Fasteners workbench based on screw-maker

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kisolre
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Re: Fasteners workbench based on screw-maker

Post by kisolre »

KurtF wrote: Fri May 06, 2022 6:57 pm but I was shooting for 0.2mm on that.
But you should not :) From the mentioned table note how the diameter difference changes from 0.019 for M1.6 to 0.060 for M39. Should we adjust all that by hand?
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KurtF
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Re: Fasteners workbench based on screw-maker

Post by KurtF »

kisolre wrote: Fri May 06, 2022 7:03 pm Clearance is the result of actual manufacturing of the object within desired tolerances.
I absolutely cannot accept your definition of Clearance. And that makes the rest of this conversation difficult. But I think I understand what you're saying.

kisolre wrote: Fri May 06, 2022 7:03 pm the M8 screw should have actually 7.972mm OD max. Fasteners should produce this size as standard.
Why the maximum? I should think the CAD software would choose the median(min, max).

kisolre wrote: Fri May 06, 2022 7:03 pm And then if you are going to 3D print it you apply 3D printing compensation so hopefully the resulting 3D printed thread will have 7.972 mm OD and not 8.0mm.
I agree with you completely here: for 3D print, you apply [clearance] to the perfect CAD object, so the resulting 3D thread will have 7.972 mm OD (be perfect too).

kisolre wrote: Fri May 06, 2022 7:09 pm But you should not From the mentioned table note how the diameter difference changes from 0.019 for M1.6 to 0.060 for M39. Should we adjust all that by hand?
Well, if we are using max diameter like you suggest, or median diameter, a valid diameter is selected for all sizes, right? And if my 3D printer needs the same amount of clearance for each thread size (as I have found in my experience), use Scale B values in FW Preferences. If my printer needs more clearance for larger diameters, use Scale A values to control it.
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kisolre
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Re: Fasteners workbench based on screw-maker

Post by kisolre »

Sorry if this is going offtopic here but...
KurtF wrote: Fri May 06, 2022 7:40 pm I absolutely cannot accept your definition of Clearance
Another article
No actual object is perfect. For a specific design you need actual physical clearance or interference after manufacture.
For a thread to work you need an actual physical clearance between the parts. You can not make them perfect, that is why you have tolerances for manufacture. So your male thread is 8.0 -0.015/-0.030 (actual size in the range of 7.970-7.985) and your female thread is 8.0 +0.010/+0.025 (actual size in the range of 8.010-8.025). If the threads are manufactured to specs there will be guaranteed clearance in the range of 0.025-0.055 so all is good.
If you are going to model the actual threads in FreeCAD (not just mark them cosmetically) you should (?probably?) model them with actual dimensions if they are going to be manufactured by a non standard method (why else would you model them?).
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KurtF
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Re: Fasteners workbench based on screw-maker

Post by KurtF »

I still don't see a problem here. We tell CAD to give us an M8 x 1.0 thread, and CAD delivers a mathematically perfect object (98% of the time anyway). This object fits right where it should in the Standards table (FW does the table lookups). As you say, it is guaranteed to fit the mating M8 x 1.0.

Since our fabrication introduces an interference fit to the mating parts, we tell CAD to add clearance to compensate the interference. Now our CAD model is a perfectly sized M8, but with radial clearance applied. It's properties reflect the M8 size, and FW preferences reflect the clearance size. Isn't this what you are after as well?
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Kunda1
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Re: Fasteners workbench based on screw-maker

Post by Kunda1 »

Noticing that this thread is getting derailed. Do y'all mind continuing the conversation in a separate thread ?
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Re: Fasteners workbench based on screw-maker

Post by KurtF »

Sorry. Opened new thread: https://forum.freecadweb.org/viewtopic.php?f=8&t=68517

I'm trying to understand kisolre's (and anyone elsee's) requirements, while I'm in the middle of working on a thread modeling tool for FW.

Side-Bar, Your Honor! :-)
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Re: Fasteners workbench based on screw-maker

Post by Kunda1 »

Indeed. A huge part of collaboration is getting on the same page communication-wise and being able to be civil and gracious doing so. Thank you in advance. :geek:
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Re: Fasteners workbench based on screw-maker

Post by Kunda1 »

Open enhancement: Add round head rivets https://github.com/shaise/FreeCAD_FastenersWB/issues/6

Per the original ticket opener:
Most of the work is already done in makeIso7380(), a rivet can be produces by optioning the code that makes the hex recess.
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Re: Fasteners workbench based on screw-maker

Post by uwestoehr »

@shaise, do you have some new stuff for the fasteners WB that we can advertise here?:
https://wiki.freecadweb.org/Release_not ... #Fasteners
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Re: Fasteners workbench based on screw-maker

Post by shaise »

uwestoehr wrote: Tue May 31, 2022 7:59 pm @shaise, do you have some new stuff for the fasteners WB that we can advertise here?:
Hard to tell what's new as the workbench was developed independently from the FreeCad versions
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