Sunday, November 02, 2014

Starting a winter bike, or should we call it an "All Roads?"  Winter bike sounds better to me - less pretentious.

The BB only has sockets for the chainstays, sort of a mongrel design, but nice because its insensitive to angles between DT, ST and chainstays.

Filing malleable metals is sort of fun.  Everything doesn't come off as chips.
  This may look like a 3D picture where you're seeing the outside of the near wall and the inside of the far wall, but mostly you're just seeing the near wall.

Filing has pushed the edge back, leaving a thin layer of metal still connected to the tube.

Here the deburring tool has started to carve that edge off.

Carving the down tube has a similar ledge.

A lugged BB is used to scribe a like for the cope.  Because this represents the inside of the shell, its actually too tight of a curve.
You can see the gap here.  A sanding drum helps make the adjustment quickly.
Soon it looks like this - tight and tidy.

The seat tube, BTW, is old Columbus SLX.  SLX used spiral reinforceing ribs at the butts to add strength with minimal weight.  This is commonly called rifling.

I don't recall having ever seen a clear pictures of this.  The Internet now has at least one clear picture now of SLX rifling.  Note, as the seat tube, this only has the rifling at the bottom.

Water bottle and front derailleur mounts are installed prior to installing the tube.

A hole for the alignment pin on the front derailleur mount.

Note the pin.


Ready to go

Filet braze between ST and BB

After filing and a little clean-up sanding with a small drum on a Dremal tool.

The lugs are supposed to be from the old Match factory.  They're nice, and come in differing angles.  This is the first time I'm using them, unfortunately, I only have 3 sets.

Finally, I'm slowly customizing my jig.  Here is a wing nut replacing an Allen style cap screw.  No longer do I have to find the Allen wrench prior to adjusting.  This is on the backside of the ST support arm.  It's so much quicker to mount/remove the ST now.  A couple more wing nuts will be substituted at other locations.

Monday, October 06, 2014

Here are a couple of pix of brazes on the chain stays:

Thursday, September 25, 2014

More cleanup prior to assembling the rear triangle.

The lugs are mostly filed,the  remaining dreck is gone from tubes.

The front triangle was placed back in the jig, and fell right into place - it looks like everything went together evenly.

The head tube and seat tube are cut to length and rough filed (not faced).

Started to fit chain stays.

It's beginning to look like a bike.

For the curious, at this point, the front triangle is 1.25 KG.

Tuesday, September 23, 2014

Pictures from 2 sessions.  Brazing and Filing, as follows.

Front end pinned and starting to flux it up.

Camera in one hand, torch in the other.

Despite bending the BB to tighten the ST/DT angle, when I started to reassemble the frame, the seat tube wanted to pull back.

A little heat on the front pulls it a bit forward and eliminates the tension.

Here's the seat lug pinned and fluxed.

The seat cluster was only pinned on one side, so I gave it a tack.  And spilled some filler.

The jigs centering cones get in the way of pinning the bottom lug edge, so a tack there as well.

Here the seat lug has been brazed, soaked, wire brushed, and is beginning to be filed.  Al little excess filler was drawn through both ports.  In general, however, the shore lines are nice and crisp - shouldn't be hard to clean up.

And here's the upper head lug at a similar point in the process.

Sunday, September 14, 2014

Back at it on a Sunday afternoon.  No quite as many pictures this time, as you'll see.

Got the BB mounted to the ST, and put the pulley mount on the ST.

In this pic, you can see that I pulled a bit too much brass through the drive side.  But, that's better than not getting complete fill.

Then it was on to the fork.  Start by sanding surfaces clean before brazing:
Here is the steerer after prep

And the crown is now brazed to the steerer.  The crown has a ledge on the bottom that the steerer butts up to.  I cut a pair of openings in the ledge to make it easier to feed the filler wire.

This is my first fork with separate reinforcing tangs.  
There is a pocket in the crown that allows the reinforcer to slide in next to the fork blade.  

You can see the pockets here.

Here the reinforcers are in place.

Apart from more fiddly fitting, there's the question of how best to approach brazing.  

There are three (or more) different weights of metal in play.  The reinforcers are quite thin.  The fork blades are medium weight, and the crown is quite thick.  Moreover, the crown has some delicate curlicues, the points of which are sharp and sensitive to heat.  

This picture better shows how a vise holds the jig while brazing.

It's just waiting for the torch and filler.

Here its been soaked, and I've begun cleaning it up.  

I'm reasonably satisfied with how it came out.  The next one will be better.

That was it for metal work today.  However, it was time to make a repair on my alignment table.  The handles of the nut (giant), that holds the BB in place, are made of what appears to be Bakelite, or something similar.  On two occasions, this has got away from me just as it reached the end of the threads, and fell on the floor.  The whole piece weighs several pounds, enough to break a handle when it falls.  Of course, each time, it landed on a different handle.  

After each incident, I've epoxied the pieces back together, and they've seemed to hold.  However, I wanted a stronger solution.  Today I sleeved the handles with knit CF tubes, I'll probably put another layer on in the future.  Right now, the epoxy is curing under a wrap of electrical tape (sticky side out).  Holes in the tape allow excess epoxy to squeeze out as you see above.

Tuesday, September 09, 2014

Got a few things done before work today, so you get some pictures.

After taking the front triangle out of the jig, I checked the alignment as pinned.

Everything was within a mm or less.  Next the top tube came off:

The tubes need to be marked where fittings will be added.  In this case, not to many bits.  A pair of triple cable stops on the top tube, and a derailleur hanger, pulley mount, and cable stop on the seat tube.  The plan is for the top tube to look like the below.
 And here it is after a quick soak:
The filler is Fred Parr's Fillet Pro from Cycle Design, and the flux was Stainless Light.  This gives good flow underneath and a nice little fillet around the edge.

The front derailleur hanger is from Richard Sachs.  His have a nice touch, an alignment nub which locates the hanger during brazing without any clamps or other holders.  You can see the nub below:
After drilling a hole in the proper location, the hanger will happily sit on the seat tube all by itself.
After some filler and a soak:
The following pix are out of sequence, the front triangle is still pinned together.  They show places where the lugs aren't fully conforming to the tubing, and need to be brought into line.
See the gap?

And below?

And that's it, what I did this morning before going to work.

More soon.