I am now the owner of a used 4x5 Tachiara, my first field camera, which is very exciting. In general itís in fine shape but it shows a few signs of carelessness from some previous owner (not the fine gentleman from whom I purchased it). Everything works, but I have a few questions regarding adjustments to be made. I donít have a close-up lens handy, so Iíll try to explain adequately without photos. Since the camera is no longer made, I donít know what parts might be available or from whom.
1. On one side, the brass ďtoggleĒ cam friction lock that locks down the lens extension goes nearly all the way down before locking and just barely locks. The other side locks fine with the toggle at about 45 degrees. The mechanism is simple but I canít see whatís under the rail. Is there a way to shore up the worn one without a custom-made part? Something I can do myself, perhaps?
2. The clasp to hold the camera closed has been removed. I see two tiny holes in the rear standard top, not square with the piece, but no hole in the base into which a stud for the hook-type clasp would have been screwed. Was this perhaps the older, wide version that clamped over the base? What may be a good source for a replacement part, or would this be a custom fabrication?
3. The focusing grows tighter as the bellows is racked out, and both the front and back swings, due to evident forcing while locked at some point (the metal shows marks) are not smooth on the one side. Would a silicone lubricant be the right kind to apply to ease these, or should I just leave well enough alone?
4. There is a tiny screw by itself in the base bottom near the front, off-center. What is its purpose?
5. Finally, itís not clear to me how to read the ruler on each side of the base, since it measures the direction opposite that I would expect for indicting bellows extension.

Thanks in advance.