Front And Rear Bumper Bars

[SmarteeBluey 10]

I needed to make a set of Bumpers, Push bars, call them what you like. They needed to be matching for the front and back of my Smart ForTwo. Problem. . Front does not have two tow hook mounts, so a second one needed to be made, as well as an opening through the front body panel.Front Bumper Anchorage:The front is a different size to the rear. I custom made both sets to the size and style needed. The front bar however, would also have to have the number plate attached, because if it is left on the body panel, it would be behind the front bars and not clearly seen.The thread on the Tow-Hook and insertion spots, are a very specific size. The cost of purchasing a Die & Tap, Bolts & Nuts to match is very costly and difficult to get locally. The closest matching thread size is 5/8 BSW (Witworth), and when re-tapping the Tow-Hook and points, very minimal changes are done to the thread pattern.PARTS & TOOLS:30mm Spade drill bit or hole saw.Round or semi round files and fine abrasive paper.5/8" BSW Tap & Drill bit to suit (preferably borrowed).2-105mm 5/8 Threaded Rod (+2 75mm 5/8 BSW Bolts. .Optional).3 or more, 5/8 BSW Nuts.2- 6mm or similar Bolts, Drill Bit & Tap to suit (size not critical).Masking Tape and Ruler.Araldite or similar bonding agent.Hacksaw and Black paint.Remove the front panels from the car, Apply masking tape, Measure from many focal points from the pre-existing hole on the Left side (looking at the front). Mirror image and transfer these points to the Right side. Drill the 30mm hole and then file and sand the edges Finish off with fine grade sandpaper.While the front panels are off, remove the front crash bar. Measure, mark and carefully drill the hole on the other side. Tap a 5/8 BSW thread, the metal is reasonably thin (compared to a nuts thickness) so not much thread is taped.Place some grease on all the thread and top of a 5/8 bolt, then screw it in just passing through the hole. Position a nut on the inside, turn the bolt through the nut till it just protrudes past it and then place a second nut on it and screw it in all the way. With a pair of long pointy nose pliers, tighten the nuts. Slacken off the nuts 1/8 of a turn to allow the bolt to turn without jamming or turning the nuts inside the crashbar. The nuts need to be held in place while they are secured firmly, and as an added precaution to stop them from unscrewing in future diss-assembly. Drill, Tap, and insert a 6mm bolt (or similar, Not critical) on the side of the crashbar, butting up against the first nut. Test to see if the bolt still can be turned by hand without turning the nuts. If you can’t, slacken off the small bolt slightly till you can.The existing nut for the tow hook in the crashbar should be re-tapped. Insert a new nut on the top of it. Using the same process as above, install a small bolt through the side to hold it. Do not forget to grease the thread of the 5/8 bolt before screwing it in place. I was going to weld the nuts in place but access to them from the back of the crash bar is very limited.Mix up an amount of Araldite and liberally pour it around the inside, around the nuts as well as the small bolt, on both sides and set aside to set. The grease that was applied earlier, should stop the bonding of the nuts to the threaded rod or bolts while the Araldite sets. When thoroughly set, cut off the small protruding bolt heads on the outside and file smooth. Un-bolt the 5/8 bolts and clean and paint any bare metal spots.A new Tow Hook will be made to suit this mod. Details later.If you have any handyman skills, it is possible to make your own set of bumpers at a fraction of the cost compared to bought ones. The Back ones are longer than the front, so they are not interchangeable. What follows is how I made mine:NEEDED (For each set)2 - 1050mm (Back) 960mm (Front) Round or Square 19mm steel tubing ( I used round).2 - Steel plates 95x40x4-5mm.2 - 60x19mm tubing.8 - 5mm countersink head SS bolts approx 10mm long.5/8" BSW Threaded Rod4 - 5/8" SS washers.2 - 5/8" BSW SS Dome Nuts.5/8" BSW Tap16-17mm & 6.5mm steel drill bits. 5mm Tap and drill bit to suit.Masking Tape / Tape measure / Pencil or biro and appropriate power tools and work bench. 4 lengths of 19mm galvanised tubing (approx 1.5m long each) and a steel flat plate 400x40x4mm. Bought from a Salvage yard seconds, suited me.Measured and cut the tubing and plates. Cleaned off the sharp edges with an angle grinder. Secured the plates one at a time in the drill press and drilled the 17mm hole in the centre. Carefully measured (twice) and drilled four 6mm holes on the corners in each plate, countersink the holes.Applied a strip of masking tape the length of each tubing. Placed them in a vice and with a straight edge, drew a line down the centre. Marked a line, 100mm (Back) or 75mm (Front) from the ends.This is where the Maths homework comes in handy! Measure and mark two holes on each end of the tubing for the SS bolts, OR place the plates centrally over the mark and mark out the holes needed. The mounting holes in the steel plates have to be 915mm (36 inches) for the back & 812mm (32 inches) for the front, to the centres.Drill and Tap the 8 holes required on each set.Cut two pieces of 5/8 threaded rod at 105mm long. Length is not critical. Cut two pieces of tubing, 60mm long.The front bars need to have two holes tapped to bolt on the number plate.Re-tap the two tow hook positions on the back of the car with a 5/8 BSW Tap.Assembly Time:I assembled them on the Smart car and drove it for a week to get used to it. I was very pleased in the way it looked so I pulled them off. I welded the plates on the back for extra strength then primed, painted them in high sparkle Silver. Bought some Black plastic end caps to complete the looks.They have been on Smartee for about 3 years now and apart from a few minor scratches they still look good. An extra set of reversing lights are attached to the rear and the number plate is attached to the front. These were my prototypes and a new set is in the planning, but the basic principles and measurements remain the same.Hope this was informative and helpful to anyone interested to give it a go. Apart from borrowing some Taps for tapping the threads, total cost for the 2 sets including paint came around to $40.00Happy SMARTing . . Rob

