spiny
Club Retro Rides Member
Wiki Admin
I am abivalent towards car electrics ...
Posts: 1,330
Club RR Member Number: 167
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Jan 27, 2018 23:16:01 GMT
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Hi All, Thought I'd make a thread for my current distraction project - a Soapbox Racer for this years Portishead Soapbox Race. Info here: www.portisheadsoapbox.co.uk/Brief history of the event - apparently it used to be a regular thing in the 1950s in Portishead, but fell out of favour for whatever reason. Last year a bunch of guys decided to restart it. I saw it mentioned on Facebook (it does have its uses ) and as i'd had a few beers, decided to enter. I rustled up a few friends to help with ideas and general pushing / co driver duties on the day and built the kart in the pics below. I had no idea what it was going to be like as an event, having never done anything like this before, I built the kart out of 20mm square tube and various go kart parts for the steering and even though we did precicely no testing whatsoever, it actually worked and did two good runs. Alas, on the third run I caught a front wheel on the 'chicane' barriers and spun, which snapped a rear wheel, so the last run wasn't so good ... All in all, it was possibly the most fun I've ever had driving something and we came seventh over all, out of forty teams. So when the 2018 race was announce, I was straight in A few pics from last years: Rod actuated brakes, pressing on the tyre - totally useless at speeds faster than walking pace it turns out The kart itself, two seater: at the top of the hill: last jump on the straight: and the damage from the spin: Unlike my other build threads (in my sig) this project has a deadline and has to be finished My MG and Van stuff has kind of fallen by the wayside the last few years, just with general apathy really, but I've decided that 2018 is 'the year I get stuff done' so at least one of them will be on the road before 2019, just need to fit it in with the soapbox build 2018 build will appear below shortly.
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Last Edit: Jul 29, 2018 19:42:18 GMT by spiny
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spiny
Club Retro Rides Member
Wiki Admin
I am abivalent towards car electrics ...
Posts: 1,330
Club RR Member Number: 167
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Jan 27, 2018 23:33:55 GMT
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Soooo, for 2018 I decided to start with the brakes. If I can get good brakes, then I'll be happier testing the kart on the local gentle hills and be happy that I can stop if I meet a car coming the other way The obvious solution is go kart style brakes, on a solid rear axle. Steering will be heavier, but I don't think it will matter too much. Mocked this up a few months after last years race: pillow bearings on a 17mm solid axle: so I 'just' need a carrier for a brake disk. But as I want to make it as difficult as possible, I decided to make it so that everything can unbolt so I can reuse the bearings (for 2019s entry perhaps) so just welding on a disk was not an option, so I decided to make a carrier. I started on Christmas day Every Christmas we pile round my parets place, which includes the garage which has my dads old lathe in it. He died suddenly a few years ago so it hasn't been getting any use, and so he isn't around to show me how to use it :/ but I spend a few months watching loads of youtube (This Old Tony, ABomb etc) and felt confident enough to give it go. So after the food when everyone else was dozing, I fired up the lathe and did this: Started with some stock aluminium bar, 50mm ish and machined a shoulder to take the brake disk. next was to drill it through, so it would fit ove the axle then part it off caught with the drill holder Then drill mounting holes for the disk and mounting holes to fix to the axle grub screws secure it to the axle, and also offer a tiny bit of adjustment bolted on and mocked up with a generic moped caliper.
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Last Edit: Jan 27, 2018 23:35:44 GMT by spiny
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spiny
Club Retro Rides Member
Wiki Admin
I am abivalent towards car electrics ...
Posts: 1,330
Club RR Member Number: 167
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Jan 27, 2018 23:45:49 GMT
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Next is the hydraulics. I got this off ebay for £22 delivered, there is no way i'd ever fit it to a car, but it should do the job here: some bench testing: I also decided to make a temporary frame to mount it all, just for practice more than anything. reused some of the tube from last years kart: and this is where I am now: since I took this pic, I have added a second disk to make the disk wider, as the caliper was running out of travel. so now it seems to grip pretty well. next up will to buy more steel tube and start on the chassis. more pics as I take them
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Last Edit: Jan 27, 2018 23:47:45 GMT by spiny
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Bookmarked. Because fun! Having built a V8 powered oil drum raft in the past, I love this stuff!
