Metric Tool

[BadCompany]

Hey I am trying to write a program that is all imperial but I need to use metric taps. When I post my rigid tap cycle the feed is messed up. I created the tool and selected "Metric Values" under the parameters but even when I post the NCI it doesnt show up as metric(1016 variable 10 of the nci). Matercam Help said any library can contain metric and imperial tools but dont give any clue how. Any Ideas I know I could just do the math and make an imperial tool with the proper tpi but thats not the point

[Rocketmachinist]

Guys correct me if I'm wrong.

Metric taps are based on how many MM per revolution vs imperial where it's threads per inch. So if you take your tap number for example m6x1. So take the of mm per revolution and divide by 25.4, that will give you the equivalent in threads per revolution in imperial. Then take that number and divide it into one. So 1/25.4=.0393 Then take .0393 and find out how many revolutions would fit into one inch. 1/.0393=25.4tpi.

 

So it's X/25.4=y and then 1/y=your tpi.

 

an M8 x 1.25 will be 1.25/25.4=.0492

1/.0492=20.3tpi

[uncle_dolan]

Guys correct me if I'm wrong.

Metric taps are based on how many MM per revolution vs imperial where it's threads per inch. So if you take your tap number for example m6x1. So take the of mm per revolution and divide by 25.4, that will give you the equivalent in threads per revolution in imperial. Then take that number and divide it into one. So 1/25.4=.0393 Then take .0393 and find out how many revolutions would fit into one inch. 1/.0393=25.4tpi.

 

So it's X/25.4=y and then 1/y=your tpi.

 

an M8 x 1.25 will be 1.25/25.4=.0492

1/.0492=20.3tpi

 

or more simply: 25.4/pitch = tpi

[Rocketmachinist]

^^^ not really. pitch(metric)/25.4=pitch(imperial). That still doesn't give you your threads per inch.

[uncle_dolan]

^^^ not really. pitch(metric)/25.4=pitch(imperial). That still doesn't give you your threads per inch.

25.4/pitch(metric) = tpi

 

e.g

 

1.25 pitch

 

25.4/1.25 = 20.32 teeth per inch???

[Rocketmachinist]

According to my droid conversion calculator. 1mm is equal to .039370079 inches.

 

Linky

 

The pitch is how far the screw will travel in one 360 degree revolution or also from crest to crest of the thread.

 

Metric screws are measured in pitch.

 

American screws are measured in threads per inch.

 

So a 1/4-20's pitch is actually a pitch of .05 or 1(One inch)/20(threads per inch). 20tpi=.05pitch

 

The conversion between the 2 are not that easy because they are not measured in the same way.

[K2csq7]

I created the tool and selected "Metric Values"

 

When you entered all the info into the tool definition did you enter the metric values or did you convert them to inches and enter your converted numbers?

 

Why create a tap? I just picked one out of the metric library and it posts just normal?

[Chris In-House Solutions]

If you are in a inch configuration and pick a M8 X 1 from the library the tool will appear as a 8 inch tool. So you need to do the math and figure out that 8mm is equal to 0.314. You also need to input the thread pitch in inches as well otherwise your spindle speed and feed rates will not appear correct.

[Colin Gilchrist]

Which Post Processor are you using? For X5, we fixed an error in the Rigid Tapping cycle to output the correct pitch based on the tool type (metric/english).

 

Here is the snippet of code from the 'pmisc2$' post block:

 

     if met_tool$, pitch = n_tap_thds$  #Tap pitch (mm  per thread)
     else, pitch = 1/n_tap_thds$        #Tap pitch (inches per thread)

[BadCompany]

I resolved the issue. The met_tool$ only is changed by NCI parameter 10016 which is only changed for full metric output it appears. What I did instead created a variable to represent if the current tool is metric captured from NCI Param 20007 bit 11. Then added an else if statement to the canned cycle to check if the current tool is metric. the 20007 parameter bit 11 represents the metric values check box in the tool parameters dialog.

 

Matt

 

 

Colin I am using X4 MU3

Did they fix the Met_tool$ to represent any metric tool?

[Leigh @ Kodiak]

I always get confused when trying to convert metric pitches into TPI, so I use THIS

[McLaren]

or more simply: 25.4/pitch = tpi

 

 

That's how I've always done it. Seems pretty straightforward to me.

[Rocketmachinist]

Well I guess I overthought the he'll out of that one

[ducati]

Can we download the program so I don't have to go online to do the conversions?

 

[McLaren]

Um, File>Save Page As...

Or, just remember 25.4/metric pitch equals tpi.