# Fork materials and design



## footloose (Dec 17, 2012)

When motor cars became more powerful, we stopped making them from wood. The same with wheels, ships and aircraft etc. Why? Because we discovered better materials fit for purpose - metals. Plastics have their place too, but without years of testing and x-ray equipment to determine the structural integrity and potential longevity of each piece - I wouldn't trust them in a slingshot fork - *not at any price*. And a broken fork in the face would be a high price to pay for our simple pleasures.

When I was young (50 years ago), I would trust a grown wood fork frame to ¼" black rubber, but with modern powerful bands shooting .44 or .55 cal lead, a designer needs to choose the right material for the job - *and that has to be a metal.*

One of the principal problems with OTT frame designs is that the forks have to be made wide enough to support a one inch wide band. This in itself presents a huge target for a fork strike. Many frames, particularly those made from a mono-directional ply wood (call it what you will) or even a form of plastic (which may have an indeterminate strength without individual testing) may simply not be up to this form of abuse and in my view should not be trusted. I know, I have experienced a fork failure with a commercial board cut.

Don't anyone talk to me about experience either. 18 years old or even 80, there is no guarantee of ability in avoiding fork strikes, and we sell to all in between.

In the end there is nothing to beat sound engineering principals being applied in the design process in the first place - the broader liability. Our public image as slingshot users is precarious enough without inviting avoidable accidents due to poor engineering design or execution.

Footloose


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## wombat (Jun 10, 2011)

Well designed doesn't necessarily mean metal. There are a lot of cheap cast metal frames being sold, I'll take one of my engineered wood frames over a cheap metal one any day!! http://kookaburrakatties.blogspot.com.au/p/streng.html http://kookaburrakatties.blogspot.com.au/p/long-grain-testing.html


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## footloose (Dec 17, 2012)

Quite so Wombat. 'Cheap' and 'cast metal' are best avoided. Your website clearly shows that you recognise the issue.

Still not happy with thick forks though for the reasons given - and they do have to be thick.

Footloose

http://www.footloosecatapults.com


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## Bob at Draco (Feb 18, 2013)

Having a welding business for a long time, I've made hundreds of SS out of metal but I don't think that is the only safe material. I've made SS out of plastic, micarta, rucarta, wood and naturals and have never had a single one break. There really isn't that much strain on a fork to need an engineer to tell you if it's enough. If you did get an engineer involved, the SS would be too big to hold in your hand.


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## Dayhiker (Mar 13, 2010)

Footloose: can you spell over-engineering? The bands aren't THAT strong.


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## ash (Apr 23, 2013)

Also, fork hits aren't that common once you get your technique sorted. I have a foolproof fork protection appendage that I like to refer to as my left thumb


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## Charles (Aug 26, 2010)

Most folks cannot draw more than 15 to 20 lbs of draw weight ... and most will not be accurate at the upper end of that range. It does not take much material strength to resist that kind of force.

As for fork hits .... well I have yet to see a natural fork of reasonable diameter (say 3/4 of an inch) that has been broken by a single fork hit. As a suggestion, take a 3/4 inch diameter well cured tree branch of some decent hardwood and suspend it from stout chord, with a good weight on the bottom. Then step back with your slingshot and see how many shots it will take to significantly damage it. In any case, if you get a fork hit and do not give the frame a VERY close examination after, then you are braver than I.

On the one hand you say: "Many frames, particularly those made from a mono-directional ply wood may simply not be up to this form of abuse and in my view should not be trusted. I know, I have experienced a fork failure with a commercial board cut." And then on the other hand you say: "Don't anyone talk to me about experience either. 18 years old or even 80, there is no guarantee of ability in avoiding fork strikes" There is a rather marked tension between these two statements. You admonish us not to rely on our own experience, but rather to rely on yours.

I suggest that pushing metal frames is a commercial decision on your part. Trying to sell them based on inducing fear is a very poor marketing strategy.

Cheers ..... Charles


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## flipgun (Nov 14, 2012)

I have plywood slingshots :shocked: Oh God! I'm gonna lose an EYE! :aahhhh:


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## Danny0663 (Mar 15, 2011)

I like using Metal and i only exclusively use metal (8mm to 9.5mm thick 6061 T6 aluminum). But unless your Joerg Sprave pulling 40lb + bands that produce 100J of energy i don't think its necessary, maybe even overkill. I think plywood is fine aslong as you use good quality materials and processes. But like Wombat has stated, there are various techniques of construction to prevent such catastrophic failure.


