Frame #1.5

As reward (HA!) to you all for the advice, guidance and warnings, I thought I'd post an update in pictures from where I started back in October or so to progress on #1.5. I'm calling my first complete frame (pictures at bottom of this post) #1.5 because I only completed the front triangle of my first attempt before making a fatal mistake. I let the ST/BB assembly twist out of phase with the TT/HT assembly as I was brazing the TT/ST joint. The BB was pointed one way while the front triangle was pointing another by a few degrees.

I have a couple boxes of junked practice joints but here's an early sample of seatlug work. Mmmm, toasty!

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With lots of practice I got a tiny bit better.

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The following few are of frame #0.5:
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You can see how I wrapped the DT around the bottom of the BB. I already had a full fillet around the base of the ST and I wasn't sure how to miter around that so, I offset the DT to the lower side: I kind of liked the detail after I cleaned it up and may try it again on other frames.
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At this point, I realize the BB was out of phase but, I had made what I felt was decent progress and learned a ton. With some offline advice from board member Alistair who lives up the street, I abandoned the effort at this point and cut it up to see if I was getting good internal fillets. I was pleased to see that I was. I'll use the shortened tubes on a kids bike or something.

The next series are from frame #1.5. Same design. Single speed utility bike with 700c wheels and 28mm tires. In these photos you can see brazing is coming along somewhat - still blobby at times. My next hurdle is positioning while brazing. Knowing where to rotate to to get best aim at the joint and best flow from the filler. I am using just standard LFB from the welding store and either Cycle Design Nickel Silver flux OR Gasflux C-04 paste. I clean the joints with isopropyl alcohol before applying flux.

All of my work is done with hand files, a vice, Paragon tubing blocks, my new marble slab and some machinist squares/rulers. The only power I use is a drill to run a flex hone to clean out the insides of the tube.

My approach was different for my 2nd attempt. On #0.5, I mitered and brazed each joint in sequence and to completion. Because sometimes there are days between my work, my brazing would deteriorate and all joints were of equal mediocrity. On #1.5, I mitered everything except the seatstays and then tacked and aligned the front triangle before putting it in the Park stand to do the fillets on all joints. With each joint getting slightly better as I worked my way around the triangle, I'm sure on average, it's better than before. I was amazed to put it on my slab and see that it was VERY close to flat with well less than a 1mm difference across the front triangle (at least by my measurements).

I made a simple fixture to hold the dropouts/CS assemblies while I tacked them. It seemed to work pretty well but the chainstays pulled in a bit during brazing so I had to cold set the right out a couple mm to restore the 130 rear spacing.

I haven't added bottle cages or other braze-ons as I didn't want to waste them just to chop the frame up again. Now that I'm confident that it'll be rideable, I'll add the fittings for bottles, racks and other stuff. As you can see in one picture, the right drop out/CS junction is not offset properly to allow the cassette to pass when the wheel is at the most forward position. I will put that in the notes for #2.5.

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I found a nice flat slab of marble from a local countertop dealer. That helped remove some of the uncertainty about whether I was aligning correctly. I changed from a Victor 100 to a Victor J28 with TM hoses which helped immensely and finally I purchased a pair of ACE/Didymium glasses with 150 magnification which also helped immensely.

This is definitely challenging, addictive and expensive...a very bad combination .

I hope I got all of the pictures attached/uploaded properly.

Thanks again for all of the guidance. I'll post more as I get closer to completion.
Duane

Quote:

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Originally Posted by duanedr

junction is not offset properly to allow the cassette to pass when the wheel is at the most forward position.

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Depending on the amount of meat at that joint you could possibly file that down a bit if you need to?

I made a similar 'mistake' on frame #1 and haven't done it since. The good thing about my mistakes is that they sink in better than when I just read about them. :)

-Bernie

P.S. nice pics and write-up btw... thanks for sharing.

Great stuff.

Have any pictures of your simple fixture for dropouts/chain stays?

I'd think you could just file down that tight clearance on the cassette then if an opening is created fill it with some brass.

Quote:

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Originally Posted by shirk

Great stuff.

Have any pictures of your simple fixture for dropouts/chain stays?

I'd think you could just file down that tight clearance on the cassette then if an opening is created fill it with some brass.

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Yes, I could file it down but it's only an issue with a 10sp cassette when the wheel is pushed all the way forward. The dropout doesn't have a derailleur hanger so, it's not an issue at all. The best type of learning experience ...I can clearly identify that I missed something but there's limited consequences.

Here's a picture of the fixture. I just used stuff from Ace. The square bar fits snugly into the square tube and adjusts for different length chainstays or seatstays. Since the square bar detaches, I can have several of them with different fixtures brazed onto the square rod for different purposes - cantilever posts, bridges or chainstays. I took this picture before I brazed a saddle onto the bar which is clamped to the back of the ST to position the rear assembly for tacking. I'll see if I can find a picture of that.

I have tweaked the dummy axle a bit from this picture to make it more secure and have some ideas on how to make the whole thing better in the long run.

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I'll post more pics over the weekend.

Thanks

I dig seeing other people's solutions.

I used a couple of cheap lengths of angle from Home Depot.

http://shirk.smugmug.com/Frame-1/i-Q...P1070365-M.jpg

http://shirk.smugmug.com/Frame-1/i-w...P1070367-M.jpg

So, Frame #1.5 is complete and I am just back from it's maiden voyage. It rides just fine - even with no hands. It's pretty flexy but, for what it is, it's grand.

I am using a Nexus 7sp internal geared hub with roller brake (which isn't hooked up yet). I had an old brass roller from some ancient roller brakes so, I added a mount for that at the bottom of the ST to carry the shifter cable (2nd to last and last picture). I don't have a picture of it complete, this was just a first mock up to make sure i wasn't too far off.

