I noticed something's up with 6135.dat—it should fit all the way onto a Technic axle pin (see for example set 8880), but the axle hole isn't deep enough—only 16 LDU, but should be a full stud.
Unfortunately I don't have this part in real life, so I'm not sure how it would have to be adjusted, but it's clearly not as simple as just extending the axle hole.
Unfortunately I don't have this part in real life, so I'm not sure how it would have to be adjusted, but it's clearly not as simple as just extending the axle hole.