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## Aussie Allan In Thailand (Jan 28, 2013)

I agree with Charles post.

Myself I use bands, and ammo/shot at the upper end of many forum members.
I have had rare forefinger strikes from 20 grams lead or heavier; all due to poor release.
Because of my brace position of my thumb and forefinger right up almost next to the bands.

Due to my set up I am very warey of metal fatigue over a long time.
As I would need a fork failure, and the resultant strike near my head, NOT.
Given metal fatigue failure occurs very suddenly, without the straining sounds one can hear in most other materials.

Therefore I am very cautious of your conclusions as a marketing tool for the naieve, and easily frightened.

Cheers Allan Leigh


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## gk1 (Nov 18, 2013)

There are plenty of applications that composites have replaced metal.
Strength is one aspect, but the other main one is feel. Metal does not have the warmth of wood.
For me, phenolics such as Tufnol are my first pick.
Micarta, spectra ply etc are newer layered materials that are perfect for this application.
The only downside is cost, but they are getting cheaper all the time.


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## Imperial (Feb 9, 2011)

other factors to consider in wood is the direction of the grain and how much strength the bands or tubes will require to pull, therefore determining the stress pull on the forks, no matter thier thickness. fork width can be smaller than the band, in your example you said wide enough for a 1" band, ive put 1" wide bands on a fork width of 3/8ths. i just tri-folded the band at the fork end. there are many options available to make a slingshot out of, but as mentioned, its all a matter of cost and labor. plywood is not mono-directional (that im aware of), its cross directional. also, use high grade construction ply.


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## HOE (Nov 13, 2010)

Jorge Sprave makes so many of his "hand-cannons" with oversized bands, all with wood.


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## crazymike (May 8, 2011)

morningwood is stronger than any metal.


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## TimR (May 22, 2011)

I don't like to draw more than 10 pounds (old shoulder injuries.) (Slingshots are harder to draw than bows, my compound pulled 50 before letoff and I was okay with that.) So that's 5 pounds a fork.

I've hung 90 pounds of weight on a plywood fork clamped to the work bench. There are probably old photos on here somewhere.

The safety factor seems ample.


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## Tex-Shooter (Dec 17, 2009)

Major manufactures take safety serious! I am only in contact with one so I will talk only about his product. Saunders archery makes slingshots of steel and plastic and all of slingshots have a fail safe design. What does that mean? That means that if there is a failure that only the bands return and if wearing safety glasses you should not suffer any serious injury. I just talked to a shooter that has a problem with a "Wrist Rocket Pro" The clip on one side pops out occasionally. He told me that the clip actually flies forward away from him. Clip failure on a Saunders flat band slingshot can be from several things. The number one cause is stretching of the clip retainer by using bands too heavy or too hard. A second cause can be from a unseen flaw in the clip retainer. The point is Saunders wanted to make slingshots that you could put bands on easy without tools and also be safe, so they designed there slingshots with a fail safe design. -- Tex


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## Tex-Shooter (Dec 17, 2009)

I also wanted to address the fine custom makers that we have here on the forum. I believe from the contact that I have had with them that they also take safety serious. I don't think that you will have a problem with shooting any of there designs with normal weight bands (9 to 20 pound pull weight) at standard draw lengths. Charles makes very good points. By the way the number one injury from shooting slingshots is shooting yourself. The number two injury is corporal syndrome from shooting too heavy of bands. -- Tex


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## Bill Hays (Aug 9, 2010)

I'm pretty sure pretty much everyone on these forums is trying to produce a safe and salable slingshot...

A good grade of plywood will make a real good frame and be a lot lighter than any metal... and the synthetics that are used out there can in many cases be much stronger than the plywood and still be lighter and more workable than the metals.

Me, I like a solid feeling slingshot that weighs less than most metal slingshots, yet just "feels right" in the hand... that's why I mainly shoot with G10 slingshots. And if you're using a ballistic grade of G10 (like many of the black colors are) then it's lighter, stronger AND more resistant to fork hits.


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## footloose (Dec 17, 2012)

Hi Charles and many other contributors,

I agree with your points referring to natural, or grown forks regarding a '*single* fork hit'. It's the mono-directional ply forks that worry me particularly. Agreed, the draw forces (on a new, undamaged and apparently well designed frame) are borderline insignificant. What I am saying is that *impacts* from high grain lead shot using double banded, high performance latexes can lead to impact cracks that the *naked eye will not see* unless you have x-ray vision. It's not the draw weight that is the problem in itself; it is the *impact shocks* that can produce *damage leading to subsequent failure under draw*. Entirely different forces.

