mooman007uk
Well-Known Member
- Messages
- 878
- Location
- Errington, VANCOUVER ISLAND, BC
well i've been threatening to do this for a while now but had neither the time or the necessary equipment to do what i needed...had some time lately and with a big thanks to Clayton from vertigo performance for lending me a mini lathe/mill combo he had sitting in a corner doing nothing. so now had no excuses so got busy
what it will be:
formula offroad
powered by an obr 57cc fullmod twin
4130 chromemoly tube chassis, 4 link suspension and solid axles front and rear ,
rampage MT tires, treads shaved off and hpi 5t sand buster paddles glued on, they're the closest to the real scoops on 1:1
either drop pitman arm steering set up or more likely a piston to piston, master and slave hydraulic steering.. picked up an oddified tonegawa ps050 for 70quid off ebay uk so whichever setup i use servo power wont be an issue.
pipes will be hacked up pocket/mini bike exhausts. cheapo ones have a nice fat belly 10" long and plenty of header to play with...only 35bucks each
motor will be mounted up front lengthways with a simple pinion and spur with jack shafts. 10mm telescoping driveshafts from a honda hru216 self propelled lawnmower for drive shafts to the axles. Shocks i'm going to try making some air over oil, springless ones with rezzies and a floating piston to keep oil and air separate
just 'bout covers it.
first up the hardest part...axles. been trying to figure these out since my last build...was coming up short until i scrapped aluminum and started thinking good ol' steel.. then i came to me,so procured the needed machine and got started.
using rampage centre diff spool and pinion front and rear.
started with this...each one is a half...
ended up with this
then set about making pinion bosses from aluminum as well as wheel hubs and steel hub flanges
so far so good, only buggered up one pumpkin half...on the last cut too...3 1/2 hrs machining down the drain...being a small lathe 1mm cuts are the max even with carbide index bits.
next was to determine how big the thing is going to be and came up with 20" from end of hex on the wheel adapters, 26" with tires and 28" wheelbase axle centre to centre,,should look scale then with the 8x5" rampig tires.
pinion boss
cut some thick walled 4130 tube and voila axle housings
machined in some grooves for some spacers that'll be welded on
rear axle shafts...using 5b outdrives welded to cut to modded hurrax shafts (these are 4140chromemoly whereas most others seem to be c45medium carbon steel), will be no pins or cups to break, one solid shaft...once all the bits are finished i'll take them to the local foundry to reset the desired hardness and temper.
the fronts will be FLM kalee cvds
rear axle with shafts weighs a hair under 1.5kg (3.3lbs) the whole build i hope to scale at no more than 18kg (39.6lb) wet which will be pretty light considering it's size and power...lighter than a rampage/blackout
with the rear axles are done bar the welding so on to the front hubs
can't start on the chassis until my engine comes and that can't be sent until OBR gets their long awaited delivery from rcmk..
hoping it shows up soon
hopefully my steering cylinders show up today so i can start on that job, once they come i'll also be able to figure if my shock idea will work or not, no shocks out there with 75mm stroke so have to figure something out.
what it will be:
formula offroad
powered by an obr 57cc fullmod twin
4130 chromemoly tube chassis, 4 link suspension and solid axles front and rear ,
rampage MT tires, treads shaved off and hpi 5t sand buster paddles glued on, they're the closest to the real scoops on 1:1
either drop pitman arm steering set up or more likely a piston to piston, master and slave hydraulic steering.. picked up an oddified tonegawa ps050 for 70quid off ebay uk so whichever setup i use servo power wont be an issue.
pipes will be hacked up pocket/mini bike exhausts. cheapo ones have a nice fat belly 10" long and plenty of header to play with...only 35bucks each
motor will be mounted up front lengthways with a simple pinion and spur with jack shafts. 10mm telescoping driveshafts from a honda hru216 self propelled lawnmower for drive shafts to the axles. Shocks i'm going to try making some air over oil, springless ones with rezzies and a floating piston to keep oil and air separate
just 'bout covers it.
first up the hardest part...axles. been trying to figure these out since my last build...was coming up short until i scrapped aluminum and started thinking good ol' steel.. then i came to me,so procured the needed machine and got started.
using rampage centre diff spool and pinion front and rear.
started with this...each one is a half...
ended up with this
then set about making pinion bosses from aluminum as well as wheel hubs and steel hub flanges
so far so good, only buggered up one pumpkin half...on the last cut too...3 1/2 hrs machining down the drain...being a small lathe 1mm cuts are the max even with carbide index bits.
next was to determine how big the thing is going to be and came up with 20" from end of hex on the wheel adapters, 26" with tires and 28" wheelbase axle centre to centre,,should look scale then with the 8x5" rampig tires.
pinion boss
cut some thick walled 4130 tube and voila axle housings
machined in some grooves for some spacers that'll be welded on
rear axle shafts...using 5b outdrives welded to cut to modded hurrax shafts (these are 4140chromemoly whereas most others seem to be c45medium carbon steel), will be no pins or cups to break, one solid shaft...once all the bits are finished i'll take them to the local foundry to reset the desired hardness and temper.
the fronts will be FLM kalee cvds
rear axle with shafts weighs a hair under 1.5kg (3.3lbs) the whole build i hope to scale at no more than 18kg (39.6lb) wet which will be pretty light considering it's size and power...lighter than a rampage/blackout
with the rear axles are done bar the welding so on to the front hubs
can't start on the chassis until my engine comes and that can't be sent until OBR gets their long awaited delivery from rcmk..
hoping it shows up soonhopefully my steering cylinders show up today so i can start on that job, once they come i'll also be able to figure if my shock idea will work or not, no shocks out there with 75mm stroke so have to figure something out.
Last edited:
