CAN'T INPUT A THREAD LENGTH

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Jan.vanderlinden
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CAN'T INPUT A THREAD LENGTH

Post by Jan.vanderlinden »

Why can I not input a thread length?
It stays grayed out.
THREAD CUTTING.JPG
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martin54
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Re: CAN'T INPUT A THREAD LENGTH

Post by martin54 »

I would need to watch the thread milling tutorial again but I think the thread length is determined from other options like the tool being used & tyhe max depth :lol: :lol: I've never tried to alter it myself, just went with what ever value it was from the max depth I set :lol:

Tailmaker
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Re: CAN'T INPUT A THREAD LENGTH

Post by Tailmaker »

It has to do with the fact that the software only calculates increments of half thread loops.

If you choose top-to-bottom, the thread start will be right at the surface with a flat loop making a nice chamfer and then go down in the mentioned half-circle increments so that you don't exceed the max depth. The milling direction will be "climb" for a right hand external thread.

If you choose bottom-to-top, you have more flexibility in the thread length, since it is max depth minus a certain offset (not sure how that is calculated). However, the software will not generate a start chamfer on top (in the current version) and the milling direction is "conventional" for right hand external threads.

kstrauss
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Re: CAN'T INPUT A THREAD LENGTH

Post by kstrauss »

I believe that the maximum thread length is calculated as:
L = M - O - P/2
where M is the max depth specified in Cutting Depths, O is the tooth offset defined in the tool database and P is the thread pitch in your Thread Definition.

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DJ-Bino
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Re: CAN'T INPUT A THREAD LENGTH

Post by DJ-Bino »

Jan.vanderlinden wrote:
Fri Sep 11, 2020 4:02 pm
Why can I not input a thread length?
It stays grayed out.
THREAD CUTTING.JPG
Hello,
when I look at your picture I immediately notice
that you specify a maximum depth of 3 ".

But entered 8 "at pitch below. I think
that was not a good idea. :)

If you use real values then the thread length will be displayed correctly.

Jan.vanderlinden
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Re: CAN'T INPUT A THREAD LENGTH

Post by Jan.vanderlinden »

What I'm trying to do is make a 1" X 8TPI thread.
This is a standard UNC thread.
The only thing it will not allow me to do is specify the thread length.
“I've learned so much from my mistakes, I'm thinking of making a few more”

Jan.vanderlinden
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Re: CAN'T INPUT A THREAD LENGTH

Post by Jan.vanderlinden »

Sorry all.
Now I see what I did wrong. :roll:
An 8" pitch relates to .125" between threads.
Amazing what a second cup of coffee does...
“I've learned so much from my mistakes, I'm thinking of making a few more”

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