The prime period of Kosmos lamp lighting was the era prior to the wide-spread use of electricity. From 1875 until WW I, lamp manufacturers were in intense competition. There were few ''standard'' width wicks used as many manufacturers employed wicks of proprietary width and thickness as an advertising advantage for their lamps.  I make customs wicks of the proper width and thickness for some of the more popular Kosmos, Matador and Agni lamps still encountered and in use today.  Click here > for custom wicks. 

Kosmos wicks go in round and come out flat. Because most Kosmos burners use gear wheels to move the wick vertically, the wicks must be of a harder, denser weave than common flat wicks made for cheap hardware store lamps - and that means they are more expensive to make. The upside down burner on the right side shows the gear wheels that move the wick vertically.  Click on the photo at right to enlarge it.

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Kosmos lamps have been made by literally hundreds of different manufacturers in the past 150 years.  Any ''standards'' are hypothetical. 8''' Kosmos chimneys are a nominal 1.50'' OD slip-fit.  The largest base diameter 10''' Kosmos chimney I have is an original signed W&W that measures 1.57'' base diameter. 7/100th is extremely close for a minimum/maximum spread. Quite common prior to WW II was a Kosmos chimney with 1.53'' base diameter designed to fit either 8''' or 10''' Kosmos lamps. Virtually any Kosmos chimney from 1.500'' to 1.57'' base diameter will fit over the burner cone and within the base of the chimney fingers.  The brass chimney fingers can then be adjusted to fit the chimney.  The precise measurement of the base diameter of the chimneys I have in stock can be found by clicking here for a pdf copy of the measurements, and clicking here for a VERY extensive list of chimney base diameters.  Only my custom chimneys have absolute guaranteed measurements; the standard, mass-produced chimneys do have some variations in dimensions.

"Goes in flat, comes out round"... by a process of 'conical curling' ... shows the triangular air port allowing air to centre of flame. Also shows direct gear drive to the wick.] Photo by Alex Marrack

Sizes of Kosmos Lamps

The wick in Kosmos lamps is flat and curled round by the gearing (shown above). The wick must fit inside the circumference of the outer wick tube.  Kosmos wicks are sold by their width, but determining that width when there is no fragment of a wick left to measure can be challenging.  Measuring the diameter and referring to the chart below is one relatively easy way to select the proper fitting wick.

Kosmos Lamps, Rough measurements     (Made since 1865 by literally hundreds of manufacturers in different countries, dimensions can easily vary.)

If there is already a wick in your Kosmos lamp, it is very easy to know what width wick you need for a replacement.  Near right:  raise the wick to make sure there is no gap or the wick is too wide and jams when raised.  The one in the photo at right is just fine.  Far right:  measure the width of the existing wick, in this case it is 2 9/16'', a 14''' wick.  And as it is a Gaudard burner and the wick can be felt, it is a thin wick.

1.  The first thing to do is clean the burner, polish, then straighten any bends or dents in the wick tubes, the outer wick tube often having dents and will inhibit any wick from fitting into the wick gap.  And of course a dirty burner is an abomination and prohibits a wick from moving.  Jewelry pliers with round, tapered noses are ideal for straightening the wick tubes.  Click on photos to enlarge them.

2.  The photo right shows a burner cleaned with hot citric acid, then polished with a brush and Q-Tips, with dents removed that still had roughness in the wick gap that would stop a wick from rising; folded 120 grit emery paper solved the problem.

3. Wrap a piece of stiff card stock, such as an index card or post card, around the draft tubes, cut to rough length, then carefully insert it into the wick gap so that it overlaps one end.  Mark the overlap.  Remove the cardboard and measure the width. Hallelujah, confirmation! It measured 2 9/16'' wide!  My photography needs serious help and the perspective of the lens is not correct, but the measurement is just fine.

It is not difficult to measure the slip-fit width to know which chimney to order.  Expensive calipers are not required.  At left you will see a child's pencil compass used to measure between the base of two opposing chimney fingers.  The compass is then laid on a rule and the width is known.  In this case I was measuring a New Juno #1 and the base diameter is slightly over 2".  A chimney should NEVER push against the base of the chimney fingers, so in this case a 2" slip-fit chimney is proper. Click on the photos to enlarge them.  If you  do not have calipers or dividers, measure the circumference of an existing chimney or inside the chimney fingers and divide by 3.14 to get the fitter diameter required. These are crude measurements, of course. To know the ACTUAL diameter of Kosmos chimneys in stock for comparison, click here.

Feeding a thick wick from the bottom of a 20''' Matador burner can be a challenge.  Making a tape extension as shown at right makes the process much easier.  The tape is pushed up through the wick gap, then the wick gently pulled up through the gearing. Flexing the wick prior to installation and leaving it with a gentle curl will help with wick installation in all Kosmos burners.