Gerome

So unless you are using the word "flatten" in a very creative way could you confirm that you are just trying to flatten that section between the slotted upright and the first joggle? Is this on pieces you have formed yourself or ready-mades?

Are you, as Frosty and Ian supposed, actually having problems forming them from scratch?

I cannot see from the photographs where your .020" is occurring, is that crowning/ burr across the width of that section or along its length? Is the whole piece twisting from one end to the other?

My slot cars used a bit of flat braided copper ribbon, so I am not familiar with these and I don't know how they are held against the track, whether by their own spring tension or another spring. If spring tension then that determines whether you anneal them before or after any process that will work harden them. Are they held fairly loosely by the car so that they conform to the angle of the track contacts? Are the track contacts flat or slightly crowned?

So my next question is why do want to flatten them? Are you trying to ensure a larger contact area? Will that effect drag? Flat is all or nothing. If the track is slightly warped would not a gentle crown be more certain of constant contact? Would polishing be an advantage?

Either way if you do just want to flatten that section and you have not been able to achieve by squeezing between a pair of flat blocks you need to hit it harder, an anvil and a flat bottomed punch for instance, which will reduce the thickness but will forge rather than just unbend it. Ian's profile tools would work with this system but wack them with a hammer rather than squeeze them with vice grips.

An alternative is to use the pestle and mortar / pair of spoons idea I outlined above to unbend them without altering the thickness. This would be in the form of a dished bottom tool and convex top tool formed from stock which will fit between joggle and upstand.

I have a 50 year old memory image of my mate with his scalextric cars poking under the contact with a screwdriver and bending with his fingers...I guess you are in a slightly different league if you are racing others in a club situation. Have you asked you fellow racers what they do or is this thread by way of getting a competitive advantage?

Alan

A different approach would be to find a local laser cutting works and ask them to cut out a male and female die out of plate matching the width of your strip, include a 'notch' in the back to suit a 'vice grip' and them just 'press' them. I hope this 'makes sense ' . As the shape is quite simple it would not be that difficult to 'hand make ' the dies using a fret saw and a file.

Depending on the hardness your stock it might help if you aneal it first by heating and quenching in water.    

Okay, that's a whole different thing than we thought you were asking and a perfect example of wanting a specific answer to a vague question.

What you want to know is how to form the brushes and keep the contact area flat. This is easy peasy. Cut two pieces of smooth wood the same width as the flat contact area of the brushes. Measure and cut the stock and use a C clamp or vise grips to clamp the strips between the wood with the 90* bends on one side the the step bends on the other. Bend the 90*s then bend the other end close to the wood and clamp it to a table top or steel plate, etc. with a piece of stock, wood, steel, etc. the thickness of the step bends flat on the plate against the up bent strips. now just bend them flat against the bottom die. Forming the hinge/hook end is as easy as using a piece of steel wire or a nail and driving it against the copper on a piece of end grain wood.

Keep it straight and or flat is WAY easier than flattening/straightening it afterwards. It's easier to NOT make mistakes than correct them.

And don't tell me you needed me to tell you to unclamp the brushes from between the first two pieces of wood before clamping it to the large flat piece to make the step bends. Awe heck you can do it all clamped to a table top if you like. Seriously there are so many different ways of making this simple piece I'm in danger of getting seriously sidetracked by different methods and mixing them up.

No rolls, special shears, nothing special needed at all, just a bit of basic technique and care. Heck, the last set of slot car track brushes I made was what 50 years ago? I stopped playing with slot cars a couple years before I got my driver's license. I'm almost afraid to ask my sister if my old slot car box is in the piles of stuff my Parents kept. Pack rats, the whole darned family.

Frosty The Lucky.