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  1. #1
    V&J T4's Avatar Now you're learning (Copper)
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    Unwin rail mounting

    I'm looking at using low profile Unwin rails in the back and I'll sort my ply flooring at the same time.
    As the van floor isn't flat, what's the best way of mounting the rails? Would it be best to have some steel plates that span the ridges in the floor to give a flat surface to lay the rails on?

    Thanks
    James

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  2. #2
    caravellvis's Avatar Maybe you actually know something (Bronze)
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    Lay 'em on the ply? Router some grooves in the ply?

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    V&J T4's Avatar Now you're learning (Copper)
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    Not keen on having the rails on the ply... tightening the bolts to an acceptable torque would be difficult if you add a compressible material into the mix, so should the worst happen, the shear stress through the bolts could have them snapping.

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    Activ8's Avatar Moderator
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    What does Unwin recommend for fixing that particular rail? Must be a common question?

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    V&J T4's Avatar Now you're learning (Copper)
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    From their PDF, the low profile rail needs to be mounted directly to the vehicle floor, the ply flooring sits under the rail edges.
    Interestingly though, the surface mount rail can be laid on top of the ply, but I can't see how you can get an even and accurate torque (11nm iirc) with a material that can be compressed under load - I've had a seat break loose because aluminium box was used to raise the seat. In the impact (stock car racing), the aluminium box compressed so the torque on the bolts was reduced, the seat could then move a bit and the bolts sheared. Not fun!

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    Activ8's Avatar Moderator
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    Are there any "clues" in their floor kits? What's the minimum length of rail as it has a M10 (?) fixing every 10cm(?) - assume it's to the nearest 10cm or fixing. Is the rail for a R&R bed? Some of the R&R bed builders offer it as an option so could be worth a chat about their specs??

  7. #7
    V&J T4's Avatar Now you're learning (Copper)
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    It's an M8 every 10.16cm, the minimum rail length would be around 11-12cm as each rail needs a minimum of two fixings.

    I finally got hold of Unwin who were really helpful once I got through to the right person - my first attempt at contacting them last week was less than successful lol.
    They have said it is safe to mount the rail on to ply and bolt through that to the vehicle floor/chassis, provided all the fixings are used at the correct spacing.

    I'm still not sure personally, but if the manufacturer says it's ok, then I'll go with that.


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    Activ8 (5th February 2019)

  9. #8
    888_special's Avatar You obviously just chat rubbish (Silver)
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    Quote Originally Posted by V&J T4 View Post
    It's an M8 every 10.16cm, the minimum rail length would be around 11-12cm as each rail needs a minimum of two fixings.

    I finally got hold of Unwin who were really helpful once I got through to the right person - my first attempt at contacting them last week was less than successful lol.
    They have said it is safe to mount the rail on to ply and bolt through that to the vehicle floor/chassis, provided all the fixings are used at the correct spacing.

    I'm still not sure personally, but if the manufacturer says it's ok, then I'll go with that.


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    I ripped some out of my van when I got it and that's how they were installed in there. Except they hadn't used large enough spreader plates under the van just some big washers!

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    V&J T4 (5th February 2019)

  11. #9
    V&J T4's Avatar Now you're learning (Copper)
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    Unwin spec 30mm washers for the fixings. The spreader plates are used for angled flooring where washers can't lay flat. I expect I'll need a few of those lol

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  12. #10
    Lubee's Avatar Privileged
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    Our rails are in the floor then we cut out a gap the length of the rails and a bit narrower in the ply floor so it fits under the lip of the rails. If you get what I mean.
    Up there for thinking, down there for dancing.

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