Article - Original or Alloy? Written by: j-man

A Sand Rover roll cage is born!

Hi and welcome to a brief glimpse at what it takes to fabricate an alloy
roll cage for a vintage tamiya sand rover.

Before i start to fabricate anything i always wear the necessary safety goggles and respirator this is always good practise before doing anything with machines etc and also stops you looking an idiot in front of Nurse glady's emmanuel down at your local accident and emergency
(you have been warned)

The following pictures show what we want to achieve

Ok so we need to next look at materials for a job like this

To start with, a job is only as good as the materials you use, you will see 1 x 8mm solid rod, 1 x 6mm solid rod, 1 x 8mm hollow round tube and
1 x 3mm threaded stainless rod.
The fabrication.. 2 x legs

First we need to take an over long section of the 8mm solid bar this will be the leg sections.
lay out an old sand rover leg and mark with a pencil for the first bend. Keep bending it until you end up with the same profile as the original
You will also notice i've marked out for where the first cut should be.

Next you will see its been cut and filed nice and flat also notice the shoulder / notch in the bottom of the leg this will take some time to achieve and is essential for the perfect fit so time taken here will be time saved in the long run. We need to obviously do this twice as there are 2 legs believe it or not!

The next step brings us to the other end of each leg. For this stage I use a 12 ton hydraulic press this is to flare the end to the same thickness as the original leg. Again mark it out as per original part and use equal hydraulic pressure. This is essential to make sure both legs are the same It looks a little rough here but we will clean this up soon.

The next step is to mark out for the hole for the roll bar to go through, we need a 6mm hole here
which is bigger than the original but the centre must be in exactly the same place as the original part. I drill this now so we can work and trim the alloy around it and it shows a lot easier where we need to be
The following picture now shows i have trimmed up both alloy legs around the hole to give them their final appearance. Double checking any measurements before you drill and file is a great idea and avoids a lot of heartache.

And finally the last stage of the legs is to drill and tap out for our 3mm stainless threaded bar.
Tamiya's original leg has a captive 3mm nut but we don't have the room for this. So drill at an angle following the length of the leg then it needs a thread tapping in then screw in your bar and finally bend it down into a position where it will go through the hole of the body shell
This is also an ideal opportunity to check they fit properly. Make sure both legs are parallel with one another and that they are of a similar angle to your original.

Now is a fantastic time to get your wife/ girlfriend to put the kettle on and have a cup of have earned it !!!

The Roll bar

I'm now going to make the centre of the roll bar using our 8mm hollow tube. Notice the original part has a chamfer to it and we are going to copy this using either a file / or sanding carefully A lathe could also be used.

When using a fine file or sanding machine be careful not to mark the face of your alloy,
The best way of getting scratches out of aluminium is not to put them there in the first place!
If you do however, use some fine wet and dry of varying grades.

Once a chamfer has been put onto your tube mark it for length cut it and chamfer the other side.
This picture shows the final piece slipped over our 6mm rod to show you what it will look like when finished.

Now we need to cut a 300mm length of 6mm rod and put a centre line on it then line it up with the original roll bar and mark with a pencil your first curve/bend, if you look at the original carefully it is slightly flared out i.e not 90 degrees. We need to bend it ,then offer it up to the original..

Now we are ready to do some assembly by adding 1 x leg then the centre tube then finally the other leg and making sure both legs are facing the same way!

Next job is to offer up to the original again and mark for the last bend , this is harder than it looks trust me, but getting this right is very important so taking some time here will stop you throwing the entire piece at the wall, once you've made the bend there's no going back!

So now we are getting close to aluminium heaven!..

We next need to over lay the original and cut off the over long pieces. Now it's worth mentioning that if you again look closely at the original, the cut we need to make is not square, it has a small pitch to it and this is very important. So i take my time and cut it, finally finishing it up with a fine file

And lastly as before we need to drill and tap for our 3mm stainless threaded rod and cut to length as per original. Once inserted the threaded bar needs bending to a slight angle

Ah i here you say it's finished !!! NO NO NO NO....
We need to check that it fits and its square and it looks gorgeous !!!

The finish!

And lastly when i'm happy with the roll bar it's polishing time, using fine wet and dry paper and a product called Autosol paste compound, this stuff is awesome but don't get it confused with Anusol which is available at your local chemist / drugstore for a very different problem i.e
rubbing bum cream on aluminium is not going to work!

Thanks for reading this and hope you find it of interest. A really big thanks also to Moosey and stevo for providing this awesome site!
They are the Mutt's Nutt's!

John (j-man)

Coming soon to Tamiya101
Making the Hilux off road trailer


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