[jwkricho]

So i had nothing to do at work today so i decided to fabricate a recovery hitch to suit the 40mm receiver. I had access to scrap metal and found some heavy duty 40mm box tube. 12mm plate would be more than enough for a 1 tonne lug but i preferred to spread the load on the shackle pin so i butted 2 lugs together and fully welded around the seam to double the thickness of the lug. I feel comfortable in gentle recovery such as tow or winch point but im not too sure about snatching even though i dont think i would need a proper snatch as im not sure how the hayman reese assembly would handle it. Let me know what you guys think.

[joel]

nice work.

[Sco-tie]

I don't doubt it would work but it sticks out soo far that it ruins your departure angle and will hit on anything. I'm not sure if your time and the output is better than what you can just buy with way less over hang and is actually rated. But for free it works.

[~_~]

Hi Scott,

Can you pleaes point me in the direction of where you can buy the machined 40mm reciever hiches?

Pete

[Gwagensteve]

No. This needs to go back into the scrap bin. When you are designing recovery equipment, you need to think super conservative.

Sorry, but there's too much wrong there.

Firstly, nothing you can attach to the tow bar is safer than just putting the strap through the pin through the receiver.

You're relying on a weld to take all the recovery load. There's no need to do that, and you'll be nervous about it forever. If the weld failed, whoever is on the receiving end of that lump is going to be in a world of hurt.

Yes to too much leverage. Both on the towbar and your own parts.

Bow shackles are for recovery. D shackles are not appropriate for vehicle recovery. (Is that shackle even rated?)

From what I can see, it looks like you could have just drilled a hole though the bar stock and put the shackle through that? Much safer and more compact.

[Jezza86]

great for reversing into radiators at the shoping centre!

[joel]

Gwagensteve wrote:

No. This needs to go back into the scrap bin. When you are designing recovery equipment, you need to think super conservative.

Sorry, but there's too much wrong there.

Firstly, nothing you can attach to the tow bar is safer than just putting the strap through the pin through the receiver.

You're relying on a weld to take all the recovery load. There's no need to do that, and you'll be nervous about it forever. If the weld failed, whoever is on the receiving end of that lump is going to be in a world of hurt.

Yes to too much leverage. Both on the towbar and your own parts.

Bow shackles are for recovery. D shackles are not appropriate for vehicle recovery. (Is that shackle even rated?)

From what I can see, it looks like you could have just drilled a hole though the bar stock and put the shackle through that? Much safer and more compact.

nearly impossible to get a snatchy in that little receiver steve, its really small, and than add mud and other crap your usually in when you need a recovery, just makes it all the harder.

the stock haymen receiver is welded...... i realise that i isnt made for shock loading of a recovery, but still...

i reckon this will be fine if used conservativley. and using a recovery strap as intended, an inertia strap. not a snatch.

ie, attaching a winch cable from a trailing vehicle and doing a slow winch.
a conservative use of a recovery strap, but from what ive seen, the correct use/knowledge of the use of a recovery strap is few and far between.


also on the approach angle, disregard i reckon, most dont leave the stock receiver in there when wheeling, so why leave that in there? just pop it in and out as you need to be recovered.


agree on the shackle, but better than a tow ball.

[Matthew]

Gwagensteve wrote:

From what I can see, it looks like you could have just drilled a hole though the bar stock and put the shackle through that? Much safer and more compact.

This

[joel]

Matthew wrote:

Gwagensteve wrote:

From what I can see, it looks like you could have just drilled a hole though the bar stock and put the shackle through that? Much safer and more compact.

This

missed that bit, also a good idea.

[dano_mung]

Matthew wrote:

Gwagensteve wrote:

From what I can see, it looks like you could have just drilled a hole though the bar stock and put the shackle through that? Much safer and more compact.

This

He used box tube not square bar stock.

I think you're all being a little harsh and missed one key detail in that it is for a 40mm HR receiver not the standard 50mm.
I agree that the best way is with no receiver, but 40mm is smaller than most strap eyes.

For OP, perhaps keep an eye out for some 40mm bar stock and drill out a hole to suit a rated bow shackle.

[jimny_timmy]

joel wrote:

Gwagensteve wrote:

No. This needs to go back into the scrap bin. When you are designing recovery equipment, you need to think super conservative.

