Viceroy TBS 1/1G/B metric threads

[Piotr]

Hi.

I've just bougth viceroy TBS 1/1G/B lathe and i'm not shure if i can cut metric threads on it. On the plate it is writen "metric" but on the thread table therse no metric pitches. Could eny one provide some info on it?

[Andy B]

Hi Piotr,
Can you post a picture of the plates?
It will help to understand what you see...

Andy

[Piotr]

Thanks for the replay
Of course i can. Pictures in attachment. I did some reading and is these the case that i need metric gaers and quadrant to convert it to cut metric threads?

[Andy B]

Well, that's an odd one!
You have a 5-position (metric) gearbox (lever to the left of the plate has 5 locations), but for some reason there is an 8-position (imperial) gearbox plate attached.
I would suggest that you set up the machine according to a metric gearbox plate (picture here - https://www.lathes.co.uk/viceroy/img14.jpg) and take a test cut just to prove it is a metric gearbox.

Andy

[Piotr]

Ok. I will try to do that today and try it out. Thanks

[Piotr]

Holy monkey. Some one did changed the thread plate. I set it according to the picture and the pitch is correct. Thank you for yours help.

[Piotr]

One more thing i can see that to set particular pitch i need to change stud gears, and i don't have them. Can You tell me where to find drawings for them?

Are those gears what i need?

[richardb]

I've recently found this very useful site myself.

I think if you scroll up 2 posts from yours currently 'ML drawings for 5" TDS1 lathes' - open it and scroll down to 'ML115 metric gearbox stud gears A-Q' it will give you want you need.

There is another useful one currently 12 posts down from yours ' Metric Viceroy TDS1/1GBL screwcutting - which I found a good reminder of operations.

[Piotr]

Ok. I'm wondering how it correspond to module gears. According to what i know the gear seams to be 1.5 module.

[Andy B]

MOD: Module (metric) = the pitch diameter (in mm) divided by the number of teeth.

DP: Diametral pitch (imperial) = number of teeth divided by the pitch diameter (inches).

So in comparison, DP = 25.4/MOD

For the most part they won't run together. You might find some combinations that are close enough to mesh, but they would be very noisy, inaccurate and prone to wear.

Another parameter in gear design is the Pressure Angle (PA). Manufacturers of similar sized lathes (e.g. Denford, Boxford, South Bend, Myford, etc) used different PA's on their gears - mismatching these will cause noise and wear.

Andy

[Piotr]

Hi

So after some triles i manage to redraw the gears. It's not perfect but it seames to be working. For teasting i 3d printed one and mounted it. Funny thing that it didynt breake and its turning, i eaven manage to cut a thread on it. Next step is to cut it ona a wire EDM maschine.

Thank You for Your's help.