Tom Porter LWB

Tom Porter's Finished 2010 LWB

The painted bare frame, ready for assembly.
Chain is added. Here's the over and under pulley
Rear stays area detail.
When I got the bike assembled I was not happy with the initial stem and bar setup. The next section will deal with how about correcting this problem.

These are the cut pieces to make the stem. Shortest and middle pieces are made from 1 x .065 tubing and the riser is 1 x.035 tubing.



 

The stem clamp with has two seat binder braze-ons added.
Internal binder for the steerer is made out of aluminum with a steel bolt to tighten the wedge. Tubing is 7/8 x .065 with bolt seat and binding wedge made from 6061 bar stock machined to fit.

 
 Internal steerer assembled.
Mounted in fork, this now will be tightened for stem to clamp onto.
Stem clamp now has a groove cut into it and 5mm bolts installed. Its important to chase the binder threads after brazing because if you dont you may get the bolts threaded in but they will stretch and bind up and break off when you try to loosen them. Yes, I found this out the hard way.

 
The bar clamp ahs custom made binders made from machined 4130 bar stock and tapped for 10mm bolts. Ive find that using the 5mm seat binders also has the bolt stretching problem when you tighten them enough to clamp the bars securely.

Riser stem is mitered in Jig to proper angle and stem clamp has a piece of tubing inserted to try to minimize heat distortion from brazing.

Now to make the handlebars using my hydraulic tubing bender. The tubing is the standard 7/8 x .065. Here the tube is set up in the bending die with the follower underneath.

This will give and idea of the forming process.

89 degrees is the sharpest angle Ive been able to make with this bend as the tube snaps back a bit. Digital level is from Sears and cost about 25 USD and takes the guess work out of bubble levels.

The piece is then reversed and corresponding bend is made, making sure the piece is angled the same using the level.
The basic double 90ish degree bends made.
This is where it gets a bit tricky. Level is used to get 25 degree bend by measuring a the flat area between the two 90 degree bends.
The final bend is made to 60 degrees, again using the digital level.
 Now the whole thing is rotated 180 degrees to get the necessary clearance from the table top. This is my old Delta table saw which burnt out its motor after 20 yrs or so. Makes a good workbench now.
Close enough to 65 degrees for me.
 Reads 65 degrees at other end though.
Again this is close enough for me.
Here is the finished product. Now needs the ends trimmed off the proper length.
This is the first set of bars. I goofed and read the 25 degrees from the wrong area. These would have worked but hit my knees when pedaling around street corners.
This shows the difference between the two handlebars. Now I have the necessary knee clearance.

 

 



The bike all together and ready for testing.

The Wheelbase is about 74 and plenty of tiller in the steering. Its been 15 years since my last LWB so I had to practice launching. It took a few attempts to get smooth but once underway its very stable and tracks very well.
 
It turns street corners like an ocean liner compared to what Ive been riding like my Dual 700c.


The next project will be completing my 700c/406 lowracer. This will need several jigs to do which I will be posting as I go.

Return to the Tom Porter plans and building page