photogravity, I really admire your Davidson tandem. What a beauty! The fillet brazing is similar to mine.
And I do still have unanswered questions regarding fender intstallation.
Two things:
1. Is there enough clearance on front wheel, and why is the clearance on the back 2x as much? By design?
2. Why are the holes for the rear fender mount so freakin' tiny? Will small diameter screws still work on rear fender "tabs", or are there fenders made for this particular small screw diameter?
Here are the details.
Here is a picture from the front of the fork:
As you can see the clearance on the 28mm tire is minimal. I measured the clearance with a caliper, and got 10 millimeters. Well actually more like 9. That's the clearance going vertically from top of tire to bottom of fork crown.
The back of the fork has a hole:
...and I believe it's threaded. Seems to be a hole for a decent-sized screw, the kind that would fit well through a front fender tab.
Now the back of the bike. The rear tire has twice as much clearance:
I measured just over 20 millimeters with a caliper. That's 2x as much as the front! Now why would they design it this odd way?
Furthermore, there is a small threaded hole on the front of the rear bridge:
This hole is substantially smaller in diameter than the hole in the back of the fork. Now why would they make this a tiny hole? Seems like a very small diameter screw won't be an ideal fit through the tab of a rear fender. Maybe with some large washers the installation would be sloppy at best. Are there fenders that have a rear one with a smaller tab hole? My Planet Bike Cascadia fenders on single bike have rather large holes in the fender tabs (that mount behind brake nut using Sheldon Fender Nuts).
I'm going to find out the exact sizes of screws that fit into these holes this weekend, with the help of a local bike shop.