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+--- Thread: Newbie with Churchill cub (/thread-4480.html)
RE: Newbie with Churchill cub - EdK - 01-09-2023
The two shafts that hold the large gears on your lathe have a spacer that you remove to stack a second gear next to the existing gears. Can you remove the two large gears and take a picture of the gear train without those gears installed?
Ed
RE: Newbie with Churchill cub - Highpower - 01-09-2023
(01-09-2023, 01:10 PM)Lockwood1956 Wrote: Just found this pic of a mark 3 Cub gear train (only a side view I'm afraid).
But it certainly looks like there are 4 gear placements in use,
What pitch are you setting up for? Some require more gears in the train than others. In the side view picture you posted you see the path of the power flow through the gear train to the lead screw. (For whatever pitch it is currently set up for.) The two back to back gears are required to move the power in or out on the studs in order to be able to fit larger gears in where needed because you can't line them all up in a single plane. Sometimes extra gears are stacked together just to take up extra space on the studs. Other times they are keyed together to serve as a drive gear and driven gear. Does that make any sense? Clear as mud right?
RE: Newbie with Churchill cub - Lockwood1956 - 01-10-2023
Hi Willie
It does make sense, thank you, and it’s becoming clear for meteoric threading inbred the extra stub shaft that I don’t currently have so I can have four gears in the train ( for 1.25 and 1.5 metric)
I currently only have places for three gears in the train
I will take more pics later today
RE: Newbie with Churchill cub - Lockwood1956 - 01-10-2023
Can you remove the two large gears and take a picture of the gear train without those gears installed?
Ed
hi Ed
I will take pics later today, cheers
RE: Newbie with Churchill cub - Lockwood1956 - 01-10-2023
IHi all
I managed to sort it, but can’t load photos from my phone ( I’m in the pub)
I manufactured a new gear stub (surprised myself)
Pics to follow tomorrow
RE: Newbie with Churchill cub - Dr Stan - 01-10-2023
I do not know if you have access to Boston Gear or maybe a similar company. You could purchase gear blanks then bore them to the required inside diameter. If you are hesitant to cut the keyway it is not difficult to do as I learned how to cut internal keyways in the US Navy's machining school. Take a look at this: https://www.youtube.com/watch?v=XcU0LTavzDM Keep your boring bar as short as possible to reduce spring in the boring bar. It's a good way to cut keyways if you do not have a broach set or shaper.
RE: Newbie with Churchill cub - Lockwood1956 - 01-11-2023
(01-09-2023, 02:11 PM)EdK Wrote: The two shafts that hold the large gears on your lathe have a spacer that you remove to stack a second gear next to the existing gears. Can you remove the two large gears and take a picture of the gear train without those gears installed?
Ed
[attachment=18170]
RE: Newbie with Churchill cub - Lockwood1956 - 01-11-2023
So, I looked at the gearing requirements for threading metric and there are 4 gears in the train and I only have three places to mount them. I initially thought perhaps i would mount two gears on one shaft, but then the gears won't reach each other.
The setup needed to be like the picture below
[attachment=18171]
RE: Newbie with Churchill cub - Lockwood1956 - 01-11-2023
So I decided I would try to manufacture a shaft (temporarily) to see if i was right.
So using my mill and lathe (set back up in original configuration, I made a shaft, with a sleeve on it that would hold the gear and spin to test if i was right?
Here it is in the picture below. I amazed myself that i managed the job, :)
[attachment=18172]
RE: Newbie with Churchill cub - Lockwood1956 - 01-11-2023
Here it is in situ
[attachment=18173]