jhodgson

Yes! I have decided to finally try to build a frame. It is going well so far ... in that I have not yet blown our house sky high or sliced my face off. I'm nothing like the kind of fabricator folks in here are, but I want to finish even if the finished product is worth only its scrap value.

I don't see too many build threads so hopefully this isn't something that's taboo. Sorry if so.

Anyway! To start, Matt Bowns of 18 Bikes was kind enough to do a design for me. I don't have BikeCAD and I don't really know anything about geometry anyway, so that was super helpful. (attached).

And here's a photo of where we stand so far:

unterhausen

Thanks for posting this, I love build threads, there haven't been enough. Once I start building I don't stop to take enough pictures, and it's a shame.

guy153

Great to see a build thread! Looks like a nice classic design of frame.

I am quite jealous of your welding table. You can probably fixture everything up on there without needing a jig.

jhodgson

Hey, thanks. It is pretty great. I have been happy with it for my various furniture and whatnot projects.

I have cobbled together some wood based tube blocks I could maybe use for "fixturing" although their likely precision is.... questionable to say the least.

unterhausen

If you don't want to go all the way to an Alex Meade fixturing setup for a table, you might consider Paragon blocks, which are not that expensive and dimensionally accurate.

jhodgson

Yeah they do look pretty great. That site is here for anyone else wondering: https://www.paragonmachineworks.com/...be-blocks.html

They were out of the sizes I wanted last time I looked, I guess because of everyone doing COVID bike projects just like me. Appears they are back in now, somewhat.

My plan for this project is to get through it on the cheap as much as possible to have the experience of building a frame.

I have a tendency to buy lots of tools which is fun but not financially sound, especially since all my work, like a lot of folks', more or less did a nose dive into the toilet back in April.

guy153

The precision on your wooden blocks is likely fine. If you can set things up to within a mm or so that's good enough. But it is useful to have a flat surface which yours probably is if you're using it to lay out the whole frame.

But I don't know how it works with lugs anyway. You presumably can't tack it with the TIG because it all needs to be covered in flux before the tubes are inserted.

jhodgson

I also don't own a TIG machine, but yeah. The table should be flat-ish. Not a surface plate but not crazy out of whack either.

David Tollefson

Loving that logo design.

GrayJay

Rather than welder tacking, traditional lug framebuilding method is to lay on the aligned frame tubes, drill 3 small holes piercing through the lug and tube where they overlap then hammer/tap a small nail through each of the holes to hold the joint in alignment while you braze the joint. On many old lugged frames, you can find the remains of the nail pins inside the tube.

https://www.cycledesignusa.com/pin-k...famous-pin-kit

unterhausen

The pins are always left, AFAIK. Stabbed myself too many times trying to fix a pinned frame.

Doug Fattic 

The reason frames were pinned in the classic era was because they were hearth brazed with a huge natural gas flame augmented by a squirrel cage pushing air into the flame to increase its heat. It predates when oxyacetylene torches became available. I actually learned how to do this when I was learning in England in 1975. We hung the frame over fire bricks surrounding the joint. This firehose size flame would more evenly heat the joint to minimize alignment issues. The pins would mechanically hold the tubes in position. The reason it is done today is a method of trying to hold alignment. This requires that the frame be held in close alignment while pinning.

Even though I learned frame building by pinning, it is not a method I prefer today. Instead I spot braze the frame to hold it together (which wouldn't be possible with hearth brazing). This allows me micro micro alignment adjustments as I am going through my frame brazing sequence. With this method my framebuilding class students are able to hold a half mm or less of alignment accuracy. I don't hold the belief that for road bikes just being close is good enough, Of course there is a point of diminishing returns. A millionth of an inch is not better (or possible) than a thousandth of an inch. But if you are a couple or more mms out puts you in the mediocre category.

jhodgson

Got in some brazing practice today. Maybe not the prettiest but they're definitely stuck on there.

Definitely easier managing heat with the Victor j28 & 0 tip. I was using a full size torch before.

Opinions welcome!

guy153

Well I don't know much about brazing but those look pretty nice to me. Neat and they're not going anywhere.

Cynikal 

Looks fine. I'm assuming you are using 56% silver, there is a little over filling of silver but nothing that can't be fixed by some file work.

TiHabanero

The first time I brazed up cable stops it surprised me how absolutely little filler was needed. Quickly learned to just touch and go to the next one. Looks like you have done them before. Doing good!

jhodgson

Yeah I did totally go too heavy on the filler.

But a little sanding and filing and now it only looks like I kinda put too much.

duanedr 

Congratulations and thanks for posting ! Your heat control seems to be in the right range so that's a great start.

With braze ons, if I add filler along the tube axis, I have better luck minimizing the drops - and as mentioned by others, you won't need a lot of filler.

As you're cleaning up the inevitable drips, be careful with your file. From the picture above, it's hard to say whether the tube is compromised - and good job practicing! - but there are a couple spots where the file has cut into the tube. In general, you don't want your file to touch the tube when cleaning up.

Keep going just keep the file away from the tube. And keep posting pictures!

jhodgson

Yeah good call. This is a practice piece so no worries, but I hadn't thought of that. Will be a concern if/when I do thinner wall stuff.

Thank you!

unterhausen

avoiding cutting into the tube is why I hate filing. I think I would have left it unfiled. You don't need a fillet around those things.

jhodgson

I just get excited when I see the filler material doing things.

HOLY **** ITS WORKING!

Will calm down next time

repechage

I have always activated the flux only once. Way, way back, when I first watched someone tack braze a frame first, I wondered about the effectiveness of the flux, for the subsequent reheating.

repechage

if there is a notion to use downtube levers, after the miter those braze-ons look to me as the levers are very near interference fit. if there is just a plan for cable stops, no issue with that.
in the future, consider sacrificial tape to manage tube scaring.

jhodgson

Yeah no worries. This is a 100% practice tube.

GrayJay

For this braze-on joint, I would probably concentrate more flame heat into the actual shifter boss, less into the tube. The molten braze will "follow the heat" and get pulled underneath the braze-on leaving less mess on the tube. Plumbers sandpaper cloth roll will do a good job for the final cleanup of a joint like this on round tube without file scarring of the tube .