Making sills/sliders

[Teflon]

Honey needs new sills, as you can see from this lot:-

Now, contemplating the options..... scrapping the car NOT being one of them!

My local friendly fabricator chappy, Dave, reckoned on folding complete new sills from sheet, butting them in and lap welding them into place, with some plate similarly formed around the bottom of the door pillars and a few other places....

But..... peering at stuff round here and elsewhere, I was pondering something more like THIS:-

(Which is on a Disco,not a rangie, but either way......) Until I realised that THAT is NOT the sill, but a replacement for the plastic sill cover..... which made me wonder a little ad to how it was mounted, and how useful it would be.....

But I came accross THIS:-

Which would appear to be more along the lines I was thinking of....

So the difference is, that is a heavy duty sill with a tree-slider attached, but it sits 'inboard' of the body-line by about an inch, so the tree slider is running under the door bottoms. Except that is only an 'L' section with a tree slider attached, welded into the outside skin of the sill, not a complete replacement for the whole box. (which I pretty well need)

But it is pretty close to what I had sketched........ if you can fathom this:-

Top is profile of sills, with dimensions of how it came from Solihull. Basically a box of sheet steel, about 1/2mm thick, made from two pieces, seamed together along the bottom edge; measuring aproxomately 100mm deep by 60mm wide, excluding the seam; while it is 1420mm long, extending merely between the body-mounts.

OK, beneath is my concept sketch; A single 100mm x 60mm box section of 3mm (Isn't that as thick as a chassis rail?) thick 'tube' to be lap welded in place of the sill section, but extended the full length between the wheel-arches, so at the top 1700mm long, but chamfered off on the bottom so it has a 'ramp' for anything to slide on.

I would loose the 1/2 inch of seam beneath the sill.... but I think the extra thickness of steel would more than make up for it! (Thinnest section I can get in that size BTW)

Now, as drawn, the chamfer is only 30mm or so deep, becouse that is all that is protruding beneath the panel line.

Is it worth it, do you think?

Is it worth the 'extension' of the sills, given they are sitting inboard of the door-bottoms, not flush with them?

Next, the tree slider loop:-

As drawn, the hoop is welded on the bottom edge of the sill section; made from 28.5mm round by 1mm thick tube, the pipe JUST fits into the gap between the bottom of the doors and the bottom of the sills, coming under the doors and out, the outside edge of the hoop running 150mm from the cill, which is 90mm outboard of the door bottom, but roughtly parallel to the outmost edge of the body.

Is this too far? Further the tree-loop extends from the sill, more leverage any 'strike' has to bend it..... Would it be better to be just 100mm from sill, so JUST protruding beyond lower edge of door?

Or would it be better to bring it out, I dont know, another 20-30mm or so?

Or forget the hoop altogether...... wondering about a strike bending it up into the door bottoms?!?

Better to have or not have?

Bottom line is; priced up, its going to cost me just £70 more to make up something like this, than to simply 'remake' as original in sheet. (Tree loop accounts for about £30 of the added £70)

I reckon its worth the doing......... but having decided so, and got a concept sketch, before handing it over.... want some input before I 'firm it up' into a design.

Advice / comments pls

And as I haven't posted on here B4; I'm not a welder, nor a newbie..... out of practice mechanical engineer, having been in 'Project MisManagement for ten years, before being dissabled. So even though I have a welding certificate I was awarded many MANY years ago, If my technical drawing is as out of practice as above.... my welding aint going to be much better, even if I could hold the torch steady!... Hence it's going to be done by Dave, an 'old hand' at the art, whose had Rangies probably twenty years..... but I dont think ever taken one 'off-road'?!?! bizarely! To my scrappy sketches and instructions.... gawd help us!

Couple of thoughts; As far as I can tell, this SHOULD be OK for RTV under ARC regs...... which is an important consideration, as now dissabled out of bike-trials, thought I might give that a try..... Scrutineer at local club thought it would be 'OK', and cant find anything explicit to say its not in the 2009 Hand-book, but some-one may offer suggestion on the topic.....

[headhunter]

Hi Teflon

You have finally made it here, welcome

I don't have a clue about your sills, but I am sure someone will be along soon.

Your post might get greater visibility in the relevant vehicle forum.

John

[bishbosh]

The tech archive is your friend . Some ideas on sills here.

Comments on your sliders - 1mm wall is way too thin. They are subjected to concentrated loads and will suffer significant local damage to the wall of the tube if they are that thin. They will probably also bend easily between the supports.

Make sure the slider sticks out further than the most sticky out bit of the door. Sounds obvious, but when a tree stoves in your door skin without touching your slider you'll be sorry!!

