I picked up an older Hobie 16 last season and started tinkering with it. Last month I took it out and noticed that the cam cleats that it came with were basically unusable. The cleats that came on the boat (not sure if OEM - see image below) did not engage smoothly and dragged on the line (to the point of damaging the line). I tried to save them, but all my cleaning and grinding was in vain.
I wanted to do it cheaply and as the whole swivel assemblies are about 60 USD a piece I chose to replace only the cleats.
The Ronstan RF5011 as it was suggested in this post: viewtopic.php?f=13&t=10216
They are designed to handle line sized 3-12mm in diameter. The jib sheet is 8mm and the main sheet is 10mm so I was good to go. The mainsheet actually looked large for them but when I tried them out they worked flawlessly. http://www.ronstan.com/marine/product.asp?ProdNo=RF5011
Total Price: 79 USD before shipping
Ronstan RF5011 ~25 USD per set - I replaced all three on the frame (the boat came with Harken mainblocks) = 75 USD - many online sources, I actually found a decent deal on amazon
10-24 1-1/2inches stainless machine screws and respective lock nuts (6 each) - 4 USD - Local Lowes
Here are a few pics of the old cleats.
I removed the two machine screws on each to show the hardware beneath.
I used a dremel tool with a cutoff wheel to grind the tabs that the springs sit against flat as well as the strength member for the cleats. I don't have a picture of it but the tubes that the cleats ride on have an end which rivets to the plate they sit on. I decided not to grind them off and remove them completely from the bottom side. Instead, looking at the gaping holes that they would leave I left a small amount of material on the top (leaving the bottom intact) and kept them as washers. It looks like they go in a bit so you can get the top flat without any risk of them falling out. It took no longer than a couple minutes a piece to complete this.
The old saddles were salvaged, but I had to bend them in slightly to get them to match up with the new assembly holes. I used a pair of channel locks to do this effortlessly.
As the holes didn't line up exactly there was a slight bind as I put them onto the newly flattened swivel plate. It just took me using a screw driver to walk the new screws all the way into place. It wasn't anything extreme in terms of binding but I hope it doesn't come back to bite me in the rear as they get older. Here is the finished product. I don't think it came out that bad and they are nice and tight with respect to the plate. Unless something is seriously wrong with your swivel assembly, I see no point in replacing it just to improve the cleats.