PVD IS Head Tube
Most framebuilders that work with steel have ignored the newer integrated headset design. I belive that it is the future. I decided to make up some very special head tubes for my bike projects.
Design
Note the increased strength on the bottom side for extending far below the down tube when using larger forks.
Stock
The 4130 stock required for this part is very rare. 1.750 OD x .250 Wall.
I ended up ordering the stock from Factory Steel and Metal Supply Co. out of Detroit, MI. EMJ Metals out of Freemont or TW Mtals would be other good choices.
The price was $18.70 per foot with a $20 cut charge from 20 foot lengths. A six foot section should be enough to get 14 x 4.5" tubes.
Machining
A bushing was required to hold the part during machining.
Finishing
Special cutters will be required to finish the frame post welding. Cane Creek P/N TL0100 (cutters) & TL1002 (pilot). A little under $200 for these babies.
Park also has cutters for Cane Creek IS. Park Tool #756-S
Campy 45/45 cutters are #761-S
End Product
This 5.500" head tube came in a little heavy at 142g. due to a few manual machining considerations and some mistakes I made in the process. I would expect that a perfect CNC version to weigh in at 125g.
A 5.00" version measured at 123 g.
Comparing this to a "standard" PVD light machined head tube (93g) and a Chris King 1 1/8" headset (98g), this design doesn't add any real weight but is a far superior design.
Upper Stack: 8.3mm
Lower Stack: 0.4mm
Jig Adapter
This adapter will need to be made so that my jig readings are true.
On The Bike
A 1mm gap on the top cap. Not sure if this is normal. The star nut has not been installed yet, but everything feels snug under hand compression.
