M_V's multitude of bikes and adventures in the land of framebuilding

Nice fillet on the stem.

Thanks, the one on the frame isn’t quite as nice but it was done first so I’m hoping I keep on improving. Might do the Bicycle Academy masterclass at some point.

The tubing for the steerer clamp and extension are from eBay, the handlebar clamp is 4130 from LAS Aero.

I have steerer/extension in 4130 too but using more of the cheaper stuff for this first ‘practice’ stem.

Got a couple little bits to tidy up in the fillet around the binder then I’ll ream the clamp, drill and slot it and it’ll be done.

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Really interesting to following your process. Stem looks good!

Awesome. How did you go about alignment for the stem?

For the handlebar clamp I went with a similar technique as you would when building a frame out a vice and doing the seat-tube, zero the level across the vice, check the extension tube is at 90deg to that, tack, check, adjust, braze.

Think I also put the handlebar clamp in one end of the vice and checked the extension tube was parallel to the jaws.

For the extension tube/steerer clamp, I had built a jig out of extrusion and ali bar but I found brazing the stem in the jig wasn't working, the ali bar I was using to replicate the steerer acted like a big heatsink so I couldn't get enough heat into that tube yet the extension tube was getting overheated. The jig did at least let me verify the mitre was right and to braze it I think I opened the vice right up and put it length ways in there and used a digital angle finder to check that the handlebar clamp and the end of the steerer clamp (which I squared off in the lathe so knew it was square to the tube) were at the same angle.

I tacked it like that and then the steerer clamp tubing happens to be 32mm od and I have about another 500mm of it so I clamped the stem to that, put that in a tube block and clamped that in the vice.

So as far I can tell I think it should all be pretty square, we'll see what its like once its on a fork and has a 750mm wide handlebar in it though...

Talking of the stem,

That's pretty sweet! I'd be over the moon if I could make something like that

Had a few days off work so got the top tube and chainstays done on my track frame.

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Looks great.

Reamed and faced the headtube at work the other day and either the cheap headset I bought is undersized or I’ve oversized the headtube.

Bit pissed off to say the least but lesson learned and I’ve got another headset on the way which I’m hoping will be a better fit.

Worst comes to worst I might just braze the cheap steel cups into the frame.

To take my mind off it I’ve started on another stem. I’ll make the steerer clamp a bit shorter this time and hopefully end up with a stem that fits on the Hummus.

90/0 deg, 100mm extension.

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The latest bit of madness to come my way is this fillet brazed speedway(?) frame.

Was bought off eBay by a colleague a year or so ago and he never built it. He is moving to another job so needs to clear out the stash of projects he has here.

Weight is about 2.75 fuck tons and it is sized for 26 x 1 3/8” wheels (though I fancy I can get a 700 in the rear of it if I move the seatstay bridge.

The current fork and crown race are not good friends (ie they ain’t ‘tight’) and there’s a quill to ahead converter stuck in the fork at the moment too.

I couldn’t help but do s bit of paint removal (the paint job is fucked anyway, lots of rust) to check it was fillet brazed and not ground down welds or filler.

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Looks absolutely hideous. I love it. :)

I should have mentioned, it’s pretty small, 45cm c2c on the seattube.

Toptube is better at 55cm.

Not entirely sure what I’m going to do with it though my mate has made his de-facto “tallbike” suggestion...

Previous owner asked me to remove the headset as he has a use for it, glad he did as I’d forgotten about this stupidity!

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Today is a good day.

New headset arrived and it does not just drop into the frame so it was just that the other one was rubbish (guess that’s what you get when you buy a £4 headset off Santafixie).

Also got started on the wishbone rear end. Reinforcement piece shaped and centre tube mitred.

Think I’m going to use one piece of tube that pierces through the centre tube to join the stays.

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Are those reinforcements actually reinforcing anything?
The joint isn't going to be any stronger is it? Just the tube beneath it for a small area

I'd love to see that with a tiny wheel cargo fork.
Maybe both: a tallbike with a tiny wheel cargo fork.

And bars with ridiculous rise.

Yeah they spread the load from the end of the tube over a larger area. The reinforcement piece may not be much bigger than the diameter of the tube but it’s huge amount more area of contact than the end of the tube would be.

I think if you filleted straight to the seattube you’d be putting a lot of heat into a pretty thin tube and that’d most likely result in distortion of the seattube. This way the hot fillet is done to a heavier piece of metal and then I use lower temp silver brazing to join that to the seattube. If the reinforcement piece gets distorted during the fillet braze it doesn’t matter as much because the filler material can take up the discrepancy.

Makes sense I guess. Fag packet maths or what?
Just wondering why you don't see it on more frames

I asked in a framebuilding Facebook group and the people replying asked about tube wall thicknesses (.8mm on the seattube, .9mm on the toptube. The tube for the centre of the wishbone thingy is top tube) and recommended I use reinforcement.

I think you see a lot of frames where the seat stays meet the seat tube at the same point the top tube does and they use a single piece of reinforcing sleeve but that wasn’t how I wanted to build so we end up with this.

Toptube is better at 55cm.

Approx 21.5"

Skinny tubed big wheel BMX I reckon. Maybe cruiser class bars.

Gotcha. Well, top work so far. Following your progress closely

Nah, brklss and imperial wheels = speedway. Tiny headtube because of regulation riser-situp bars.

I know. I was just giving a suggestion for how he could use it (if it's too small to use as it's intended function).

Sorry, didn't make it very clear.