Sorry, but there's too much wrong there.

Firstly, nothing you can attach to the tow bar is safer than just putting the strap through the pin through the receiver.

You're relying on a weld to take all the recovery load. There's no need to do that, and you'll be nervous about it forever. If the weld failed, whoever is on the receiving end of that lump is going to be in a world of hurt.

Yes to too much leverage. Both on the towbar and your own parts.

Bow shackles are for recovery. D shackles are not appropriate for vehicle recovery. (Is that shackle even rated?)

From what I can see, it looks like you could have just drilled a hole though the bar stock and put the shackle through that? Much safer and more compact.

nearly impossible to get a snatchy in that little receiver steve, its really small, and than add mud and other crap your usually in when you need a recovery, just makes it all the harder.

It fits quite easily...

[Jezza86]

jimny_timmy wrote:

joel wrote:

Gwagensteve wrote:

No. This needs to go back into the scrap bin. When you are designing recovery equipment, you need to think super conservative.

Sorry, but there's too much wrong there.

Firstly, nothing you can attach to the tow bar is safer than just putting the strap through the pin through the receiver.

You're relying on a weld to take all the recovery load. There's no need to do that, and you'll be nervous about it forever. If the weld failed, whoever is on the receiving end of that lump is going to be in a world of hurt.

Yes to too much leverage. Both on the towbar and your own parts.

Bow shackles are for recovery. D shackles are not appropriate for vehicle recovery. (Is that shackle even rated?)

From what I can see, it looks like you could have just drilled a hole though the bar stock and put the shackle through that? Much safer and more compact.

nearly impossible to get a snatchy in that little receiver steve, its really small, and than add mud and other crap your usually in when you need a recovery, just makes it all the harder.

It fits quite easily...

the words wernt necicary, the pic told 1000.
this as a recovery device "that you have to go easy on" is a good way to kill a sierra driver.

[Jezza86]

jimny_timmy wrote:

joel wrote:

Gwagensteve wrote:

No. This needs to go back into the scrap bin. When you are designing recovery equipment, you need to think super conservative.

Sorry, but there's too much wrong there.

Firstly, nothing you can attach to the tow bar is safer than just putting the strap through the pin through the receiver.

You're relying on a weld to take all the recovery load. There's no need to do that, and you'll be nervous about it forever. If the weld failed, whoever is on the receiving end of that lump is going to be in a world of hurt.

Yes to too much leverage. Both on the towbar and your own parts.

Bow shackles are for recovery. D shackles are not appropriate for vehicle recovery. (Is that shackle even rated?)

From what I can see, it looks like you could have just drilled a hole though the bar stock and put the shackle through that? Much safer and more compact.

nearly impossible to get a snatchy in that little receiver steve, its really small, and than add mud and other crap your usually in when you need a recovery, just makes it all the harder.

It fits quite easily...

upgrade the receiver to something standard? more cost i know, but handy if you get caught out and have to tow ya mates boat home...

[Sco-tie]

~_~ wrote:

Hi Scott,

Can you pleaes point me in the direction of where you can buy the machined 40mm reciever hiches?

Pete

Sorry I missed the 40mm part. Doesn't seem they make ones for that size yet. Theres a good point to use the pin and if you are using the correct rating recovery gear it should be easier to fit into the hole.

[jimny_timmy]

Jezza86 wrote:

jimny_timmy wrote:

joel wrote:

Gwagensteve wrote:

No. This needs to go back into the scrap bin. When you are designing recovery equipment, you need to think super conservative.

Sorry, but there's too much wrong there.

Firstly, nothing you can attach to the tow bar is safer than just putting the strap through the pin through the receiver.

You're relying on a weld to take all the recovery load. There's no need to do that, and you'll be nervous about it forever. If the weld failed, whoever is on the receiving end of that lump is going to be in a world of hurt.

Yes to too much leverage. Both on the towbar and your own parts.

Bow shackles are for recovery. D shackles are not appropriate for vehicle recovery. (Is that shackle even rated?)

From what I can see, it looks like you could have just drilled a hole though the bar stock and put the shackle through that? Much safer and more compact.

nearly impossible to get a snatchy in that little receiver steve, its really small, and than add mud and other crap your usually in when you need a recovery, just makes it all the harder.

