Hi Vince
Maybe some day you will share your experiences with this device (ie tricks) and elaborate. In the meantime...one need spools...metals ones. Where do those come from? Maybe from Nik N Tick? Shanghai GP3 127?
As far as metal spools go, eBay is your friend. You can usually find them for $5 each. I just bought 9 of them for $44. Even when I use Rerapan (which comes on plastic spools), I roll onto metal spools in the camera.
‘Tricks’ for using that Camerhack cutter: First, I’d tape the leader of the paper to the 120 take up spool. Why? The reason is that when you are re-rolling the cut film from that spool onto a 127 spool, when you get to the end it will maintain the tension on the film and keep the roll tight. If you didn’t tape it, the film would lose all its tension when it leaves the 120 spool and that is a heap of trouble. So what I do is when it gets to the end and you feel the ‘pull’ from the tape, I hold onto the winding knob, then lift the top off the compartment, and then hold the tension on the 127 spool with one hand while removing the tape from the 120 spool with the other. It also reduces the possibility of the tape that secures the film to the backing paper from binding and creating a bulge in the roll.
Second thing I do - just as a precaution - is to roll the film in a changing tent (I don’t have a darkroom, so I use a Photoflex Changing Room), both when rolling the film onto the 120 take up spool (as it’s cutting the film), as well as when I’m rolling the cut film onto the 127 spool. I know that you’re ‘supposed’ to be able to use this device in daylight, but I don’t like to take chances, so I do it to reduce the possibility of light leaks.
Third thing I do is to cut the end of the paper at #16 and then cut a tongue there. Then I unroll back to frame 10 (using the 6x6 numbers) and cut the film there and tape it. Why? The main reason is because the 127 flanges are smaller than the 120 spool flanges, and the length of 127 film is less than 120. So to make sure my rolls aren’t too ‘fat’, I cut back both the paper length and the film length. Maybe I’m stating the obvious here, but just in case!
So really that’s about it. I have pretty good luck with Ilford Pan F - I haven’t tried any other film so far, as I need to use slow film with the Ermanox.
I should point out that since I’m using these Rollex-Patent 127 backs for my Ermanox, I’m getting 8 exposures per roll (it’s 4.5 x 6cm in horizontal orientation), which is what I’d get in a regular roll of 127. I’m not sure how many you’d get from 4x4 or how the numbers on the paper will line up, so you may have to sacrifice a roll of 120 to see how that would all work reliably for you.
Please bear in mind that I am certainly no expert when it comes to cutting 120 film down to 127 format. Generally I find it to be a pain (takes me about 20 minutes per roll from start to finish), but as I say in the long run it’s more economical than Rerapan and it allows you to use much better film than Rerapan.