Fillet brazed steel bikes, handcrafted in Oklahoma.

Archive for February, 2010

Tooling:)

I finally got a 100mm dummy axle to set up in my fork jig.

That’s the old setup, it’s just an axle and there’s nothing to keep the dropouts in phase. The pointy things are for building seatstay wishbones, the ends of the tubes rest on the points as I fit everything up. I’ll keep those and refine that setup as well. I can switch the fixture out to do either job.

So I took the new dummy axle and stuck it straight into the lathe and started turning a 1″ section in the middle down to 1/2″ diameter.

The block that’s going to hold it is 1″, so that center section will mean that when it’s in there it’s centered.

The 3/8″ hole gets drilled out to 1/2″, and the block gets cut in two.

The axle sits in the half round trench in each side of the block and the bolts squeeze everything together.

Now I just need to make some big fat washers for the axle to hold the dropouts down nice and tight. Then I’m set. Like I said, I’ll keep the tube points, but I think I’m going to replace the old rusty axle with a 1/2″ rod turned down to 3/8″ on the ends. It’ll have a 1″ center section just like the dummy axle, and fit nicely in the block. A lathe is a wonderful thing, indeed.


Visitation

Remember Perry’s 29 with the internal cable routing? He brought it by today all built up. It’s cool when you see one of your creations in the hands of its owner. Especially when you’re out on a ride with them. But, bringing it by the house is still pretty cool.  He took sharpies to it, then had it clear powdercoated.

The funny little markings are copies of runes carved into the rocks up at our rocktastic local riding area, Turkey Mountain.

That one looks like a 29, but it’s actually someone’s name. One of the explorers who carved the runes in the rock, I guess.

In an unfortunate turn of events, one of the powdercoaters cleaned off a few of the markings before he realized they were intentional.  Most of them survived though.

Maybe the trails will dry out soon so he can ride it off road.


Cleo’s 29er 3

I’ve got a little bit done today, so here’s the scoop

There’s the seat tube with the sleeve where it needs to be. I take it back off and coat everything with flux, then slide it back on.

Back to the old stand by Gasflux blue flux for this deal. I’m just not used to the stuff I got from Freddy Parr yet, and I really don’t want to have crappy penetration here.  This sleeve is gonna have the top tube and the seatstays brazed to it, and it’s an important structural area.

You heat everything up and when it’s a dull cherry red it’s hot enough for the brass to melt and wick in between the tubes. Capillary action, just like in 7th grade science class. (Who knew you’d ever care about that after the test?)  You feed the rod in at the edge, and then you can move the flame over the surface and the brass underneath will follow the heat, allowing you to pretty much fill the whole space. This also lets you remove blobs at the edges, by moving the brass until it finds a spot to flow into.

Done. Now it’s in the sink, soaking the flux off. I might get more done tonight, and if I do it’ll get posted tomorrow.


Cleo’s 29er 2

I got a bit more work done, so here’s another post. This being my first bilaminate frame, I’m just realizing how much work this is. I’ve got all the lug sleeves cut

and this is the one I brazed on in the last post. It’s got all the flux off, and it’s mitered. This cut very nicely on my lathe with the homebrew tube clamp.

I also got the seat tube sleeve done

Then I went on to cutting the seat tube to fit the bb shell.

The holesaw is mounted on an arbor from Paragon Machine Works, purveyor of fine framebuilding supplies and tools. The one modification I made was to drill a 1/8″ hole in the center of the arbor for a piece of weld rod to slide into. That’s the thing sticking out, and I use it to point to where the center of the radius to be cut will end up. I take it out once the tube is lined up.

The flash seems to stop that thing cold, but it’s spinning.

See?

Then I checked it for square, cleaned it up with a file and tacked it to the bb shell.

because having your seat tube in the center of your bb is a good thing

I put a tack in the front and back, then tinned the whole joint just a bit before putting a small fillet around the front. The tacks hold it in place, and let you adjust it a little to insure that it’s square.

Then I ‘tin’ the whole joint, meaning I heat it up and run just enough brass around to coat the whole joint but not build up. That will hold it in place really good, but there isn’t enough brass to pull it out of alignment as it cools (and the brass shrinks). The small fillet around the front is because the down tube will cover that spot, and I don’t want to leave it bare, but I don’t want to trim the end of the down tube to clear the fillet. I want it to go right up to the corner where the seat tube meets the bb. (Gospel from the book of Garro)

I’m still getting used to this new flux, it looks burned every time. It’s not, but it looks like it. Anyway, that’s in the sink. I think I’ll go downstairs and take it out when I’m done with this post. These things always feel just a little bit like talking about fight club. But, inquiring minds want to know.