Seat post clamp bolt

[LeftyS7]

I find that a 4 mm is too small and strips the head but a 5/32" fits tighter. Does Giant use SAE bolts?

Actually I converted and 4mm is larger than 5/32" My apologies.

 

[NeilJ]

I find that a 4 mm is too small and strips the head but a 5/32" fits tighter. Does Giant use SAE bolts?

Historically bicycles use whitworth size nuts/bolts.

 

[LeftyS7]

British bikes, true historically. Not now. European bikes, no. Commonly used now are Metric. Have you ever seen a Whitworth hex wrench set? They did not even have hex bolts back then.

 

[Alaskan]

Whitworth fasteners are part of a quaint English history and are no longer used as the UK transitioned to the metric standard. There is one global exception: the standard tripod mount on all SLR cameras and, where fitted, on compact cameras, and therefore on all tripods and monopods, is 1/4 Inch Whitworth. Also Whitworth thread angles are still used on pipe fittings in the UK.

I had a reduction gear/transmission on my boat which was commissioned in the UK in the mid 1970s. It had a mix of Whitworth and metric bolts on it. Much as I hated using crescent wrenches on it, in Alaska, getting Whitworth wrenches in the 1990s was impossible.

As lefty said, metric has become the global standard for fasteners and I, for one, am glad of it. Now to get the US on board and get rid of SAE.

 

[LeftyS7]

Whitworth fasteners are part of a quaint English history and are no longer used as the UK transitioned to the metric standard. There is one global exception: the standard tripod mount on all SLR cameras and, where fitted, on compact cameras, and therefore on all tripods and monopods, is 1/4 Inch Whitworth. Also Whitworth thread angles are still used on pipe fittings in the UK.

I had a reduction gear/transmission on my boat which was commissioned in the UK in the mid 1970s. It had a mix of Whitworth and metric bolts on it. Much as I hated using crescent wrenches on it, in Alaska, getting Whitworth wrenches in the 1990s was impossible.

As lefty said, metric has become the global standard for fasteners and I, for one, am glad of it. Now to get the US on board and get rid of SAE.

I agree but we're too pig headed. Tried and failed.

 

[dAz63]

Yeah, Rolls Royce make aircraft engines, they use metric threads throughout, however for the US market those metric fittings have imperial heads and sockets because Boeing didn't want spend millions in buying new tools,

Hermle is a clock movement manufacturer in both Germany and the USA, I had two movements on the bench one day, same model, one made in Germany, one made in the US, so basically identical, interchangeable parts between the two, and both used metric threads, however the German movement used 6mm hex nuts, the US movement used 6.35mm hex nuts or 1/4".

 

[LeftyS7]

Interesting. What did the US do when it started making Rolls Royce Merlin engines in WW2?

 

[Nova Haibike]

I find that a 4 mm is too small and strips the head but a 5/32" fits tighter. Does Giant use SAE bolts?

No, it is metric. The bolt or your wrench could be poorly manufactured. If the wrench has seen a lot of use, it could be worn out. If you have a set of Torx wrenches, sometimes a T25 will remove a slightly rounded out 4mm hex bolt.

 

[LeftyS7]

No, it is metric. The bolt or your wrench could be poorly manufactured. If the wrench has seen a lot of use, it could be worn out. If you have a set of Torx wrenches, sometimes a T25 will remove a slightly rounded out 4mm hex bolt.

Thanks, that's what I thought. No I didn't round them out and I have several sets of hex keys and they all fit the same. I'm afraid of rounding them out using the 4mm key.

 

[Nova Haibike]

It is very possible that the bolt was over-torqued to begin with.