Double custom thread.

[bob.s]

Does a double thread, starting 180 degrees apart, make it easier for the user to mesh the threads and allow a greater travel distance with fewer revolutions?

[bob.s]

Hi there, yes it is the plastic bottle type of thread that I am trying to obtain and have seen many videos on Youtube of how it can be done in Fusion 360 using coils, but no matter how hard I try I can never get it to work for me. My problem is making sure the male thread and female threads mesh properly with the correct tolerances as I have not yet acquired a sufficient skill set to accomplish this.

Thank you for your reply.

Bob.

[TheCADWhisperer]

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@bob.s wrote:
…. many videos on Youtube of how it can be done in Fusion 360 ...

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Post web link to the YouTube video that you would replicate and your *.f3d attempt here. (Post dummy file if your design is proprietary.)

[bob.s]

Hi again,

Again thank you for your interest and taking the time, but I am so stupid when it comes to computers and all of this type of work, that I have know idea what you are talking about. Many years ago I was a Jig & Tool design draftsman and thought that experience would allow me to download Fusion 360 and get started on my project idea quickly. That was my first mistake, while I love working in Fusion and know it is an incredible programme , it has taken me over 2 months of practise and watching videos and I still cannot complete what I would say is a very simple design. I am now 76 years old so I know the problem is mine, not Fusion 360's. One lad on YouTube calls his tutorials "Master Fusion 360 or die trying" and that is what I felt was happening to me. While I will keep learning in Fusion, I have decided to contact a reputable plastic molding manufacturing company, which was my intention at some point anyway, to see if they think the idea is marketable and, if so, have them complete the design and hopefully get it into production.

Bob.

[TheCADWhisperer]

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@bob.s wrote:
….I have know idea what you are talking about. ….

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Let's break it down into smaller steps.

Do you have 

1. A link to a YouTube video that demonstrates something similar to what you want to do?

This is an example of a Click>> YouTube link<<here.

[chrisplyler]

@TheCADWhisperer

It was my intent to argue that when a given thread is converted into a 2-start configuration, it is accurate to say that the helix angle is adjusted to allow the necessary room, and inaccurate to say that the thread profile is shrunk.

If one instead chooses a smaller thread profile to work with (which is certainly fine if he is targeting a specific pitch), he must still adjust ITS helix angle to get a 2-start configuration as well.

[TheCADWhisperer]

I had to go back and re-read the entire thread.

I got confused between your response and @etfrench response.

Your response in 11 was accurate statement.

My response 12 was not accurate response to 11.

The OP must be entirely confused by now...  

[etfrench]

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@chrisplyler wrote:

@TheCADWhisperer

It was my intent to argue that when a given thread is converted into a 2-start configuration, it is accurate to say that the helix angle is adjusted to allow the necessary room, and inaccurate to say that the thread profile is shrunk.

If one instead chooses a smaller thread profile to work with (which is certainly fine if he is targeting a specific pitch), he must still adjust ITS helix angle to get a 2-start configuration as well.

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Or you can start with a thread with the desired helix angle, then alter the thread profile.  Either way will produce valid results.

[chrisplyler · Accepted solution]

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@etfrench wrote:

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Or you can start with a thread with the desired helix angle, then alter the thread profile.  Either way will produce valid results.

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Well, like I said, you can choose a smaller standard thread size. Is that what you mean by "alter?" At that point you're doing what I said.

Or do you mean scale it down to some custom, non-standardized specification?

[bob.s]

Hi Guys, 

I want to thank all who responded to my inquiry, but I have had a discussion with a company in the plastic bottle, jars, mugs and all types of plastic container business and they have come up with a thread that is not really a thread, but more of a pattern of short lengths of threads aliened in such a manner that it reduces not only the amount of plastic required, but also the cost of the mold by eliminating some specific action within the mold required on traditional threads. This would seem to meet my design needs.

Thanks again,

Bob.