Help with triumph frame i.d

[Chimp]

Hi all
I have a front section from a old triumph frame which iwas hoping to use as a basis for a custom build , but having trouble identifying which year it it . There are a fair few easy to find lists on line but the number doesnt seem quite right . The number seems to indicate its a '54 5ta which would make it a swingarm frame , but it has a H in front of the number , which according to the lists would make it a late 60's frame . They both have completely different engines so im kind of stumped .
The frame reads 5ta H46*** . Can anyone help ?

[kestrel]

[Bezzer]

Looking at the Triumph book I've got I can see why you're confused but the way I read it at first....
From 1950-1956 when they were pre unit engines they had the model designation and H to denote it was a twin under 650cc so 5TA H 46*** would put it at 1954. 54 was the last year of the sprung hub, 55 was the introduction of the swingarm.
From 1957 when they introduced the unit engine they dropped the model part and started from 101 again so H 46*** would be an under 650cc twin 1966 model.
But seeing as the 5TA model was from 1959-1966 it must be the 66 model, very confusing the way it's written.
____________________
I used to be indecisive but now I'm not quite so sure.

[Chimp]

Cheers , thats cleared things up .