oh that’s way better
solidly a “Small” in modern progressive trail bike geometry, which would then add about an inch for each additional tshirt size
Do you put a washer under your bottle bosses?
I do if I’m using silver. Not brass. Just coz if it’s luggy I’ll put a lug on it. Not luggy? No luggy.
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Why not with brass? Brass is sturdy enough to reinforce the hole by itself and silver isn’t (tc: never used silver) ?
My theory is that brass is strong enough on its own and can bridge larger gaps so why bother.
Thin tubes and un-reinforced bottle boss holes is a recipe for cracks down the road whether you use silver or brass.
I like silver for brazeons since it flows so easy and cleans up real fast. I put on some hose guides yesterday with silver and didn’t even need to soak. Just 2 min of running under hot water with a toothbrush and then I hit it with a wire brush.
I have a bunch of bottle bosses with wide heads I often use on their own since the reinforcment is basically there. On the frame above I used paragon blind stainless bosses and the heads were small so I used stainless M6 washers as reinforcements squeezing them in a tube block to give them a curve. Same washers as reinforcement for the Di2 routing holes.
Oh I should note I always used the bosses with the big lip.
funny enough I’ve been looking at this
going into a 0.4 tube, adding a 0.5mm washer will triple the strength under side loads, 90% as string as a
OTOH it doesn’t do anything against the stress riser under frame tube bending
But, using a washer thicker than the tube wall seems to make things worse, increases the stress where it meets the tube tube. I expect that would apply to wide head bosses too.
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So it looks like as a general rule it’s better to use a washer than a star for a reinforcement, as long as you stick to thickness of reinforcement ≅ thickness of tube. I’ll have to do that on my next couple of frames (particularly the one that I set aside some 1⅛" 7/4/7 for.)
Been doing aluminum practice lately. Got two tubesets from Nova once I’m ready but also need to make an oven for aging. A frame sized insulated box with the guts of an electric range is about all I have room for.
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Man, those are lovely welds. What are you using to do them?
Everlast 200DV. I’m lucky to have the distributor nearby so I could pick it up in person and I can easily hassle them if I have any issues. Aluminum requires AC and higher amperage, which is why I bought the machine I did. For steel bicycle tubing you can get away with a much cheaper set up.
I never felt that taking a framebuilding specific course was worth it when I could just read forums and mess around on my own. I gotta say that taking a community college TIG course was really good investment. No way I could have figured this out on my own.
Sup welder bro. I still haven’t even set mine up yet though. I only have 120 out in the garage though, still deciding if I want to move it to the basement and share the dryer outlet or maybe pull another line out to the garage.
It was a couple months after I bought my machine that I finally got it set up. I put a dedicated outlet in the garage at the same time I did the wiring for my mill. Mine will run on 120 though, just at a lower max amperage and duty cycle.
HY nice work 
Fuck yeah so nice seeing tarckers tinker with bikestuff!
One of these days I’ve gotta get one of those.
A jig or a bringhelli one specifically? I may be building my own soon. I’ll reach out if I put it up for sale.
A jig of any sort, since right now I’m using this thing:
(miter the tubes in the basement/bike mess, fit them into the jig and reset the lug angles in my living room, then carry the jig out to the garage to braze the front triangle, then pop it out of the jig and freehand (with an angle & an axle square) the chainstays. It’s somewhat baroque, and will fail miserably when I get around to gluing up an O/S frame.)