Bottom Bracket Bending Rods
 

I went to the local blacksmith and picked up a couple of hot rolled steel rods to fit the down tube and seat tube sockets on a standard bottom bracket.


I put a taper cut on the ends of the rods so both of them can sit in the sockets at the same time, however how deep into the shell must they go? I assume as long as they are past the end of each socket it will be OK, however some input on this is appreciated.

Some of the bending bars of mine (made by Omar Khiel) have miters in their ends that mimic the 73* and 60* angles frequently found with lugs. These two placed in the shell, miter to miter, make for a fair insertion amount for each bar. Andy

are you spreading the angle, or making it more acute?

3 degrees acute.

The junction of the ST and DT in the BB shell is limited to the very end of the opening where they meet, however on the outer portion of the socket that is where the rods can go further into the shell. I have tapered the rods where they meet at the junction so more of the rod can be pushed into the shell, however how deep into the shell is necessary?

I made these. I really like having the weight of these inside the socket. they dont' flex at all obviously and I can use them as anvils to then close up the sockets to fit the tubes tightly. As the end relief suggests, these interlock within the shell. The relief is cut with a hole saw on the mill. The other ends of these bars will be turned to the other sizes as needed. The middle bar is for 22mm chainstay sockets.

Please excuse the dimpler testing left overs in the background!

https://live.staticflickr.com/1906/4...d6a443cc_b.jpg
Blacksmithing by Duane Draper, on Flickr

Duanedr, thank you for the pics. The tapered end of my rods look much the same as yours. Should be interesting to give it a go. I believe I will need to grind out a little material on the outside inner edge of the sockets to achieve the angle needed.