Strong weatherproof latch?

[ATL ZJ]

I have big plans for a steel storage box/cooler for the back of my buggy, and I'm trying to figure out what type of latch would work best to keep it's lid securely closed. Non-buggy guys- don't run away with your tails tucked- these could also apply to tire carriers..... My requirements are pretty simple:

1. Latch must be weatherproof (either stainless or ~zinc coated)
2. Latch must be strong enough to withstand a several hundred pounds of force against the lid of the box without springing open. (The box won't have that much weight in it, but I'd prefer to overbuild as it MUST stay closed in rollover situations.)

Here is what I've found so far...


"Latch-action toggle clamp"- 2000 pounds holding capacity. Latch receiver plate would be mounted to lid and latch handle would be mounted to front of box with the handle down. The negative here is that the lip on the front of the lid would have to be reinforced to be VERY strong.


This one is exactly the same, but adds a safety lock. Every time you close the latch, the safety lock engages and must be depressed for the latch to reopen. Same downside as above regarding the lid's lip, but also potentially inconvenient for ease of access. However, much better than a 50 lb ammo box impacting someone's skull.


This one has the same 2000 lb load rating, but would allow the handle to be mounted on top of the box lid (which would be far easier to attach and easier to access it seems). However, there is no safety lock.

What do you guys think? Which is the best combination of convenience and safety? How much force does 100lbs of tools, water bottles, and gear generate when it slams against the lid of a box 6-12" above?

[BigDaveZJ]

How much force does 100lbs of tools, water bottles, and gear generate when it slams against the lid of a box 6-12" above?

If you cushion that 6-12" probably a lot less than you think. Even with the just the Action Packers that I've been using in the Jeep ratchet strapped in place, the heaviest stuff goes on the bottom and then the top of the box is usually blankets, jackets, stuff like that. If you've got 6-12" of room in the box, sounds like plenty of room to me to stash some of the softer lighter stuff.

Depending on the size of the box too, I might be inclined to run 2 latches.

[JordanA]

150lbs of gear + say 2 meters/second squared would be about 30ish pounds of force, I think...

It changes quickly though... 200 lbs of gear, parts and tools accellerating at around 10 meters/second would generate about 200lbs of force. I mean, what is the max accelleration of a rollover anyway? It isn't like you're running the baja or something.

edit: I would agree with Dave and say why not add a second latch? Creating redundency in the system is only going to make it less likely to fly open in a roll over. I would go with #2 with the safety lock, x 2. It wouldn't be any more difficult to open with two latches, it'd just take what... 2 more seconds max?

[rstrucks]

This one has the same 2000 lb load rating, but would allow the handle to be mounted on top of the box lid (which would be far easier to attach and easier to access it seems). However, there is no safety lock.

What do you guys think? Which is the best combination of convenience and safety? How much force does 100lbs of tools, water bottles, and gear generate when it slams against the lid of a box 6-12" above?

The one pictured above is almost identical to the one I used on my tire carrier. I thought I would have issues with it popping open but it has yet to happen after about 5K miles. You just have to be careful about where the pivot point is in relation to the catch. If you get it right it self tensions and will stay shut. Its easy to use too.

In a couple of weeks you can check mine out in person. I might even have an extra latch assy kickin around.

[LouisianaZJ]

i would use a 2.0 impact factor on the static load, so 2.0x100lb = 200 lb force on the lid

[CurtP]

Would rubber T-handle draw latches be sufficient? Cheap, easy and available with nylon, zinc-plated or stainless strikes at McMaster. There's also a "work-load rated" version. Page 2927 and 2928 of their online catalog.

T-handle draw latch:


Work-load rated:


Fuck - they have a shit-ton of draw latches to pick from - looks like most of them are available in stainless steel too.

[ATL ZJ]

Thanks for the thoughts guys.

Gentle rollovers and even hard flops can create quite a shock on impact. In the past, something has come dislodged every time I've laid my rig over... hoping to change that streak with some hard-mounted storage. I wish there was a definite formula for determining how much force a rollover creates...?

