HARTNER
egg grading scale

Hartner egg grader

This egg scale was made by G. Hartner Präzisions- und Schnellwaagenfabrik from Ebingen in Germany. It is rather easy to put an age to this specimen thanks to the verification stamps in the control weight and in the lead seal of the screw between the base and the housing: 1959-1978. I have not found a patent of this egg scale design, not in connection with the name Gustav Hartner. In full this egg scale is called Eiersortierwaage, meaning egg sorting scale or egg grading scale. The chart of this scale goes from 40 up to 75 grams. Above this are the weight classes denoted by capitals in color areas: E = 40g-45g; D = 45g-50g; C = 50g-55g; B = 55g-60g; A = 60g-65g; S = 65g-75g. Nowadays, since 1996, yet another egg weight division is used in the European Union, also again with letters. S (up to 53g); M (for 53g up to 63g); L (for 63g up to 73g); and XL (for 73g and higher). In the USA one uses two additional classes: Peewee for the tiny, lightweight eggs and Jumbo for big heavy eggs. One also considers the weight in ounces per dozen eggs, and the average weight per egg in the weight class. The German egg scale of Ph.J. Maul, see here, also has the capitals, but the letter E is not present. On a rare variant of this Maul egg scale, the weight class letters are replaced by numbers and there is again a slightly different classification of weight classes. 1 (= 80g-70g); 2 (=70g-65g); 3 (=65g-60g) 4 (= 60g-55g); 5 (=55g-50g); 6 (=50g-45g) and 7 (=45g-40g). This Hartner might be termed the Mercedes-Benz amongst the egg scales. The parts are made very solid. The scale housing and the base plate are made of cast aluminum. The scale has knife edge bearings as the main pivot points to move accurately and sensitively. The movement of the mechanism can optionally be locked with a transport lock to

back of the Hartner egg scale

prevent damage. The transport lock must be activated by turning the red knob at the bottom of the base plate, while in the meantime the egg scale should be loaded at a value between 55 and 60 grams. This can not be called really convenient. This egg grader has - and this is very special - a magnetic damping. This shortens the egg weighing time because the scale is quickly stopped. The magnetic damping already was applied in the egg grading scale of August Fabian, see there. This type of egg graders was calibrated annually. The test weight of 50 grams was calibrated also and also received a verification stamp when approved. The house fairly protects the mechanism and the pointer and the dial are behind glass. Yet, quite some dust and dirt comes inside in the course of time, as can be seen in some photos. The dimensions of the base plate are 21.8 x 11.1 cm. The scale house is 20.5 cm high. The height including the egg cup is is 26.7 cm. The Hartner egg scale complete with its test weight weighs itself 2357 grams. The nameplate at the right side indicates the function: EIERSORTIERWAAGE, has stamped the identification number 91315, and at the right the admission sign in the shape of an angular Z, with in it above the letter L, the distinctive letter for Eiersortierwaagen, and there at the bottom the authorization number 302. There exist also copies of the Hartner egg scale with 302p at the bottom of the admission sign Z. This p indicates probeweise Zulassung, meaning a provisional admission. [information received from Claus Borgelt, chief editor of the journal Mass und Gewicht, for which many thanks]. The lower part of the nameplate shows the name and location of the plant: G. Hartner Ebingen, Präzisions- und Schnellwaagenfabrik.
Hartner has made this egg scale to about 1980. Below are a lot more pictures of this Hartner egg grading scale.

side view left	top view with recessed the 50 grams control weight	side view right
an egg in the Hartner	just above 70 grams in weight class S	with a smaller, lighter egg
the control weight with verification stamps starting in 1959. the last stamp is 1978, there is also down a banderole mark of a German gauging office	this Hartner logo dates from the sixties	at the right side a spirit level is present a good tool to easily level the egg scale

the screw that is securing the scale house on the base plate is sealed with a 1978 labeled verification lead	the factory plate at the right side of the scale shows the function, the stamped identification number, and at the right the admission sign, the angular Z, containing L and 302 [see text above] and finally, the manufacturer's name and location	at the back of the lead seal is a banderole of a gauging office
after cutting the seal and the removal of a single screw the scale house was dismantled and the mechanism is clearly visible	the parts are pretty firm and robust	in the two holes of the upright strip on the base plate at the front of the photo the scale house is hooked, the screw with the seal lead is situated at the other side
the egg scale was rather dirty and dusty	cleaned but not yet painted	cleaned, painted and reassembled
The refurbished egg scale	the old wear tracks are still visible under the new coat of paint	the 50 grams control weight on top of the scale house

check with the weight

the pointer stops exactly at 50 grams

stripes of measure per gram from 40 to 75 grams

[move the pointer over the photo] animation: the scale without and with an egg in the egg cup

[move the pointer over the photo] animation: the control weight moves from the right front into the egg cup

[move the pointer over the photo] animation: with and without an egg

left the magnetic damping, center and right knife edge bearings	the magnetic damping ensures a fast stop	quite robustly constructed knife edge bearing
front of refurbished egg scale, still without the scale house	back of the refurbished egg grader	two rubber coated rods are the end stops for the scale movement
The back was also quite dirty and dusty	with the check weight in the egg cup	with the check weight in the egg cup
extensive use caused a battered house	inside of the cast aluminum house	the glass plate is inserted from below into the house slots
inside egg cup	the removed egg cup	egg in the mounted egg cup
the egg scale rests on three support points, the support at the center back is fixed and not adjustable both front supports are easy adjustable to level the scale	on the bottom is also the red rotary knob for the transport safety here maximum unscrewed = inoperative	here the red rotary knob is turned inwards at the max, the transport safety is thereby put into operation
at the right the aluminum arm rests against the vertical brass threaded rod: the transport security is off	at the right the aluminum arm is maximally pushed up by turning the brass screw rod inwards: the transport security is in effect	the aluminum arm right is still clamped while the brass screw rod is already in off-position; move the egg cup a bit to free and lower the aluminum arm and so restore possibility of movement

a Hartner egg scale next to a Fabian egg scale, which is greater still!