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spiny
Club Retro Rides Member
Wiki Admin
I am abivalent towards car electrics ...
Posts: 1,330
Club RR Member Number: 167
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Jan 28, 2018 10:00:40 GMT
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Resized all the pics up there ^ so should now load a bit quicker Planning the build with Sketchup this time round. Last years was built as I went along, with no real measuring as such, which meant it was longer on one side than the other and taller on one side to the other. This year I'm going to attempt to do it properly, measure everything twice, grind down welds, use the pillar drill more etc etc. Fingers crossed and all that
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MiataMark
Club Retro Rides Member
Posts: 2,954
Club RR Member Number: 29
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Jan 28, 2018 10:41:28 GMT
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I love watching the Red Bull Soap Box challenge and would love to compete.
When is the race I'd like to come and watch, I'm only down the road (M4) in Swindon.
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1990 Mazda MX-52012 BMW 118i (170bhp) - white appliance 2011 Land Rover Freelander 2 TD4 2003 Land Rover Discovery II TD52007 Alfa Romeo 159 Sportwagon JTDm
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spiny
Club Retro Rides Member
Wiki Admin
I am abivalent towards car electrics ...
Posts: 1,330
Club RR Member Number: 167
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Jan 28, 2018 17:55:56 GMT
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I love watching the Red Bull Soap Box challenge and would love to compete. When is the race I'd like to come and watch, I'm only down the road (M4) in Swindon. Sunday 15th July 2018 fingers crossed for nice weather
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Jan 29, 2018 10:23:18 GMT
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Can I suggest when you finally need to anchor the brake disc that you file a flat in the bar where the grub screw will go big enough for the screw to grip as it will work much better and will have less chance of slipping on the bar when in use.
Nice machining work there.
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Last Edit: Jan 29, 2018 10:25:12 GMT by peteh1969
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spiny
Club Retro Rides Member
Wiki Admin
I am abivalent towards car electrics ...
Posts: 1,330
Club RR Member Number: 167
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Jan 29, 2018 11:42:27 GMT
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Can I suggest when you finally need to anchor the brake disc that you file a flat in the bar where the grub screw will go big enough for the screw to grip as it will work much better and will have less chance of slipping on the bar when in use. yeah, i'll be drilling 'dimples' for the four grub screws, so that the carrier can't drag itself around the axle when I hit the brakes. Nice machining work there.
cheers, this is literally the first thing I've ever made on a lathe. Still lots of learning to do though
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Jan 29, 2018 13:20:06 GMT
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Can I suggest when you finally need to anchor the brake disc that you file a flat in the bar where the grub screw will go big enough for the screw to grip as it will work much better and will have less chance of slipping on the bar when in use. yeah, i'll be drilling 'dimples' for the four grub screws, so that the carrier can't drag itself around the axle when I hit the brakes. Nice machining work there.
cheers, this is literally the first thing I've ever made on a lathe. Still lots of learning to do though No need to drill dimples just file a flat wide enough to take the pointy bit of the grub screw that way it will have something to bite into a dimple is hard to drill and would allow movement weare as a flat will work much better and give less chance of movement.
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spiny
Club Retro Rides Member
Wiki Admin
I am abivalent towards car electrics ...
Posts: 1,330
Club RR Member Number: 167
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Jan 29, 2018 14:03:39 GMT
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No need to drill dimples just file a flat wide enough to take the pointy bit of the grub screw that way it will have something to bite into a dimple is hard to drill and would allow movement weare as a flat will work much better and give less chance of movement. cool, didn't know that
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Jan 29, 2018 17:53:49 GMT
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like this very much, my fil has a soapbox racer as well and takes part in competitions in Germany(where the in-laws live) with some good results over the years. He build his over 30 years ago for his sons and started competing himself 5 years ago(at age 65) after he rediscovered it in his shed.
