oops, I miss read it, you want caps
No worries though, once you made the plug to the dia you want, find the center of the plug and use a forestner bit and drill a hole a tad smaller and a tad deeper than the bolt head, then all you do is tap the plug ( now a cap )onto the bolt head.
1978 Tayana 37
Freedom comes when youíre ready to sail away. True freedom comes when you donít have to return
Cut off from the land that bore us, betrayed by the land we find, where the brightest have gone before us and the dullest remain behind, .......but stand to your glasses, steady,.......tis all we have left to prize, raise a cup to the dead already, hurrah for the next that dies