Wing Strut Bolts - Washers?

[LSHAvenger18]

We are just about to fit new wing strut bolts to an Auster J1N.

The book (not updated since 50s/60s) clearly shows no washers under the bolt heads.
The aircraft arrived with washers under the bolt heads!

Does anyone have a best practice please?

Thanks,

Simon

[coxargus]

I have found the same anomaly during my Argus rebuild - are the bolts the correct length? - I found some that were one size too long.
Frank Cox

[Bill McCarthy]

I would put the washers under the bolt heads in order to spread the load in the area, act as a bearing surface- if the hex heads “dig in” without them, they can tear the undersurface.

[LSHAvenger18]

Thank-you Bill, those were my thoughts too.

Yes thanks Frank, they look correct length.

Simon

[austerity]

The strut tangs are a loose lateral fit in the fuselage fitting so the bolt should only be nipped up otherwise the fitting will be distorted. I think washer as necessary to achieve this with the plain shank taking all the load.

[LSHAvenger18]

Thank-you Neil,

good info,

Simon