Speed Feed for Stihl FS110

[Cedar Row]

I got an oregon Speed-Feed 375 head (by accident,I ordered the Shindaiwa 450) to use on a Stihl FS110, but the m10 x 1.0 arbor bushing doesn't fit the Stihl m10 x 1.0 arbor shaft. It is close, but doesn't go (I didn't try forcing it). Has anyone else run into this problem? Metric left-hand taps are hard to come by, they come from China and take weeks to arrive.

 

[Rookie1]

The ones I bought for work had different adapters and the one for Stihl fit fine. I thought Stihl were opposite from most trimmers for rotation. Id either send back or do more research.