Adventures in 3D printing chastity belts

[Tracker]

That is the definition of rigid, isn't it??

The difference between Rigid and flexible isn't as clear as you might think. At least not when you ask an engineer. Take a rope for example. If you pull on it, it wont stretch (much) which makes it seem rigid. But if you bend it, it deforms easily, which makes it seem very flexible. So, a design can be rigid or stiff in one way, but flexible in another.

What I believe molly was trying to say is that the belt should bend along the center line, but remain stiff about the cross section (so you can't pull the edges away from your skin). Think of it like a tank track. Flexible across the joints so it can bend, but wont slip off sideways. Such a design could be accomplished with lateral reinforcing ribs, but that wouldn't exactly give a smooth profile.

Overall, not impossible, the trick (as always) is to try and find the right fit, material, design, and manufacturing method to make it work. Easier said than done obviously, but that's what you hire engineers.

[molly]

What I believe molly was trying to say is that the belt should bend along the center line, but remain stiff about the cross section (so you can't pull the edges away from your skin).

That's what I was trying to convey! Tank tracks is a great analogy! I drew this last night to help me explain this better than I had so far. I was hoping it was worth 1000 words

bending-forces.jpg (47.97 KiB) Viewed 9618 times

Overall, not impossible, the trick (as always) is to try and find the right fit, material, design, and manufacturing method to make it work. Easier said than done obviously, but that's what you hire engineers.

Men and women walk differently:

Female walk: https://www.youtube.com/watch?v=G8Veye-N0A4
Male walk: https://www.youtube.com/watch?v=vq9A5FD8G5w

There are some mechanical differences between male and female which makes this so. Men tend to take longer strides with their feet slightly more apart than women. Women tend to use their waist more when walking then men do. Women's legs tend to be slightly longer, proportionally to total height, than men. Weight distribution is different as women tend to have more mass in their hip bones than men and collect more body fat there. I said "tend to" because everyone is different but it should be obvious that men and women walk slightly differently overall. Fashion models exaggerate the difference when walking the runway.

When all these subtle differences are put together, the result will likely be the shield will have a tendency to slide left and right more for women than men. To compensate for that, the design has to allow for slight bending and twisting so as the body moves, the shield covers what it's intended to cover. But, rigidity is necessary for it to serve it's purpose.

This in my opinion is where most belt designs fail. Too much flexing or not enough flexing. This furthers the idea that a generic, pre-made belt won't work well for everyone, especially active people like myself because walking around a one-floor house is very different set of movements from doing any kind of sports, climbing stairs, going to work and getting up and down 20 times to go to meetings, get coffee, etc.

I hope you don't conclude I'm raining on anyone's parade. I'm trying to help by offering information you may not have considered. All of this went into the design I'm wearing now and the difference between it's comfort and the lack of comfort I experienced on other, purchased belts, is significant.

Most of us could tolerate an uncomfortable belt for a few hours in the bedroom for kinky play, but wearing it 24/7 for years on end is a totally different ballgame.

[Larrup]

Forces applied to the front or back of the shield should allow flexing.

I was thinking the exact opposite. The problem I was thinking about was preventing fingers being shoved under the shield to masturbate. If the shield can be deformed, in a direction normal to the body, then fingers can get in.

The distance between the navel, looped underneath, ending at the small of the back changes as well. Standing, it will be a slightly longer dimension than sitting down.

... with a little flexibility in contour so when the wearer sits down, the belt can compensate for that just enough to not dig into skin or become miserably unpleasant.

So, when measuring, should the woman be seated?

On the other hand, when she is standing, or lying prone, or lying on her back, you want the belt to work -- to prevent masturbation. You don't want the belt to become loose enough that she can masturbate in those positions. So if that is the ultimate goal, it seems that perhaps she must tolerate the discomfort of the belt digging harder into her waist when she sits.

I appreciate your comments, because I am seriously thinking of becoming a belt designer and manufacturer. I have been studying material properties of stainless, and have concluded that type 316LVM is the best for belts. I need to learn how to weld. I already know how to operate machine tools like lathes, presses, and milling machines.

[Larrup]

There are some mechanical differences between male and female which makes this so. Men tend to take longer strides with their feet slightly more apart than women. Women tend to use their waist more when walking then men do. Women's legs tend to be slightly longer, proportionally to total height, than men. Weight distribution is different as women tend to have more mass in their hip bones than men and collect more body fat there. I said "tend to" because everyone is different but it should be obvious that men and women walk slightly differently overall. Fashion models exaggerate the difference when walking the runway.

When all these subtle differences are put together, the result will likely be the shield will have a tendency to slide left and right more for women than men. To compensate for that, the design has to allow for slight bending and twisting so as the body moves, the shield covers what it's intended to cover. But, rigidity is necessary for it to serve it's purpose.

Does the Fancy Steel belt from Australia fail for this reason?

[molly]

I was thinking the exact opposite. The problem I was thinking about was preventing fingers being shoved under the shield to masturbate. If the shield can be deformed, in a direction normal to the body, then fingers can get in.

Oh, you do want to design the belt so fingers can't be slipped behind, but rigidity is not the sole answer. You want the material to resist the forces that can be applied by a finger while having more tolerance for body movements. Here is a diagram:

bg-movements.jpg (20 KiB) Viewed 9559 times

The red band on her waist is the waist belt.
The white line is the shield and connecting pieces fitted snugly while she is standing up.

As you can see in the right side of the picture, that shape isn't even close to matching the contour of her body when she sits down. The green line represents the shape it should be. This is why a belt made of absolutely rigid materials isn't a good choice - she can't bend, sit, walk up stairs, etc.

