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Mar 30, 2016, 09:54 PM
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1:64 - 1:87 scale RC cars conversion


RC car working hard top convertible (1 min 9 sec)

RC 1:64 scale cars Hot Wheels (0 min 28 sec)

RC micro truck 1/64 scale (0 min 27 sec)

RC converted 1/64 scale HotWheels (0 min 33 sec)

I have lots of info and help on converting 1:64 - 1:87 scale cars to RC by hacking servos and die cast models if anyone is interested.
Last edited by vtolman; Jun 06, 2016 at 03:53 AM. Reason: Add video
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Mar 30, 2016, 10:18 PM
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Servo hacks for motor drives

PZ15320 drive servo conversion slideshow (0 min 31 sec)

Read the conversion instructions under the this video at YouTube called ... PZ15320 drive servo conversion slideshow.

(Update - see posts #20 & 21 & 45 for smaller 1.7 gram servos used)

Most brand of servos have a similar layout and number of gears so these instructions may held hacking other brands.
My Emax servos had no stops inside and full teeth on the output spline gear so are good for modifying for continuos rotation (but sometimes I don't use the last output spline anyway)
Basically we are relocating the circuit board inside (or outside) and fitting an axil right through the middle of the servo and all three plastic cases and it's glued into the output spline with the axil protruding both sides of the servo so it can have wheels glued on.
The Emax ES9251 is the smallest servo I have tested at this stage. (8mm wide)
This servo hack with the 6 original gears will give a scale speed from very slow to about 25mph at a wild guess.
With only 4 gears it's faster.
I find 6 gears is good for around town scale driving and tight parallel parking etc.
It leaves the servo looking almost original with all it's original gears in place.
I have also remove two gears and made a faster version using only 4 gears.
Grinding the splines off the output shaft will reduce the width of the servo which helps fit between narrow wheel track cars.
Use Emax ES08 or ES09 or similar spec servos (space permitted) if you want a fast and powerful car.
The Emax ES 9051 can be hacked with these same instructions and it has a little more power than the ES9251 but is a little bigger so it fits in the larger cars or SUV.
ES9251 hack.
First remove the sticker (or screws) holding the 3 servo case parts together.
Remove the top and bottom cases.
Photo the gears in place and or write down to memorize their positions.
Remove all gears and place down in the sequence required to reinstall.
Careful ... keep them in a container ... they are so small and easy to lose.
Remove the steel center pin from the underside of the last output shaft spline.
It may have a small white plastic D- bush pressed onto it which turns the trim pot underneath the middle servo case.
Remove both the metal pin and the D- bush as they are not needed (keep these if you want to reverse this back to a normal servo)
Leave the trim pot in place (the new axil should fit through it and have clearance)
Lift out the circuit board and tape it outside the servo and also tape it up - to avoid electrical shorts and game over
Under the last output shaft is a separate sprocket gear - now find a drill bit and axil which matches its hole size and drill through from the top of the last output spine shaft center to allow an axil to loosely slide right through the output shaft.
Critical - drill it as square and central through the output shaft as you can manage.
I used a 0.7mm drill bit and size #5 or #6 darning needles for axils in the ES9251.
Now assemble with the output spline shaft only and drill through the 3 servo cases where necessary so the axil can protrude about 5-6mm each side of the servo for the wheels.
I pushed a sharp needle (axil) through from the top to mark the inside of the bottom servo case for the hole position.
This axil will allow the separate gear under the last output shaft to spin freely as it originally did and it should not drag on the trim pot or bind on the 3 servo cases if all is aligned correctly.
Sometimes I used a small round file to make clearance for the axil and remove the flat side of the D shape inside the hole center of the trim pot to stop the axil slightly dragging on it and moving the center position (this is not always necessary if it has clearance and you have aligned all three servo cases holes correctly with the trim pot.
Clean and Replace all gears and axil (but not the circuit board and lower case) and test the servo is now spinning the output shaft smoothly and consistent. (Axil is glued in latter)
If your hole is off center a bit and binding as it turns remove all gears and ream the drill bit slightly to realign the hole through the output shaft or servo cases and reassemble. (Slightly bigger holes are not a big problem)
It will probably not stop fully running in the mid stick TX position as the trim pot position was likely bumped so you simply adjust the trim pot with a tiny flat screw driver from the bottom until it stops turning. (First set all TX trims to center)
Latter when assembled it can also be further fine tuned to stop running at neutral stick position by adjusting the transmitter servo center trims.
Now with axil fitted in position (servo on its side) use a drip of epoxy and place it around the screw hole in the output spline so it sticks to the axil. (Doesn't need much glue as there is very little torque and you may want to remove it again)
Briefly spin it up for a few seconds as the glue dries to check it's running true and smooth again without a big wobble. (A very small wobble is ok if it is not binding as it won't really be noticed as the vehicle drives but aim for perfection to begin with)
Don't get any thin glue down past the output spline as it may bind up the separate gear under it (use thick glue or glue it when the servo is on it's side to stop gravity drawing thin glue down)
Now replace the circuit board on an angle in beside the axil inside the servo and cut a hole in the lower servo case as it will be very limited for space now and need an extra 1-2mm space then tape over the lower servo case hole.
Relocate the servo lead wire exit position to suit your layout only if required.
Tape up the servo cases together again and it's now ready to glue the wheels on.
ES9251 or ES9052 Faster 4 gear hack version.
For clarification if we are calling the motor pinion gear #1 and the output shaft spline gear #6 you will be removing the output shaft #6 and gear under it #4 and the metal shaft and white plastic D.
Now gear #5 in the sequence is moved and now used in the output shaft position glued to the axil. (This gear has the same teeth as #4 but has more glueing area inside its axil hole.
I made a Perspex (plastic or nylon etc) grommet or washer which fits neatly inside the top of the top servo case for the axil to now run in and stop lateral axil movement (my washer was about 1.5 - 2mm thick )
Now the servo is about 3mm narrower in width without the spline sticking out.
Another way to do it --- remove gear #5 and discard it and simply glue an axil to both the gear #4 and output #6 and you can cut off the spline outside if you need the servo narrower between the wheels. (If width is ok with spline keep it on as it's good to glue one wheel to it also)