It fits quite easily...

the words wernt necicary, the pic told 1000.
this as a recovery device "that you have to go easy on" is a good way to kill a sierra driver.

Huh?

[Jezza86]

recovery device that you have to be sympathetic too("I feel comfortable in gentle recovery such as tow or winch point but im not too sure about snatching") sounds like a death trap. someone will hit the gass trying to get you out and die
not saying you will get bogged, and need a recovery so harsh, but im all about 6sigma risk management and this looks like something ive seen kill a bloke before

[Jezza86]

unlikely scenario with a critical outcome. sorry to go all riotinto

[jimny_timmy]

I'm a little confused as to what you mean... No recovery with a snatch strap should be performed at great speed. The strap being inside the hitch and held in with the pin is the safest way possible to do this IMO. The force is centred and evenly distributed throughout the whole chassis. Absolutely no different to the hitches sold for the 50mm receivers, just a couple of kgs lighter.

I'm assuming you think that's attached to the towball?

[Jezza86]

jimny_timmy wrote:

I'm a little confused as to what you mean... No recovery with a snatch strap should be performed at great speed. The strap being inside the hitch and held in with the pin is the safest way possible to do this IMO. The force is centred and evenly distributed throughout the whole chassis. Absolutely no different to the hitches sold for the 50mm receivers, just a couple of kgs lighter.

I'm assuming you think that's attached to the towball?

It fits quite easily, Is yours a 40 or 50mm reciver tim.
I was thinking bout the potencial hunk of flying dshackle attached to flying metal.
Your pic is 1000 words on how to recover with minimal risk. Best practice.not attacking you
If you have a 40mm reciver and can fit a strap in it then that is s very good and that strap should be the standard for 40mm recivers
If yours is 50 mm and theres nothing to fit a 40 mm reciver on the market so you hav to mak or improvise a soloutun such as the origional post then prehaps a 40mm reciver isnt good enough in the maximum reasonable scenario even for a light car. Mabie upgrade to a 50mm might afford additional flexability and recovrrability at lower risk.

[joel]

hah, i myust have the wrong snatchy, as the bastard is heaps wider than yours.
what is that one? an ARB one?

if it fits in on the original pin that easy.... i retract most of my previous statements.

[Sco-tie]

As you only run a light weight jimny you can get the lighter snatch traps around 5000kg even then its over kill. But being so light makes them way cheaper, even bunnings stocks light weight snatches. Havent tried them yet but they are rated so for $30 it's worth a shot.

[jwkricho]

Original Poster here was just asking for an opinion hear but to my understanding 1 inch of good weld can take 1 ton of vertical hanging for force from a decent fillet you would think that that the hundred mil of horizontal weld would be able to withstand the kinetic energy unleashed within the snatch strap. I was thinking about welding a tube through the bar to spread the load on the receiver pin but that still wouldn't reduce the shear forces on the bolts. If could afford it i would have it load tested to see what it could withstand but to my understanding it would be able to take more shock load then the tow bar hence why i wouldnt snatch off it unless it was load rated to at least a safety factor of 5. but im 100% confident that it would suffice for a gentle recovery

[got_bar_work]

I got a proper 50mm one and took 5mm off each side in the mill
Other option is to get a hook, some heavy wall 40x40 ,2 longer 12mm bolts , some plates to make up as spacers and bolt the hook in the end of the tube.
No need for a shackle then

[SierraDan]

If you cut 100mm off that put a new hole in it and use a rated shackle.

Its gotta be better than a lot of peoples recovery points

[Gwagensteve]

jwkricho wrote:

Original Poster here was just asking for an opinion hear but to my understanding 1 inch of good weld can take 1 ton of vertical hanging for force from a decent fillet you would think that that the hundred mil of horizontal weld would be able to withstand the kinetic energy unleashed within the snatch strap. I was thinking about welding a tube through the bar to spread the load on the receiver pin but that still wouldn't reduce the shear forces on the bolts. If could afford it i would have it load tested to see what it could withstand but to my understanding it would be able to take more shock load then the tow bar hence why i wouldnt snatch off it unless it was load rated to at least a safety factor of 5. but im 100% confident that it would suffice for a gentle recovery

You're correct, the rough guideline is 1" of weld = 1 tonne. However, as you point out, that's not a dynamic load, and it's not taking into account leverage.

