Adventures in 3D printing chastity belts

[Tracker]

Hello ladies.

First I must admit that I am male, so sorry to intrude into your sorority. But I am hoping you can offer me some insights and ideas. This is a cross post from another forum here:

http://www.chastitymansion.com/forums/i ... lts.14774/

The start of the post talks mainly about the male side of things, but later half talks more about the process of making the waist belt itself. Given how chastity belts (rather than cages) are actually more popular amongst the ladies (for obvious reasons) I thought this forum would have better insights into belt making and wearing.

If you don't want to read the entire post, here is the summary:

1. I want a belt for myself
2. I am an engineer
3. I like building stuff, and have a 3d printer, a 3d scanner, and am in need of a project
4. I didn't like the design of current belts on the market.

So I decided to put my skills to use and try reinventing the belt. Here is my most recent work:

First up, you can see the scanning itself. This is done while wearing tight underwear to give a better shape to the waist.

http://i.imgur.com/aW7zank.jpg

And then the clean up afterwards (right side done, will be mirrored over to the left).

http://i.imgur.com/UPxMwSP.jpg

I have decided to use cables to post tension the structure. So you can see what I am talking about, here:

http://i.imgur.com/snQByXw.jpg

The belly plate, hip belts, and back plate are separated by small gaps, with wires running across them. The top wire runs from the belly plate, around the hip belts, through the back, and to the front again through the other hip belt. Likewise, the bottom wire runs from the belly plate, through one hip belt and back plate, down to the crotch plate, back up to the back plate, and then across the other hip to the belly plate again. And some more pirctures here, too large to show, click to see:

http://i.imgur.com/8WrIuLV.jpg
http://i.imgur.com/2z6l9gD.jpg
http://i.imgur.com/P99uYAS.jpg
http://i.imgur.com/WXLqgSR.jpg
http://i.imgur.com/5jy2aeO.jpg

This last one shows a close up of the belly plate. One of the nice features about this method is that the cable lengths can be individually varied by adding in shims. Those are just little U shaped plastic pieces that sit between the cable end and the side rest. ass you can see here, more shims pulls the belt in tighter. This allows you to make the gaps between the belt pieces larger or smaller, and thus adjust the tightness of the belt. Since the shims can come in any thickness, you can vary the size of the belt by any amount. Here I have 1/2" and 1/4" shims shown. So it is easy to control the tightness in 1/8" increments (could be smaller if needed).

Likewise, since the back cable (that goes down your but) is connected in a similar fashion, you can control the tightness of that back cable as well by adding or removing shims. As such, the top cable controls belt size, the bottom cable controls back cable length. It is fully adjustable.

Also shown is how the connection between the crotch plate and belly plate can be adjusted. While not included in this model, it is possible to do a similar shimming approach to make the crotch pulled up tighter or looser to the belly plate.

Of course in the final version, there would be a locking plate that covers the cable ends and V from the crotch. But this is still a fit check prototype.

So how does it fit (warning, some male anatomy showing):

http://i.imgur.com/JbcqxeG.jpg

Pretty well.

Another benefit of this cable approach (aside from being easily adjustable) is that the back passage is much better. As there are now 2 cables instead of 1, it goes around the anal opening, allowing for easier bathroom usage. It also goes to either side the tip of the tail bone, so you don't get pressure on that point.

If you want to read more, the other forum post has more detailed info.

But on to the point of this post. Do you have any suggestions for improvement? Insights that you have gained from wearing your belt for a long duration? Perhaps things that you would like to see changed about your belt that could be incorporated into this design. Suggestions for hygiene, cleaning, etc?

I am also curious to your insights on padding/linings. I have tried several. There is some closed cell foam medical grade splint padding I have used. It is very cushy, comfy, water repellent so it works in showers. But it can't handle abrasion from things like toweling off. Nor does it breath well. Going bare without padding is obviously easier to clean and sturdier, but not as comfy. I assume you have experience wearing waist belts for extended durations, so what did you find that works well?

Anyways, please leave me your thoughts.

[fitherin]

I have little knowledge of three D printers, But by the time I had read all your script and ideas viewed the results so far?

All I can say is WOW if it fits as well as it looks it has a future,Your cable spacers system is relly neat!

Look forward to seeing the completed versions with locking cable cover and Ladies shield version.

Well done!!

Steve

[susieo]

try posting in the modification section, too. I think your design looks wonderful, workable. What kind of material are the main pieces made from? I am wearing one of those Chinese ones...not good. The good thing about your design is the adjustable factor. I have a lot of weight to lose (mostly in the belly) so being able to adjust the belt as I lose weight is a plus. Also the other important aspect to myself and my potential keyholder is no access or ability to masturbate. It doesn't have to be made of steel. It just needs to be some way to show it hasn't been removed, and it needs to be totally masturbation proof. I'd love to help you with the design or give you input. There are several women here who would really appreciate your design. There aren't currently any mfg of belts that are adequate other than Tollyboy and that is virtually a business that is dead at this point due to lack of interest in the business from the owner. Someone said women who wear chastity belts are like unicorns, difficult to find; but I bet if there was a decent product we'd come out of the woodwork.

[Tracker]

The belt is currently made out of ABS plastic (same thing legos are made from). However, that's just for prototypes and fit checks. I plan to make the final version of the belt out of Food Grade nylon. It is stronger, more flexible (without stretching), lighter weight, smoother surface, lower friction, capable of being washed in the dishwasher, and of course, food grade. The cables are 304 stainless steel, with nylon coating on the wires down the back.

[Larrup]

I am an engineer

I am an engineer also, but not a mechanical or aerospace engineer as you are.

