Starting to draw the new frame and have a few questions. With an eccentric BB are holes bored where the tube meet the BB?
Going to fabricate the rear dropouts as this will be a mixte frame with a Rohloff. What is the minimum thickness you would consider for a DO material?
Thanks!

Tom- The handful of eccentric BB shells I've held in my hands were all socketless, for fillets or welding. Given the amount of heat/time at temp for doing BB shells I would need I don't think I want to loose any of the shell's material at the tube joint by cutting a big hole in it. Shells already go through some distortion WRT their faces as it is. A vent hole is a very good idea though.

Dropout thickness can be dependent on a hub's axle and the retention manor (nutted/QR). But independent of the hub 3/16" thick is about the thinnest i would consider for "common" steel. I've read of makers using thinner but... If a QR axle is in play than the dropout needs to be thick enough to allow the axle end beyond the locknut/endcap and QR conical spring to fit after the QR cam is closed down. More typical is 1/4" plate. With IGHs be careful of too thick a dropout as some IGH axles are only so long and thus will run out of axle nut/axle engagement if the dropout is too thick.


Here's an example of a 1/4" plate dropout and an alloy hub shelled SA AW where the axle is JUST long enough to fit the axle nut. Note this dropout has a SA wide slot and those little toother and tabbed anti rotation "washers" SA hubs otherwise wanted were not needed, reducing the needed axle length beyond the locknut. Were I to do this bike again I would use a thinner plate for this hub. Andy

Thanks Andy. I do have eccentric on our Comotion Tandem but was hoping to not disassemble to check!
As get the DO designed I will post a pic. I want to incorporate a rear kickstand mount in the rear so 3might get creative with those DO!