Hey folks,

 

Maybe someone on here can help me with this....

 

How well can LEGO be dated using the various markings on the bottom of pieces?

 

Do markings like Pat Pend., Pat Pend. (obscured), etc. fall within very specific dates?

 

Would some vintage sets have had a mixture of both markings in the same set for instance?

 

 

Also, is the there a timeline anywhere which outlines when sets went from using old production pieces or markings, to newer production?

 

Like, since when have the current types of brick (thinner sides, different type of plastic etc) and plates been in use?

 

Or is there anywhere where I can find this kind of info?

 

Thanks!

Okay, found some useful info here:

 

It seems like there was a transfer period where different markings were used in the same sets.

 

http://www.leggodt.nl/items/lego/date-patpend.php