P38 winch bumper build

[landroversforever]

On 5/17/2023 at 1:52 PM, elbekko said:

You can see that here:

 

In that case it looks like it's enough to have the loops inline with the chassis. It also means that you've got the loading on each leg in double shear. 
 

Edited May 18, 2023 by landroversforever
To correct some shoddy wording!

[bishbosh]

Ohhh it's been a long time since we had an argument about thickness of plates for winches!😁

By the time you have made 3mm stiff enough to prevent any flex cracking your alloy winch housing you would be better off with 5 or 6mm.

Bent 20mm round bar angled as suggested to pick up on  both chassis leg plates is definitely the way forwards.

Talking of forwards, feet forwards will  be a more efficient use of material.

My only reservation about the design overall is you will not be able to see the winch drum which I think is a mistake.

 

[ped]

i'd use 8mm min for the winch to chassis and 5mm for the bumper ends
no point making it flimsy and yes it'll weigh a bit more but 3mm is tissue paper

[landroversforever]

6 minutes ago, ped said:

i'd use 8mm min for the winch to chassis and 5mm for the bumper ends
no point making it flimsy and yes it'll weigh a bit more but 3mm is tissue paper

It’s not though with the right design. I’d also rather I bent a bumper than the chassis. There’s no need for it to be that much of a boat anchor!

[ped]

to make 3mm as strong as 8mm you'll still bend the chassis so you may as well go the 8mm route imo  and not risk the mount bending when on max pull
if you weld stiffeners down the chassis leg you can distribute the forces better
 

[landroversforever]

22 minutes ago, ped said:

to make 3mm as strong as 8mm you'll still bend the chassis so you may as well go the 8mm route imo  and not risk the mount bending when on max pull
if you weld stiffeners down the chassis leg you can distribute the forces better
 

It's more of a hit at the ends which will bend a chassis rather than worrying about the winch cradle. 

[ped]

if its smacked heavily at a corner it will bend the chassis tbh either way
crumple zones are designed to save pedestrians not vehicle integrity

[elbekko]

3 hours ago, bishbosh said:

Ohhh it's been a long time since we had an argument about thickness of plates for winches!😁

By the time you have made 3mm stiff enough to prevent any flex cracking your alloy winch housing you would be better off with 5 or 6mm.

Bent 20mm round bar angled as suggested to pick up on  both chassis leg plates is definitely the way forwards.

Talking of forwards, feet forwards will  be a more efficient use of material.

My only reservation about the design overall is you will not be able to see the winch drum which I think is a mistake.

 

That's a good point, it would probably be wise to put another slot in it somewhere so I can see the drum.

[miketomcat]

11 hours ago, ped said:

i'd use 8mm min for the winch to chassis and 5mm for the bumper ends
no point making it flimsy and yes it'll weigh a bit more but 3mm is tissue paper

Whilst I think 3mm is to flimsy for the tray/mounts (fine for the wings), 8mm is way overkill. Remember it's only bolted to a 2.5mm thick chassis and land rover only rate their chassis for a 9500lb winch (series to defender).

Mike

[elbekko]

Yeah, 8mm seems massively overkill. And I can always add bracing later on if need be, but I doubt I'll need it.

[geoffbeaumont]

14 hours ago, ped said:

if its smacked heavily at a corner it will bend the chassis tbh either way
crumple zones are designed to save pedestrians not vehicle integrity

Crumple zones? On a P38...?

[ped]

fair enough each to their own but why spend all the effort making something not strong enough in the first place stronger when you can start with something that is already strong and will do the job without all the extra faffing about,unless you just like faffing for the sake of it

[Wytze]

12 minutes ago, ped said:

fair enough each to their own but why spend all the effort making something not strong enough in the first place stronger when you can start with something that is already strong and will do the job without all the extra faffing about,unless you just like faffing for the sake of it

I think that is just about what would you like..?  One lump or two.. kind of thing?      My bumper is all 5 mm, but it's heavy..     With a bit more thought, saving weight and still keep it strong is not bad.  

[daveturnbull]

The winch bumper was the cause of the demise of my previous land rover. Had the 'wings' been a thinner material, they would have distorted rather than twisting the chassis when one got hooked round the kerb stone.

[landroversforever]

23 minutes ago, ped said:

fair enough each to their own but why spend all the effort making something not strong enough in the first place stronger when you can start with something that is already strong and will do the job without all the extra faffing about,unless you just like faffing for the sake of it

Because too many people just bolt stuff on without a care for how much it weighs. I bet there's a few at, or close to being, their weight limits. 

If you've got the skill set or others to call on, then there is no reason not to make something with a better design that isn't just throwing more material thickness at it. 

