# Chilbro



## ZDP-189

Sorry, no slingshot to show. Just a concept sketch:










But I reckon it'd work.

Dan


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## joseph_curwen

nice


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## ZDP-189

BTW, I read that the original Milbro was about 140mm (7 1/2" long) and 6mm (.25") thick at the handle. Is that correct?


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## huey224

that is a great idea.
maybe have one with one hole a bit like the dankung but with a hole the size of the original milbro.


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## Dayhiker

This NEEDS to be made!!


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## whipcrackdeadbunny

ZDP-189 said:


> BTW, I read that the original Milbro was about 140mm (7 1/2" long) and 6mm (.25") thick at the handle. Is that correct?


That's about right, but the original was a little too thin for me anyway. It's about as long as your hand and fits into your pocket ...


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## whipcrackdeadbunny

Looks great by the way.


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## Sam

Interesting idea, the Dankung tubes would definitely provide superior performance to the square rubber the_ Milbro _design typically utilises. Just out of interest what program are you using for these technical diagrams and does it have a good free or open-source alternative?


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## ZDP-189

Microsoft PowerPoint. Image capture and resizing with Microsoft Paint. Open Office maybe an open source alternative, but I don't know how to draw using it.

Chinese bands can actually be done with single holes.

Pete, will you sell me one of your Milbro Copies?


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## Sam

ZDP-189 said:


> Microsoft PowerPoint. Image capture and resizing with Microsoft Paint. Open Office maybe an open source alternative, but I don't know how to draw using it.
> 
> Chinese bands can actually be done with single holes.
> 
> Pete, will you sell me one of your Milbro Copies?


Oh OK, what about your 3d renders? I want to be able to print my designs out to an exact measurement, for templates.


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## Pro-Shot (UK) Catapults

ZDP-189 said:


> Microsoft PowerPoint. Image capture and resizing with Microsoft Paint. Open Office maybe an open source alternative, but I don't know how to draw using it.
> 
> Chinese bands can actually be done with single holes.
> 
> Pete, will you sell me one of your Milbro Copies?


DAN I JUST SENT YOU A PM
Pete


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## whipcrackdeadbunny

Hogancastings said:


> Microsoft PowerPoint. Image capture and resizing with Microsoft Paint. Open Office maybe an open source alternative, but I don't know how to draw using it.
> 
> Chinese bands can actually be done with single holes.
> 
> Pete, will you sell me one of your Milbro Copies?


DAN I JUST SENT YOU A PM
Pete
[/quote]
Oooh! Exciting.


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## harpersgrace

Great idea ZDP, I like your renderings.

You can do them on a milbro just like on a natural, only you need slightly thicker tubes than what I have, or slightly smaller holes or they tend to slip and need to be adjusted often,


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## Dayhiker

I want to cut one of these out of an old circular-saw blade. Sandwich the handle between micarta slabs. How's that sound?


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## huey224

that is a good idea.
but how will you cut it out?


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## Dayhiker

huey224 said:


> that is a good idea.
> but how will you cut it out?


I have this wicked sharp pair of scissors and. . . just kidding.








Angle grinder and dremel and carbide-tipped drill bit.


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## Flatband

You know I love the name "Chilbro". Square tubes anyone? (Think about it!) Flatband


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## ZDP-189

If you don't mind, I have experience cutting such things. The brute force approach can work, but it can also be frustrating, inaccurate and can leave stress fractures. If it's a hardened blade, you should fully anneal or at least over-temper the blade.

If it's HSS, you're out of luck.

If it's a carbide tipped circular saw blade, I haven't experience cutting them.

For your application you don't need edge holding, so why not use mild steel or something else easier to cut. Milbro fork arms are narrow, so you'll need 4mm mild steel or 6mm aluminium.


