Wednesday, August 29, 2012

Martins 650b day 2...

One aspect of custom frame fabrication that many people do not realize is just how long some processes take.  For example, I spent 11 hours today in the shop working on the headtube and cable routing insert.  The time was interspersed with updating the blog, email, etc.., but this gives a good perspective of the time commitment involved with manually machining your own parts.

I started with the headtube, a 44id Paragon Ti stock.  The plan is to create an internal cable plug that will take the cables/hoses through the headtube and allow passage around the steerer and into the top tube/down tube.  I have the design I need completed, now just to create the parts.

To do so, the head tube wall needs to be reduced a few thousandths, so in and out of the lathe it goes for boring.
 
The insert starts off as a solid piece of 1.00" 6/4 Ti.  I measure it all out and then draw the basic design to give me a visual to follow.
 
 
The sides are machined off to give the correct profile...

 
Once the profile and width are established, I then begin drilling through the cable pass holes.  6/4 Ti is extremely tough stuff, so it takes 5 steps to get to the final profile for each hole.


Skipping ahead a bit, I've profiled the top and bottom edges to allow an index point against the exterior wall of the head tube and then cut a curved profile into the inside aspect to match the ID of the headtube.


The finished piece ready for fitting to the head tube...5 hours


Here's the waste material off the bed of the mill from all the processes...

 
Next, I have to layout and then machine the relief hole around the headtube.  This is a one shot deal, too big and it's on to a new head tube.  I spent a good 30 minutes setting up and double checking my math and layout before cutting...

 
After machining, its a perfect fit...

 
A view from the inside of the tube...


All washed, degreased, and ready for welding...



And with a little time under the hood, she's all welded up and smoking hot...


Add in lunch and about 25 emails between Christi and I, and a full day has passed.  Would like to see more progress, but the little touches take time.

cheers,

rody

6 comments:

Jamenstall said...

where is the like button.

dicky said...

Good lord.

dicky said...

Good lord.

Joel said...

Wow! I'm going to be following this build with excitement.

-Joel

rmb said...

Awesome.

Meriwether said...

Rody,
I see the need for such an internal routing "guide" for the head tube on a Ti frame, but on a steel frame have you used a similar method but instead brazed tubes in through the head tube? Seems like a great way to go if you're wanting to run 3 internal cables and don't want that many holes in the top or downtube...?
I want to try this out so if you have any tips they'd be much appreciated!
Thanks,
Whit