Ever seen the secret stash chamber on a Tomos A3?
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| Hidden catch reveals ‘secret’ cache |
Reach behind the saddle, tug on the catch and lift the seat to reveal it. Big enough for a flick knife, length of string, pet mouse, gum, porn mag, bong and all the other appurtenances a two-wheeled Tom Sawyer likes to carry around, not quite big enough for a helmet (unless you have the opposite of hydrocephalus), fuel can, or anything else even vaguely useful (that is, if you have no need to stab, tie up a parcel, grow an ear, chew, wank or huff).
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| Big enough for small stuff, too small for big stuff |
The answer? A rack or carrier.
I have a welder, some scrap metal, a bench and an hour or two of free time – by an amazing coincidence, almost the exact ingredients for making one. Given I could’ve bought a factory example for six quid on eBay recently the exercise is admittedly pretty pointless, but I’m stingy, like making things and have an aversion to fattening eBay’s off-shore bank account so homebrew it is.
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| The remains of a school chair will soon become… |
What I don’t have is a pipe-bender so a project such as this requires careful planning in order to use pre-existing bends or else cutting and welding to get the necessary shapes. Here’s an example of what I’m hoping to copy:
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| …a copy of this, the OE Tomos rack |
First step is to cut out suitable lengths and cross pieces for the main part of the carrier. Next, is to turn ‘slugs’ on the lathe to strengthen the joints and provide something substantial to weld to. The alternative is to sleeve the joints but slugs have the advantage of being invisible once the welds are ground down.
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Careful cutting and welding preserves the bends and obviates the need for a
pipe-bender. Now all I need to do is lay out the pieces on the bench, toddle off
to bed and wait for some hungry elves to come and make it into a rack |
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| Turning solid steel ‘slugs’ to strengthen pipe joints |
With the cross pieces shaped to match the diameter of the sides, the slugs turned and the various pieces held in place with a clamp I broke out the welder and set to. At least, I tried. No wire feed. Hmm. Nothing would persuade the wire to emerge from the torch.
My welder is a cheap(ish) Clarke 130EN Turbo which I use gasless with flux-cored 0.8mm or 0.9mm wire. Working back from the tip to the liner, everything seemed fine so time for a strip down and look-see. With the insides exposed I put a meter across the wire-feed motor which showed DC present. So far so good but other than ‘clicking’, it wouldn’t shift the wire.
Reflecting on the problem over a mug of coffee, it struck me there’s a gearbox fed by the motor which has (as you might guess) plastic pinions clotted with grease. Maybe the gears were seized? Though the whole shebang can be removed as a unit I thought I’d try a little heat first to soften the grease. Using an old hairdryer, I heated the gearbox and pulsed the torch trigger while twisting the speed pot to and fro. Half a minute or so of not very hopeful heating, pulsing and twisting and… success! It began to feed. Either the gears were gummed up, or there was dirt on the speed control track or something else equally minor yet devastatingly terminal. Anyway, here it was working again.
Unless it’s in the hands of a pro, a flux-cored gasless welder produces a strong but messy result. I’m no welder but I don’t mind ‘finessing’ the weld afterwards. However, and as is its wont, having sat for a while the flux-cored wire was blighted by moisture resulting in ugly, weak porous welds. You can counter this by maintaining a >3/4” wire length at the tip. Heat from the weld evaporates the moisture before it reaches the joint but it’s even harder to produce a tidy job.
However, welding difficulties aside, the rack began to come together:
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Next morning…
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| …and the elves have done their work |
I want to attach side guards as per the OE rack to keep a pannier from fouling the wheel, there’s some cleaning up to do and paint obviously, but pretty much the rack is together. I’ll post an update when it’s in paint and finished.
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Now there's just this piece to weld in place, two brackets to make to
support the carrier behind the lamp cluster, a spruce up and some paint |
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