Newbie with Churchill cub

[Lockwood1956]

Hi all

New to all of this and have recently sold my Chinese lathe (which i havent got that much experience on) and replaced it with a Churchill Cub mk3. have also purchased a Dore Westbury mill.

I have been trying to set up for metric screw cutting and when I swap the gears to the ones listed on the plate inside the end cover, they dont match up

I have it set up currently with 120T gear at the bottom, 110T intermediate ad 30T at the top (which is the settings on the plate at the base of the gearbox

Lathe works great and I’m having a lot of fun with it. I would like to learn how to set it up for metric threads, if anyone can shed light on this for me I would be most grateful

I purchased the operators booklet from Lathes.co.uk but it doesn’t help me as there is no gearing info in there



Kind regards
Bob

[EdK]

Is your leadscrew metric or imperial?  

I found this on the lathes.co.uk website. Not sure if it's applicable to your version of the lathe.

"Screwcutting was taken care of by a 4 t.p.i. 7/8" in diameter leadscrew driven from an enclosed, splash-lubricated gearbox operated by two dials and capable of generating 30 pitches from 10 to 76 t.p.i. and 30 sliding feeds from 0.001" to 0.0076" per revolution of the spindle. While the sales literature claimed that additional changewheels of 30t, 60t, 60t, 110t and 120t were provided with each machine to extend the threading range from 2.5 to 75 t.p.i. (and the  feeds from 0.001" to 0.030"), an examination of machines in use appear to indicate that the original gear train (for a gearbox-equipped lathe) used a 30t drive gear, 110t idle gear and a 120t  gear on the gearbox input shaft. Stored outboard of the idler gear and gearbox input shaft were gears of 45t and 50t - but with no sign of the 60t gear. At extra cost an additional nine (unspecified) changewheels were available to generate metric pitches from 0.20 to 8.0 mm pitch (these likely to have included a 127t or 63t.)"

Ed

[Lockwood1956]

Hi Ed
thank you for the reply


I have the extra gears but when I try to set it up as described on the metric gear cutting info plate inside the head stock cover i cant get it to work (gears end up too far apart!!!)


I’ll take some pics of the info on the lathe which will hopefully help as I’m not sure my post adequately describes the situation

the lathe is capable of cutting metric threads, (and I have extra gears ) my ineptitude in setting it up is the issue i think!

Kind regards
Bob

[Lockwood1956]

   


Here is the info plate for metric thread cutting

[Lockwood1956]

   

This is the plate on front of Lathe and it is set up as depicted 
30 teeth on top
100 teeth on inter
120 teeth on Feed Box

[EdK]

Can you take a picture of the gear train and post it?

Ed

[Highpower]

(01-09-2023, 06:39 AM)Lockwood1956 Wrote: This is the plate on front of Lathe and it is set up as depicted 
30 teeth on top
100 teeth on inter
120 teeth on Feed Box

These are for cutting imperial pitches only. For metric pitches you need to use the gears listed for the particular pitch you want to cut.

[Lockwood1956]

(01-09-2023, 12:16 PM)Highpower Wrote:

(01-09-2023, 06:39 AM)Lockwood1956 Wrote: This is the plate on front of Lathe and it is set up as depicted 
30 teeth on top
100 teeth on inter
120 teeth on Feed Box

These are for cutting imperial pitches only. For metric pitches you need to use the gears listed for the particular pitch you want to cut.

Hi Willie

Cheers for the reply, yes, that much I already knew ( I think)

It’s setting up for metric cutting that’s causing me the issue, I think i may need another gear stud, or a compound with two gears on the stud

I’m off to take a pic of gear train, to aid my inability to ask a clearer question 

Back soon….

[Lockwood1956]

       


OKey dokey


Pictures attached, in second picture i am pointing to where I'm beginning to suspect a second spindle may need to be attached (it's a separate spindle slot).

The metric cutting guide refers to 4 gears for 1.5mm pitch, so i either need two gears on one spindle or a second spindle?

[Lockwood1956]

   

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, which leads me to believe I need a second gear stub, or I need to make one, (not sure my skills are developed enough at this point)!!