If I were still at work, I would have used our lathe and made 3/8 - 1/2 reducing bushings. But now that I am retired and my time is more valuable, I'd try to find some long 1/2 bolts and bend them to L shaped as Old Coot suggested.
I haven't lost any T handles from my JTs yet but the do move in travel. I have several spares, but I actually thought about cutting one side of the Tee off and let gravity help.
Cathy & Jeff
2013 Sabre 32RCTS / 2012 Ram2500 Hemi
Nights Camped: 2015-140; 2016-137 YTD; 160 Planned