Five Sided Bolt

Apparently they are designed not to be removed.

**LINK**

Edit: Suzuki have also apparently fitted seven sided bolts on some of their bikes!

Edited By Vic on 07/07/2019 12:08:31

Nooo! Just not by muppets with only open ended spanners!

I'm not surprised now that it turns out to be part of a Smart car. A friend of mine had one for a few years, he told me that even the simplest work on the car cost an arm and a leg because of what had to be removed to get at anything.

 I have seen a variation of Torx with five lobes. I have just looked at Vic's post "one sided fastener" and there is the five sided fastener, what a coincidence! 

Edited By old mart on 07/07/2019 19:26:51

Edited By old mart on 07/07/2019 19:44:55

The first time I saw a Torx bolt was on the front brakes of a ford when I was a mechanic. Luckily the Snap-On man managed to get drivers for us within a few weeks. Spline tools for the cam belt jockey took a little longer ...

Tamperproof fasteners are a waste of time, almost within hours of them appearing the tool to fit them will appear online, they may deter a a few people but the determined will not be denied.

Mike

I might normally agree with you but there seem to be more than a few mechanics complaining they can’t get 5 sided sockets for the smart car?

eBay "pentagonal socket"

Bolts with five sided heads have been used by Japanese manufacturers of "cassette" type fuel injection pumps for many years.

Like the three sided nuts and for the governor shaft on the Bosch EPVE fuel pump, I suspect that there will be only one source for a suitable socket; at a price!

Remember, some years ago Ford used 7mm Allen capscrews on their disc brake callipers.

Ever tried setting up the steering rack on a Renault 4, 6 or 16, without the genuine Renault equipment?

Fitting a new handbrake cable to an original VW Beetle?

Fitting new timing belts to a Rover 75?

In both these latter cases, the fixing is torqued to about double the range of anything an amateur will have, and then you have break them loos, so even more torque required. Not many have 3/4 drive impact wrenches!

All intended to keep the dealer network busy, rather than the D I Y er!

Howard

A few years ago our team had a new racing car chassis delivered from the USA and almost all the bolt heads were aircraft type with 5 sides. When we asked why, the manufacturer said they were stronger and smaller to save weight. We asked them to send us the spanners and sockets to fit the car. A few days later some sets of Bonney tools arrived with a bill for several $1000s of dollars! They cost more then 10 times the price of regular Snap-On tools for regular hex bolt heads! They were not the easiest tools to work especially the open-enders as they couldn't be slid in normally they had to go over the head of the bolt.

We replaced all the bolts with regular hex and sold the 5 sided stuff to an aircraft repair company who were delighted to get tools with official paperwork for aircraft use. Every spanner, socket and ratchet etc. had it's own serial number and paperwork!

Howard mentions Ford as using 7 mm Allen cap screws on brake callipers. Not the only culprits. I first encountered 7 mm hex sockets on SAABs more years ago than I care to remember. Sourcing the key was bit of problem then. Pre E-Bay, limited tool stockists down here and the Snap On man was, um, sniffy to the general public!

7 mm is getting more common. Seen it in several unexpected places over the last few years. Seems to have become the de-facto standard for M10 shallow flat head socket cap screws. My book says 6 mm key is supposed to be standard, same as button head, but all the ones I've seen are 7 mm. Presumably higher torque rating. Full depth M10 socket cap is 8 mm key of course. Both shallow and full depth are 16 mm nominal diameter but button head is larger at 18 mm. Which has caught a few folk out.

Worth making sure your key set has 7 mm in it.

As the years go by I get steadily gladder that I splashed out on a long series imperial / metric double set with 13 keys each side. 0.050 to 3/8 imperial, 1.5 to 10 mm metric. £25 bargain about 25 years back from Homebase of all people who, unsurprisingly, couldn't shift them at £50.

Clive