It simply doesn't work that way, my man.
A baritone is a longer scale, hence a longer neck, different geometry, etc.
I suppose you could with some radical rebuilding and some fine luthier skills, but......
....I'd say you're better off buying a new baritone.
my brother tuned his guitar down to that once. he used some really heavy strings and just tuned it down and said it worked fine it was just not what he needed at the time.
just for the record it was a Les Paul also but a cheap epiphone.
I've done it. It's difficult because of the bridge. You need bigger strings which, depending on the frets, could make it impossible to have correct pitch across the board. Also, the bridge has to have enough room to move the low B saddle back. On a Les Paul it might not pan out. I'd go after a strat and cut the spring in half on that saddle.
By the way, we've all seen basses that are short scale so, length has nothing to do with it.
A barritone guitar is a longer scale.....not just tuned down to B with bigger strings. Not that you can't get decent results by simply tuning down to B, people have been doing that for years.
i want to go to baritone because i played my buddy's and fell in love with it. i'm really not interested in tuning down to b, but there's something about it that makes it sound different than you normal guitar, say tuned to d. it sounds full and warm. just beautiful imho. i think i'm in love.
i´ve done it with a 25.5 scale, if you analize it, thats the scale of 7strings guitars, you need .12-.56 or .13-.58 strings, good tuners (think sperzel) an adjustable bridge, and some luthier adjusting, you´re ready to go
Length has a lot to do with tone. I have a short-scale bass, and while I love it, the low E simply does not match a full-scale instrument, nevermind a 3/4 upright.