I turned the slack adjuster the wrong way on my DR Trimmer and broke the bottom part which is left hand threaded. DR Power is sending me a new one but I figured I would try to print off a replacement. You can't find this part by itself anywhere I looked. It's doesn't even have a part # in the manual.
Measuring the threaded part I broke measured 0.303" and ~7.7mm which should be 5/16" but it had a little play in it so 3/8"-18LH ended up being the thread I needed.
It prints with the threads being complete so you need to cut out the slot for the cable to slide in. It turned out great.
Another never to be found in the store glad to have a 3d printer to be able to make what I need part
0.4 nozzle used but if you have a smaller one for the threads to be even better that would be good.
I used makergeeks PLA which is stronger than regular PLA. If it breaks I will reprint in makergeeks Raptor series PLA and anneal it.
Clean out the groove for the cable using a box cutter/razor knife etc..