i agree, double sirolocks are a pain, not so much to get them in, but to have to take them out on freshen-ups. that's why i typically use the wider singles or buttons if the customer will pay the little bit extra for them. (spirolocks are usually included with the price of the pistons)
here's a picture of some buttons with over 1000 passes on them. the oil ring actually holds these in place. when that's not the case, they are cam ground to go in only one way.

another, can't get much easier than that.

that's what i mean as far as assembly, they go together so easy a caveman could do it

i thought there was something i was missing. to me i always thought buttons were great but there must be some reason they didn't get more use in our applications. yes the spirolocks are reliable if properly installed but the buttons are just so simple. i still don't understand why they don't get more attention. i can't really remember seeing any mention of them on any automotive piston site, on the bikes that's all we used. is there any downside in our applications? like i said on the bikes they were teflon or aluminum with a teflon insert. are all the automotive ones aluminum?

this is just my opinion, but buttons are better suited to the race motors and not your average daily driver. like i said before, they're better for combo's that require more frequent freshen-ups as opposed to motors that will likely not be torn down for many years or 50,000 miles.

THX furr all the chit-chat guys ... it has been a long, LONG time since I have put together a "floater" piston motor. That - JUST ONE - was a 440 I picked up in-a-basket off of Tradin' Times(weekly classified ad newspaper) in the Detroit area. MT pistons with the big-ole pop-ups AND Dykes rings ....

THAT had the spiril locks and what a PITA ... but that motor FLEW. 119 mph through the muffs ...spinning the tires.

OK now .... makes a lot of sense to go to the piston manufacturer for buttons .. but HOW ABOUT these old-school TRW's ? .....

dHam or M S ...whatcha' got ?