A4 strength

[captainboo]

Try A2A4, they sell some A4 80 bolts.

http://www.a2a4.com/acatalog/A2A4_FU..._BOLTS_53.html

[RestlessL]

or Westfield Fasteners

http://www.westfieldfasteners.co.uk/ScrewBolt_M.html

J

[vyv_cox]

I looked through my nuts and bolts collection on board, bought in a variety of chandleries between Holland and Greece. I was quite surprised to find many A2 and A4 -70 grades and even some A2-80 nuts. I had some good quality countersunk Allen bolts which were also labelled A2-70. The convention seems to be that the lowest grade is simply marked with the composition, higher grades with the strength. My collection suggests it is not difficult to find the higher grades.

[AngusMcDoon]

My collection suggests it is not difficult to find the higher grades.

What I have so far not said is that the offending part is a 45mm M10 carriage bolt. These are not so easy to find.

[AngusMcDoon]

Just spoken to Sea-Screw, and their A4 bolts are property class 70. He agrees with what has been said here that my broken bolt, being unmarked, will be a 50. He also said that buying an A4 class 80 carriage bolt off the shelf would probably be impossible anywhere and would have to be specially made if anyone wanted them.

[vyv_cox]

What I have so far not said is that the offending part is a 45mm M10 carriage bolt. These are not so easy to find.

But it does sound as though you are not looking for a higher strength one, which should make your search less arduous.

[AngusMcDoon]

But it does sound as though you are not looking for a higher strength one, which should make your search less arduous.

I'm not, but I started off not knowing anything about A4 strength grades. Having spoken to a supplier the fact that their products are marked with a strength grade gives me confidence that they are a quality assured product and not some nasty Chinese cheese metal thing from Ebay. I have now ordered the parts I require.