We're replacing the standing rigging step-by-step. Last year we replaced the forestay (together with the roller furling) and the backstay wire and load bearing block. This year we decided to invest in new turnbuckles, fix the cracks in the spreaders, replace the jib halyard wire and most of the running rigging lines.
The old rigging screws had some thread damage and were not rotating/tightening after some point and I spotted a suspicius area on one of them that looks like there might be a crack developing in the steel. We decided it's time to get them replaced. We ordered two 1/2" (for the 7mm shrouds) and two 5/8" (for the 8mm shrouds) rigging screws with toggles from Seldén. For the 5/8" one we had to order the conversion kit (306-558-03) too as in 1998 the clevis pin diameter was changed from 13mm to 15.8mm. The chainplates we have are still 13mm for both.
The spreaders on our Isomat mast also developed a few centimeter crack which was probably caused by incorrect transportation during mast stepping earlier where the spreaders got stuck somewhere and got stressed. We noticed it when we took down the mast after we bought the boat. During the next a year it seemed like the crack kept expanding (to ~5cm) so it was really time to do something about it
We took them to an aluminium welder, who filled the crack with new material and layed on some extra thickness to strengthen it. It could be sanded and polished, but we decided not to, avoiding to remove any of the new layup. It cannot be seen from the deck anyway and strength is more imporant up there.