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First time machining internal threads on YAM lathe. What settings do I use?

WCRiot

Plastic
Joined
Jul 29, 2018
You can click on any of the images to enlarge them.
I am working with a Yam/Yag lathe
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I don't have the user manual and more importantly i have done any internal threads. I have always been fortunate enough that i can use a tap. Well now i have a project that is an M48x1.5 pitch. The tap is so expensive that I have no choice but to learn.

I know it's going to be tricky but i am hoping the people here can talk me through the setup or point me to a YouTube video that can help me figure out what levers go where.

Below are the handles I'm working with. I have ordered the tool. So its go time!
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Here is a GUESS on some of it. You have some more to figure out, like how to set the 30 / 45 / 1.

I'll further GUESS that the 30 and 45 are "standard" installed gears - like the gear "picture" (HINT - open left end gear cover to see these)

(I have never seen or been around a Yam)
 

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Here is a GUESS on some of it. You have some more to figure out, like how to set the 30 / 45 / 1.

I'll further GUESS that the 30 and 45 are "standard" installed gears - like the gear "picture" (HINT - open left end gear cover to see these)

(I have never seen or been around a Yam)

Thanks. That's about as far as i got too....
What do these two handles do?
IMG_0012.jpg
 
I think a YAM lathe may be a copy of a Moriseiki or a Webb lathe. You may have more luck finding info on them that will apply to your lathe. And I think the Moriseiki is a copy of another make under license?
Bill D
 
To add to all the above, if that lathe has an English pitch lead screw, which it probably does, you can't open the half nuts when cutting a metric thread or you will loose index. You have to stop the spindle and reverse it for each threading pass. Just saying.
 
Look what i found:
IMG_0013.jpg
This label was on the door to access the gears of the lathe.

Something weird is going on with the machine now. Now that I have the lever changed from Feed to Thread, the autofeed for the carriage isn't working even though the lead screw is turning.
 
Yang appears to still exist. I found what seems to be a US Rep: YangMachines - CNC Machine Tools Company - Yang Machines.

I'd give them a call. Maybe someone still has the manual.

I also found the company in Taiwan. Use the information on the metal label to search.
Thanks I emailed them. Will call them if i don't hear back soon

To add to all the above, if that lathe has an English pitch lead screw, which it probably does, you can't open the half nuts when cutting a metric thread or you will loose index. You have to stop the spindle and reverse it for each threading pass. Just saying.
I have watched some Youtube videos of people threading Metric threads with this machine. Unfortunately none of the videos show how to set the machine up for threading. Luckily the thread i am doing doesn't have to be too accurate, so if i can get by it should suffice.
 
Changing feeds to threads DISABLES feed. I'll suppose you DO know about half nuts and that lever on the carriage apron - that is what is used for THREADING

Add Thumbnail showing Half Nut Lever for THREADING

Look what i found:
View attachment 263739
This label was on the door to access the gears of the lathe.

Something weird is going on with the machine now. Now that I have the lever changed from Feed to Thread, the autofeed for the carriage isn't working even though the lead screw is turning.
 

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Changing feeds to threads DISABLES feed. I'll suppose you DO know about half nuts and that lever on the carriage apron - that is what is used for THREADING

Add Thumbnail showing Half Nut Lever for THREADING

I didn't know that but i just tried it and that did it! SO now i need to figure out how to ensure i have the correct speed/feed and I'm there!
 
Which lever is the Port/No.?

Take a look at Post #4 above and see if that does anything

You also need to make sure your "a" gear is 30 teeth and your "b" gear is 45 teeth - that requirement is right on the chart

When you get ready to give it a try do it on a text piece - and be sure and read what Dan had to say above in Post #7
 
Ok guys. I have been threading for a few hours here and there. Mostly practicing.
I have the concept. This video is very helpful and the guy has my same machine YouTube

I screwed up a few parts so switched to Aluminum and also switched to making external threads because that is much easier to inspect and observe while the machine is running.

i need a 1.5 pitch but from what i am calculating I'm getting a 1.6 pitch

Am i reading the chart correctly that i should be on Port No. 1?
 
Am i reading the chart correctly that i should be on Port No. 1?

That is what the chart says

Are a and b gears 30 and 45?

Note the "flow" from top to bottom

a gear turns an idler that turns 127 gear

127 gear is fastened to 120 gear

120 gear turns gear b

IS ALL THAT JUST SO???
 

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Here it is in picture form (click to enlarge)....

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Yes i confirmed the correct gears are in place. The large gear actually says 45 on it. The small gear i had to count the teeth

Here is where i am at with the process. O.D. and I.D. threads both i am measuring a pitch more like 1.6 instead of 1.5. This makes sense as my mating part which is certainly 1.5 pitch goes in about half way then binds.
This is happening on the test parts from Aluminum and the actual steel tubes

Another issue i am seeing is the surface finish is very poor quality. I tried using the tool straight and trying the 30degree angle on the Compound slide. Same quality of finish.

I believe there is alot of tool deflect maybe even some part deflection. I believe this is happening because i will perform multiple passes at the same depth of cut and still take of material.

Are there any suggestions?
 
Are there any suggestions?

Confirm what lead you are cutting as per that set up

This can be done using a mag base holding a dial indicator with enough travel.

With mag base on bed and tip of indicator on tool post, see how much of a reading you get with half nuts engaged, all back lash out and hand turning chuck.

One full turn would get you 0.05906" if things were set up to cut 1.5mm pitch thread

With enough travel on indicator you would see 0.5906" in ten full turns

Anything more or less just says you need to correct what ever is wrong with the set up

Worrying about finish is for later when you are actually cutting 1.5mm lead
 








 
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