Wednesday, June 27, 2012

Having started cleaning up and filing lugs, it seemed likely that some of you would find some pix interesting.  With no further adieu, here they are:

Thursday, June 21, 2012


I haven't brazed a lugged frame for a while, but I did today.

Since I last posted brazing photos, I've replaced my torch.  I was doing a second pass to build up some filets when the old torch started to go crazy.  I replaced the valves, but it still wouldn't hold a position for either gas or 02, causing the flame to keep changing.  Random flame size and gas/02 mix make it hard to braze.  And the second pass came out very lumpy.  Naturally, I caught plenty of grief for it.

But that issue is long past.  I use a Smiths torch, which offers a life-time warranty, so I'll have to send the old one in for service one of these days, which will give me a spare.  That's one of the benefits to using high-quality American products.

Anyhow, today I was doing a double oversize frame with Dazza's Slant Six (actually they have a new name now, but its less memorable to me, in my old age). .

Sunday I installed the brake cable tunnel in the top tube, and mitered and fit up the main triangle.  Finally, I brazed the chain stays to the  BB.  I like to do this first and insure my alignment between them and a foundation of a frame.  I use brass filler here, and then use silver later when installing the seat and down tubes.

Today I started by installing H20 mounts, and a chain catcher and cable stop on the drive side chain stay.

From there, I cleaned up the lug edges, sanded the insides to a clean fresh surface, cleaned the tube ends, inside and out, and fluxed the mating surfaces on the lugs and tubes.

Then its time to put it all together in the jig, and set the pins that will hold everything together.  I don't know about anyone else, but I find this to be a messy job, with flux slipping out of the joints, while I try to hold the everything together as I fit the jig back to the frame (or is it the other way around?). 

Also, there are always one or two pins that want to come loose as I set other pins.  It's important that the pins hold well, because we move from here to the alignment table and I don't want things shifting between work stations.
First I double check the chain stays - they're centered to within less then a mm.  BTW, that's my antique Starette height gauge that I got for a song on theBay - it works great and much cheaper than anything new.

Now lest you think I'm cavalier abut the rear alignment, my experience is that heat in the frame will shift the stays - so there's no point in trying to move things around.  We'll check again later.

Next I check the alignment of the main triangle.  The down tube needed a little adjustment (about a mm), it required the remove of a pin, and its replacement in new location.  Then all looked good, so I made sure the pins were tight, one more check and its time for flux.

The Slant Six upper head and (and especially the) seat tube lugs are long.  So the filler needs to be pulled a bit farther than with some other lug sets.  But I use Stainless Light Flux, which is effective at cleaning, and holds up well to time under heat.
That's a fluxed joint with pins sticking out.  Which naturally leads to brazing.

There are a couple of spots with a little overfill, but not too bad overall.  Since these pix, I soaked the flux off the joints, trimmed off the pins, filed the pins down on the inside of the head and seat tubes, and reamed and faced the head tube.  I should have taken a picture of the faces, which have a perfect circle of fill between lug and and tube, maybe I can add those pix later. 

After than, it was time for an hour and a half riding, then dinner, and off to write you a few blog posts.  All in all a busy and productive day.

A stranger visits

Wow, its been a long time since I visited this place!

Where to start?  Well, I recently got a new helmet: a Lazer 02.  After trying to purchase at a local bike shop, I ended up going to the local Performance - everyone else was out of stock for anything from Lazer.

Let me back up.  I've been wearing cycling helmets for a long time - starting with an MSR (that's Mountain Safety Research -  and yes, it was a modified climbing helmet), with a bright yellow hard-shell, complete with a generous three round holes (the diameter of my index finger) front and rear for ventilation.  That helmet was very much appreciated when a front tubular rolled off the rim, landing me on my back in the parkway (fortunately), still strapped into my pedals, with my hands still on the brake hoods.  Can you tell that when I started riding, I had no role models for how to properly install a tubie?

I think there are times and places where a helmet is entirely optional, but, I don't allow my children that choice because I don't think that they are ready to make a thoughtful judgement.  And to encourage their helmet usage, my wife and I always wear a helmet when on the bike.  So, with all of us always wearing helmets, its that much  more important that they fit and work well.

Normally I wouldn't bring up so mundane a topic, but I think that the 02 is a brilliant design.  Fitting it is not dependent on the rider's head shape.  Which is cool.  And most riders can fit in a single size.  Which is also cool.

First from a shop's perspective: many fewer sizes and models need to be stocked to address various sizes and shapes of riders heads.  SKU counts in the industry are pretty crazy, and anything that can help a local bike shop limit its SKUs,without limiting service, has be good.

More importantly for the riders, its possible to select a color and size (most won't need to go to the extra large, but a simple measurement at home will tell the story).  No worries about fit - just turn the dial until it fits, and you're done!

Let me caveat this, some reader(s) has no doubt tried the 02 and found it not to their liking.  I can respect this.  But, this fact doesn't undermine the idea that most people should be able to easily get a great fit with an 02.

OK, I can be a geek for design, but I think this one is neat.  I just don't know why they don't apply it to the rest of their helmets.

The 02 has effective ventilation (copious sweating qualifies me as a tough tester), and the helmet quickly goes unnoticed by the rider, neither pinching, slip-sliding, wiggling, or in any other way calling attention to itself.  So what's not to like?  Actually, I'd like designers to come out with silent helmets.  One of the beauties of helmet-less riding is the absence of wind noise.  But I'm resigned that a quiet helmet is probably still a long way off.

On the other hand, there has been a recent trend towards lighter helmets.  Spend your money if you want - the lightweights may cost 2 - 3 times what an 02 does.  But, I don't see a helmet as a smart place to try to reduce weight.  It has been pointed out to me that some lightweight helmets use special new expanded foams that do a better job of shock absorbing.  That may be.  And, to the degree this works, great.  But, I don't find, even after a century ride, that I  notice the weight of my helmet on my head.  So what's the benefit to a lighter helmet; maybe bragging rights?

However, if you can feel the difference in helmet weights (generally we're talking about going from 300 to 200 grams, or about a 0.2lb weight loss), or if you just like some aspect of the design of a lightweight helmet, and its been certified, go for it.  I'll still respect you in the morning.  But I'm going to hold to the notion that a helmet is last place one should look to save weight.

So that's my 2 cents on the Lazer 02 and bike helmets in general.

Dissenters are welcome to leave comments.