The front wheel is just something I had handy. I'll be building up a nice wheel for the front with a SON hub. I still need to add a little cable guide to the underside of the BB for the rear brake cable and a small tab to secure the brake arm - which is why it's not hooked up yet. Then I'll add fenders etc. I have just used rattle can clear coat on it so far as I expect to sand parts off to add braze ons for racks and such. I didn't spend a ton of time smoothing the fillets to perfection. I could already identify places where I had cut into the tubing and where the fillet wasn't big enough to make a nice radius. I plan to ride it for a year (or until it breaks) and then cut it up and see where I am. I have concerns that flux is inside the tubes (is this an issue?), internal fillets aren't as good as they should be and I'm not using enough filler. Looking at Doug, our hero asks: Are these typically where newbies fall short or should I be worried about something else?

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The next project is a fork. Probably for the 24in kids MTB. I have the bits, I'm just building a fork leg bending mandrel(?). Then I have the parts to build a fork jig based on Alex W's design. That ought to carry me nearly through July. Then I will start work on a 24in MTB for my son. Then I will work on something for me for a daily rider. Now that I've used System 48, I may try something with lugs.

Further Learnings:
Forum Members = awesome
Still wondering how I justify a 3 week 'business trip' to Niles Michigan
Lighter torch (J28) is better than heavy torch (Victor 100)
Measurably Flat(TM) surfaces inspire confidence
Wade at Cycle Design is very helpful
System 48 and Fillet Pro are revelations compared to LFB
Holy crap is this hard
Holy crap is this addictive
After paying a shop to prep the BB and HT, the cost of those tools seems pretty reasonable.
Drill press = gateway drug for mills and lathes

Thanks everyone again for all of the information.

Thought I'd add to this thread to keep my progress in one place.

Over the past several weeks I've been working on a fork leg bending tool. I used mahogany wood and cut a fairly tight radius. I think I started with something like 5" radius but as I cut it, I got a bit off the line. I have a few more pieces of wood so I'm counting this as the practice attempt.

I was going to use a router to make the groove but, got impatient so, I just cut a 'V' with a coping saw and then rounded it out by wrapping a fork leg with sandpaper and went at it. Showing the wood who is boss, so to speak.

Thanks everyone for posting pictures either here or on picture hosting sites as I borrowed quite a bit from each of you. Everything came from either Ace or OnlineMetals.com's scrap bin.

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My new drill press has been a great addition to making this fixture. It makes me want a mill or lathe but, until I learn more about metalworking, I think this is going to be just fine.

Since one cannot have too many benders, you may find that keeping the die closer to the mandrel helps keep the metal being bent from distorting. It looks like the fork leg did pretty well with your bend however. So if you're thinking about modifying, make the pivot lower so the roller follows the bend, get a handle on that thing for leverage maybe like this:
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Yes that's Mr. Rodrigez hiding in the back;)
cheers
andy

Is that roller adjustable? I went back and forth on where to put the handle pivot but didn't really consider mounting it that much lower but now that I see it, it makes perfect sense.

Do you insert anything in the tip so it doesn't get deformed by the bolt/clamp as you're bending? I did but now that i'm measuring it, I think the deformed part would be cut off anyway so, maybe that's not necessary. I will continue to insert my bolt either way as it just seems to make sense to me.

I think the blade came out fine but it's right at what I would guess is the limit to how far it could be bent without compromising integrity. I'm not sure I would use this as it is but, that is based more on superstition than science or experience.
Thanks again

Yes it slides up and down the rails, since it was hard to get it perfectly lined up in version 1.0.
The wheel/die was from McMaster, the aluminum fork bender Patericks design from Northwest Castings.
I haven't smushed the tip with the screw, a lot of holding comes from the aluminium thingy holding it down.
Your bender is fine, just some suggestions for your next one, like if you need to bend seat stays etc.
cheers
andy

for those who want to re-build the wooden bender: Mahogany is pretty pricey and Ash or Beech may be good alternatives. Both are used for ax handles and other high-load applications.

I found a scrap 2x10 at a local woodworking shop . I got about 4 feet of it for $20 or so and I figure I can make 3-4 molds from that length. I agree, I could have done this cheaper. I like the look of the mahogany though. it has a nice rich luster to it. I finished it with linseed oil.

it looks awesome! that is a killer price for mahogany... good work, i am sure it makes you smile every time you use it.

Quote:

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Originally Posted by duanedr

I found a scrap 2x10 at a local woodworking shop . I got about 4 feet of it for $20 or so and I figure I can make 3-4 molds from that length. I agree, I could have done this cheaper. I like the look of the mahogany though. it has a nice rich luster to it. I finished it with linseed oil.

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Thought I'd post an update. I originally built it intending to use an old Shimano internal geared hub with the roller brake and upright bars. After riding it a bit, I remembered why I took that hub off whatever I had it on before. It's terrible. Here are pics from what it spent it's first 2-300 miles:
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STarting at the front, the fork was just a cheap stand in. I built a proper fork and it's ready to install this weekend. It has a lot more rake so, should handle nicer than it did.
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Then moving on the back, I've added a derailleur hanger, rear canti posts and a cable stop as well as a small noodle under the BB for the Ft Derailleur cable:

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I'll soak it tomorrow and then sand off the rust and repaint with the rattle can clear coat that it's currently covered in.

As I was doing this, I wondered about the following:

- rear cable stop material - I used pretty thin walled (.028in) tubing from Spruce and i'm wondering if it'll crush under hard braking. Should I add a triangulation brace? Probably now that I think of it.
- Is Silver (system 48) ok for attaching that cable stop?
- I used brass on the canti posts but would System 48 or other silver work assuming the gaps are reasonably small.

As always, feedback welcome.