New PBT key caps slide off the costar inserts. Spacebar tilts!

[Machinus]

I purchased a set of PBT keys to replace the wearing stock ones on a MJ2. The profile is slightly taller than that of the stock keys. The keys mounted directly on the switches work great, and the 2u-sized keys have only a small amount of rattling or imbalance. I think this is because there is mininal tilt during press of those keys. However, if the spacebar is pressed anywhere other than the direct center, the cap slides off the insert on the opposite side, instead of depressing it. I have tried wrapping the inserts in plastic and teflon, but this does not fix the problem at all.

Are my (costar) inserts just worn out? Was the spacebar poorly molded? I have noticed there are not many options for different plastic inserts, which I would definitely get if they would fit more snugly into the keys.

[Riverman]

I've always had good luck with small pieces of Scotch tape.  I put a small square piece over the hole in the keycap, and then press the stabilizer insert into it.  That always seems to snug up the fit on loose stabilizer inserts.  If yours really are worn out, you can buy new ones fairly cheaply from WASD Keyboards.

[mrvco]

It's possible that the space bar is not 100% aligned (warped, low mfg tolerance or whatever).  I have my Costar stabs lubed and the lube seems to do a nice job holding them in place while I press on the keycap.