Edited March 11, 2014 by SmarteeBluey

[tolsen 630]

Looks nice but I got my doubts as to the suitability of the chosen 5/8 x 11 BSW threads. Original threads are ACME 5/8" - 8 TPI. Thread diameters may be similar but profile and threads per inch are too different.

[SmarteeBluey 10]

I Know some people cringe about mixing imperial threads with metric. When I went to the local Nut&Bolt specialist, they said the thread type I wanted would have to be made up as it is not a standard off the shelf type. Threaded rod would be 10 times the price as the standard, let alone SS cap nuts etc. I spoke to the tool maker at work and recommended that the imperial alternative would not cause any structural strength or damage, as long as the tow hook with the car is not mixed with the standard.New Tow hooks for Smartee needed to be made (as said above) as the existing modified one/s could be a problem if needed to be installed in a hurry.I inquired about Eye Nuts to the specific size needed. They were not available on short notice in 5/8" BSW thread as needed, close in Metric and a re-tap required. Not in stock, so I left.Went to a builders Salvage yard looking for something completely different, low and behold I found 2 large Eye Bolts. Normally used to lift heavy equipment. For the massive sum of $1 for the 2. I could not wait to get home to modify.Cut the bolts flat off at the base, Drilled a 13.5mm hole in each and then the slow task of tapping the thread with the pre-loved 5/8 tap, I bought from eBay for $5.A cleanup with a file, wire brush, and emery paper.Then a test fit. To remove the nut from the car and screw this Eye Nut in it's place takes about 1 minute. No need to remove the bars, Very pleased with the results.Now the choice is, do I paint them or get them Chromed Once again, I hope this is helpful information.Happy SMARTing . . Rob

[Vulicevic 0]

I Know some people cringe about mixing imperial threads with metric. When I went to the local Nut&Bolt specialist, they said the thread type I wanted would have to be made up as it is not a standard off the shelf type. Threaded rod would be 10 times the price as the standard, let alone SS cap nuts etc. I spoke to the tool maker at work and recommended that the imperial alternative would not cause any structural strength or damage, as long as the tow hook with the car is not mixed with the standard.New Tow hooks for Smartee needed to be made (as said above) as the existing modified one/s could be a problem if needed to be installed in a hurry.I inquired about Eye Nuts to the specific size needed. They were not available on short notice in 5/8" BSW thread as needed, close in Metric and a re-tap required. Not in stock, so I left.Went to a builders Salvage yard looking for something completely different, low and behold I found 2 large Eye Bolts. Normally used to lift heavy equipment. For the massive sum of $1 for the 2. I could not wait to get home to modify.Cut the bolts flat off at the base, Drilled a 13.5mm hole in each and then the slow task of tapping the thread with the pre-loved 5/8 tap, I bought from eBay for $5.A cleanup with a file, wire brush, and emery paper.Then a test fit. To remove the nut from the car and screw this Eye Nut in it's place takes about 1 minute. No need to remove the bars, Very pleased with the results.Now the choice is, do I paint them or get them Chromed Once again, I hope this is helpful information.Happy SMARTing . . Rob

CHROME!!!Nice job

[dsokolow 0]

rear aluminum bumper with steel backing under 100.00