The question would then be how much flexing is too much?

Well, I weigh 125lbs and assuming my legs are 25% of that, there is about 90lbs pressing on the chair surface when I sit down. Some of that is passed to the chair from my fanny, some of that is passed to the chair from the bottom of my shield. Because my shield would make contact due to its slightly cupped shape, it will resist bending and try to push the waistband up. Since my waistband fits snugly and I'm also muscular, my waistbelt doesn't go up so the shield and the connecting piece behind (i.e. between my butt cheeks) will flex.

Because the back part is much narrower (1/2” versus 2-3” depending where the comparison is made), the back does the majority of the flexing and the cupped shield over my ladybits stays where it’s designed to stay.

This is what happens when I sit. The front remains against my tummy, the shield remains against and covering my ladybits, and the 1/2" wide part going up my back hovers away from my skin as it's pushed out.

My husband (who designed my belt) wanted to include a strong spring in tension out back so when I sit there would be tension preventing the back from moving away from my skin but he couldn’t find a suitable spring because it would have to tolerate showers, soap, shampoo, conditioners and perspiration and not corrode. This is why the back of my belt is solid.

By the way, I exaggerated the drawing left to right to illustrate the point. In reality, the narrow part between my butt cheeks doesn't move out all that far and remains between my cheeks, just not against my skin when I sit.

I’ve mentioned I’m very athletic in several posts was not to brag but to show people how much of an anchor point my waistbelt is. My waistbelt remains where it is all the time no matter my position or movements. Since I have very little body fat underneath, it doesn’t shift. Muscles have less “give” than body fat. Having solid anchor points is key to keeping the shield where you want it.

So, when measuring, should the woman be seated?

For my current belt, my husband measured me a multitude of ways standing, sitting, laying on my tummy, laying on my back, and standing with one foot on a stair. He factored in some kind of numerical weighting then averaged them together to what became the dimensions of my belt.

So if that is the ultimate goal, it seems that perhaps she must tolerate the discomfort of the belt digging harder into her waist when she sits.

My belt is most comfortable when I’m standing or laying down. Fairly comfortable when walking, and tolerable when sitting. As all things we design, they become a sum of compromises.

By the way, I don’t stick fingers or objects behind my shield to masturbate, yet I masturbate often. All it takes is pressing a against the front shield and oh… my… God… ! My shield is slightly cupped so my labia isn’t touching the metal either, but the vibrations transmit through the shield’s perimeter where it touches my skin surrounding my ladybits, vibrating them by proxy. If my husband locked me up with the large, heavy stainless dildo inside, my blasphemous exclamations are oh-so-loud.

If you think that’s bad, a couple times my husband handcuffed my wrists behind my back when he had to only work a half-day, thinking that would prevent me from buzzing my shield. Little did he know I was able to kick it up off the floor onto the bed, bump the power switch to high, then grind my shield on the vibrating head.

I appreciate your comments, because I am seriously thinking of becoming a belt designer and manufacturer. I have been studying material properties of stainless, and have concluded that type 316LVM is the best for belts. I need to learn how to weld. I already know how to operate machine tools like lathes, presses, and milling machines.

Mine is 330 and my husband selected that over the others because it’s the most corrosion resistant, as he (and I) were concerned the belt might corrode over time after being exposed to soaps, hair products in the shower and perspiration. That doesn’t make our choice correct, I’m merely sharing why we picked it in case that's helpful. My husband is a huge fan of "overkill".

[Tobbe]

Some I can agree with you, Molly, but you exaggerate the differences how the belt works at various motions. If you use cable, the belt will more follow her skeleton at the back.

[molly]

Some I can agree with you, Molly, but you exaggerate the differences how the belt works at various motions. If you use cable, the belt will more follow her skeleton at the back.

I did said I exaggerated my drawing to illustrate the point

What I was trying to convey to Larrup is locating the shield matters so much more than how flexible it is because covering the ladybits is a very key design feature. Rigidity in it's mounting achieves that moreso than it's thickness. At least I think so, though I'm not an engineer.

A cable out back would definitely take the majority of flexing of the belt and that's a great solution. I don't like cables but that's my preference, nothing more.

[Americaone]

AMAZING WORK!!! Hope it works because if you can pull it off i will be wanting some special model to be made for me!!

Check out my other posts on cnc laser cut chastity belts on this forum thanks for your efforts to make this!!!

[Tracker]

I have noticed from my own designs that the double cable up the back holds the front crotch plate pretty snuggly regardless of how much you bring your legs up. I am having more problems with the back plate while bending than anything else. That being said, my original single cable design definitely put alot of unpleasant pressure on the tail bone. The double cable design does seem to tighten very slightly when sitting, but I think the fact that it isn't resting on the tail bone or anything solid seems to alleviate the problem.

However, that being said, it isn't something I have payed really close attention to. Being male, the crotch plate's tightness against the perineum doesn't really matter. There isn't anything down there to safe guard. With my current design, it sits pretty snug. I can get a finger under there if I try hard enough, and maybe pull it 1/4" away from my body if I pull the back cables really uncomfortably tight, but that doesn't do anything for me.

I guess it would be more a problem to address for the female version.

[pappad]

I registered so I can contribute to the conversation.

I designed these two objects on thingiverse for 3-D printed chastity cage, modeled after the Holy Trainer 2.

They're not complete, and hopefully someone will take up the basis of the project and turn it into something better, as I have limited modeling skills.

https://www.thingiverse.com/thing:1174575
https://www.thingiverse.com/thing:1440856