can't thread hole with 1/8 npt

[gargoyle27]

i think it must be an error in the program, but i can't put a centre point on a sketch, and then use it to put a NPT thread, most of the other threads are available, but not NPT, is there another easy way of putting that thread in multiple holes? (i don't really want to put 24 individual threads in holes)

[MarkFlayler]

Works fine here. Can you attach a screen shot of your Hold dialog with the part in the background or better yet, attach the part.

[MarkFlayler]

If you are trying to put an NPT on in a already pre-drilled hole then you are using the software incorrectly. The thread command should only be used for external or conical threading. For internal threading, use the Hole command.

[gargoyle27]

If you are trying to put an NPT on in a already pre-drilled hole then you are using the software incorrectly. The thread command should only be used for external or conical threading. For internal threading, use the Hole command.

 

the problem im having is it won't let me make an npt thread using the hole command, it has other threads listed, but not npt, the only way it lets me, is if i add it to an existing hole, i just don't want to have to do it 24 times

[MarkFlayler]

What version of Inventor are you using?

Have you modified the Thread.xls Excel file before?

Do you have all the options I show in my attached picture above?

[gargoyle27]

here is my hole dialog box

[gargoyle27]

i'm using inventor 2009, and no, i don't have the same options

 

i haven't modified the thread.xls before and don't have a program that can anyway

[MarkFlayler]

You have to choose the last radio button instead of the Threaded Hole.

 

From left to right you have Drilled, Clearance, Threaded, and NPT Threaded. Look right above your OK button in that image and look at my selection there.

[gargoyle27]

that is where npt is all the time, why would it be under a different radio button?

[MarkFlayler]

The threaded radio button is for straight threading while the NPT is for tapered threading.

[gargoyle27]

now it's giving me a monster sized hole, i select 1/8 and the hole/thread is more like 3/8

[MarkFlayler]

Note! Pipe sizes do not refer to any physical dimensions. The outside diameter of a pipe or fitting must be measured and compared to a table for size identification. A 3/4" NPT pipe thread has an outside diameter - OD - of 1.050 inches.

[gargoyle27]

why does it make it a different size depending on if i use the hole tool, or the thread tool?

[MarkFlayler]

With the Thread tool, you can put any thread on any surface for representation. Its just how the tool works. So I can put a 1/2 thread on a 1 inch diameter and the software doesn't care. What it does do is choose the closest to the size you have first and then you can override it.

[gargoyle27]

so because i told it to, it will put 1/8 npt thread into a 1/8 hole, even tho 1/8 thread is closer to 3/8? why wouldn't it change the size of it? then i would have at least realized before this point that thats not how it works

[kencaz]

so because i told it to, it will put 1/8 npt thread into a 1/8 hole, even tho 1/8 thread is closer to 3/8? why wouldn't it change the size of it? then i would have at least realized before this point that thats not how it works

 

Don't bother trying to find the major or minor diameter of tapped holes. The software will do it for you...

 

Use Point data ("Point, Center Point" option from your sketch panel), while in sketch. Array the points circular, (as Mark's picture also points out), or rectangle whatever is required.

 

 

Now the hole feature will find all your point data and you can choose whatever tap size or through hole you wish and it will make the appropriate sizes for you.

 

 

It's also better then using the Thread feature because your drawing files, (idw's) will import all the tap/drill info into your drawing for you.

 

KC