Curt, those rubber doodads might work well for other things, but they look pretty chintzy and unsafe for an application like mine. I'm addicted to mcmaster so whatever latch I choose will come from them.

Dave, in all honesty, there will probably be less than 6" of empty space between my cargo and the lid. The box will be relatively short to prevent me from carrying more junk than I need to bring on the trail. Hopefully I can sqeeze by with a single heavy-duty latch.

Ryan, this box will come together over the next month, so I will definitely check yours out when we are at Windrock to see how it feels.

Keep the thoughts coming if you guys have anything to add.

[LouisianaZJ]

yes, you can calc. the actual force but you need to know how much you would be accelerating. Assuming you are not going faster than freefall 2.0 x static load and maybe throw a 2.0 safety factor ontop of that... should be OK. IMHO

is 2000 lbs on the latch the working load or the breaking load on the hinge?

[ATL ZJ]

As an extreme example, let's say I do a forward endo on level ground at 30mph. Can you calculate that? 2000 lb is the rating on the latch. Hinges are TBD, but they will be beefy as well.

...any suggestions on hinges?

[paulkeith]

Cam,

Have you thought about trying to mimic the latching action of a truck toolbox lid...or just buying a lockable truck box? My box uses a rotating T handle that's flush mounted to the side of the box, it spins a hook inside the box that grabs a loop fixed to the underside of the lid. Strong, weatherproof, ergonomic, lockable. I can take pictures of what I'm talking about if you think its worth looking into.

I've dug through mcmaster, can't find a way to build what my box uses.

Paul

as far as hinges, I'd go with mcmaster's piano hinges. 1/8" leaf, 3/8" pin 4' wide hinge looks to be about $25.

[CurtP]

Curt, those rubber doodads might work well for other things, but they look pretty chintzy and unsafe for an application like mine. I'm addicted to mcmaster so whatever latch I choose will come from them.

It was just a thought. I've seen quite a few of those rubber draw latches on farm equipment holding some heavy-assed shit together - they were all over the old IH combine, along with a few cast iron versions. I did see some versions that were all stainless, with no rubber draw on page 2929 at the very bottom.

Do you have a sketch of the design?

[ATL ZJ]

Paul, good call on the piano hinges. I guess those could be mounted on either the inside or outside of the box? Hard to tell from the diagram. I thought about using a production truck toolbox, but figured that narrowing it might be as much work as building what I really want from scratch.

Curt, as always, the sketch is in my head. Dimensions for the box will be somewhere around 24"x 24" x 12" tall. My basic plan is to replace my existing bowed rear cargo floor with something sturdier, and mount the box to it. The front part of the box (closest when you open it/ facing the rear of the rig) will be a cooler/tub (with draincock through the floor). It will seal to the lid of the box. The middle part of the box will be the largest compartment for tool and towstrap storage. I'll also section off part of the box nearest the hinges with a bolt in panel. Sometime in the future, I'll use that compartment as a speaker/marine amp enclosure since my rig no longer has any tunes. Sound logical?

[CurtP]

I've dug through mcmaster, can't find a way to build what my box uses.

I just did a search for "T latch" (without the quotes). Page 2925. Found a really cool cable operated dual latch setup on page 2926 (part number 3985A42). Pretty pricey though.

Curt, as always, the sketch is in my head. Dimensions for the box will be somewhere around 24"x 24" x 12" tall. My basic plan is to replace my existing bowed rear cargo floor with something sturdier, and mount the box to it. The front part of the box (closest when you open it/ facing the rear of the rig) will be a cooler/tub (with draincock through the floor). It will seal to the lid of the box. The middle part of the box will be the largest compartment for tool and towstrap storage. I'll also section off part of the box nearest the hinges with a bolt in panel. Sometime in the future, I'll use that compartment as a speaker/marine amp enclosure since my rig no longer has any tunes. Sound logical?

Sounds like a lot of stuff going on in a 2'x2'x1' box!

