# New member What is new to me threading dial



## Whiskers31 (Jan 24, 2022)

I have purchased an Italian lathe. It cuts metric and imperial without changing the change gears. It has a strange threading dial numbered from 0 to 9.  When threading , engagement of the dial requires consecutive engagement numbers for example 5678
Or 123 etc.   this is only way to engage the same helix Each pass. Has anyone else encountered this it is new to me thanks.


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## YYCHM (Jan 24, 2022)

This sounds like a @RobinHood question.  He just restored an Italian lathe (CMT Ursus 250 ?).

Welcome from Calgary....


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## Whiskers31 (Jan 24, 2022)

Just trying to get used to all its quirks it seems to be a different kind of dock in many ways


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## Whiskers31 (Jan 24, 2022)

Another pic I also noticed that The ways both crossfeed and longitudinal self oiled. By the way I guess I should’ve said this before Craig I appreciate you getting back to me thanks for now it’s getting time to shut it down in southern Ontario


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## Susquatch (Jan 24, 2022)

Welcome from Farm Country south of Chatham Ontario. 

Never heard of such a thing. If you ever figure it out, I would love to know how that works and why it works that way.


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## trlvn (Jan 24, 2022)

Welcome from Oakville.

There is a very brief overview of the maker of your lathe at:



			Gornati Lathes
		


Yours looks similar to one of the pictures.  You might try contacting the owner of that site (Tony) to see if he has any leads for you.  He would probably appreciate pictures of your machine.

Craig


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## 6.5 Fan (Jan 24, 2022)

Welcome from SK. Sounds like an interesting machine you have.


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## Whiskers31 (Jan 25, 2022)

Thanks. Susquatch , trlvn , and 6.5 fan.


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## RobinHood (Jan 25, 2022)

@Whiskers31 congrats on your Italian lathe purchase. If that machine is made to anywhere near the standards my Italian CMT Ursus 250 is made to, you won’t be disappointed.

Here are the contact details of the manufacturer.





They most likely will have a manual for your machine. It will be expensive.

The plunger on the top right hand side of the carriage looks like either a manual way lube pump (Z and X axis - compound is probably manually lubed). It could also be operated automatically as you traverse the carriage (sounds like what you are suggesting).

The threading dial looks similar to what I have on the Ursus. Mine has 4 + 4 + 8 divisions; yours has 10.





Your lathe has a 2 TPI lead screw (as shown on the data plate in your first picture).

The easiest (but not fastest) way to thread on any lathe is to set the thread to be cut (either TPI if SAE or thread pitch if Metric) based on the data plate. That involves setting levers and gears correctly. Then engage the half nut and fwd/rev the lathe spindle for the passes and never open the half nuts until you are done. This works in all thread systems, for any thread, with any lead screw.

A more productive way is use the half nuts for the passes. However, there are some caveats:

Typically, with threading dials when cutting in the “on side threading” of the lead screw (imperial lead screw + imperial thread [or metric + metric]), divide the thread to be cut by the lead of the lead screw. EG, 16 TPI/2 = 8.  So in that case, you should be able to engage the threading dial on any even number on the dial. For 13 TPI (for example), you have to select a number on the dial and only engage on it as 13/2=6.5 which is not a whole number.

Now if you thread metric with an imperial lead screw (“off side threading”) you pick a number on the dial, and leave the half nuts closed and forward/rev the spindle to make subsequent passes - that is the easiest way. There are ways to do it opening the half nut - but it gets a bit more complicated.

To confirm, I would get some ABS (or other soft material) chucked up and set the lathe to the lowest speed. Pick a thread, set the gearbox up and, staying well away from the chuck and the tail stock, just do scratch passes. You will be able to see what happens right away. Speed up the lathe as you get more comfortable. Turn off the scratches and try another thread.

Having to engage in subsequent number to stay in the cut leaves me to believe that there is a set-up error.


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## Whiskers31 (Jan 25, 2022)

Hey thanks for getting back to me Robin Hood. It appears there is a small pump in the carriage oil reservoir and the aluminum thumbscrew on the right of the top of the carriage seems to be some type of needle valve to metre the oil to the Ways. I also saw have discovered that I can use the thread dial on either metric or imperial threads and engage the same helix each time as long as I engage on the next number each time works on imperial and metric. It has a coolant tank built-in to the base that it sits on I never use coolant though. There must be some kind of a brake to stop the spindle because there is a micro switch attached to the clutch lever however the Break apparently doesn’t work because it does nothing. I think it’s a wiring issue and more. It does seem to be a well-built machine. I had previously emailed Gornati service but I haven’t received a reply. I will try again. It did not come with a steady rest or a follow rest or a four jaw. I will be working to acquire these things or building them. it has what I believe to be a D 1–4 cam lock on the spindle , I May build an extra backing plate for a Four jaw when I get one thanks for the reply much appreciated


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## RobinHood (Jan 25, 2022)

Roger the flow adjusting valve. Makes sense.

It is a very strange use of a threading dial - but hey, if it works…

Agreed on the possible electrical issue regarding the brake. Pulling the headstock cover and chasing the wires all the way from the control to the brake should shine a light on the issue.


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## Crosche (Jan 27, 2022)

Welcome to the forum! Looks like you are already in good hands.


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## Whiskers31 (Jan 27, 2022)

Thanks Crosche. I’m new to forums in general so there is a learning curve to how it all works. Some people catch on very fast , then there are guys like me . It is interesting website. Thanks.


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