Sub $150 RJ Follow Focus Review

Gregg MacPherson said:
The big defect with these units I think is that the spindle holding the plastic drive gear is wrongly designed, making it weaker and giving a potentially huge backlash. The machined slot in the spindle is too big. It's about 2mm and the pin it fits is about 1.4mm, so on it's own this fit will lead to a lot of backlash. ....
Click to expand...

A trick that worked well was I cut a 5mm wide strip from some film stock and looped that over the pin. Job done if you are rarely switching the drive gear from front to back.

I had some other issues, like a really rough bearing and the steel shaft developing some end float. Being curious, I pulled the gearbox apart. The pin actually measured 1.82mm. I replaced that with one measuring 1.95mm. It looked like the the pin was not perfectly centred. The result, with what is probably a happy combination of machining errors, is almost zero backlash in the drive gear. I did have a bad bearing, which improved with a little oil, but really needs replacing. The end float was due to the grub screws securing the gear or collar not being tight enough. The grub screws had been manually ground shorter, so their shape was a bit compromised. Also, I may be mis remembering, but I think the assembly order on that shaft was wrong, the rubber O ring was on the wrong side so the gear was not centred properly.

This may all sound bad, but I just see these as inconsistencies in quality control in a develop and build process that is just too rushed. With some tinkering this looks like a very usable unit if you have some skills and not much money.

Cheers
Gregg.
 
You must log in or register to reply here.
Back
Top