Thinking that it may be better off starting out with something pre-fabbed, I searched Northern Tool's website and came up with a few options. They're pretty pricey though - a 24"x18.75"x18" aluminum diamond plate box is $290. A 24"x18"x18" steel box with stainless door is $220. Interestingly enough, Northern carries box latches too, so you may want to take a look to see if they have anything that may work for you.

A Google search turned up a Dee Zee 24"x24"x12" diamond plate "ATV trailer toolbox" for $255. Looks like Delta also makes some steel boxes close to your dimensions as well.

A few poly boxes came up too, but I didn't look that hard at them because I figured you were looking for something metal.

One thing did kind of stand out for me though - the pictures of what you were looking at are external draw latches. The manufactured boxes I found all had internal latching/locking mechanisms which would take away a bit from the internal volume of the box, but does appear to make the boxes more secure when locked.

[paulkeith]

My basic plan is to replace my existing make-shift-rear-axle-bump-stop-that-bowed-when-the-front-end-fell-off-the-hi-lift rear cargo floor with something sturdier, and mount the box to it.

fixed.


This is how my toolbox hinge is set up.



I dont know if you were planning on using a lid with a lip on it though. I think it'd be a good idea as it'd help significantly with the weather-proof-ness.

I was thinking more along the lines of Curt in regards to the production boxes. Several of the 'traditional' truck box manufacturers also make plain old square ones. I bet you'd be flirting with the mid 200s after steel, latches, hinges, etc. You do lose the customization aspect though...

[ATL ZJ]

Yes the box will have a lip on it's lid. I like that hinge placement Paul. Probably will copy that.

OK, OK here is a sketch of the box. After all, pictures speak 1,008 words right?



I want the lid of the box to be level when the rig is on level ground, so the forward-facing side of the box will have to be taller than rear-facing one. It'll likely end up wider and longer than 24", but I want to keep it relatively narrow so I can transplant it into another chassis sometime in the future. The main downside I'm noticing with the square truck boxes is that most of them are front loading... super inconvenient in my application. I think I can crank this out for around $100, even with steel, a quality latch and hinge. And I enjoy this stuff so labor doesn't matter.

Questions, comments, concerns...?

[greengc4x4]

I like the idea of using two of the clamps with the saftey feature

[BigDaveZJ]

lol at the neighbor's fences and leaves.

If you weren't going to transplant it into another chassis in the future I personally would try to fill that whole area with the box, but like we discussed in some other threads wheeling style can play a big role in what you need for storage.

Are you going to plan for any insulation for the cooler part?

I'm really liking the idea so far.

[ATL ZJ]

Are you going to plan for any insulation for the cooler part?

Yes. Obviously I don't want to drink out of a bucket of rust, so I thought about coating the entire cooler partition with an underwater epoxy coating. These are supposedly the best type of coating/paint/sealant for constant immersion in water. By coating the inside walls of the box, I could fill the entire front space with beverage containers. However, there wouldn't be much insulation from the hot outside walls of the box in the summer sun, especially if I paint it black. On top of that, McMaster's epoxy coatings run $50/quart!

Here's the other issue... As the ice in the cooler melts, the cans/bottles will get wet (obviously). So it's likely that you'll drink some of the "cooler water" on the opening of your can/ bottle. Certain epoxy coatings can withstand immersion, but are not recommended for use in potable water. McMaster's aren't. Others meet an NSF 61 standard, which equates to approval for use in potable water, but these also are extremely expenive.

Now I'm thinking about doing something much simpler. I'll probably just recess a galvanized utility tub into sheetmetal, and mount it so its rim can seal on the underside of the box's lid. Cost: $22



Then around it, I'll use 25 feet of 3" wide, 1" thick fiberglass insulating pipe wrap. Cost: $6



For the lid's sealing surface (against the tub rim), I'd like to use something that offers thermal insulation and has sound-absorbing properties. Maybe some skinned acoustical foam insulation or something similar.

