Dating hemingray glass insulators. Hemingray glass company
Date codes were embossed on most insulators made afterand the majority but certainly not all of post production was made in clear colorless or off-clear glass. This is especially true of later machine made bottles, i.
Bottles or jars with wide mouths like the jar pictured under Question 15 below may occasionally pre-dateto as early as aboutsince semi-automatic press-and-blow machines were being used to some degree by the mids.
Suction scars can not be produced by feed and flow automatic machines i. Bottles which have all the primary characteristics noted above 1, 3, 4 without the suction scar 5 were produced by non-Owens automatic or semi-automatic machines and are somewhat harder to precisely date, though the vast majority post-date also.
A suction scar is present on the base of Owens Automatic Bottle Machine produced bottles.
In another instance, worker opposition was so strong that the machine operations were abandoned! The presence or absence of bubbles in the glass and relatively even distribution of the glass throughout the characteristic is not a primary feature of either machine-made or mouth-blown bottles, though there are strong trends.
More specifically, non-Owens machine-made bottles with narrow necks similar to the amber beer bottle pictured earlier will always date after and typically after regardless of what type machine they were produced on since the first blow-and-blow semi-automatic machines capable of producing narrow necked bottles copied after English machines invented somewhat earlier were first made or used at that time in the U.
The Covington factory also re-opened for a short time in the period.
Lightning rod insulators, and various sizes of spool insulators were also made. Less commonly-seen are examples found in a beautiful rich teal green glass, as well as cobalt blue.
In any event, the suction scar is never found on mouth-blown bottles though suction scars are sometimes referred to as a pontil scar by the unfamiliar. The very last glass insulators made were produced at the Indiana Glass Company factory located in Dunkirk, Indiana, using molds that had been moved from Muncie to that location.
The business offices remained at Covington untilat which time all operation was moved to Muncie. The main source that implies that the WT in a triangle mark was still in use as late as was a chart printed by Owens-Illinois, as mentioned by Bill Lockhart in his article, here: Officially, an antique is an object at least years old…….
See the machine-made section of the Bottle Bases page for more information on these scars.
Machine-made bottles tend to have few if any bubbles in the glass and the thickness of the glass is usually more uniform throughout the bottle as compared to mouth-blown bottles. However, a large majority of bottles in the U. Most machine-made bottles have mold Free dating apps japan about the thickness of Dating hemingray glass insulators hair while most visible mouth-blown mold seams tend to be several times as thick, higher, but more rounded.
Hemingray began as a small operation in Cincinnati in For instance the Carr-Lowery Glass Company Baltimore, MD began automatic bottle making inbut retained some hand-blowing operations until at least when Dr.
In the glassmaking trade, these seams along with the side mold seams within the finish or just below are referred to as "neck ring" or "neckring" seams since they were formed by the separate neck ring portion of a machine mold Tooley For more info on Hemingray and Hemingray products, check out these sites: Be aware that bottles and jars made by early to midth century press-and-blow machines do not usually have ghost seams, since the parison mold was usually one-piece, but will typically have a valve mark on the base see 6 below.
In one glass factory a wall had to be erected between the hand operations and the newly installed machine to prevent sabotage. Though patented and first used to a limited degree inthe first Owens Automatic Bottle Machine licenses were granted to other manufacturers in late making the effective "beginning" i.
These numbers help to determine general dating break probabilities for both machine-made and mouth-blown bottles. Mouth-blown to Machine-made Transition Era: