Gear train on a Warco 290V lathe

[peter spainParticipant @peterspain73968]

Hi Everyone

Has any body here have a Warco290V lathe?If so is it possible to advise on the changing of gears for screw cutting.

The manual is not clear to me,nor are a lot of things now,any info will be much appreciated.Thanks in advance

[JasonBModerator @jasonb]

is it the actual tooth counts to ger a set pitch you are not sure of or how to physically change the gears to the setup you want?

[peter spainParticipant @peterspain73968]

Hi Jason

Thanks for the prompt response.

Youve got it.I,m finding it difficult to understand completely the drawing in the manual.

i have gone through the process of changing gears etc so i,m ok with the assembly etc but what goes where to achieve the specific thread is baffling me.

[Grizzly bearParticipant @grizzlybear]

Hi,

I don’t have a Warco myself.

However:

Take two: https://www.bing.com/videos/riverview/relatedvideo?q=Gear+train+on+a+Warco+290V+lathe&mid=03435B8566EE78F4918C03435B8566EE78F4918C&mcid=743FB1CC44C24570971241AFD80AE155&FORM=VIRE

[JasonBModerator @jasonb]

Rather than look at the side view of the gears shown in the manual it i sprobably easier to relate the numbers on the chart to the sides of the gears as you are looking at them.

So if you look at the image below The top pait of numbers relate to the top two gears, left and right

The second pair of numbers relate to teh middle pair left and right agaon

The last line will be a single gear on teh end of teh leadscrew which can be on one or the other side depending on teh gear train.

[peter spainParticipant @peterspain73968]

Thanks Jason

Certainly a different way of looking at it.i will give it a try.

All the best

[Howard LewisParticipant @howardlewis46836]

What you are looking to set up is the correct ratio between Chuck and Leadscrew, so that the Saddle moves to cut the required pitch of thread.

So, if the Leadscrew is 3 mm pitch, to cut a 1 mm pitch thread, the geartrain must run the leadscrew  at one third of the speed of the Chuck

To cut a 1.5 mm pitch thread the leadscrew would need to rotate at half the speed of the chuck.

If the chart does not make this clear, you need to work out what gears will, produce this, possibly including an Idler, just to move the Saddle min the required direction, usually towards the chuck.

Just a plain idler does not affect the overall ratio, it just reverses the direction of rotation of the leadscrew, relative to the chuck.

If the train includes a compound gear, than that will affect the ratio.

On a mini lathe, or any other lathe, a 20:80+20:80 train will rotate the leadscrew in the same direction  but at 1/16 of chuck speed, (4 x 4:1) If the geartrain were just 20:60:80, the leadscrew would rotate at 1/4 of chuck speed, but in the opposite direction.

If the train were 20:60:70:80 the leadscrew would rotate at 1/2.625 or almost 1/11 of the chuck speed, and in the opposite direction to the chuck

Those are the basic principles  Driven / drivers to find the ratio.

Hope that this helps, understanding, rather than adding confusion.

Howard

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