I collimated my skymaster 20x80 (or is it 75? It's raining so I'm not going to the shed to check) binos yesterday using the sunlight method.
As bonus, there was a nice big sunspot and a fainter one also visible on the sun images, so I was able to show the spots to my son and his friend.
I only did conditional alignment this time plus a bit of exploration of the collimation at min-max IPD, as I didn't have much time to spare.
To make it easier to follow the sun, I had mounted a ball head on the side of my dobsonian telescope while it sat on its equatorial tracking table, and taped a piece of cardboard to stick out to the side of the rear of the telescope. The pre-ruled test sheet (two vertical lines at my IPD 65mm, and a single horizontal line) was fixed to the cardboard with clothes pegs. Distance from the eyepieces to the screen was about 500mm.
The skymasters don't seem to have eccentrics, so I was only using the prism adjustments. I found it much easier to understand what (conditional) misalignment my binos had with this method. Close to the eyepieces, the solar images projected onto the screen were at IPD (since the binos were adjusted to this, so they must be), while at 500mm distance, the images were about 15-20mm further apart. So the optical axes were pointed inwards, meaning for me to merge views I would have to accommodate outwards, which is not comfortable.
Adjusting the screws, I could watch the movement of the images on the screen very easily and objectively. I couldn't get them quite to the correct alignment even with the screws bottomed out. So it seemed that I would have to investigate the objective end of the binos.
Unscrewing the "beauty cap" and then a spacer barrel which holds the objective end bracket to the hinge, I could see that the fit between the bracket and the barrel around the objective is a sloppy fit. I cut a couple of thin plastic shims and slipped them into the inner sides of the gaps, pushing the optical axes apart. With this modification, I then had sufficient range in the prism screws to be able to adjust to conditional alignment without bottoming out the screws.
I adjusted to make the bottom and left sides of both images touch the horizontal and vertical lines of my screen respectively, then tried them out. The alignment was much better, merging no longer required effort.
Next step will be to also check at min/max IPD and see if I still have alignment at those extents. If not, I'll be going over the diagrams from Raphael again to check what the likely misalignment is.
Testing and adjusting the conditional alignment this was was really easy.