====== Seiko 5100 ======
Seiko's **51 Stream** was a family of midrange [[automatic]] watch movements from [[Seiko]] produced in the late 1960's into the early 1970's. It is notable for the [[quickset date]] [[pusher]] located inside the [[crown]] and this function was the namesake for the Seiko "Presmatic" line. It was produced by [[Daini Seikosha]].

Three 51 Stream movements were introduced in [[1967]]: The 33 jewel 19,800 A/h **5106** found in the domestic "Seikomatic-P", and two "Seiko New Fives", the basic 23-jewel **5126** and the "DX" (deluxe) **5139** with 27 jewels. In [[1969]], a [[Hi-Beat]] (28,800 A/h) "Presmatic" was introduced with a new **5146** movement sporting 27 or 30 jewels, just as the 5139 was phased out. The movement stream began disappearing just one year later, with the 5106 and 5126 ending production in 1970 and the last surviving member, the 5146, gone in 1971.

The 51 Stream is somewhat similar in appearance to the Daini-produced [[Seiko 5200|52 Stream]], introduced in [[1969]] as the ultimate mechanical movement from that company. It is a fairly advanced movement, with [[hacking seconds]], [[hand winding]], a "tadpole"-style [[fine adjuster]], and [[quickset date]] (though the day is not quickset). All 33 jewels are functional, with 6 being cap jewels and jewels on both sides of the [[barrel arbor]]. It lacks the bilingual day wheel of other contemporary Seiko movements.

===== Variants =====
^Movement ^Date ^Winding ^Speed ^Hands ^Date ^Jewels ^
|5106A |1967-1970 |Automatic |19,800 A/h |Hour, minute, seconds |Day and Date |33 |
|5126A |1967-1970 |:::|:::|:::|:::|23 |
|5139A |1967-1969 |:::|:::|:::|:::|27 |
|5146A |1969-1971 |:::|28,800 A/h |:::|:::|27 or 30 |


===== External links =====
  * [[http://seikoholics.yuku.com/sreply/211/Seiko-51-Presmatic-SeikomaticP-family|Seiko - 51 Presmatic & Seikomatic-P family]]


<WRAP ud ud_mov>

**Description:**
  * [[Automatic]] movement

**Functions:**
  * Hours, minutes, seconds
  * [[Automatic]] winding
  * [[Quickset]] date wheel
  * [[Hacking]]
  * [[Hand winding]]
  * Day wheel

**Data:**
  * 23, 27, 30, or 33 [[jewels]]
  * 19,800 or 28,800 A/h

**Production period:**
  * [[1967]]-[[1971]]
</WRAP>

{{tag>Movements Automatic_movements Seiko_calibres Daini_Seikosha_calibres}}