Could the construction of the "stick" holding the bucket be used to set a date? If LIMA used two U-beams or something (see the LIMA 1201 image above) up to a specific year for this "stick" and then switched to using a tube?
Loose thoughts ...

The LIMA 601 (not 604) had a "stick" of U-beams (or similar)
and was in production between 1933 and 1935.
It was replaced by the 302.
How many years would it take to get the model number up to 604 for a 1.5 cubic yard model?
https://books.google.se/books?id=8svyOXSaZkAC&pg=PA201&lpg=PA201&dq=LIMA+shovel+boom+design&source=bl&ots=c8MMltUcgQ&sig=ACfU3U18L0hNucS-_oT1VirU8POxSYzo9g&hl=sv&sa=X&ved=2ahUKEwie-O6C49ngAhXDyaYKHcOoC7EQ6AEwDnoECAEQAQ#v=snippet&q=LIMA%20604&f=false

Robin - My thought exactly but so far I have not been able to find any reference that indicates the Lima used a single beam main strut up to such and such a date and after that used the twin beam main strut.

The FOR SALE unit that I posted photos of early on in this thread is a twin beam unit and the ad said it was built in 1951.

The Lima Paymaster 34 appears to be a scaled-down version of the 604. This picture is from a 1945 Army Technical Manual :



TM 5-1312

PS : talking about pics, has anyone noticed the promoting image posted in the initial post is reversed ?

H.P.

I noticed but didn't have the energy to comment

I suspect we have some graphic artist who knows nothing of the subject. Wanted a left facing photo to better fit the layout, thought the machine was symmetrical and just flipped the picture. After that the client either never spotted it or just went along with it.

The 604 shown in the video shipped from Lima in June 1946. It and another that shipped two days later are believed to be the original prototypes of the 604. Less than 500 were built thru 1967.

I love the model, and plan to buy one but fear my model building skill won't do it justice.

Welcome to Kitmaker and the forums Adam!

/ Robin