THE Parker Jack-Knife Safeties

The Cap that Can’t Leak, consists of a Parker Jack-Knife Safety double cap, one inside the other. The outside cap «A» screws on the barrel in an ordinary way. «B», the inside cap, screws into the outside cap, the top extending out of the end of the outside cap. After the outside cap is in position, an extra turn on the protruding inside cap forces the outside cap tight against a special shoulder of the barrel, enclosing the pen in an ink-tight chamber. The air pressure in this chamber prevents a flow of ink from the pen point, even although the pen is carried upside down. Even if the ink does escape, it cannot get into the outside cap, or smear the nozzle of the pen. You will always find the Parker Jack-Knife Safety ready to write at the first stroke, flowing freely and evenly.

The Jack-Knife Safeties were Parker’s entry into the safety pen market. It was protected by patent US1,028,382, filed in 1909 and granted on June 4, 1912. This date would be imprinted on the caps shortly afterwards. Previously, the caps were marked as «PAT. PENDING» and «PATENTED».

Jack Knife inner cap that fit snug to shoulder section when the pen was inserted, so that ink didn't leak.

The model line was the mainstay of the product line throughout years 10’s and, in the early 1920s, until 1922 in which the JKS 26 model became the Duofold that would revitalize Parker sales and be the beginning of the standardization and reduction in the number of styles and models in its catalog although, after Duofold, Parker continued offering Jack-Knife-style pens.

In a 1909 ad, Parker introduced this fountain pen so: “Something new and novel, yet a business-like safety pen. A short, efficient, attractive fountain pen that you may carry anywhere you carry your jackknife. Put it in your vest pocket, upside down -any old way- throw it in your grip or handbag, without fear of its leaking. The ideal pen for a lady to carry in her handbag.

The January 1910 edition of Side Talks shows the Jack-Knife with a turban top but still shows a conical section. The nozzle of the pen was made a trifle wider than in the regular pen and with a flat facing. The cap was fitted with a secondary cap which has a thread on same and which turns easily inside the regular cap.

1909 first Parker Jack Knife with conical section.

We would have to wait until the beginning of 1910 to find the Jack Knife pens with its particular cup silhouette section.

Sectional view of safety when cap is in proper position, and pen and ink locked up.
A Jack Knife with its particular cup silhouette section.

The JKS series was made of hard rubber. The series 2X are plain surface holder, while 2X½ were chased. The fraction 1/2 following the model number denotes a pen holder chased.

Most of the Jack Knife fountain pens that have arrived at our collections are black hard rubber. Less frequently it was manufactured in mottled and, much more infrequent, in red, so red Jack-Knife nets are extremely difficult to find.

The Parker Jack-Knife could be supplied in black plain, black chased, mottled or red hard rubber.
The Parker Jack-Knife could be supplied in black plain, black chased, mottled or red hard rubber.
Parker Jack-Knife Safety imprints.

The JKS 2X series was just a size designation of the Parker product line, so for a higher model number, the greater the pen circumference. Number 20 was the narrowest, followed by the 24, 25, 26, 28, and then the Giants. The model 23 had the same diameter as the 20 basically but mounting a point #3 in place of #2 furnished with model 20.

A Parker no. 20 Jack-Knife eyedropper in red hard rubber on an early JKS box.

Since its inception, the Jack-Knife models could be fitted with fancy mountings at special prices, if it were desired. Any Jack Knife pen could be trimmed with one or two gold bands by adding 50c at the regular price for a gold band and $1.00 for two gold bands.

A #24 Parker Jack-Knife Safety eyedropper. Regular length, plain barrel with two fancy gold bands. It price was $4.00 more $1.00 extra mounting two gold bands. Photo in collaboration with FiveStarPens.

In addition to pen 25c. extra (75c. gold plated and 5.00 solid gold) all Parker Jack-Knife safety caps could be fitted with a little ring fastened to the end of the cap so it may be suspended by a chain. Parker distinguished these variants with the initials S.R. because of their «Screw Ring».

By January 1910, the Jack-Knife line was off and running. It was available in various style holders; plain black, black chased -except the Baby sizes-, red, and mottled hard rubber. All models were available from  #20, #23, #24, and #25 with its Regular, Baby,  chased, and T-cap variants. On special orders could also be served numbers #26, and #28. Any of these Jack Knife pens can be ordered with one or two gold bands by adding 50¢ or $1.00, respectively, to the regular price.

