2wheel-Lee's Adventure in Frame Building

Ok, finally a moment that STR is working and I have some photos handy.

I still haven't spent the time to figure out how to upload photos into an album here, so I'll simply upload them directly here and make the comment above it.

As I said early on, my first goal is to build frames using a technique called fillet brazing. Although I found the deal on the oxy/acetylene setup, I still needed to learn to braze. I bought a bunch of chromoly tubing from www.aircraftspruce.com and a bunch of brass and flux to braze with from www.henryjames.com.

I cut and mitered a lot of joints. This gave me a lot of practice with mitering so that my joints were nice and tight. This takes a lot of file work. Up until now, I've been using a 10" bastard half-round file. I just bought 12" and a 14" files. The contour of these larger files better match the shape of the tube I'm mitering the tube to. I haven't used them yet, but I know it will make the job easier.

Although I only did one joint at a time, after mitering the tube, I brazed it to another tube. I cut them into small sections so I can see my penetration. My early joints really sucked. Over a few days and after doing a few joints, my joints got worse. #-oMy joints have since improved, but I still have a long ways to go until I can do good file-free fillets. That just means more file work in later steps. This is only a partial sample of my practice joints.

The white stuff is flux. I cleaned the flux off of some of the joints by soaking the joint in hot water. I didn't bother with some of the others.

 

Before I could start my frame, I created a full-sized drawing of the frame. At the time I took the photo of the drawing, I didn't fill in the seatstays or chainstays. But the points where they attach are pretty much shown, so actually drawing them in would have just been for a visual. Actually, if I remember correctly, I didn't have the dropouts in my hand at the time.

The drawing allows me to constantly check if the tubes are mitered and brazed at the correct angles. It also gives me all my reference angles. Really, the drawing is one of the most important steps in frame building.

 

Unfortunately, I never took a picture of all the tubes and components that will make up this frame. Oh well. #-o

We like to think that frame tubes are straight. Unfortunately, even the nicest tubes aren't straight. I put each tube on a couple V-blocks and checked which way they are bowed with a dial indicator. After the high spot was marked, I put the tube on some U-channel and drew a straight line down the whole length. By doing this, I can put the bow up or bow down, instead of sideways. It really doesn't matter if it's bow up or bow down. It's particularly important to do this with the seat tube.

 

Nice work Lee. Its a learning process.

 

One of my biggest regrets is not taking more photos. And those that I did remember to take, I wished I would have used my nice camera instead of my small point and shoot.

So this is the first significant frame joint: the down tube to the head tube. Some refer to this as a "hockey stick."

I initially tacked the joint, then I held it up to my drawing to make sure the angle was correct. After that check, I did the full fillet braze followed by another check. I was lucky that I didn't need to do any cold setting.

Here I have it soaking in hot water to remove the flux. Hot water is the only way to remove this flux. That stuff is hard! It can't be filed at all.

 

Half the fun of building the frame is solving problems. Since I'm doing everything on the cheap, I try to fabricate as much stuff as I can.

Using a bunch of birch hardwood, I made these tubeholders in various sizes. The black reinforced rubber piece holds the two halves together to make it easy to put the block halves on the frame with one hand while working the vise with the other hand.

 

sweet! i cant wait to see the finished product!

 

How hard is it to Gauge the right heat for the metal Lee. I know the hardest thing for me to learn when binding metal is proper heat/penetration without making it weak.

 

OK, now we're getting somewhere!

There are so many things going on at this point. I have my HT/DT assembly and the bottom bracket and seat tube (BB/ST).

This is the point where you have to remember to get the BB facing the right direction. I can't tell you how many times I repeated to myself that the right hand threads are on the left and the left hand threads are on the right. Got that?

My jig is a bunch of 3" right angle steel I bought at Schorr Metals in Anaheim. It's nothing special.

To aid in alignment, I drilled and tapped holes into the steel and threaded in some bolts. The bolts help ensure that the seat tube and the heat tube are on the same plane.

Note that red angle finder in the middle helps me ensure that my down tube and seat tube are at the right angle - very critical!

The first step was to tack the joint. After tacking the joint, I checked my alignment. I was way off! I miscalculated. While trying to cold set it, the tacks broke, but that was ok. I simply retacked it and checked again. It was nearly perfect! I brazed it up. I still have a long ways to go in improving my heat control.

After brazing, my alignment went out a little, but nothing a little cold setting couldn't take care of.

 

I don't know...I'll let you know when I figure it out.

Just kidding...kind of.

Initially, when the flux turns clear, you're close to the right temp. For brazing brass, when the metal is a dull red, it's pretty good. Bright red is too hot. One of the challenges is as you add more brass to the fillet, you cool the joint. Lots of eye hand coordination. And you have to control both hands! With brass, an indicator that you've cooked it is when you see copper around the edges after it's cooled down. I'm doing pretty good in that regard, but I'm still cooking flux.

It takes lots and lots of joints to get welding/brazing mastered. This is a skill that no one just has - it's developed over a long period of time.

 

Ok...before going to bed, I have to show something kind of cool.

