Orbit America road rat vs. Cannondale FBNPNA ft. home-made rack

Three projects for the price of one!

Number one is an Orbit America frame in 531st. I bought this off Scilly.Suffolk (not going to @ people because I'll drag half the board in). I bought it because it was my size and had groovy paint. And was cheap. Here's a picture of it with some bits on in a mock up build:

Here's some close-ups of the paint. It's rusty in places, hence the "rat" status of this bike.

I'm sorry I'm not better at photographs.

You'll see a Sigma stem (?), Soma Hwy One bars, Campag Mirage x Mavic M4 wheels, and a Record seatpost that's too short. There's only about 45mm of post in the seat tube there. The groupset is Chorus carbon 10-speed. I'm not going to photograph that because the light was fading. How is that "rat" you ask? I don't know. Shut up.

Still need a seatpost, the wheels need retensioning, possibly need tyres although I've not checked what I have lying around.

My wife asked me, as I was assembling the bike in our martial chamber, what it was for.

"Cylcing," I replied.

"In what conditions?" she continued.

"Summer."

"How is this different to your other bikes?"

"None of my other bikes are blue."

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Number two is based on this frame and wheels

I'm going to convert it to flat bars with a 1x9 drivetrain made from Sora parts. I never liked it as a road bike the way I had it set up, and before I'd used it much I'd nicked a few parts off it so it's sat unused in the garage since July.

I'll de-sticker the wheels, use the middle ring of my (fugly) Sora triple cranks and I've got a Deore LX 9-speed shifter and Sora mech. Saddle will be a Rolls or a Regal cos I have them lying around. I need a Hollowtech BB and might treat myself to a shiny new 9s chain.

Need possibly some tyres. I reckon I can get 28s in there. I'm not having mudguards but I will have a front rack (see next post). I need some grips. This has been a real source of irritation for me as I basically want to pay as little as possible for them, yet want them to look somewhat interesting as the bike's otherwise all black and silver. I missed some red, white and blue Lizardskins on eBay the other day (white rubber with red and blue lockrings).

Inspiration has come from Spotter's Jose Alvarez and Verbs and Nouns's Cannondale Rack.

BONUS PART THREE - brazing a front rack

Inspired by the home-made racks of Hulsroy and M_V, I have decided to build a rack. This was also intended to save me some money vs. the hens' teeth Soma Porteur option but it's probably going to cost more with everything factored in.

I've done my research, and with some help from Hulsroy and some of the nice blokes at Herne Hill Makerspace I've got a plan.

10mm mild steel tube with 1mm walls in a grid like this:

Then bosh some stays on!

Easy.

I'm using MAPP gas and a lot of the advice on that comes form US sites, so getting exact info on what (UK available) brazing rods to use is tricky, but I think I'm settling on Silver-Flo 55.

Alex Wetmore's blog is a really good source of rack brazing tips, which I've leant on heavily. I shall order the tubing tomorrow.

"None of my other bikes are blue."

#smackdown

It's about time: I'm pretty sure it was in black & white when I sold it...

Yeah! Logo would suggest I build up the Cannondale for road and the Orbit for rack, since it has eyelets (I think).

I'll have to make do with p clips on the Dale or make the rack so it can be QR mounted .

Also remembered I need shallow chainring. bolts for the cranks. This is becoming a shopping list.

I've tried SilverFlo 30 recently - works fine with a propane torch and is cheaper due to the lower silver content.
One thing that does help when brazing is to reduce heat loss: I made various shapes using fireclay and assorted tins that can be placed around a joint. Commercially made fire bricks would also work, but I had half a tub of KOS to hand and I'm a skinflint.

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Cheers - do you have a preferred source for the rods? Johnson Matthey say it's not a good filler metal but maybe you mean 302?

I've no idea how many rods I'll go through, including the ones I'll need to practice.

1? 2? 10?

http://www.ebay.co.uk/itm/SILVER-BRAZING-SOLDER-FLUX-KIT-Johnson-Matthey-Ag130-x10-rods-Easy-flo-flux-/182005843945?hash=item2a6064c7e9:g:TSAAAOSwd4tTwXkU

I’ve found it flows adequately (very clean steel and more flux than you would imagine) and readily fills the sort of gap left by fitting parts made by hand (saw, file, abrasive cloth in a drill arbour)
At risk of hijacking your plan / thread: curves are also a possibility without resorting to a pipe bending jig if you want a back to your rack or safer front corners.
Twenty (ish) junior hacksaw cuts passing about 90% through the tube will allow a right angle bend. The closer together the saw cuts are, the smaller the radius of the bend. Braze up and file to give a smooth curve...

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The front rack I made used around 40cm of 1.5mm dia. brazing rod including filling the slots for the bends if that helps with estimating costs etc.

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Looks very tidy! Is that powdercoated? I was going to weatherproof mine in as cheap a way as possible, which might be Hammerite. Even cheaper would be not using it in the wet.

Re. the fire bricks - did you find that made an appreciable difference? Some internet sources recommend them but it's difficult to know if I will because there are the variables of torch/gas/size or workpiece/melting point of filler to consider.

I think MAPP (technically now MAP Pro) is hotter than propane but could be wrong.

How much time did you spend cleaning the steel before fluxing? And how far around the joints did you paint the flux on?

Finish is rattlecan, possibly plastikote, done some years ago - it now looks a little tired where bungee hooks have worn through to the metal, and I keep meaning to give it another coat when the weather improves. Or not, and call it patina.

