Flat Pack F1 Car: Assembly with Ikea Bolts

ikeanboltsmerc2

F1 rightly occupies a place at the top end of engineering and technology. But that is not to say that F1 cannot take inspiration from most unusual of places.  Many who follow this blog have inevitably been involved in the technically taxing assembly of flat pack furniture.  Unbeknown to us the clever fasteners used in straight and right angle butt joints are equally at use in F1 cars!

 

Barrel Nuts

Ikea_BarrelNut

Fastening thin bodywork or even larger structures like engines together on an F1 car is always a problem.  Stiffness and lightness are the key aim, but carbon structure of the car is an obstacle to both at times.  As these joints tend to work in tension, part-A wants to be bolted to part-B, tightened and then not fail when under load.  An obvious way to do this is to has a threaded bolt going into a threaded insert.  Placing a threaded insert into a F1 carbon structure is difficult, both as the insert invariably requires another metallic part to be bonded into the structure, then there needs to be enough structure to prevent the insert pulling out or the insert’s threads failing.

barrelnut_PU_Tub

This problem is analogous to bolting crumbly chipboard sections together in your Ikea furniture, the point loads of a threaded fastener do not work in chipboard and the low cost aspect of flat pack furniture deters the addition of stiffening threaded inserts into the otherwise cheap chipboard matrix.  So we see joints made up of fasteners going into larger diameter barrel nuts.  The barrel nut provides the stiff threaded structure but its large size means it spreads its loads effectively into the chipboard, reducing the point load in the chipboard itself.  While a fastening solution good for tension, but not good for torsion, we also see these flat pack fortunate joints aided by wooden dowels to prevent the structure twisting and pulling the barrel but fastener in ways that might break the chipboard.

barrelnut_RWEP

Just the same approach is used in F1, the strong tensile joint of a bolt into a barrel nut perfectly suits the issue with carbon fibre.  Now a large diameter hole is needed in the carbon, no metallic insert is required, just the replaceable barrel nut.  So we can see the engine is bolted into the back of the Monocoque with just such a flat pack solution, thin sections of bodywork such as the rear wing endplate mounting are joined with barrel nuts, creating the stiff aero assembly without the need to compromise the thinness of the parts for a stronger bolted up assembly

 

Cam lock fasteners

Ikea_camlock

Another flat pack feature that translates to F1 cars is the way the nose bolts to the chassis.  We often see damaged noses replaced in seconds at a pit stop with the mechanic quarter turning a fastener and the nose easily being released.  Again like the issue with joining up assemblies in tension, the nose and moncoques do not want to have large threaded assemblies inside them.  So the F1 nose is mounted much like the quarter turn fasteners used for right angle joints in Flat pack furniture.

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ikeabolt-nose

These consist of a pin and a cam fastener, where a rounded end feature of the pin slides into the tapering slot around the barrel shaped cam fastener.  When the cam is turned, the slot pulls the pin in tightly towards it making for a stiff assembly and the taper provides enough grip on the pin to prevent it loosening.  Usefully for quick nose changes, the reverse process to loosen the joint, the pin is ejected by the tapered slot helping the nose come off the front bulkhead.

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