Whether such powerful bands are accurate is a matter of debate, depends on the fork design, and in any case immaterial to this argument. If they can be fitted, many users *will.*

As to your *quotes* of my post, I'm unclear as to your point. Where is the 'tension'? All I am saying is that even the most experienced of us are capable of an occasional fork hit (or are we all infallible?). Anyone who does not learn from their own experience has something missing, but a wise man can learn from the experience of others too. If you regard this as an admonishment you entirely miss my point, and I wonder why you do.

I also feel some disquiet about the tone of your reply which seeks to attack my motives rather than acknowledge my safety-driven concerns. The fact that I am sore that an apparently reputable manufacturer supplied me with a potentially dangerous (but nevertheless expensive) product seems to have escaped your attention. If criticism of bad practice in design or supply is a taboo on this forum, and the defense of same is tolerated, I am clearly in the wrong company.

Finally, *employing a metal frame in my design is indeed a commercial decision on my part because I view this topic from the perspective of an engineer and I will push it because the good reputation and safety of the sport is in my best interest long term, and yours too actually*. I don't offer commercially available board frames because I consider them a business risk in an increasingly litigious world. A bought ply gives you little insight over its integrity internally. It may look very attractive in a shiny finish, but without sophisticated testing facilities, you can only assume sound internal structural integrity.

All that aside, fat forks are still a big target for a strike, which compounds the problem.

Cheers, Footloose

P.S. I have decided not to order my next new BMW to be supplied with wooden wheels. *That is definitely a fear-driven decision.*


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## Dayhiker (Mar 13, 2010)

That's just silly! This whole thread is silly.


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## Lacumo (Aug 18, 2013)




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## Aussie Allan In Thailand (Jan 28, 2013)

Could not agree more.

Allan


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## footloose (Dec 17, 2012)

You may think that Dayhiker. What's silly about design integrity?


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## parnell (May 20, 2012)

Nothing is silly about design integrity. Safety is very important and has been thought out and tested quite extensively by many experienced sling shooters who have promoted and developed the sport.

What is silly is that you appear to be trying to promote your product...as stated above, through fear.


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## Imperial (Feb 9, 2011)

@ footloose- from your posts i see that you already have a very negative outlook on slingshots and their safety. one that to me seems to be based on your paranoia of some sort. many credible opinions have been given, you just seemed to ignore them. it appears to me that no matter what, your mind is made up and that you will never be able to allow yourself to enjoy a slingshot. the only thing left for me to say to you is this- slingshots aint for you, give it up, look for another hobby that best makes you feel safe. thers a slingshot thats made by nerf if you're still interested in giving slingshots a try. good luck to you in your quest for the ultimate fail safe hobby.


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## Dayhiker (Mar 13, 2010)

footloose said:


> You may think that Dayhiker. What's silly about design integrity?


Well, there is "design integrity" and there is falderal that calls itself design integrity. You're writing in the falderal section, sir. And in case you don't know it already, steel fails sometimes too. I have had three knives made by reputable manufacturers fail by unexpectedly snapping. One was a paring knife made by Chicago Cutlery that simply snapped when I dropped it on my kitchen floor. Another was a Dexter boning knife which snapped while I was cutting some fluffy fiberglass blanket. Another was a machete that snapped while I was chopping through some fairly soft weedage.

Now since this is a hobby where many, if not most of us like to make our own products, your suggestions would take away at least half the fun, for who among us have the ability to properly inspect each steel slingshot before shooting it to make sure it isn't going to snap? Let alone the fact that many of us have neither the the tools nor the desire to work with metals.

By the way, never mind the steel wheels on your BMW -- why don't you just go ahead and buy a tank. It would be a LOT safer.


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## Charles (Aug 26, 2010)

I have several metal framed slingshots, but I do not carry them ... seldom shoot them. They are much heavier than I like in my pocket, and I do not like the feel of them in my hand.

Fiberglass and similar materials have replaced a LOT of metal components on automobiles for various reasons ... weight, corrosion resistance, vibrational damping, heat and acoustic insulation, etc. Metals are good for some applications, but there are many considerations besides strength to consider.

We seldom design products for the WORST case scenario. I do not want a steel stock on my shotguns or hunting rifles. Sure, if you fall down a lot and bang your gun a lot on rocks in the process, you can eventually break a wooden stock. But I do not want to lug around a steel stocked shotgun, nor rest my cheek on one.

