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cj7hawk

Automated, high-accuracy, ISO compliant, thread creation LSP file.

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cj7hawk

Hi All,

 

I wrote this software for a CAD application called CorelCAD and I know it works on Graebert's ARES Commander as well, and it should work on Autocad and other LISP based systems, but I'd appreciate it if anyone could check.

 

Maybe most CAD packages come with something like this now? I don't know, but I do know it's a novel way to calculate threads, with very high accuracy, and that conform to ISO standards for thread faces. There are two routines, NUT and BOLT. Bolt calculates external threads, and Nut internal ones. It's not very well written, but it seems bug-free and works well enough. It may require interactivity when it completes it's two "LOFT" commands, but on CorelCAD I use the defaults and just hit enter.

 

Hopefully it might help others who need to create threads. The routines are optimised for 3D printing application, and allow offset on internal threads to allow appropriate clearances, though you can manually set the clearance for external threads by choosing a smaller diameter.

 

When run, it will ask for basepoint, diameter, pitch and indexes ( starts ) - and can create multi-start threads for optical purposes and such. Or perhaps even specialist helical gears. It also creates all threads in the direction of the Z axis. I haven't included reverse gears - but a 3D mirror will create one.

 

The application takes a unique approach to thread creation, generating a longitudinal cross-section in 32 segments and then using LOFT to join them together. It creates each bolt in two halves ( to avoid loft-related issues with torroids ) and them union's them together.

 

It cleans up the final solid part, by masking off at a length and filling in the inside. External threads are created solid and complete, and internal threads are subtracted from another solid.

 

This approach also allows bottoming threads to be easily inserted into solids.

 

Well, I hope you like it :) It's my first post. I came here some time ago looking for an easy way to make threads, and on not finding one, I wrote my own. I hope it attaches OK :)

 

isothreads v0.12A.lsp

 

Regards

David

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Dadgad

Welcome to the CADTutor team! :)

 

And thanks for bringing something to the party.

I am too busy to check it out right now, but sounds interesting.

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ReMark

A quick test using AutoCAD 2014 confirms the routine appears to work as indicated.

 

Thanks for sharing David.

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cj7hawk
A quick test using AutoCAD 2014 confirms the routine appears to work as indicated.

 

Thanks for sharing David.

 

Thank you ReMark - that's very much appreciated - Can I ask what the behavior is when it comes to the two loft sections? Does it drop into interactive mode, or does it just complete the task autonomously? On CorelCAD/ARES I wasn't able to get it to complete without the two default LOFT manual interventions, but on reading about AutoCAD, I wondered if it might complete entirely by itself.

 

Thanks

David

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BIGAL

Isn't CORELCAD a registered software name you may want to think about another name lawsuits are expensive ask Mr Mac Donald the local hamburger shop owner.

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cj7hawk
Isn't CORELCAD a registered software name you may want to think about another name lawsuits are expensive ask Mr Mac Donald the local hamburger shop owner.

 

Hi Bigal,

 

CorelCAD is a trademark of Corel corporation, or something like that, yes. It's a software package made by Corel, which is powered by ARES, and contains Corel support features to interwork with other Corel products.

 

But the program I wrote is called ISOTHREADS, not CORELCAD ? So I'm not sure quite what you mean? Also, I wrote the program for CorelCAD specifically and Corel are well aware of it, and very supportive ( thank you Corel ! ) - :) So I'm actually pretty grateful for their help.

 

But the program seems like it would benefit the CAD community at large, rather than just the smaller CorelCAD community, so I thought I'd post it here.

 

The problem earlier versions of CorelCAD had, is that they didn't implement SWEEP correctly, and attempting to cut a thread by sweeping a triangular shape around a spiral is not possible, due to a bug. The bug is being fixed, but there is no workaround for threads in older versions, so I wrote my own. I was originally going to just write something basic, but ended up making a general program that simplifies incorporating ISO standard screw-threads into any design. Accurate screw-threads are important to me, because I use 3D printers and need to have printed parts work with existing physical threads on other parts.

 

It does make building threads very simple ( only takes a few operations ) and also builds threads that conform to the correct ISO profile. By releasing it to everyone to use, I am hoping that others will be able to take advantage of it and that it will simplify their work also.

 

Regards

David

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ReMark

I only did one very quick test but from what I recall after answering the required questions the program then ran with the design. I can run another test if you want.

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cj7hawk
I only did one very quick test but from what I recall after answering the required questions the program then ran with the design. I can run another test if you want.

 

Sorry to make the request, but thank you if you can do that - From a coding perspective, to maintain best compatability, I just want to know if an interactive screen pops up twice while building each half, which requires pressing enter or clicking "OK" or if it just goes all the way from the last question right through to the final bolt/nut - :)

 

Thanks

David

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ReMark

Sure, I can do that.

 

I'll be back.8)

 

Addendum:

 

Test completed. There were no interactive screens. Answer the questions, wait while program does its thing, finished. I tested the routine using AutoCAD 2013.

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ReMark

ISOThreads1.JPG

Results of test done using AutoCAD 2013.

 

Metric template.

Diameter = 30

Pitch = 2

Length of threads = 25.4

Visual style = Conceptual

 

Note that on systems where the user has the minimal amount of RAM installed the process may take some time to complete.

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