Hey guys, i'm trying to cut a 17mm x 1.50 thread on my lathe and i'm having some troubles. I only have enough experience to write programs with IGF feature then i am able to go back and edit.I typically machine everything in inches and now I have a job that requires a metric thread and i'm stumped!!! I got my IGF scren to display metric on every dimension ,however when it asks for thread dimensions it asks for TPI and you cant input a decimal point for the pitch of 1.50. Could someone look at my line of programming and point me in the rite direction: G71X16.2Z-13.5H0.0866D0.5U0.1B60F1J1.5M22M73M32
Ha ha, its only easy when you know it.Thank you for your help it was very much appreciated!
You could also do this if you are running in inch by using F1.5/25.4.
I see that you are running metric instead of our inch mode, but thought that you'd be interested to know that math can be used in the program virtually anywhere.
So leave the J value at 1 and use whatever is easiest for you for your F value.
One of the reasons to use the math is that the control will calculate out the pitch to a much smaller value (more decimal places) which will give you a more accurate thread. even if you are only off by .00005, it adds up to .001 error after 20 rev's or so.
isn't it better to switch to metric mode? therese are just a couple parameters to change.
But yes, your machine will actually position finer in metric than inch.
I've asked Okuma to give us 5 decimal places in inch as a standard spec, but no positive response yet...we do have one lathe with it as an option and yes, it kicks a$$! We held a +- .0001" tolerance with few problems.
sorry for off-topic, but
all of the inspection equipment and prints are in inch
United States is the first empire in the world, pronounced to establish SI (=metric measurement system) as a only standard long ago ... how that could be?
The US is IMPERIAL through and Through!
Everything is measured in Miles down to Inches...
All units are Imperial.
Thread sizes for US threads are all IMPERIAL!
They think they know Metric, but hey, remember one of the last probes sent to Mars? They, the esteemed egg heads in NASA, screwed up a simple unit conversion between Metric and Imperial and then lost the probe somewhere between here and there! Pretty dumb and very expensive screw up!
BTW... did you not know that SI is French in origin?
As for programming threads in IGF... (going on memory here so some details might be slightly incorrect)
Entry of the thread pitch is in the field "Lead" or "F" as specified on the drawing... 1.5 in your case.
Lead is output on the G71 line as the value "F"
Leave the value for TPI as 1, this value if set other than 1, will be output as "J"
To program an Imperial thread on a machine set for Metric you set the lead to 25.4 and the TPI to the number of threads per Inch.
Now, before you go on about not being able to input a value of 1.5 in the TPI field do this:
Multiply the TPI value by what ever amount you need to obtain a whole number.
ie if you require 11.5 TPI Multiply this by 2 to get 23
Now multiply the lead by the same amount i.e. 25.4x2=50.8
Now enter the Lead as 50.8 and TPI as 23
This will output F50.8 J23 in the G71 cycle.
The machine will then cut 23 threads per 50.8mm, or in other words 11.5TPI.
As for cutting Metric threads on a machine set up in Imperial...? Have never done that so can not help.
I hope this helps,
I would not say 25,4mm = 1". It is not accurate. There are information sources where more digital places are used.
I would advice to not fear of switching control parameters. Maybe numbers will look wierd at the begining. Okuma has no problems with different measurement systems. A lot of our clients are making parts according imperial units on Okumas along with metrics and no problem. They just switch the parameters.
To mbm and to phx
I think thread height H is wrong and should be 1.624mm
Everyone else on here understands that we PRIMARILY use inch in this country, and MOST of our inspection equipment is also inch. Why do you try to make off-post comments that don't help anyone? Is it just to increase your post count?
Unless you are helping solve the problem. DON'T POST! You only succeed in irritating those of use trying to sincerely help others.