End Finishes for Tubing 

There are several choices you can make for how we finish the open ends of tubing. You may want to simply make it finger-safe, or strengthen the end, or seal against the end of the tube.
The following series of photos illustrates a variety of end finishes we routinely provide.

 

Scribe cut; the corners are sharp, the surface is pretty flat on tubing larger than 2"OD, but not perfectly so. This treatment is definitely "roughing it", and inexpensive

Saw cut; the face has a ground finish, the corners are finger-safe, and some small chips are possible. This may be enough to make a good seal against a soft gasket. This also enables tighter tolerances in terms of the length of the tube, up to about 4" OD. Larger tubing requires lapping; see "tooled and lapped" below...

Fire cut or fire-polished; the end has been melted, and has a full radius that is smooth. This fused surface makes the glass stronger, as there are no breaks in its surface tension. This finish is common, but makes holding tight tolerances more difficult

Heavy fire-polish or "beaded"; the tube end has pulled together by surface tension induced when melting the glass, for an even stronger end. The extra strength comes from more glass at the end.

Lapping; same bead as above, mechanically lapped flat to provide a sealing surface. The outside edge is strengthened and the ground surface will seal well against a flat gasket or o-ring. We routinely lap or grind flat surfaces for flanges at sealing interfaces using diamond tooling.

Tooled and Lapped; large diameter tubing with a tooled flange and lapped flat. We can form the end of tubing into many shapes. When length overall is critical, we prepare this end first, as the reference point.

 

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