Gents,
Re Thackery washers. See https://www.polished-stainless.com (which is Surplus Supplies tel. 01636 636735) See menu on left. At bottom click on ‘Everything Else’. Scroll down to Double Helix Spring Washers. He list a 3/4″ double helix steel. Might be worth a ring. I have had excellent service from them. Usual disclaimer.
Regards/Ian
