Loose InterMountain F3 Shell - Fix?

[Brian M]

As the subject line says, I've got an InterMountain F3 where the shell just slips off the frame when I pick it up.  I can press the shell down enough such that the four nubs on the side of the frame should be engaging the slots on the shell that usually hold the shell in place.  But the shell must be just a little wider and those nubs aren't locking it in place.  Wondering if anyone else has figured out a solution to this problem?  Do I epoxy some plastic on top of the nubs on the frame and sand them down so everything fits again?

Thanks,
Brian.

[thomasjmdavis]

I recall encountering something similar when I first put decoders in mine, and discovered that something inside wasn't clearing as expected. Essentially, the shell was riding about .005 too high, and not engaging correctly. I think it was a simple matter of making sure every odd bit was in place, and then pressing down just enough to get the shell to "click" on.

[djconway]

A piece of masking tape on the frame solved my loose shell issue

[Brian M]

Thank you for the replies, just wanted to follow up with what I eventually did to solve this.

I had the same idea of using some small bit of masking tape on the frame, which helped, but didn't fully solve my problem.  Upon taking a closer look at the locking tabs and how they engage on the frame, I figured that the tabs weren't proud of the shell side enough to do their job.  I shaved the four tabs/nubs off and super glued four little bits of 0.015" x 0.040" strip styrene in their place.  This did the trick, and now the shell locks onto the frame as it should.

-Brian.

[mecgp7]

I was going to comment originally as the masking tape was a good idea. Since it didn't work well for you and you came up with a solution, I thought I'd report what I have used which is double sided carpet tape over the nubs or on the inside of the shell. As a side note, I use carpet tape as a place holder for a million things. My favorite trick is to use it when body mounting couplers. Stick the coupler box exactly where you want it with the tape and use it as the guide for the drillbit.