Quite a light side load (in comparison its ultimate yield) on that bracket would result in it bending at the transition from the flat bar to the square bar. That's going to apply some pretty heavy loads to the vertical section of the weld from the flat to the box.

Also, the distance from the shackle to the existing receiver is adding massive leverage to the tow bar in the event of a side loaded recovery.

In the case of receiver hitches, the simplest solution is the best - with a strap poked into the receiver hole, the strap can fail (no big deal) the pin can fail ( awkward, but not a big safety issue) or the whole tow bar could get pulled off the car, which is nearly impossible. In fact, if you were stuck that badly and hooked to something with that much pull, you'd be as likely to rip the axles out from under the car than pull the tow bar off - the axles are held on with less bolts.

However, with that part, if it fails, theres going to be a big heavy chunk of metal attached to a big heavy shackle flying through the air.

Sure, you could get your bracket tested. I'm sure it will withstand plenty of force in a tensile machine. What you can't anticipate is the effect of the leverage your part is putting into the stock tow bar, especially under a side load.

Good on you for having a crack, but the #1 rule of a recovery point is it needs to be conservatively designed, over engineered and simple. In the case of your design, it didn't need a weld at all, so you're adding complexity, risk, and variables by adding a weld where it wasn't necessary.

Drilling a hole in the 40mm SHS as close to the end of the receiver as possible to accept a rated bow shackle would have been all that was required if you needed a recovery point for use with a winch hook or similar. Anything more than that is adding risk.

Steve.

[jwkricho]

good point steve the most common sense comments. Ive overlooked the fact of a side load although ive never intended to side load and would prefer to use a pulley system to keep the pulling force central to the bar I honestly think that lug thickness and the amount of weld would withstand my safety factor of 5x weight of the static load intended to be pulled. but i had overlooked the amount of force placed on the hitch pin and tow bar bolts which would be amplified with the leverage of the centre point of the shock and the dynamic kinetic energy of a full snatch

[Gwagensteve]

Snatch recoveries are often carried out at an angle. Not a huge angle, but an angle nonetheless.

With respect, this is why it's more complex to design recovery points than people imagine. The more you know about types of recovery and what goes wrong, the less you want to make a recovery point. (well, especially one that requires welding stuff to stuff)

It's also kind of ironic that the bigger and crazier the car, the less critical recovery points are. A driver of limited experience in a standard, or close to standard car tends to get stuck much harder than a heavily modified car.

Steve.

[jwkricho]

fair point i would say should of kept it simple. It is too much of a liability of damaging someone elses vehicle or killing someone. however unlikely.

[joeblow]

Gwagensteve wrote:

It's also kind of ironic that the bigger and crazier the car, the less critical recovery points are. A driver of limited experience in a standard, or close to standard car tends to get stuck much harder than a heavily modified car.

Steve.

Not ironic at all, bullshit I call. I've been sitting on replying to this for some weeks as it has me scratching my head.

That statement pretty much goes against every recovery I have done for the past 20 odd years.

Regardless of the driver a stock or close to stock vehicle will not get stuck as much as a heavily modified vehicle.

A novice driver in a stock vehicle will get stuck, no brainer. I will be easy to recover. A novice driver in a heavily modified vehicle will get it into big trouble.

A stock Sierra, for example, will usually come to a halt where it is easy to recover. For example it will bottom out while the ruts are still shallow. Not only that but due to the smaller size tyres, light weight and shallow ruts a recovery will be easier.

A heavily modified vehicle, with larger tyres and lockers, will get stuck in a much more difficult spot and or difficult terain. Not only that but a heavily modified vehicle is, well, heavy usually. If it has 33's or above, and stuck in ruts, they will be quite deep ruts. There will be a lot more resistance getting a modified car out than a stocker.


And to the OP, I've seen far worse.

[Big-bear]

joeblow wrote:

Gwagensteve wrote:

And to the OP, I've seen far worse.

Me to. It's a nice looking weld but hmmm…still makes me a little nervous