How to change which end of a cylinder the thread starts?

[david.antliff]

I have a shouldered cylinder that I want to put a thread on - specifically from the left hand end (as per picture below), extending down about half way along the shoulder.

However when I apply the thread operation to the cylinder, it starts from the wrong end of the shoulder. 

I can use offset to move it down the cylinder, but this doesn't seem correct to me as it will depend on the shoulder length, which may change.

How can I make the thread start from the left end?

[patilsm · Accepted solution]

Hi @david.antliff ,

Thanks for your post.

Please check below screen cast, for thread start your selection should be respective side where you want to start the thread.

 check attached screen cast below

Regards,

Sagar Patil

[david.antliff]

Thanks, that looks simple, and in fact I tried that myself but it always created the thread from the same (inner) end of the shoulder. I will try again soon, maybe I misclicked every time I tried it.

[david.antliff]

It must seem like a really silly question. I tried your suggestion and it worked fine. However I would swear that it didn't work this way the first time I was trying to get this to work, and I spent quite a while trying to get it to. In the end I used a hard-coded offset. Now I revisit it, rewind my history, and try clicking on the obvious left end and it creates the thread correctly as expected. Am I going mad? Do a significant number of Fusion 360 users report feelings of craziness? Sometimes I feel like this software is gas-lighting me.

[david.antliff]

Nope, I tried it with a new shaft and it always starts the thread from the inner shoulder rather than from the end I click on. Your demonstration works when it works, but sometimes it doesn't. I'll just have to use the offset to move the thread to the correct end of the spindle.

[david.antliff]

Actually I think I know what the problem is - can you try this? When you extrude your spindle, make the extrusion distance a negative number (i.e. extrude in the opposite direction). I'm using a parameter so I have to make the number negative to go the "other" way. If you do this, perhaps you'll see the same problem I'm seeing.

EDIT: actually, no, I tried redefining my extrusion to be positive and it didn't resolve the problem. No matter what I click on to start the thread, it always starts from the shoulder not the tip, in my particular design.

[erik_mid]

It seems to me like if I edit an existing thread feature and try to change it's starting position, it doesn't work. But if I delete that feature and start a new one, it will then start from the end I select.