As for a good hardwood natural fork withstanding fork hits ... it will take a heck of a lot more than one fork hit to do any significant structural damage. Again, I urge you to try my suggested experiment. Hang up a well cured 3/4 inch hardwood branch and start taking shots at it with your slingshot. You will find that it takes a LOT of hits to do any significant structural damage. A natural fork will shrug off not only ONE fork hit, as you suggest .... it will shrug off many.

Once again I will say that marketing products based on fear is a very poor strategy. If one feels there is really that much danger, then perhaps one should not even be in the business, much less shooting for pleasure.

Cheers ..... Charles


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## Dayhiker (Mar 13, 2010)

Charles said:


> Once again I will say that marketing products based on fear is a very poor strategy. If one feels there is really that much danger, then perhaps one should not even be in the business, much less shooting for pleasure.
> 
> Cheers ..... Charles


 :headbang: Right on, Charles. I don't know if Mr. Footloose is marketing anything, but I am quite sure that slingshooting isn't the sport or hobby for him.


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## myusername (Oct 5, 2013)

trololololololololol


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## footloose (Dec 17, 2012)

parnell said:


> Nothing is silly about design integrity. Safety is very important and has been thought out and tested quite extensively by many experienced sling shooters who have promoted and developed the sport.
> 
> What is silly is that you appear to be trying to promote your product...as stated above, through fear.


Hi parnell,

Testing *has* been thought out by* many* (*and most)* experienced sling shooters, yet there are suppliers out there who sell defective products made from inadequate materials. I have had one. There are no regulations or guidelines as to design or production of slings (yet) - I throw out some and suddenly I am a pariah. Why is this so controversial a topic? Is this the only industry in the world where the unscrupulous will sell *rap? The thing you should be afraid of is the supression of discussions like this, the embace of allcomers and dodgy products. That will lead to the arms of the regulators who would love to see us off the map.

I get that I am perceived to be promoting my product, but understand this. I am otherwise seriouly employed in other stuff and couldn't possibly produce more than 6 pieces a month if I tried. Not exactly an empire is it?

What I promote is the best materials for the job and if you think that I am coining it in form this blog, you seriously over-estimate its impact!

Footloose


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## footloose (Dec 17, 2012)

Hi Dayhiker,

Knives and blades of steel are subject to temper, and done badly, will be brittle. The core of a good blade will be of a different temper to the cutting edge. If yours broke through dropping it on the kitchen floor, change your supplier, or don't drop it.

You are talking of a completely different aplication which is irrelevant to this thread.

Footloose


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## footloose (Dec 17, 2012)

Charles said:


> I have several metal framed slingshots, but I do not carry them ... seldom shoot them. They are much heavier than I like in my pocket, and I do not like the feel of them in my hand.
> 
> Fiberglass and similar materials have replaced a LOT of metal components on automobiles for various reasons ... weight, corrosion resistance, vibrational damping, heat and acoustic insulation, etc. Metals are good for some applications, but there are many considerations besides strength to consider.
> 
> ...


Hi Charles,

*'We seldom design products for the WORST case scenario' * (read: we sometimes do).

*Thank you, my point entirely.*

You clearly think that my point in this thread is a marketing ploy. You delude yourself, and others. Footloose production is already stretched and has no plans for expansion.

*When joining this forum I thought that it was to further knowledge through discussion. Sadly, I find that rather than have a mature debate, I encounter a disappointing, small minded defensiveness of the cowboy fringe which will inevitably usher in the regulaters. It seems that anything remotely critical is stomped on, so saying anything is pointless.*

*Not all of what is out there is good.* But you seem determined to defend it.

Meanwhile, I will continue to be in the industry and shoot for pleasure, but seek the company of the more open minded.

Thank you and goodnight SlingshotForum


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## flipgun (Nov 14, 2012)

'Bout Time.


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## Lacumo (Aug 18, 2013)

If this is a final farewell, I applaud your decision and hope you stick with that decision. Do keep your word and don't let us down.


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## KITROBASKIN (May 20, 2013)

No doubt this subject matter can be touchy. And this IS the internet. Let's keep discussion informative, and let people speak their minds. Disagreements are necessary and some will speak with more...expression. How does this thread look to a newcomer so far? Personally, I don't know who footloose is but I hope he does not leave in this way.

And no posting ponies.


