dpc wrote: ↑
28 Sep 2018, 02:59
I was actually responding to GenioDiabolico who probably just wants to get his book collection scanned and not mess around with new steel cables and pipe lengths.
Yes I'm sure he does! Perhaps you may find accurately gluing 6 joints easier than making one cable, but I didn't having unsuccessfully tried gluing twice (and why I looked for another method). Others may have the same difficulties I had or may find gluing easier too. I suppose what anyone will find easier and faster depends on what suits their skill and temperament. I also didn't care much for messing around with primers and fast drying glues.
Nevertheless, here's why I think it was harder for me to glue the handle together (and why I failed).
Although the handle looks simple enough, there are 4 elbows which allow several degrees of freedom (4 or 6 depending on how you count). These are the various rotations the parts can be put through. Any misalignment in these rotations will twist the handle out of shape and may make it unusable. Depending on the severity of the misalignment, you might be able to salvage a misaligned handle, after gluing, by force flexing it into place when attaching it to the platen.
Now the standard method for gluing PVC parts is to first assemble them, without glue, and then place matching index marks on the two parts to be glued, like this:
https://cdn2.tmbi.com/TFH/Step-By-Step/ ... PIP_05.JPG
Although this works fairly well for typical construction jobs, it didn't work so well for this job, for me, because there are 6 independent joints whose index marks need to be accurately aligned and even a slight miss-alignment (even just the thickness of the mark itself) in just 2 or 3 of the 6 can render the handle severely twisted. I tried to reduce the miss-alignment by using very fine marks, but even then I was unsuccessful, and invariably something was always off (although in theory it shouldn't be) by the time the handle was finished. Perhaps it was because I glued each joint one by one. I'm not sure.
So then I tried gluing all 6 joints at one go so the handle was assembled, with glue, and I could twist it into shape as a complete unit before the glue dried. But it was difficult with the fast drying glue used for PVC and I failed again.
And so that is why I decided to try the cable. It turned out be simpler, easier, faster and more forgiving to error (as the handle could be simply twisted into shape, so it's all square, after assembly). Others may find the same, but as I said, everyone will, in the end, choose what they feel will be easiest for them.
Making the cable took me 15 mins on my first attempt and actually it doesn't need to be very precise, just snug so the handle parts don't loosen. I gave detailed instructions on how I made the cable with my plans for the original version of the scanner here:
See step 9, on page 24, of the first PDF (at the above link), and step 1, on page 34, for assembly. These instructions, for my original version, would remain the same for the current design.
So it's a trade off between trying to ensure 6 joints are accurately glued (and if not, re-starting from scratch and wasted parts/time) vs making one cable, reasonably accurately, that one might need to attempt a second time and no wasted parts, other than a short length of cable, and 10-15 mins of time.
Nevertheless, the unglued version has the added advantage in that it lets me disassemble the handle and insert the bike break leaver/trigger so I can use my point and shoot camera (which doesn't have an electronic remote trigger option) when I want better quality images than smart phones offer.
As for separate handles (glued or fastened with cables) for each platen, yes, that's obviously the way to go if one is going to be changing platens a lot.