At the same time, the Jack-Knife #15 and #45 could be ordered. The JK #15, very similar in style to the regular No. 15, but with No. 20 Jack Knife size, with different types of pearl slabs in the barrel held in place by two gold bands. The cap was covered with the same gold filigree with space for engraving the owner’s name as was used on the regular No. 15. The JK #45, also a #20 size pen, mounted corrugated pearl sleabs of various styles and colors held in place by decorative gold bands. The cap was plain black, but mounted at the end with a pearl crown or a fancy stone setting imitating amethyst, emerald, ruby, etc.

Completed the JKS 1910 catalog the filigree models #14 and #16, sterling silver and rolled gold, respectively. Both were available in baby size with a small ring at the end of the cap to hang on a necklace, or in regular size without a ring at the same price.

Parker no. 14 Jack Knife Safety eyedropper. Sterling Silver Mountings. Price $5.00. Courtesy of Luiz Leite.
Parker #15 Jack-Knife eyedropper Baby length filled alternating plain pearl and abalone slabs covered barrel. About 105mm. capped. Price $7.00.
Parker #16 Jack Knife Safety eyedropper, Gold Filled Mountings. Price $6.00.
Two #45 Jack-Knife Safety eyedropper regular size next to a #45 Baby size. Courtesy of Luiz Leite.
Two #45 Jack-Knife Safety eyedropper regular size next to a #45 Baby size. Courtesy of Luiz Leite.
Parker's picnic. George S. Parker, standing left with his wife Martha, on the birthday of his father, Norman Safford Parker (sitting, in the center of image). Norman's house in Randalia, Fayette county, Iowa. October 18, 1911.

At the end of 1911, was introduced the Jack-Knife Safety #48, an plain gold filled overlay. There are two versions; no. 48 without engraving chased on its holder for $8.00 and no. 55, same as this but finished in silver at $7.00.

At the same time was cataloged the Jack Knife Safety #49 furnished overlay 18 k. gold cap and barrel with deep lines engraved effect and beautiful floral designs on top and bottom. It was $10.00. It also had a silver version, the JK No. 56 at a cost of $8.00.

No. 48 Baby Jack Knife Safety. 18K Rolled Gold plain barrel. Price $8.00. Courtesy of Tsachi Mitsenmacher.
No. 49 Baby Jack Knife Safety. 18K Rolled Gold. Price $10.00. Courtesy of Luiz Leite.

From the beginning of 1912, Parker offered full legth versions with long barrels of all their regular safety styles. Parker presented it like this: “Last year many of our friends asked us to make the Jack-Knife Safety with a full-length barrel, due to many customers who wanted to carry them upright in their pocket and yet they have the safety function. We have done this now.”

The JKS models arrived in four lengths: a long full-length, usually 130-135 mm., a regular about 110-115 mm., the ladies’ size in models #20 and #23 for 100-105 mm purse wear, and the smaller vest pocket Baby of approximately 90 mm. long.

Black Parker Lucky Curve Safety eyedroppers. Long full-lenght, regular, and baby sizes. Courtesy Tsachi Mitsenmacher.

Towards the second half of 1912, the cup-shaped nozzle gave way to a more standardized section.

Parker Jack-Knife ad in Saturday Evening Post. August 30, 1918.
No. 55 Baby Jack Knife Safety showing a less stylized section. Sterling silver plain barrel. Price $7.00.

In 1913, for an additional 25 c., Parker introduced the option of attaching to all Jack Knife, except the Baby sizes, a little ring at the end of the safety cap to hang from a chatelaine.

In the same year, Parker began producing the new «press the button» self-filling in slip cap line  replacing the «click-filler».

Early Parker "press-the-buton" self-filler pen. The Cornell Daily Sun. Ithaca, New York. September 30, 1913.

At the end of 1914, the Jack-Knife Safety series was redesigned replacing the «turban» top with a new flat top style safety cap (the same as Duofolds over time). On the other hand, the Jack Knife pens were now available as press-the-button self filling in addition to the existing eyedroppers.

Parker pen #56 Jack-Knife button filler furnished with washer clip.

1914 was a great year for new products from Parker, so at the beginning of the year they introduced the PARKER BAKELITE pen, a wonderful pen whose barrel looks like clear amber and through which you can see the ink and the wonderful workings of capillary attraction as harnesssed by the Lucky Curve feed in the eyedropper versions. Parker developed three colors in Bakelite; one shade of green and two shades of red and pink.

Parker Bakelite Jack-Knife no. 71 in plush hinged box. Was $6.00. Transparent barrel, gold crown and band on cap with a ring for chain or ribbon. (Courtesy of John Danza).

