Your step looks to be a modified Kenyon 4873 K-10942 mast step that was machined to accomodate the exit blocks. The edges for the exit blocks don't have the smooth edge of the cast one.
Had similar issue on my '85 h34. Pulled the stick and found part of the plate broken off and the broken piece nowhere to be found (see pics). I was told by the PO that he'd never even seen the step and had no idea. Most people gave me similar advice re: side loads not so critical, etc. and they have a lot more experience than I do. But it worried me enough to hunt down a new one. Found replacement at rig-rite.com to fit the Kenyon 4873 (also pictured). This one is cast with the exit blocks in place. Found it at:
http://www.rigrite.com/Spars/Kenyon_Spars/4873-cruising.html
Here's their part description (there's no picture for this part, but there is one for the K-10942):
4873 Mast Step - Special: K-11671:
Mast Step, as
K-10942, above, but with sides cut out to allow for use with mast with welded deck-level exit blocks.
As used on Hunter 34. Special Order item.
Regardless of what you have, this is the only place I was able to find Kenyon mast steps. You have to fax the order. I'm sorry, but I don't recall the price.
Hope this helps.
dan.
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