Belt Making Experiments II

[dashingdarla]

Note: The pictures I've attached can be seen better if you click them once - they get a little bigger and the scroll bars go away.

Now that my husband has been wearing his Chinese-made belt and bra for a while (Initial Review Here), both units have taken approximate shape of his body which is useful for other measurements, such as body depth, since I cannot shove a tape measure through his spine and out his navel to measure that depth.

I removed his belt and re-locked it, setting it upside down on the table and had him compress the long sides (front and back) a little bit to approximate how it fits when he's wearing it. We came up with 6-1/2" inches inside to inside.

To confirm that measurement I had him stand next to the kitchen table sideways and I put a 2x4 on the table, sticking out, resting against his belly, and one behind him resting on his spine. I made them parallel, and the result was very close to the same dimension - a little larger because his current belt is snug and does some squishing.

With a belt depth of 6-1/2", and his overall waist measurement being 28", I took the circumference of a 6-1/2" circle (20.420") and subtracted that from 28" and calculated 7.58" of his waist measurement unaccounted for. I cut the circle in half and separated them by 3.79", which is half of the 7.58", representing the front and back straight portions of the shape. Like so:

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Pretty cool, huh? Next up, I decided to mock the belt out of aluminum, simply because it's easy to work with and available at home centers at a reasonable price. I bought a 2" wide, 36" long, 1/8" thick aluminum bar for $10 and change (and tax).

Next up was finding something that's 6-1/2" diameter to bend it around, and I came up with what looks to be an engine pulley of some kind. A very rusty engine pulley. But, it's exactly 6-1/2" outside diameter so it's perfect. I chucked the protrusion on the back of the pulley into my metal lathe like so:

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The next step is to clamp the aluminum bar to the pulley, and I used a metal clamp and start the bend. I prevented rotation of the chuck by inserting a chuck key into the keyhole so that it rests on the lathe bed. This allowed me to use both hands to bend the aluminum.

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The next step is to rotate the pulley a bit, and bend the aluminum some more.

There, now I have a 180 degree bend, and one side of the belt formed. The aluminum I purchased is a bit springy, so that's why I slipped on the adjustable crescent wrench which you can see in the top of the picture. I'll deal with that later.

And here is a side view, looking down the lathe bed so you can see the full 180 degree bend:

The next step is to mark the center of the bend, which intersects through the center of the pulley, so I know where to measure the 3.79" from, which will be the center of the second bend for another 180 degrees. If I do this correctly (which will be attempted after dinner), the aluminum bar should end up looking very similar to the diagram at the top of this post, minus any springyness that will inevitably be part of the mix.

Also, I should have a few inches of overlap on the front, which I'll cut off and through both ends so they line up, which is where the crotch strap will clamp the two sides together and extend downward. I haven't measured any of that yet as I'm just working on the waist at this point.

Enjoy.

[dashingdarla]

Well, I couldn't wait until after dinner I wanted to see how it turned out. Because the lathe bed is in the way of the already formed side of the belt, I had to clamp the belt underneath the pulley and pull up rather than pull down as I did before. Again, I put an old chuck key into the chuck's key hole in order to prevent rotation:

And then I pulled the aluminum flat around the pulley and ended up with approximately the right shape, matching the original diagram.

I'm going to have to re-clamp the other side to make it round again because I ended up twisting it slightly which ruined the nice round curve of that side. Like I thought would be the case, there's quite a bit of overlap to be shaped into "tangs" that will go into the locking mechanism that I will be making as part of the crotch belt for the two sides of the belts to latch into.

[dashingdarla]

And here is a topview of the locking mechanism, at least the design of it.

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Basically the top part is a block with a wide groove machined underneath, and two holes bored through it, threaded to match the locks I purchased:

The locks are Frandon #2615 and are pushbutton locks, latching when the center pushbutton is pushed in. To unlock, the round key is inserted into the lock's opening around the plunger, and turning the key causes the plunger to pop up into the key body. I don't know if this will be the final design but I saw the locks online and just had to buy a few of them to play with. These locks are tubular locks but only have four pins and thus easier to pick than the computer case locks Pyra Gorgon referenced on another thread, but I thought they'd be a fun starting point for this. To lock, one just inserts the belt tabs machined into the belt itself then push the plunger down, no key necessary. Removal requires the key.

Someone PM'd me a short while ago and suggested aluminum is a poor choice for belt construction - I'm commenting here because I imagine others might have the same thoughts. I agree, and this is a prototype and making it out of aluminum is easier to work with (and less costly) than stainless steel.

[fitherin]

WOW They say neccesity is the mother of invention

Love the work you have done so far and those push locks so neat and simple

Part 111 soon I hope

S

[Lizza1]

The word is "necessity" fitherin!
Lizza

[Pyra Gorgon]

Great work, Darla!

[dashingdarla]

Thank you both!

Obviously, the waistband won't be a single piece and have to be hinged. Since it's a prototype, I'll probably use a 2" cabinet hinge on each side.

I was surprised how springy the aluminum is. Thinner metals tend to bend and retain that bend far easier than thicker stuff.

[CylonSexFiend]

The hardened aluminiums like T5 and T6 will retain their shape better than the Al you are using, If you can get them to bend in the first place. You will need a bigger lever. (and perhaps a better locking mechanism for your lathe)Also if you slightly over bend the Al it will spring back to the position you want.

Why are you thinking of putting hinges in the sides of the waistband ? by the look of the spring in the Al it looks like you could just stretch the waistband open enough to squeeze in.

You could anodize the belt to prevent poisoning the wearer if there is a place in your area to do it.

[dashingdarla]

I often use softer materials to experiment with. The pattern for this belt was made out of denim, test fitted to the wearer, then transferred to aluminum as the first metal prototype.

Aluminum is easy to cut, bend and shape and once the final prototype was completed, I lined the inside with duct tape and had the wearer put it on for a week to see how it fit. Minor adjustments were made, then the tape was peeled off and the aluminum then became the rigid pattern to use as a guide for the plasma cutter. I just haven't cut out the stainless yet. Holiday season, many distractions

[Pyra Gorgon]

Yanno, the more I think of your new pushpin lock design, the more I like it!

Gee...wish I'd a thought of that!

Great creativity juices there, Darla!!!

And since the tabs slide in from the sides, the boxing of the locking block prevent sideways torsions...clever.