Can someone give me the lowdown on Stihl's shaft profiles and gearbox attachments?

[TerraForte]

I recently picked up a used Stihl "pole saw".

The craigslist ad said it ran great! Telescoping model that extends to like 15 feet or something crazy.
$200!
WOW.

Then I noticed it had a hedge trimmer head on it. Hmm...kinda weird, but it was the 135° degree articulating variety. Didn't know Stihl sold those in that configuration, so I assumed someone swapped it out. I'm game. I love my Echo PAS-266, but the equivalent attachment is $280. So I figured the deal just got a lot sweeter at $200 for a running Stihl mid-high grade power head, the telescoping shaft, AND an articulating hedger!

I've taken apart several small engine tools, so I know motors, and shafts, and gearbox heads can all be interchanged... within reason.

I read a comment somewhere about someone selling a brand new pole saw gearbox because "it won't fit my HT103. It's for the *older* HT103's with a different shaft"
I read a similar comment elsewhere, too. Something about the profile of the shaft being changed from a square to a star pattern or something?


Can someone give me the lowdown on this so I can figure out interchangeability and such?

 

[MowLife]

Most attachments are interchangeable as you said. On the square shafts there is flex and solid shaft type...just make sure your not using flex shafts for pole saws, hedge trimmers or straight shaft edgers. The drive shaft is going to have to match the attachment but you can change clutches on the motor side for different shafts.

 

[TerraForte]

Most attachments are interchangeable as you said. On the square shafts there is flex and solid shaft type...just make sure your not using flex shafts for pole saws, hedge trimmers or straight shaft edgers. The drive shaft is going to have to match the attachment but you can change clutches on the motor side for different shafts.

Thanks for the reply. Can you elaborate a little bit?
Do you know how many different types of shafts there are? Like square vs 6-point star? Just 2 types of profiles, or more?

Also, do you know when they switched? I feel like someone implied they switched around 2015 and created 2 'eras' of shafts. Like all the pre-2015 stuff interchanges, and all the post-2015 stuff does, but you can't mix.

Just trying to figure out what I can safely snatch off craigslist, or other classifieds.

 

[MowLife]

I don’t have access to the stihl parts lists anymore but someone who does should chime in. I’m pretty sure there were at least 2 different types well before 2015 but not positive.