This allows you to make the gaps between the belt pieces larger or smaller, and thus adjust the tightness of the belt.

Is there a possibility for pinching? How can it be alleviated?

3d printer

What are the material properties of the meltable plastic used in 3d printers? How strong are they? How resistant to shear? What is their tension limit (per cross-sectional area), before they fail? When a person sits on the belt, some parts of it may be in compression. What is the compression limit (per cross-sectional area) before the plastic fails?

Based upon the answers to those questions, what is the minimum required thickness of the belt, measured in a direction normal to the body surface at that point?

Finally, at the ChastityMansion site, you say:

the hip is a complex 3D shape and plastic can't easily bent into shape like metal can.

There are some videos of bending Lexan and/or other plastics on YouTube. Search for them. It can be done cold, or hot. The easiest bends, of course, are one-dimensional (along a single axis). But see also all the vacuum forming videos on YouTube. So two-dimensional bends of a sheet of plastic can be done also, by heating the plastic, using a mold, and using vacuum forming.

It is probably possible to make a mold of someone's hips by a two-step process. First you make the negative, then using the negative form, you manufacture the positive form. And finally you use the positive form to vacuum form heated plastic. It is not clear to me how to cut it after it is molded, because it will be a complex 3d shape. It is clear that it must be cut after it is molded, otherwise the vacuum forming process won't work.

It now seems to me that a belt made completely out of clear (or white) Lexan (except for perhaps the wire between the buttocks) is possible. But it must be individually fitted to the individual who will wear it. It is not clear yet whether or not the waist belt can be one piece -- that is -- if there is enough give for the belt to be stretched for putting it on and taking it off, or if the waist belt needs to be multiple pieces. But there probably will be enough flexibility for a one-piece waist belt. My Lexan paddles are amazingly flexible (without breaking).

A belt made out of Lexan probably doesn't need any sort of liner, because the plastic almost certainly won't irritate the skin, as certain metals (like nickel) do. Furthermore, the Lexan can be polished smooth.

And a belt made completely out of Lexan has a very certain visual appeal, especially if it is clear, and you can see right through it.

[Larrup]

It now seems to me that a belt made completely out of clear (or white) Lexan (except for perhaps the wire between the buttocks) is possible.

Thinking about it more, it isn't so clear. Because Lexan is flexible.

The front shield over the vulva needs to be rigid. Perhaps that can be accomplished with ribs on the outside of the shield, and a set of ribs on the inside which hold the shield away from the vulva. T-beams and I-beams are much stronger than flat sheets.

It is clearly an area where experimentation will need to be done.

[Tracker]

To answer your questions:

I haven't had issues with pinching yet. The wire is offset from the body about 1/8" with only a gap of about 1/2" (at most). Since the gaps are at the front of the belly and the back plate where the body is relatively flat and tight the skin doesn't stick out enough to touch the cables. Also, the edges of the plastic at that point have a 1/8" radius to them. So they don't really cut in.

The material I plan to use is either Taulman 680:
http://taulman3d.com/news.html
or Tritan:
http://taulman3d.com/tritan-spec.html

Both are food grade, but the Tritan is stronger, chemically polishable, and easier to print. Nylon 680 however comes with much more certification and can be steam cleaned.

I also have hopes to use Alloy 910:
http://taulman3d.com/alloy-910-spec.html

It is stronger than both alloys, and prints at a lower temperature making it easier to use supports. However, it hasn't yet gotten FDA food grade approval yet. (Should be food grade, but testing isn't done).

As far as how that corresponds to the required thickness, that is more a function of the cable channels. Need 1/8" for the cable holes, and then 1/10" of nylon on either side of the cable. So thickness is .325" or about 1/3". Given how the waist belt is about 1.5" high (mostly for comfort, to spread out the load) that would be .5 square inches or 2400 lbs of breaking force with the 680 (4100 lbs with the alloy 910). Combined with the cables which can handle 1800 lbs each, it is more than you can pull off. You could easily make it thinner if you got rid of the cables.

That being said, 1/3" doesn't stick out too much to make it obvious. The belt sits at the narrow of the waist, so it kinda hides itself in there. Also, the cables are in the middle of the belt, resulting in more of a oval shape as opposed to a bar with large edges. If you look at the picture in my first post, you can see it is pretty low profile for fitting, and not noticeable at all under even mildly loose clothing like a T shirt. Probably would see it under a bikini, but not for everyday clothing.

As for the bending, you can obviously do it with an oven and a form, but it is a major endeavor that is hard to make fine adjustments. Unlike metal which you can bend by hand over a chair edge. It basically has to be done right the first time.

Making a belt by vacuform as you say is possible. The male mold could be 3d printed from the scan taken. But I don't have a vacuum former. Plus, that doesn't alloy for things like internal cable passages, the complex shape of the belly plate's locking mechanism, or in the case of male anatomy, things like penis chambers.

[molly]

The front shield over the vulva needs to be rigid.

The more you increase rigidity, the more accurate the shape and contour must be.

Belt design needs to take into consideration how our bodies change shape as stand, walk, sit, run, climb stairs, and rest. You can see how this works by measuring around your hips while standing up, then re-measure after sitting down. Your gender and BMI doesn't matter, you'll get different measurements. 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.

The front shield doesn't necessary have to be rigid, but it can't stretch under tension or warp under compression. My point is, there's an optimum balance point combining the wearer's comfort and the capability of the material, and the range of motion that's to be allowed.

[Larrup]

molly wrote:

The front shield doesn't necessary have to be rigid, but it can't stretch under tension or warp under compression.

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

[molly]

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

No, rigid means unable to bend or be forced out of shape; i.e. not flexible. I'm suggesting rigidity in length and shape is good, 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.