In 1914 Parker filed patent for a new and innovative washer clip. This new Parker clip long or medium length barrel would be offered in German silver nickeled at 25c extra. Gold plated was 75 c., and solid gold was $5.00.

In the same year, inspired by the Jack Knife self-filler, introduced Ivorine, a small, colorful pen focused on the ladies’ market as target. This eyedropper model did not settle on the market because the casein, permeable to ink, dirty the colors.

Parker #76 Jack Knife Safety trimmed with gold band. Courtesy of Rachel Agypt.

From 1914, in addition to pen 25c. extra (75c. gold plated and 5.00 solid gold) all Parker Jack-Knife safety caps could be fitted with a little ring fastened to the end of the cap so it may be suspended by a chain. Parker distinguished these variants with the initials S.R. because of their «Screw Ring».

Parker Black Giants with nickel and gold-filled washer clip. Courtesy of PBA Galleries, Berkeley, CA. (photos © Justin Benttinen).
A Parker Jack-Knife with "proper name".

In 1916, Parker introduced the collapsible no. 70 eyedropper, a new shaped Parker Jack-Knife gold-filled especially designed for a graduation, present, or birthday gift.

In the same year models #26 and #28 was catalogued as a Jack Knife pen.

Parker #70 collapsible Jack-Knife Safety. It was $12.50.
Parker no. 28 eyedropper red Bakelite. Courtesy of Five Star Pen.

The Parker Trench, an eyedropper pen with a long end cap intended to hold ink tablets, released in 1918 was also supplied with a Safety cap.

Parker #20 Trench Safety full length.
No. 51 Parker Jack Knife Safety sealed self filler. Gold mounting in center of barrel with space for engraving name. Price $3.50. Courtesy of FiveStarPens.
No. 32. Parker Jack Knife self-filler sterling silver. Price $6.00. Ring for attaching to chain.
Parker Jack-Knife no. 66. Price $3.75. Equipped with gold plated ring fitted into cap crown gold covered.
Parker no. 84 Jack-Knife Safety sealed. Courtesy of Luiz Leite.
Parker no. 90 Jack-Knife self-filler mounted in silver. Courtesy of Luiz Leite.

In 1920, a new factory, costing $375.000, was built and completed on the corner of Court and South Division Streets.

Parker factory building completed December 1920. Photo from Gruver collection.
Parker no. 98 Jack Knife mounted in gold and furnished as self-filler. It price was $15.00. Courtesy of Antique Digger. Fort Myers, FL.

With the Duofold arrival in 1922, Parker continued to offer Jack-Knife-style pens.

Parker Duofold Quality ad. The Michigan Daily. October 14, 1923.

In the second half of 1923, with the success of the new Duofold verified, the company reduced the Jack-Knife line and presented them as a new style of a pen which it had given the moniker «Parker D.Q.» -meaning Duofold Quality. This pen, in two models, for men and women, sells for $3.00, less than half the price of a Duofold Senior. It was a black rubber pen, with distinctive chasing, designed for that marker that wants a pen «Duofold» quality but less than the Duofold price.

By 1925 the «DQ» model was renamed as «Parker Black and Gold» pens in black hard rubber. In 1930, when this series was manufactured in Permanite celluloid and streamlined silhouette they were known as Raven Black and Gold. Together, these fountain pens are known as the «Black Lines».

Parker D.Q. imprint.
Parker #37 "Black and Gold" Duofold's times. Black hard rubber. Chased alternating lines and plain band pattern. Courtesy of PBA Galleries, Berkeley, CA. (photos ©Justin Benttinen).

Parker’s safety principle would continue with the double cap that also features the Vacumatic pens.


  • 1914/1918 and 1922 Parker catalogs.
  • 1909/1922 Parker SideTalks and Parkergrams, the Parker´s dealer magazine.
  • Sorgatz, L. (February, 1994) «A History of the Parker Jack-Knife Safety Pen.» The Pennant magazine, Vol VIII, nº 2.
  • Fountain Pen and Pencil. The Golden Age of  Writing Instruments. G. Fischler & S. Schneider. Ed. Schiffer Publishing, Ltd. 1990.
  • Plumas Estilográficas. Jonathan Steinberg. Ed. Edimat Libros. 1998.
  • Tsachi Mitsenmacher pens collection.
  • Luiz Leite pens collection.
  • L. Michael Fultz collection.
  • John Danza collection.
  • 900 Parker ads. Pre-Duofold.
  • Parker Safety patent US 1,028,382.