[Invisible]

I know nothing about the strength of metals and different manufacturing techniques.

I've read that bent metal rod is stronger than cast metal (not sure about board cut metal), and that cold bend is stronger than hot bend. However, I'm wondering; how was the rod that a bent metal rod slingshot was made of manufactured? Maybe the rod itself was cast metal?

The other thing is to define "strength". I can think of two types of strength that I care about when it comes to a slingshot:

1) strength to withstand the force applied when drawing the bands back. I think this might be called "tensile strength".

2) strength to withstand the force of a fork hit (when the ammo hits the fork). I think this is "impact resistance" although I don't know what word is best to describe it.

Are there any other kinds of strength that are relevant? Maybe resistance to being scratched (for example if dropped onto concrete or stone floor), which I suppose could be called "hardness".

I'm just trying to understand more about the strength of a slingshot frame. I'm quite risk averse and like my slingshots to be strong and tough. I prefer metal slingshots, particularly steel, and I tend to like those that have a good thickness of metal all over the frame. I would like the metal to be at least 6mm thick (ideally thicker) in any plane that goes through the centre of that area of the frame, although I imagine that the thickness in the direction that the force is applied in is the most important.

I typically use 9.5mm steel balls with 1842 or 2040 looped tubes or single theraband flats, although I would like a slingshot to be strong enough to handle 2050 or 1745 looped tubes, or double theraband gold if I decided to use them (probably with heavy ammo such as 16mm or 14mm lead ball),

Sometimes I see slingshot frames that I like the style of but am not sure how strong they would be (e.g. if part of the frame is quite thin metal in places). I do tend to like "overbuilt" stuff though for extra peace of mind, so maybe I'm being too fussy.

Just wondering what people think about this subject?

 

[Alfred E.M.]

How are stainless steel rods made?

To make stainless steel, the raw materials-iron ore, chromium, silicon, nickel, etc. -are melted together in an electric furnace. This step usually involves 8 to 12 hours of intense heat. ... After various forming steps, the steel is heat treated and then cleaned and polished to give it the desired finish.

I've owned several cold bent stainless rod frames and many cast in stainless. IMO, the 360 round groove Fox Antelope from Dankung (Right) is the newest and best of the lot ... doubt if you'll find anything stronger.

 

[snydes]

I'm of a similar mind set - not interested in a frame failing under tension. I like to build my slingshots and as an engineer and a woodworker, my interests lie in the wood realm. Logically, anything can fail, but I'm thinking plywood can have hidden voids that you can't see, so I've never been a fan of trying that. Solid wood "board cut" frames could have cracks that develop unseen. Natties could have undetected cracks, voids or grain anomalies that could lead to a failure. Now, I don't lose sleep over any of this as the likelihood of a catastrophic failure is very unlikely with any of these, but I do think a laminate of 3 - 1/4" hardwood strips may be the inherently strongest wood frame ... so that's what I tend to prefer. I know nothing of G10, other than it's stronger than wood and very attractive. Of course solid metal is the safest option if you don't mind the weight.

With regard to the OP's concerns regarding dropping strength and frame hits, I've never worried about how strong a frame is with regard to dropping one on a concrete floor - wood is clearly the loser in that category. I don't want to jinx myself but I haven't had a frame hit since I starting building full size frames - only had those with narrow fork frames. So I guess I prefer this type of frame - just feel a bit more comfortable as I know what's "inside" it & that there's no cracks ...

 

[Sean Khan]

I do tend to like "overbuilt" stuff though for extra peace of mind

Here we go....

https://slingshotforum.com/topic/123000-the-mighty-industrial-the-battle-tank-of-slingshots/

 

[Alfred E.M.]

... how strong a frame is with regard to dropping one on a concrete floor

304 stainless is considered malleable and ideal for frames. 440 stainless is more brittle and has been known to crack if dropped just so on a hard surface ... but not always.

I believe all of mine are made of 304 including the above 360 model out of 9mm stainless rod.

 

[Pee_Drizzle]

Hey invisible.

Steel rod is drawn and rolled, usually hot rolled but sometimes cold rolled. Its never cast. VERY few steel products are cast as a final process.

One thing to be aware of is weld points, my 4th frame (which can be found in the homemade section) has a weld smack bang in the middle, right where the forks meet the body, its the worst possible location, the steel is only 4mm thick everywhere, and the weld is ground flush. But i welded it myself and i know i got good penetration and heat control.

Even though its so reletively thin, its plenty strong. I would happily blast half inch steel ball bearings into it at 300fps all day long. Its mild steel, so it isnt brittle. If it were cast iron, a single such impact would absolutely shatter it.

If you have a purchased steel frame slingshot with a weld point near the middle, that could be a concern, if they didnt know how to avoid cavities or particularly weak brittle weld edges, it could fail from a shock impact.

 

[cromag]

Frame strength has two components as I see it. Tension and impact resistance. I doubt if many (if any) can exert a "pinch force" exceeding 20 lbs so failure under draw tension is much less of a concern than impact strength needed to withstand a solid fork hit.

 

[Rockstar]

Pretty sure people are referring to cast zinc when they're talking about a metal slingshot breaking. I don't see either cold worked or hot worked steel making much difference, but theoretically a cold worked rod will keep it's temper (though it probably didn't have one) and there would be more metal fatigue in a cold worked rod than a hot worked one. But in practice I don't think it's going to make any difference, apart from cast zinc being pretty bad.

 

[Pee_Drizzle]

Pretty sure people are referring to cast zinc when they're talking about a metal slingshot breaking.

Yes of course, i was just giving an absurd hypothetical to point out how varied the properties of different metals are.

And for the hot/cold steel rod, i was just talking about the manufacturing process of steel rods. They are drawn and rolled, usually got rolled right after the drawing process, but some rods are left to cool then rolled down to the desired thickness cold.

 

[Sandstorm]

Those ones you see being bent around on the YouTube shorts are most likely 1/4” mild steel. I actually have a tabletop bending jig (I’m a silversmith by trade) but never thought about using it to make slingshot frames. Until NOW that is!! Haha! Tractor Supply here I come! Get ready for some crappy slingshots!