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## KITROBASKIN (May 20, 2013)

Flipgun, I have always respected your opinion. Can you elaborate why he should leave this way?


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## Lacumo (Aug 18, 2013)

Just a personal opinion, but&#8230; I think speaking expressively is fine but being arrogant, obnoxious, offensive, condescending, imperious, disrespectful and contemptuous toward others as an ordinary style of self-expression isn't fine. I don't view the attributes in that latter group as acceptable styles of self-expression simply because they're part of somebody's style of self-expression.


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## KITROBASKIN (May 20, 2013)

Thanks Lacumo. Just read the footloose website (mostly). Found this:

Upon purchase and/or use, you agree that footloosecatapults.com and its owners and its employees will not be held responsible or liable for any consequential,direct or indirect or special loss, injury, accidents or damage to any person,persons or property, howsoever caused, by the catapults, bands, ammunition or any other items that we produce, promote, and/or sell. In all cases, the user assumes full responsibility and all risk associated with the use of our products.


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## flipgun (Nov 14, 2012)

KITROBASKIN said:


> Flipgun, I have always respected your opinion. Can you elaborate why he should leave this way?


In my opinion he was not encouraging a discussion as much as stating his opinion without any interest in considering the point of view of dissenting opinions. Every coin has 2 sides. If one is trying to defend a point then one must give credence to the possibility that there is room for error in their presentation and be willing to accept that others are unconvinced of the validity of their arguments. We have, in this situation, the conclusions of one person-V-the observations of a community. When they argued in concise and logical fashions he said, (In essence) "Well! Fine!" and left in a virtual huff. So my conclusion must be, "Don't let the door hit on the butt on your way out."


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## Charles (Aug 26, 2010)

flipgun said:


> KITROBASKIN said:
> 
> 
> > Flipgun, I have always respected your opinion. Can you elaborate why he should leave this way?
> ...


 :yeahthat:

He was looking for agreement, not a discussion.

Cheers ..... Charles


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## Jaximus (Jun 1, 2013)

Man, who doesn't like wood? Wood is awesome. My entire house is made of it. The ships that brought the first settlers to America were made almost entirely from wood. The wheels of the wagons that tamed the West were made mostly from wood. The handle of my hammer is wood. The handle of my ax is wood. Wood is inexpensive, readily available, light weight, easy to work with, comes in a million different varieties, is versatile in its applications and more than tough enough in the hands of a competent designer. In other words, my friends, wood... is good.

Why the assault on wood? What has wood ever done to you? I would be more afraid of picking up one of the cheap alloy frames than picking up a cheap wood frame. Should we make space shuttles out of it? Probably not. Slingshots, though? Wood is more than up to the challenge.


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## myusername (Oct 5, 2013)

Jaximus said:


> Man, who doesn't like wood? Wood is awesome. My entire house is made of it. The ships that brought the first settlers to America were made almost entirely from wood. The wheels of the wagons that tamed the West were made mostly from wood. The handle of my hammer is wood. The handle of my ax is wood. Wood is inexpensive, readily available, light weight, easy to work with, comes in a million different varieties, is versatile in its applications and more than tough enough in the hands of a competent designer. In other words, my friends, wood... is good.
> 
> Why the assault on wood? What has wood ever done to you? I would be more afraid of picking up one of the cheap alloy frames than picking up a cheap wood frame. Should we make space shuttles out of it? Probably not. Slingshots, though? Wood is more than up to the challenge.


me. never liked the look or feel of wood. but it is very useful. strong and cheap.


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## Dayhiker (Mar 13, 2010)

Alright, this isn't a thread about "design integrity", it concerns a field of engineering design known as "strength of materials", i.e., "you don't need a sledge hammer to swat a mosquito," Mr. Footloose. People study strength-of-materials charts and data in order to find out what is the best and most economical material to use for the job. I suggest you use your design expertise to study this subject as it pertains to slingshots lest you make a fool of yourself.

BTW, I think my reference to steel in knives was more relavent to this thread than you understand. Are you saying a brittle, improperly tempered steel will break if used to make a knife, but won't break if used as a slingshot? If that's what you think, there have been instances of failure reported here on the forum that will prove you wrong.


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## Aussie Allan In Thailand (Jan 28, 2013)

Nice to see that type of attitude, only believing himself to ever be correct, go.

Good riddence is my opinion.

Lord knows that I have strong opinions about several issues.
But at least I acknowledge my values work for me; and everyone else is entitled to their own, which work for them.

Cheers Allan


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