[ped]

4 hours ago, daveturnbull said:

The winch bumper was the cause of the demise of my previous land rover. Had the 'wings' been a thinner material, they would have distorted rather than twisting the chassis when one got hooked round the kerb stone.

They're not supposed to run on there side though

Provided you walked away in one piece (which i hope you did) then that's the main thing

[ped]

 

My 

4 hours ago, landroversforever said:

Because too many people just bolt stuff on without a care for how much it weighs. I bet there's a few at, or close to being, their weight limits. 

If you've got the skill set or others to call on, then there is no reason not to make something with a better design that isn't just throwing more material thickness at it. 

I can see that in many landies i see going down the road

And in the same way you can strengthen thin plate thicker materials can be lightened or smaller sections of thicker plate can be used

My winch bumper on my work truck is a factory 6mm for a h14 same as supplied to utility landy except for the bumperettes they're are box section and as strong as the original but lighter

If i were to fab it from scratch i could inc to the main mountings for the winch to 8mm but then skeletonize much if it reducing weight but still keeping the strength

[elbekko]

7 hours ago, geoffbeaumont said:

Crumple zones? On a P38...?

It has crush mounts behind the stock bumper. That's about it.

1 hour ago, ped said:

If i were to fab it from scratch i could inc to the main mountings for the winch to 8mm but then skeletonize much if it reducing weight but still keeping the strength

I mostly wonder why the 8mm. Especially if there's barely any twist in the system when mounting the winch feet-forward. 5mm, especially in a U-channel, should be more than plenty strong.

Remember: as I have it now, it'll be a 5mm U, with 3mm plate welded top and bottom of the U. I don't think it'll move.

Hence my initial design brief: try to make it strong without just throwing heavy plate at it.

7 hours ago, ped said:

fair enough each to their own but why spend all the effort making something not strong enough in the first place stronger when you can start with something that is already strong and will do the job without all the extra faffing about,unless you just like faffing for the sake of it

In that line of thinking I could just do a Nige and make everything out of 10mm plate. I'd rather "faff about" and try to find an optimal design. This is not a winch challenge truck either, the goal is mainly self recovery and maybe some marshalling-type stuff.

I'll try and get some drawings sent out to get stuff cut out. Would be nice to get it in by Seven Sisters, but we'll see. That's not far away and I've got a lot to do...

[ped]

1 hour ago, elbekko said:

It has crush mounts behind the stock bumper. That's about it.

I mostly wonder why the 8mm. Especially if there's barely any twist in the system when mounting the winch feet-forward. 5mm, especially in a U-channel, should be more than plenty strong.

Remember: as I have it now, it'll be a 5mm U, with 3mm plate welded top and bottom of the U. I don't think it'll move.

Hence my initial design brief: try to make it strong without just throwing heavy plate at it.

In that line of thinking I could just do a Nige and make everything out of 10mm plate. I'd rather "faff about" and try to find an optimal design. This is not a winch challenge truck either, the goal is mainly self recovery and maybe some marshalling-type stuff.

I'll try and get some drawings sent out to get stuff cut out. Would be nice to get it in by Seven Sisters, but we'll see. That's not far away and I've got a lot to do...

10mm is a bit excessive lol
i often forget not all have access to 3phase welders mag drills that will cut 2.5" holes in heavy plate plasma cutters oxy torches
i spent my first 10 yrs of work as a welder /fabricator making anything from railings to portal frame buildings then at a company making tankers trailers and vehicle bodies
i could be accused of going belt and braces on some stuff

[Escape]

With regards to crumple zones, I can (unfortunately) confirm even the standard bumper on a P38 is strong enough to bend the front section of the chassis, if you hit something at the wrong angle.

IMHO, the bumper only needs to be strong enough to be able to rest it against a tree or rock without risking it bending back into the bodywork. Not to take the force of a proper impact. The standard bumper is a bit flimsy, 3mm should be fine, without adding lots of weight. The winch cradle on my previous P38 was mostly 3mm with 5 or 6mm reinforcements. I still have the remains, as I planned to recreate it for the current one. I should do some measuring, but the design Ben is doing is definitely an alternative to consider. And if we build 2, that would mean halve the R&D costs for each. 🙂

[elbekko]

Order is in with the local lasering guy. The 5mm bits will be S355, the 3mm bits S235. Cradle and skidplate bent by the lasering guy, the curved plate I'll attempt to do myself. €280 ex VAT, can't complain about that.

Now hope it fits

 

[Bowie69]

That's good value in this day.

[landroversforever]

That's not too bad at all!

[elbekko]

Indeed. He had some leftover 5mm S355 that he can cut it out of, that helps with the price I'm guessing.

[Ed Poore]

What was the final weight in the end? I know mild is just over the £1k/tonne here but if it's an offcut paid for by another job then it's just profit.