There are different opinions on mounting rock / tree sliders - some bolt to the body, some to the chassis. My personal preference would be to bolt to the chassis. It is stronger and will carry the load if you use the sills to jack the car up rather than asking the rubber mounted body mounts to carry a load they were never designed for. I would avoid bolting to both as this will create a rigid connection betweeen chassis and body that doesn't exist currently. As I say, personal opinion.

[HoggyN]

I would avoid bolting to both as this will create a rigid connection betweeen chassis and body that doesn't exist currently.

I'm looking to do the same thing and I've been peering under RRC and Disco sills at recent shows and sortouts. I must admit I was a bit surprised to see so many sliders that were rigidly mounted to both the body and the outriggers. It wasn't just the DIY versions either.

[Teflon]

The tech archive is your friend . Some ideas on sills here.

Been through the tech archive; where most 'input' to my consept sketch has come from; and the two pics I used as examples.

first one, not being a replacement for the rotten sill behind, second one only patching the outer sill skin..... and cut around the door pillars, to my structural sensibilities, incorporating too many stress raisers for the full benefit of the added strength to be seen.

Using box, to replace the entire sill, inner and outer, to my mind, first removes the lower lip where the inner and outer sill are normally joined, and provides a pair of equal stregth members to share the load evenly, while the smooth bottom should allow anything that strikes it to slide smoothly without snagging.

Comments on your sliders - 1mm wall is way too thin. They are subjected to concentrated loads and will suffer significant local damage to the wall of the tube if they are that thin. They will probably also bend easily between the supports.

1mm wall thick tube for the tree-loop... I agree, thicker could have advantages, but in weighing up all the suggestions, came down from near two inch pipe and 2mm thick, first becouse of price, but also space, but lastly, the 'battering ram' principle.

I actually DONT want the things TOO strong, I'd rather they got bent and absorbed hefty impact, than put all that force into the strenghtened sill, and hence to the body-mounts......

I was thinking 'weak link' if the loops take THAT muich of a hit, and bend or break, first it gives me a cause to pause and think about what the heck I am doing, and second, not SO onerouse to chop them off with the angry grinder and weld on new hoops, than have to start trying to get in and repair ditorted body mounts and out-riggers........

Make sure the slider sticks out further than the most sticky out bit of the door. Sounds obvious, but when a tree stoves in your door skin without touching your slider you'll be sorry!!

Do take your point about extending them further out. Measurements I have suggested put the outer edge of the tree loop 'just' beyond the widest virticle of the panels above...... bu maybe 1/4" or so.

Hence question about tucking them into the door bottoms or extending them out an inch or so....... still undecided.

Notion goes something like firther out they extend, more 'advantage' any 'strike' will have on them; extending them out, beyond vehicle outline makes the vehicle wider, so can give you more reason to strike something in a 'narrow' gap.... Tucking them in, gives you more clerance and less leverage, but less protection...

Practically, where's the compromise to be made?

Tree's USUALL are wider at the bottom....... when you negotiate an obsticle like this, you are USUALLY on a lean, away from the verticle, so the body is tilting to your advantage...... so pro's and cons?........

Would you say, 1" beyond the outline profile, rather than my suggested 1/4" or would you go further, perhaps as far as the width of the wing mirror, maybe 4-5"?

That's roughly what side steps on my last two rangies gave me, which mounted lower I was forever using as 'sliders'! Was hoping that lifted and 'tucked' compared to steps, these tree-loops might get a bit less of a bashing!

My near-side step on the 'old' rangie is hanging about three inches low, the bracket now so mangled that it lifts right up and bears on the plastic sill covers, as soon as it strikes anything, while the tubes themselves are so 'dinged' I really sont see much future for them....

Original 'thought' was to pull them off and remake / strengthen the brackets, then to simply cut the rails out and weld them to the H/D box sill....... but.... I dont think it's worth it, looking at the state of them!

There are different opinions on mounting rock / tree sliders - some bolt to the body, some to the chassis. My personal preference would be to bolt to the chassis. It is stronger and will carry the load if you use the sills to jack the car up rather than asking the rubber mounted body mounts to carry a load they were never designed for. I would avoid bolting to both as this will create a rigid connection betweeen chassis and body that doesn't exist currently. As I say, personal opinion.

Yes! This was source of a lot of head-scratching. Side-steps were attached to out-riggers.......

Within the practical constraints, it would be useful for whatever takes a 'strike' to bear that load and spread it into the main structural member, the chassis.

