Witch is stronger?

[stunks]

Stainless steel or high carbon steel witch one is stronger as in bolts?

[gorber]

I reckon wizards are stronger than witches.

[brin]

its best to get high tensile bolts as stainless steel bolts even 316 grade is relatively soft in comparison

[Paulice]

High carbon generally speaking but it depends on what you want it for, high carbon has very little to no flex stainless would give a little and bend then breaks, HC would not, but then you have many grades of HC 4.4 being the lowest/softest and will bend easier than 12.9 that would snap with little to no bending.

[stillakid]

Loads of info on the web, Inconel 718 is pretty tough, little guide here. ROCKCRAWLER.com - Grade 5 vs. Grade 8 Fasteners

[gowen]

Grade 8.8 steel and Grade A4-80 stainless bolts are about equal in strength for structural use. If you need more strength then your looking at either 10.9 or 12.9 in high strength steel. Generally 8.8 and 10.9 are available as hex heads (for spanners), whereas 12.9's come as cap screws (use Allen keys)

[ChrisB]

Carbon steel hopefully.

[Grant_beltcp]

I use 12.9 grade high carbon steel bolts for anything that takes high shear loads or whe bolts normally suffer from rounding off. Stainless steel are worse than align's bolts for general strength and rounding off. It's quite soft. Stainless is only used for visual purposes as it won't rust.

[bolders]

I use 12.9 grade high carbon steel bolts for anything that takes high shear loads or whe bolts normally suffer from rounding off. Stainless steel are worse than align's bolts for general strength and rounding off. It's quite soft. Stainless is only used for visual purposes as it won't rust.

To be fair you can get stainless steels with tensile strengths up in the 1000MPa range not far of the 1200MPa of 12.9 high carbon steels.

Stainless is not just one type of material, it is a name to describe an entire family of materials that can have quite different properties. For example austenitic SS tends to have lower tensile strengths and can not be heat treated but it has good ductility and is extremely good at cryogenic temperatures and actually gets stronger. Conversely martensitic stainless is higher strength, can be heat treated but tends to be more brittle.

The trouble with using these very high grade carbon steels is that in theory they will be much stronger and have better fatigue life (fatigue is derived from tensile strength, load magnitude and number of cycles). However in order to realise these benefits you need extremely good quality control and material quality (as used in aerospace for example) as small defects in the material (scratches etc) can cause a component to fail from fatigue, long before its predicted life, due to its reduced ductility and resistance to crack propagation.

I would bet that these 12.9 type bolts that we can are not subjected to these high levels of quality control needed so using 8.8 bolts maybe a better compromise. It would be interesting to do some testing in order to get some definitive answers on this.

[Grant_beltcp]

Although stainless steel's can be hard - the off the shelf SS bolts are almost always of the soft variety. I've never seen them offered in higher grades.

[bolders]

Although stainless steel's can be hard - the off the shelf SS bolts are almost always of the soft variety. I've never seen them offered in higher grades.

I think you have hit the nail on the head here. I don't use stainless bolts on my helis and I am really not a fan of these SS screw kits that are available.

[LaurenceGough]

Although stainless steel's can be hard - the off the shelf SS bolts are almost always of the soft variety. I've never seen them offered in higher grades.

+1 for helis it's always carbon for me, but for frame bolts stainless steel is normally enough. To be honest most kit parts work just fine, but if the need arises first thing I look for is a high grade carbon steel bolt.

[dani_r]

Anyone know what steel main shaft and feathering shafts normally are? (something I've always wondered!)

[Grant_beltcp]

Feathering shafts and main shafts vary depending on manufacturer but they tend to be hardened carbon steel. Hardness seems to vary on them.

[ChrisB]

I have an aluminium feathering shaft at home but I don't think Mikado make them any more.