Propane can be marginal at the kind of section you'd want for a rack, and the flame from my GoSystem AP2010H is probably quite diffuse compared with MAPP specs. Firebricks can make all the difference, as can care when clamping the work - too close and your clamp becomes a heat sink. The thing about a home made fire brick is that it uses less gas and is cheaper than buying a bigger torch.

A lot of mild steel comes oiled or lacquered to prevent rust in storage - this needs removing a good 50mm either side of each joint, if only to avoid setting off smoke alarms. I usually remove the lot before doing anything else, using an angle grinder with a wire brush, and the same angle grinder+wire brush to clean up after brazing / before painting.

Flux should be a smooth thick paste, so that a generous amount can be applied close to the joint - I try to stay within a few mm to reduce the area where solder or braze might pool on the outside rather than flowing into the joint. Painting flux on to the actual joint surface before assembly often works better than clamping and painting flux on afterwards.

I appreciate the input, thanks.

Just ordered the steel and the rods/flux.

I'm wondering how exactly I'll attach it to the bike. At the bottom I can do p-clips (easiest) or work out some method to attach it using the QR - any suggestions?

At the top I'm thinking a bent strip of steel that bolts in behind the front brake, but how to attach that to the rack? The Soma Porteur uses bolts and eyelets within the frame to allow the metal bracket to slide, allowing for variation. Are eyelets easy to braze in?

If there is a part of the fork which is both circular in section and a standard (plumbing) diameter then munsen rings might be a more engineered solution than P clips? I've used them to hold rigid panniers to a 1950s moped rack, and a frame for a lead acid battery to handlebars, and been satisfied with their load carrying ability.

Much of the fitting hardware for the Soma Porteur is to allow a single design of rack to fit a variety of bikes - if you're making a custom rack for a specific bike then many of the adjustment options shouldn't be necessary - the long slot in the rear bracket can be replaced with a single accurately placed hole (or short slot to accommodate errors in measurement) and a single bolt rather than the two or three needed on the Soma to compensate for the lack of contact area under the bolt head. You could even be brave (confident that no adjustment will ever be needed) and braze the tang directly to the rack.

An eyelet in the form of a short metal strip with a hole to receive a nut and bolt should be straightforward, provided the end of the strip is accurately filed to match the tube section.
I suspect the Soma has some sort of captive nuts on the underside of the middle section: this is more challenging unless you've got use of a lathe. Just brazing a nut to the outside of the tube doesn't give much usable thread - I'd be tempted to cross drill the middle section where you want the bracket to fit and braze in an insert made from (say) 8mm bar, bored and threaded M6.

I suspect a drawing would be better than text - I'll sort something in the morning and see if I can photograph something meaningful in the garage...

The graphical equivalent of thinking out loud...

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More thoughts...

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Thanks. This is massively helpful. I very much prefer option B as I can do that without recourse to tools I don't have. I also have slight (but scientifically unfounded) reservations about drilling an 8mm hole across a 10mm tube!

I assumed a larger tube diameter ... what diameter do Soma use?

Similar arrangement but at a smaller size shown in the photo - 10mm tube, 6mm inserts, threaded M4, to hold a bag in place which limits the size of the payload. The bag is held on with straps on the outside of the rack using M4 machine screws with washers to spread the load - sufficient to hold things in position but probably too small to carry major loads.

I'd be worried about a overloading significantly larger rack using 10mm mild steel?

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I won't be putting significant loads on for sure. I think Soma use thicker tubing but it has a stated load of only(!) 30lb. I'd not be putting much more than a change of clothes, lock and a packed lunch on there.

Alex Wetmore again has some good opinions. He seems to reckon 10mm is fine for a "heavy duty" porteur rack, going down to 8mm and even 6mm for smaller or lighter duty racks.

I suspect Alex is talking from experience whereas I'm using caution and overkill. If you've already ordered the steel I'm sure it will be fine - at worst you'll need a lighter packed lunch.
Attached - plan C which avoids drilling through tubing or trying to join parts with significantly different sections, but will need use of a lathe - there must be someone on here and local to you? If not, I could put something in the post.

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Just found this thread, awesome!

Love that 90% cut and bend idea. Think I'll have to give that a try on something.

Bracketry is looking like it's gonna be way beyond what I went for which was namely nuts brazed to stuff.

I've been employing my brazing skills(?) to make a wee bit of jewellery lately, want to make something bike related again though. I need a rear rack from my Surly but given that that will need to stand up to off road abuse, not too sure that I'm up to it.

Nuts brazed to stuff will work, but you lose the last mm or so of thread due to creep of braze and bolts not being effectively threaded to the end - this becomes a high proportion with small sizes. Having clearance beyond the nut by drilling into the tube allows all the thread to be used.
One (more) possibility is to braze a nut in place, drill through the nut and tube using a core diameter drill, and follow it with a tap to extend the thread.
Regarding a rack for off road use, I made one by cutting and shutting the frame of a garden chair, making use of the existing bends. The bike already had a drilled brake bridge, and at the bottom of the rack stays are short lengths of tube brazed at right angles to accept a stepped sleeve. The biggest issue so far is attaching stuff to it...

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our martial chamber

Please elaborate.

Sorry for lack of updates here. Just waiting on the tubing and solder to arrive. The rack seems to have generated the most discussion so far! I might be able to put the 'dale together this weekend, with only the rack to do.

The Orbit will have to wait until I can get some fiddly last bits together.

Solder literally arrived just now! Helpfully contains some "how to silver solder" instructions because...

...although someone from SLMS might be able to help me.