Sounds easy enough, doesn’t it?
A few clicks and two objects get merged into one.
So quick and hassle free compared to trying the same in a simple CAD program which might take and hour or so to complete.
Similar for removing things from an object, again just a few clicks.
That is of course if the parts are set and classified properly as otherwise the button won’t work.
Everyone seem to love using Studio for this these days and had someone asking me why his parts never fit, too tight he said…
Was a fellow Aussie and after a bit of back and forth we decided to do a quick videochat so he could share his screen in real time.
The problem became obvious right away once I saw it was like a big screw fitting.
He designed the screw part but not the nut part.
Obviously you can just substract one from the other…
Well…
If you like to do things like passthrough toys or other things that require a tight but still lose enough fit tolerance come to mind…
Thankfully his ‘screw’ was very rounded everywhere and with a massive pitch.
After some careful stretching in just x and y the preview looked to have an acceptable clearance.
He Emailed me later to say it is still a bit tight but works.
Got me wondering how many users might struggle with similar issues.
I admit that I try to avoid using Studio for what I consider CAD operations.
So I struggled a bit trying to work things out.
You know old dogs and learning new tricks…
Why the hassles ?
Why not just select the two object to work with and done?
Anyway…
For simple things like a plain cylindrical fit one might be able to eyeball things with a few test prints.
But anything more complex…
FMD means one has to work with tolerance to make parts fit.
But there seems to be no way in Studio to set a certain minimum clearance for the result of boolean operations.
And well, the enlarging game is more a miss than a hit.
I knew why I do things in CAD but is this just me or am I missing something I studio that makes those ‘has to fit’ operations easier?
Looked for a youtube I saw once, from an old woodworker who was threading a hole in wood and he went through the whole thing about how to figure out what amount of thread percentage and what size drill to use based on screw size. The engineers Black Book has Calculation of Tapping Drill Size and other interesting stuff. Basically it’s what you need to figure how much thread % between the nut and srew engages to give a strong connection without binding. Basically for softer stuff anywhere from 60 to 75 %, usually 75%. Here is a quick non-chart method for imperial but I am sure they are around for metric.
So if I understand your friends method correctly , no you can’t just have the hole in the nut be basically the same size as the outside surface of the screw.
I guess if someone did enough of that type of printing they could come up with their own version of the formula for a consistant clearance between screw and nut or through trial and error come up with a size difference.
And I personally don’t know of any setting in a slicer to auto-calculate that.
Not that I am very experienced with 3d or CAD. I am struggling with Fusion 360 to replicate a spur gear that has a slight helical bias to the teeth. And I have looked at some of the options on MakerWorld and the internet and non-quite fit.
Replicate as in you have a worn/broken one you want to re-create ?
There might be ways to get it done that you have no considered yet.
What’s a helical bias ?
I do quite a few gears and threads feel a bit lost?
Any pic available by chance ?
Anything looking similar to these?
it drives a worm gear so the teeth are at about a 3 degree slant to mesh with the spiral. I’ve been working with the 360 import a jpg and convert into an object but I am totally new at this so it is slow going. Trying to figure out if I can do it without having to sketch it.
60 teeth standard profile…
If you give me the dimensions I whack one up for you.
Just the diameter where the teeth end and the diameter where the start should do.
Rest I can work if it is a standard module gear, otherwise I just make it from scratch.
If you need precision rather than just a working gear measure the distance between two tips of the teeth as well.
Not sure if you need the inner shape and the hole or if you can do this part, let me know…
Can you measure the required angle for the worm gear?
I assume if it a quite tight fit in the gear but can’t tell by the pic whether it is left or right.
Thanks for the offer, might just take you up on it. Other things going on right now so it make take awile to get info to you… The general gear specs are pretty easy, it’s getting the actual teeth degree that is the hardesd. Doesn’t look like a standard 20.
I know your problem 
Was in he same boat a few years when needed a new gear for my speedo in the car.
Had to into the gearbox of course.
The old one started ‘slipping’ resulting in a bouncing needled at times.
When the new arrived it the shop and tried to swap them I was confused.
The new one looked completely different for teeth.
Went back to the shop and tried to complain.
The guy explain I should just swap and it will work, the old one looks so different because it is worn out.
With worm gears the profile isn’t any more complex than for involute gears.
Two main differences >
Usually the radius for worm drive is removed from the gear.
The teeth of the gear have a slight angle, matching the pitch of the worm drive.
If you go with the pitch radius of the old gear and are lucky enough that a standard involute like 1.5 for the modulus will fit it is easy.
Extrude the profile with a matching pitch angle.
Remove a ‘ring’ from the outside to match the worm drive.
Not ideal but works just fine.
For some things, like these old style, wind up music players you can often find a slightly helical main gear while the worm drive gear is shaped to fit the gear.
These worm threads look a bit weird because here the worm part has ‘stumpy’ teeth in the middle, while towards the end they grow and get sharper - to fit the helical involute gear.
It would be a bit unusual if someone created a custom thing if cheap standard gears are available, so I still bet on wear and tear.
Even if not it is possible to get things to match with good measurements and a few test prints.
Always keep the required FDM tolerances in mind though…
