23
DescriptionOld logo - smaller stud recess - corner-pip - no mold-id
From1958
To1959
This generation is among the most complex generations to figure out. It's the last generation whithout mold identification numbers. At the end of the fifties, LEGO had scaled up their production, so that muliple molds were being used in paralell. This makes identifiying the various molds extremely hard. The process of identifying the molds is based on testing out a lot of different hypothesises regarding mold-specific properties. The result is with high certainty not correct, but without a lot more samples to work with, a best guess of how many molds that were used - and how the mold members were arranged.
The different 2x4-molds were identified in the same order as they are named - starting with the most obvious differensiators.
| Molds | Identifying feature | Secondary feature | Notes |
|---|---|---|---|
| 23a | Stud-recess-size | NA | Diameter of stud-recess about 2mm. |
| 23b | Mold id alignment | NA | Mold id right - bottom to top. |
| 23c | Mold id alignment | NA | Mold id left - top to bottom. |
| 23d + 23e | Mold id alignment | NA | Mold id left - bottom to top. No good differensiator found between 23d and 23e. |
| 23f | Mold id alignment | Pat-pend size | Mold id right - top to bottom - small pat-pend size. |
| 23g + 23h + 23i + 23j | Mold id alignment | Colors | Mold id right - top to bottom. Quite indestinguishable molds, so molds are based on colors of available samples. |
The different 2x3-molds were identified in the same order as they are named - starting with the most obvious differensiators. Compared to the 2x4-molds the process of identifying the different 2x3-molds was a bit more straight forward.
| Molds | Identifying feature | Secondary feature | Notes |
|---|---|---|---|
| 23k | Pip | NA | Pip left. |
| 23l | Pip | Mold id print | Pip right - weak mold id (except for mold member 16). |
| 23m + 23n | Pip | Colors | Pip right. Two different molds identified based on origin and colors. 23n has a bit smaller stud-recess diameter, but mold member 2+4 both have very matching bottom pattern on both molds. Some other samples does not have matching patterns. |
The 2x2-molds share some of the same identifying properties as with the 2x4-molds, but because of the square-shaped nature also adds new complexy with different logo orientations. There are just a few samples available, so there is potentially a much larger complexity here that more available samples will reveal.
| Molds | Identifying feature | Secondary feature | Notes |
|---|---|---|---|
| 23o | Stud logo orientation | NA | Horizontal stud-logo. |
| 23p | Stud logo orientation | NA | Vertical stud-logo. |
The 1x2-molds come in two different sub-categories. There are molds with stud-logo along the brick length, and other molds with the stud-logo across. Within both categories there are mold evolutions across generations - with the same mold being modified from having large stud recesses to having small stud recesses.
| Molds | Identifying feature | Secondary feature | Notes |
|---|---|---|---|
| 23t | Stud logo | Evolution | Stud logo along. Evolved from 21ah. |
| 23u | Stud logo | Stud recess size | Stud logo along. Both small and large stud recesses. |
| 23v | Stud logo | Evolution | Stud logo across. Evolved from 21. |
| 23w | Stud logo | Pip positions | Stud logo across. Mold members identified by pip positions. |
| 23x | Stud logo | Pip positions | Stud logo across. Members not matching 23w patterns. |
There are a lot of samples available for the 23w mold, which should have had 48 mold members. Based on my findings, some members are non-existant. The missing members form a quite specific pattern (with one strange exception), when arranging the 48 members in four columns:
| 1-12 | 13-24 | 25-36 | 37-48 |
|---|---|---|---|
| Missing | Missing | Missing | Missing |
| Missing | Missing | Missing | Missing |
| Found | Found | Found | Found |
| Found | Found | Found | Found |
| Found | Found | Missing | Found |
| Found | Found | Found | Found |
| Found | Found | Found | Found |
| Found | Found | Found | Found |
| Found | Found | Found | Found |
| Found | Found | Found | Found |
| Missing | Missing | Missing | Missing |
| Missing | Missing | Found | Missing |
I have no good explanation for mold member 29 and 36, but otherwise the missing mold members are the uppermost and lowermost members within the mold. One can suspect that there were technical problems with transporting the plastic to the outer mold members when going from 24 to 48 members, and that they decided to remove those mold members from the mold after testing it. There are similar patterns within the 23v-mold, but with less systematic positions of the missing members.
Only one mold is identified for each of the two brick types. Please note some similarities between these two molds (23q, 23r) and the corresponding molds with 'Tall Wide Straight O'.