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spiny
Club Retro Rides Member
Wiki Admin
I am abivalent towards car electrics ...
Posts: 1,330
Club RR Member Number: 167
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Jan 30, 2018 14:16:25 GMT
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12m of 20x20 2mm wall tube glad theres no weight limit for this comp
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Jan 30, 2018 15:41:31 GMT
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Please tell me there is an 8512 in that box?
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spiny
Club Retro Rides Member
Wiki Admin
I am abivalent towards car electrics ...
Posts: 1,330
Club RR Member Number: 167
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Jan 30, 2018 21:29:59 GMT
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Please tell me there is an 8512 in that box? yep, with printer. And it works got given it a while back, both drives needed stripping, cleaning (removing the old drive belt whuch had turned to goo) and new belts fitting. All works fine now
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spiny
Club Retro Rides Member
Wiki Admin
I am abivalent towards car electrics ...
Posts: 1,330
Club RR Member Number: 167
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Jan 31, 2018 12:37:17 GMT
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Dug out the remains of last years frame, ready to strip it and start using it as a base for this years. Front view - leg room was a bit lacking as I'm using go kart steering, which normally goes under your legs on a real go kart From last year - you can see the lack of leg room. I'm going to extend the steerring column and sit further back. My 'co pilot' has declined to race in the car this year so it's just me I bough the wheel carriers, and guessed the angle to fit them, worked surprisingly well, so thats staying, but will get a reweld just in case. wheel carrier fitted Top view And everything removed, leaving a flat 'chassis' This years design calls for the wheels to be inside the bodywork, so I will have to extend the chassis to make it wider. Ideally I need to add metal in front of the wheels, but I'm wary of 'digging in' after a jump, as I have seen many people stack it on youtube vids. So perhaps a hidden skateboard wheel or skid plate or soemthing like that just in case. But months to go before I gte to that stage
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Last Edit: Jan 31, 2018 12:40:53 GMT by spiny
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spiny
Club Retro Rides Member
Wiki Admin
I am abivalent towards car electrics ...
Posts: 1,330
Club RR Member Number: 167
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Some more welding today, making a start on the front. As mentioned above, this years theme needs the wheels to be inboard of the body, so I'm extending the old chassis to make this happen. I've also decided to go wheelbarrow wheels all round, as they are light-ish and have metal rims, so should be hard to break As the ones I've ordered off ebay haven't turned up yet, I stole the wheel off my actual wheelbarrow as a stand in. I'm leaving the wheels forward of the front of the chassis to avoid any part of the kart hitting the ground after a jump, but I'll be making some plywood bodywork to extend the front, which can be sacrificial in the case of a dubious landing. Wheel trial fitted. Not sure what bore the ebay wheels have yet, but plenty of options to make them fit Different view: wheel well mocked up side view just tacked in place here to make sure the wheel doesn hit anything final placement checks welded and ground down steering attached as a clearance check Othr side to do now
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spiny
Club Retro Rides Member
Wiki Admin
I am abivalent towards car electrics ...
Posts: 1,330
Club RR Member Number: 167
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Wheels These will probably be on the front, and will see if I can get a sensibly priced pair of 10inch for the rear.
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Last Edit: Feb 5, 2018 17:23:24 GMT by spiny
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One point, good job on the disk mount. When karts mount discs like this they use a keyway 1/4sq or 6mm to stop the disc rotating on the axle.
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Yeah, I was going to comment on this too. I'd want more than grub screws transferring the torque from axle to brake disc. If you've got 3 and the shaft is lightly drilled for their tips then it may suffice, but if they let go....... hello hay bales!
Looks like fun though - pity there is no usable hill in our village......
Nick
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1967 Triumph Vitesse convertible (old friend) 1996 Audi A6 2.5 TDI Avant (still durability testing) 1972 GT6 Mk3 (Restored after loong rest & getting the hang of being a car again)
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