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## ZDP-189

After he contacted me, I was going to make this as a gift for Pete, but it looks like he has his own similar, but very exciting plans so I'll move onto new projects. As a parting comment on this idea, having spoken to danny on this, I have come to the conclusion that* it would probably be quite dangerous* as drawn if cast in thin aluminium. The 'open ears' design in Chinese slingshots depends on a thick section of laser cut stainless steel. This design is much weaker for these reasons:


Aluminum is more likely to flex and fatigue than stainless
Castings are weaker than cut billet
The Milbro is thinner than Chinese ball-in-tube slingshots
The ears as drawn show weaker a form than the Chinese design
Any casting flaws or inconsistent finishing could be catastrophic. Pete has a high standard of work, but the potential is there
The main danger is the 'ears' opening up and releasing the tube end to slap the user in the eyes. A secondary danger is the arms may fail at the stress riser below the 'ears' flinging the tube, ball and ear back at the shooter.

If a similar design is implemented, then it should use 'closed ears' rather than 'open ears' which have a slot for more mechanical strength. The 'ears' should be more built up, possibly utilising a flange and the arms should be engineered to bend rather than fail at one point. The whole design must be extensively tested before marketing.

If you're having trouble with terminology of Chinese tubes with terms like 'ears', please refer to danny's thread on Mel's forum (Link).



harpersgrace said:


> Great idea ZDP, I like your renderings.
> 
> You can do them on a milbro just like on a natural, only you need slightly thicker tubes than what I have, or slightly smaller holes or they tend to slip and need to be adjusted often,
> >image<


Thanks. That looks like a good idea and closer to the original design. Another idea would be to simply engineer a hole suitable for a single Chinese Tube in a 'closed ears' configuiration, but both ideas still need testing before being promoted commercially.


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## Dayhiker

Dan, it's just that I have a few of these carbide-tipped saw blades to make knives with and I'm not into knives right now. They do make nice knives, though. But you are correct. Maybe I will wait til I can get a piece of ally.


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## ZDP-189

Dayhiker said:


> Dan, it's just that I have a few of these carbide-tipped saw blades to make knives with and I'm not into knives right now. They do make nice knives, though. But you are correct. Maybe I will wait til I can get a piece of ally.


I am surprised carbide tipped blades make nice knives. Do you know what steel the disc is?


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## Pro-Shot (UK) Catapults

ZDP-189 said:


> Great idea ZDP, I like your renderings.
> 
> You can do them on a milbro just like on a natural, only you need slightly thicker tubes than what I have, or slightly smaller holes or they tend to slip and need to be adjusted often,
> >image<


Thanks. That looks like a good idea and closer to the original design. Another idea would be to simply engineer a hole suitable for a single Chinese Tube in a 'closed ears' configuiration, but both ideas still need testing before being promoted commercially.
[/quote]

Hi Dan you are right that the design you have leads its self to a few minor problems but nothing that a bit of over kill would not put right?As i said in my pm to you we have already got a slingshot /catapult very near the designe you drew.?I think some one said in a thred on an earlyer desigen we are all trying to re invent the wheel? and as more designes come out this will keep on happening.
i have addressed the problem you and dan have identified with the saddel consept on both sides of the slingshot /catapult witch will house the tubes in avery safe way and also increase the tube life as with all our slingshots/ catapult we will of course carry out field trials before we make them open to the genaral public for sale.The metal we use in the manufacture of our products CAN NOT BE
conpaird to some of the LOW GRADE METAL THAT IS COMING OUT OF china on the dang kung rip offs.
all the best
Pete


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## ZDP-189

Pete, I fully agree. Yours is hand cast in quality alloy by craftsment who care for customers that can tell the difference.

For clarity, I don't mean that the original Milbro design is too weak, that your recasting is flawed or that I have any reason to believe that they can't handle a pair or double pair of Chinese bands.

I just want to point out that the skinnny aluminium split rings I drew would probably fatigue and open to the point where the ring snaps or opens wide enough to let the tube through.

If I had to redesign it, I would not split the ring, use a bigger fork tip and more gradually blend the tip into the fork arm. No doubt your design is already sufficiently well engineered, but I wouldn't want you to be led astray by my faulty design.


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## huey224




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## whipcrackdeadbunny

huey224 said:


>


I know, "Faulty design" don't worry guys, I'm sure you'll iron out the creases, and we all wait in anticipation.


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