The riddle of the immovable latch & the off-centre door knob

[JohnD]

you can screw the spung ball in and out for a deeper or shallower projection. I've known them fitted on interior doors and work well if the door is a reasonable fit. In my previous house I think they were fitted in the 1920's when the downstairs was renovated to Art Deco style and the original horizontal sashes removed (I later got some again, and still prefer them in a panelled door).

I think the rollers are superior to the balls. But I don't know how to adjust one as big as this (haven't used this type).

 

[Deleted member 174758]

The ones we had on the last job (where every apartment had a double door cupboard) were fitted in the tops of the doors. They had a screw "projection adjuster" which was hidden under a separate face plate. Adjusting them entailed carrying round a stubby PZD#2 and hoping that the door installer had actually routed them in right. Where they hadn't it was a door of job to adjust the fit/rechop them in with a sharp chisel. On most of the smaller roller latches I've seen you just push the roller down into the body and then rotate it to adjust (and they helpfully eeven mark them with the rotation direction):

That one you illustrate must have an adjuster screw somewhere or other, surely?