Hello,
the “fluid.s2f” abstraction is quite complex:
and the following abstraction does the same:
if I’m not wrong.
Sadly, you are 
I so wish Pd handled that sort of conversion better, this patch took me ages to think of all exceptions… see with the attached patch:
test-s2f.pd (299 Bytes)
sorry…!
There’s this weird situation where it works, after “kdtree”
here kdtree outputs “1”, I was using fluid.s2f until recently when I found out this was working:
very strange…
indeed - what we post is a peculiar symbol that is accepted by symbol… but if you try in your patch to send “123” it will bail… so I reckon I was tired of the complicated limits (no float no this no that) and did this abstraction that should work with any float.