# Gear box 820 or 825 compatibility with model 200



## martik777 (Dec 29, 2017)

Will either of these QCGB's be adaptable to the model 200 plain change gear  lathe?


----------



## Nogoingback (Dec 30, 2017)

This question has been asked before and I believe the answer is basically no.  Having said that, nothing is impossible,
but it's not a bolt on deal.  There are a couple of threads on this subject: I'll try and hunt them down.


Edit:  Look on the Logan sub-forum for a post from Woodzi titled "QC Gearbox".  There's a link  that takes you to
some information on that subject from Scott Logan.


----------



## RandyM (Dec 31, 2017)

Here is a link to that thread.

https://www.hobby-machinist.com/threads/qc-gearbox.63171/#post-520517


----------



## Terrywerm (Dec 31, 2017)

At one time I considered adding a QCGB to my Logan 200. There is a way to do it, but you have to get just the right gear box to make it work, and then it requires a certain amount of retrofit work. Sorry that I don't remember the details, but it was about ten years ago now that I considered this.

Anyway, I ended up doing a project that required a custom thread - a double helix actually, and I was able to do it with change gears by calculating for a double start 1/2 TPI - in other words 1 thread every two inches. The lathe was not powered for this but used a Dremel tool mounted to the toolpost and I turned the chuck by hand, allowing the lathe to provide the gearing to guide the Dremel to cut the helix.  I could have never done it without change gears. I decided at that point to just keep what I've got as changing the gears adds a little time to my projects, but it is only minutes per change. Not a big deal for me.


----------

