not used the glass cutter from McMaster Carr, but all of my attempts to cut pyrex tubes had failed until I used the following method. Spiral wrap entire tube with one layer of masking tape, scribe to the desired length through the tape only, very gently clamp the tube in the three-jaw chuck, mount high speed grinder with one-inch diamond cut off wheel in tool post. Run lathe in reverse at very low r.p.m. , feed crossslide slowly, cooling and lubricating with w/d40. This works without failure every time. I hope This is helpful. Gary

 

[portlandron]

Second Ogaytd suggestion.
That is the only way that has worked for me.
I have also done this job in my vert mill. Put the cut off wheel in a chuck and placed the tube in a wood block which had a hole drilled in it to fit the OD of the tube. The tube was held vertical in the block and did not stick out the bottom of the block. I just slid the bloc around on the mill table to do the cutting.

 

[cfellows]

I have successfully cut pyrex test tubes with a wet tile saw. I have the harbor freight model that costs $59.95 + $6.99 shipping in the U.S.

http://www.harborfreight.com/7-portable-wet-cutting-tile-saw-69231.html

It does leave a little chipping around the end, but that can be fixed with a propane torch. The Jan Ridder's version would probably give you a cleaner edge.

Chuck