Steps did that, and the 'weak link' was the bracket, then the out-rigger, BUT as soon as the bracket 'went' the step was bearing on the sill.......

Meanwhile, the bracketry, hanging beneath the sill, and at right angles to the direction of travel, meant that there was less clerance, so more likely to recieve a strike, AND for that strike to 'snag'.........

So, backing up in my thinking, notion was to 'add lightness and simplificate' as the old addage goes.

Using HD box for the sill seemed a good idea as it was a lot simpler than fabricating from sheet, if not 'adding lightness'. Actual guage, though was deturmined by what I can get section in, and that's the 'lightest' guage I can find for 60x100.

Using box, removed the lower seem between inner & ouiter sills, as mentioned, so seemed like a good idea to extend the section the full width between the arches, and chamfer the bottom edge to give as smooth a profile as possible to obsticles.

And the following notion was to add the tree-loop as a 'finishing touch', again, keeping things simple and as smooth and uncluttered as possible.

So the first 'objective' of the project was to simply cut out and replace a rotten section of steel.

Second objective was if possible to make that job as 'easy' as possible

Third objective, IF I'm doing works in that area, can I for any little extra effort, make any significant 'improvements'.....

So what I have come up with, is a 'heavy duty' sill, NOT a sill protector. As such, the thinking is, it's NOT a bit of 'under-body' protection, it IS the underbody.... but a bit re-inforced, so that it can survive without protection..... or at least survive MORE without protection.

In cold analysis of the debate between attaching protection to the sill or the chassis; conclusion I came to was, the 'best' way to do it was definitely to mount to the chassis, and only the chassis, as you suggest....

Looking at how I could do that, gavce rise to a LOt of ideas, and made me understanda bit better why a lot of the more curious mountings have been used.

The most 'elegant' solution I came up with, was to make a 'low-profile' body-sill. Rather than 4" deep, as standard, make it just 2" deep, but from doubled up 1" wide thick box, to substitute for the strength lost from halving the depth... but bearing in mind, that with protection the sill itself shouldn't have to be SO strong.

THEN, to make up 'propper' sill protection, using 3" as the main member, under the door bottoms, with a tree-loop off that.

Then, to cut the outriggers off, and remake in 4" box, for added strength to the chassis, but with a second box tube inside the section to take an extension telescoping inside it, that would be welded to the slider member on the outer edge and bolted through the out-rigger.......

Not EXACTLY but close to some of the examples I've found in archive on here and elsewhere.... some of them have actually added seperate outriggers to support the slider..........

Having contemplated THAT...... I realised I was departing seriousely from the original objectives; I was NOT designing something to replace the original rotten sill, NOT making life 'easier' for myself, and adding a huge amount of complexity to do something pretty much beyond what was intended........ basically, great idea but far beyond what I 'need'......

And having pondered that, I looked at the old side-steps again, and considered whether I'd get as much protection from either making those good and fitting them up around a 'plate' repaired sill, or buying new or better second hand ones to go round a plated sill...........

The answer to which was 'probably'..... but not as 'elegantly'.... and not as 'smoothly'...... so back to the mantra 'Add lightness and simplificate'....... given that I can seriousely re-inforce the sill and add a bit of protection to it for £70........ IS that a good idea...... which I decided it was........ so having made that decission, time to check the merit of it, and 'tweek' the details...... Hence the post.

Bottom line is, I'm NOT building an 'extreme' challenge vehicle here; its an 'every-day' all-round road car, used for ..... err..... I was going to say 'gentle' green-laning...... but I dont think that really 'fits' with the description of destruction wrought on my old side steps does it! OK...... used for 'fairly' seriouse green-laning, and future hope of contending 'club' RTV events.

It doesn't have a 'lift' kit...... and I have little intension of fitting one. I have rarely run out of suspension travel, and really dont want to upset the allround balence of the car and bring about a load of other 'problems' just for the sake of a couple of inches of break-out........ She runs on 205's..... which are my biggest limiting factor, and before I do anything major to her, those will go in favour of 235/85's to give me an extra 1 1/2" inch under the axles, and every where else........

So, she is pretty much stock, and the thinking is, OK, lets NOT get carried away here.... I dont WANT an 'extreme' challenge truck, I like what I've got..... it just grates every time I clonk something underneath..... so rather than try and stop it clonking...... which I'll never do...... I'll just find something bigger to clonk it with...... lets just make it a bit tougher so that when it clonks...... its not going to have such dire consequences...... mean-while the 'clonk' giving me a 'twitch' and hopefully making me back off a bit!

any of that make sense?

So, from advice..... idea seems 'sound' question remains over width of hoop.........