[paulkeith]

not super keen on the galvanized tub idea.

just brainstorming here, what about putting a production cooler inside that partition of the box, fixing the cooler itself in place, attaching the cooler lid to the lid of the storage box so that its located to seal the cooler when the storage box lid closes...? you could run the cooler drain out through the box to keep your drainability option. probably much better insulation with this idea. coleman has a 36qt 5 day unit for $50 with 26" x 14.75" x 14" exterior dims. could be made to work.

[ATL ZJ]

Ha I actually have that cooler and it fills quite a bit of my storage floor. Also the lid isn't removable on mine so I'm not sure if it could be mounted to the box lid.

Most importantly, 14" is too tall for my liking. The galvanized chest is only 7 1/4" tall. I was really hoping that the front part of the box could be 12" tall or less. Ideally, someone would make a hard cooler with a removable lid that is 24" wide and about 8" tall. The only production cooler I've seen that could potentially work is the Igloo Legend 12. I know I could fit one, if not two side-by-side.

You don't think the rim galvanized tub would seal well against cushy material? In addition to the rim acting as the seal, do you think a divider between the partitions could act as a secondary seal?

[paulkeith]

True that. I just think I'd pursue something plastic instead of steel. I just have a feeling that that galv tub will be a PITA. I'd be more inclined to buy a production cooler that has the footprint dimensions you want and chop the bastid up to get the height you want. I dunno...better insulation, more sealing options.

Your sealing theory(ies) work well with your proposed latch system as they'd provide a good bit of clamping force to compress seals.

edit: So, did a little reading. Looks like DIY boat guys make potable water tanks out of plywood coated in epoxy all the time. Looks like you can get a quart of the west systems epoxy they use plus hardener for $55. thoughts?

[FortCollinsZJ]

Why not have a box made of UHMW that would sit in the front portion of the box, it would be food safe, easy to clean, and would fit perfect, or even aluminum, TIG it together and not even worry about using sealant because the welds wouldn't leak. Just make it slightly smaller than the actuall storage box so you could wrap insulation around the cooler portion.

I drew this up to give you and idea of what I meant, also I thought that if you made the top fold open twice, it would be much easier to get into. See the two compared.

[hkszx2]

Why not have a box made of UHMW that would sit in the front portion of the box, it would be food safe, easy to clean, and would fit perfect, or even aluminum, TIG it together and not even worry about using sealant because the welds wouldn't leak. Just make it slightly smaller than the actuall storage box so you could wrap insulation around the cooler portion.

I drew this up to give you and idea of what I meant, also I thought that if you made the top fold open twice, it would be much easier to get into. See the two compared.

on the second one if you put the hinges in the middle and had it open up from either side would probably be easiest to get into ? so that way if you needed tools you could only open the tool side or vice versa

[LouisianaZJ]

As an extreme example, let's say I do a forward endo on level ground at 30mph. Can you calculate that? 2000 lb is the rating on the latch. Hinges are TBD, but they will be beefy as well.

...any suggestions on hinges?

I could, but dont feel like doing the calcs.

[ATL ZJ]

Why not have a box made of UHMW that would sit in the front portion of the box, it would be food safe, easy to clean, and would fit perfect, or even aluminum, TIG it together and not even worry about using sealant because the welds wouldn't leak. Just make it slightly smaller than the actuall storage box so you could wrap insulation around the cooler portion.

I drew this up to give you and idea of what I meant, also I thought that if you made the top fold open twice, it would be much easier to get into. See the two compared.

Wow thanks for illustrating so well. Where do you buy formed UHMW shapes? Is it not exorbitantly expensive? I bought a 4 foot long strip of 3" wide UHMW to machine 5-6 fairleads from and it was almost $40.

The aluminum is something I didn't consider but I don't have access to a TIG welder or any local friends with one. I don't see what's so wrong with the galvanized tub by comparison, haha. Maybe a little backwoods, but I like unique.

Don't you guys think that the folding lid would reduce sealing force near the middle hinge? For cost reasons, I'd prefer not to have a split "scissor" lid, because I'd have to use two latches.