Here is the joint after a lot of time with a file, sandpaper, and a little Dremal work. This is another skill where I have a lot to learn through practice. As much as I'd like to use the Dremal more, you really have to mostly use the file and 80 grit sandpaper. Joining pieces of metal together is fun - filing and sanding is not. This alone may eventually push me to learn to TIG weld.

 

Yea crazy Lee. I rebuilt this large tub grinder for a landscape company. I had to cut out the face of the conveyor belt with a Oxy/Acet torch. problem was, it was rusted in more spots than others. So when I welded in the new sheet metal for the new conveyor, I really learned how the heat affected thinner areas to weld to. Crazy difficult project. Finding the pillow block bearings for the hammer mill and attaching them was another project in itself. Plus I added a fixed hammer mill from a swinging hammer . So the bearing and hammers had to be custom built.The original company was out of business so it was all custom. I even had to custom order the rollers and belt. 6 month project. It was fun, and I learned a lot. I even had to wire in new timers for operation hours on the tub and motor. Not to mention, I had to take this thing apart with a Back- Hoe and some chains.
Looked like this

 

i like the finished joint. just clearcoat the finished frame to show off all the brass.

 

I'm also willing to lend a hand. I have a JMR notcher and a JMR machanical bender (but only a 1.75'' die). Oxy acetylene sucks by the way. You should tig weld your frame, it'll be stronger (and a lot prettier)

I also have tons of other random fab stuff laying around if you need anything (I use to build roll cages for race cars and offroad trucks for desert racing)

 

looks like it's coming along great lee! I've been starting to become more interested in doing frame building recently, but I just don't have the space to do it. until I do, I will live vicariously through you :bang:

 

Nice job on the sanding/filing! If you do that to all the joints, after the painting, it can pass for a carbon frame...until they pick it up.

 

Wow... this make you really appreciate what makes a good frame.

Great picts!

 

Bryan, it really is a fun adventure. Something I'm sure you'd enjoy. You may be surprised how little space is required to build a frame. I built a rather large work bench, and all I seem to use it for is for my drawing and a place to set things. I pretty much work in a 5' x 5' area. I'm either standing in front of the vise or standing around the frame when it's in a bike stand. Because what I'm doing is relatively simple tasks, I don't have any special heavy equipment - not even a bench grinder or drill press.

I didn't really have much space to work with, which is why I'm doing this on my patio. I do need to install a light so that I can work past dark (the porch light just isn't cutting it). I've actually spent a fair bit of time working while wearing an LED headlight on my head to see what I'm doing.

As I may have said earlier, I was looking at ordering a custom fillet-brazed frame. Although I never questioned the cost, I also now have a true appreciation for those artists - and that's what they are - who build these frames for a living. Now I'm not talking about those companies that work on the assembly line prinicple, but the one-man shop. It requires a lot of time and patience. Granted, after you have a bunch of frames under your belt, so to speak, things go faster, but it's still a lot of tedious work.

Thanks. I've seen photos of frames where the guys did such a wonderful job with their brazing that they didn't have to file or sand at all. Sure, it's not quite as smooth, but those looked really impressive with a clear coat. Being able to do that is a lofty goal for me!

By the way, the weight of this frame complete (yes, it's nearly complete at this point) is about 4.2 pounds - that's not bad for a steel frame! My steel Surly 1x1 is over 5 pounds. And I have faith in my construction that this frame will be around far longer than most carbon frames. And no, I have nothing against carbon frames (my roadies are carbon).

 

I actually have a JD2 tube notcher, but it is only moderately helpful. The hole saws don't cut a perfectly shaped cut that matches the tube shape. It still requires a fair bit of filing to get the miter within tolerance.

Hmm...I'm not sure exactly how to address that. In the frame building world, there is seldom debate as to which is stronger between O/A and TIG. Even some of the best custom frame builders use both techniques. Keep in mind that we're not talking about 0.125" thick material such as for a roll cage, but tubes with a thickness of 1 mm or less. The only time that O/A vs TIG strength debate seems to come up on the framebuilding forums is when a newb comes along who doesn't have an understanding of the joinery of thinwall tubes. However, I surely wouldn't braze a roll cage.

I doubt you'll find any proof showing that TIG welding thin tubes is stronger than fillet brazing. In fact, even if you go off of ancedotal information, you may actually find that fillet brazing may be stronger. But I'm not going to argue which is stronger, but be careful on underestimating the strength of fillet brazing.

Nonetheless, this is simply a hobby that will result in a few frames for my wife and I. My OA setup cost less than $100, which is significantly less expensive than a good TIG machine. And although I could borrow a TIG, that's more of a hassle than it's worth. If for some reason this turns into more than a hobby (doubtful), I may consider a TIG machine for production work.

By the way, ever note the old Schwinns that were made in Chicago? The have a reputation for being nearly bullet-proof - even when the old Sting-Rays were converted to early BMX bikes. Well, those Schwinns were fillet brazed.

And as far as TIG being prettier, well...when it comes to steel frames, I disagree. You should check out the work of some of the better-known fillet brazing custom frame builders. It's smoooooth...

 

Sweet! Nice work Lee! Can't wait to see the finished product.