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Please help with thread cutting

rscott9399

Plastic
Joined
Jan 19, 2022
So I am trying to learn how to cut some threads. I am using a Siemens 840D controller on a fryer easy turn lathe.
I am using the manual thread program.

I would like to cut a 1/2 inch 20 thread or 20 threads per inch

The thread program only gives me the option of inches/rev or inches / min for the feed rate.
It seems a bit absurd to me.

How can I convert 20 threads per inch - > inches per rev?
I dont get it. Tried googling but have not found some simple formula
Can someone lend a hand?

I thought for a second all I have to do was say 1/20 - .05 inches per rev
I tried that and put a pitch gauge on it and its not even close.

I am at a loss
 

Kevin T

Stainless
Joined
Jan 26, 2019
Ok I was bored... and curious.

Did you review this?


He programs a thread at 1:04:50

Do you not have the pitch field shown? Yours would be 20 right?

The rest of the part was setup starting at 51:10
 

Matt_Maguire

Stainless
Joined
Oct 17, 2011
Location
West-Central Illinois, USA
So I am trying to learn how to cut some threads. I am using a Siemens 840D controller on a fryer easy turn lathe.
I am using the manual thread program.

I would like to cut a 1/2 inch 20 thread or 20 threads per inch

The thread program only gives me the option of inches/rev or inches / min for the feed rate.
It seems a bit absurd to me.

How can I convert 20 threads per inch - > inches per rev?
I dont get it. Tried googling but have not found some simple formula
Can someone lend a hand?

I thought for a second all I have to do was say 1/20 - .05 inches per rev
I tried that and put a pitch gauge on it and its not even close.

I am at a loss

0.05" per revolution. 1"÷20=.05". If you put that in for IPR and it did`t work something else is wrong.

Good luck,
Matt
 

FredC

Titanium
Joined
Oct 29, 2010
Location
Dewees Texas
I thought for a second all I have to do was say 1/20 - .05 inches per rev
I tried that and put a pitch gauge on it and its not even close.
I think the question is too basic to respond to. (1/20 - .05 inches per rev) is correct your gauge may be off. If you have a scale that reads in tenths of an inch, you will see 2 threads per tenth of an inch. They are measured center to center.
 

rscott9399

Plastic
Joined
Jan 19, 2022
Thanks for the replies

It appears that no matter info the feed rate on the machine won’t change
 

rscott9399

Plastic
Joined
Jan 19, 2022
I have been trying to reply for an hour the website is either censoring me or it’s broken

So the issue is the federate.
After trying to cut a thread all day long , I have realized no matter what settings I change the feed rate is stuck at 196 inch per min

I’m if I ask it to make a strait cut at .0001 inches per minute it will not. It just goes to 196 inches per minute.

I have the feed overdrive at 100% so it should of just been at .0001

The only way to force the feed rate slower is the override. Which means the feed rate can now only be a multiple of 196 inch per min

Hence why my threads are all screwed up.
Has anyone seen this before?

I am shocked to hell to see that in strait cut mode “bulk material removal” even when I intentionally make the federate .0001 and hit cycle start it will not listen and just does whatever it wants.

Really regret not getting a haas
 

kustomizer

Titanium
Joined
Aug 17, 2007
Location
North Fork Idaho
I have been trying to reply for an hour the website is either censoring me or it’s broken

So the issue is the federate.
After trying to cut a thread all day long , I have realized no matter what settings I change the feed rate is stuck at 196 inch per min

I’m if I ask it to make a strait cut at .0001 inches per minute it will not. It just goes to 196 inches per minute.

I have the feed overdrive at 100% so it should of just been at .0001

The only way to force the feed rate slower is the override. Which means the feed rate can now only be a multiple of 196 inch per min

Hence why my threads are all screwed up.
Has anyone seen this before?

I am shocked to hell to see that in strait cut mode “bulk material removal” even when I intentionally make the federate .0001 and hit cycle start it will not listen and just does whatever it wants.

Really regret not getting a haas

I would think inches per revolution would be better than inches per minute

This has examples in metric, it does seem more complicated than it needs to be
https://cache.industry.siemens.com/dl/files/403/28755403/att_79171/v1/PGT_0407_en.pdf
 

rscott9399

Plastic
Joined
Jan 19, 2022
Thanks for the comments

So this isn’t a conventional program
Not sure if you all have worked with this thing before or not.
Think of it as more like a pre canned function.
It’s not a full up program
It’s a simply pre canned function in the controller under the turning menu called “thread”

You set a hand full of parameters and let it go
I have set them all up correctly and the machine will not adhere to the feed rate no matter what I do

It’s hard to screw this up because you just type in a few things and hit cycle start.

The feedrate is the problem. No matter what I do , if I run the feedrate in the program at inch per rev or inch per min or whatever it doesn’t matter.

It will only run at 196 inches per minute
The feed rate over rise is set to 100%

In the feed rate box it even shows I have it set to .05 inch per rev then when I hit go it immediately goes to 196 inch per min which is basically it’s rapid

The rapid control is turned off and if I use the manual feed joy stick it runs at the .050 that so specified but the it immediately jumps to 196 if I run the program

I don’t know why this forum will not let me post pictures i have been trying all night to post the screen shot for you all

All the current YouTube videos out there have a new version of the controller. This one is from 2010
None of the videos or even the manuals
Apply.

I can’t believe i can’t even find a Manual online for this.
No one had a simply threading example. It is always something 800 times more complicated with undercuts or this or that
I just want a manual with basic strait threading instructions. Why is that so hard Siemens.
I’m glad the machine has all these other million features but how about basic threading.

Buyer be wanted , save your $70k
 

guythatbrews

Cast Iron
Joined
Dec 14, 2017
Location
MO, USA
Try 20 instead of .05

2010 machine huh? More than even chance something is wrong with the control. Will the machine cut a linear interpolation with .050"/rev feed or does it just feed at your 196"/min rapid? To test don't make a deep cut just a scratch like first threading pass.

Have you tried getting a legacy manual from the machine dealer?

Fryer Machine Systems Inc. - CNC toolroom lathes milling machines machining centers

You'll probably have to pay but sounds like you are paying with lots of time anyway. They might give you tech support either for free or a fee.

Looked this up on fryer website and in lathe manual download they show some threading stuff. Shown is a snippet.
Can't really figure the "P" row out. 16_0_/100"? WTF?

fryer lathe.jpg

So P usually designates pitch which is the reciprocal of TPI. In your case the TPI is 20 threads/inch and the pitch is .05 inches/thread. Have you tried entering 20? If that is what the control is looking for and you enter .05" instead then the control is thinking you want a thread with a pitch of 20", or .05 threads/inch, not .05"/thread. Thus the machine feeds as fast as it can.

This may be your problem. Try 20 instead of 0.05. Can't hurt.


Good luck!
 

CITIZEN F16

Titanium
Joined
May 2, 2021
Could something be set to metric, IPM, or could the feed override setting been altered. I am not familiar with that controller, but on many I have worked on you can change a parameter and alter the override setting to where 100% on the dial gets you 50%. Or you could make 100% on the dial gets you 200%. Is this a new machine? Used, and been sitting a long time, recently moved?
 

rscott9399

Plastic
Joined
Jan 19, 2022
I figured it out
Waste of 2 days
I will Post the answer when I get home tonight
Thanks all for the emotional support!
 








 
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