Emax ES09MD (or ES09A or ES09MA) HACK MOD
It's a bit overkill .... a cheaper ES08A is good enough.
Basically it has the last output spline completely removed and that whole side of the servo case cut off (to make it smaller) and the axil goes through the next gear along.
It is both slow and medium speed (scale about 30mph) and powerful but bigger for trucks or buses - my old blue Chevy pick up has it but I trimmed down the servo cases at their join positions and then I had to make a hole for the bottom of the motor to reduce the servo height from 25 to 23mm to fit it inside the 25 mm wide chassis box aluminum but it also has skinny 2.5mm wheels so it kept its original old school overall wheel track appearance.
As above instructions remove the gears and take photos etc.
Discard the output shaft and metal shaft and plastic D thingy under it. (None of this is used)
Move the circuit board (tape it up so it won't short circuit on anything) and unclip the trim pot from below (most have small clips on the trim pot) and move both outside the servo (they won't fit back in it again and you could rewire them to fit somewhere else in the vehicle if needed)
Grind a recess in the cases (when you know where) for these wires for reassembly latter on.
Drill an axil hole through all 3 servo cases where the last gear and axil now is and cut off that side of the servo (all 3 cases) about 2mm or whatever you like beside the axil position (this amount left on beside the axil determines it's ground clearance when driving as the servo is taller in the upright position)
Clean and reassemble the gears and axil and test it all runs true and smooth.
Twist the axil with fingers to check not binding.
Adjust servo trim pot for neutral power at TX mid stick.
Tape up the trim pot so it's not bumped again.
Mark or measure the last gear position on the axil and remove them both and epoxy (leave no excess glue on shaft where it spins) and reassemble and when the glue is still a bit green test it's all spinning smoothly again.
If it's binding or turning rough then remove it before the epoxy is way too hard and redo it again (straight axils are a must ... big needles worked for me also)
Make a thin alum or brass cover for the exposed part of the servo innards and drill and grind a small slot just for the last axil gear to protrude neatly through it then use a few drops of epoxy glue to hold this cover on ..... Or make this cover so it can be screwed to the bottom of the car chassis as I did on the old blue Chevy pick up.

On the bus I completely stripped a damaged servo (CORONA DS238MG) for gears and motor and pot and board and reassembled the gears in the alum bus chassis and made new gear shafts and epoxied it all in delicate alignment.
Perfect attention to alignment and avoiding binding is not easy and I don't recommend it unless you are very patient and accurate.
But this hack method may be very useful if you have a real tricky layout where the servo hack mod won't have the space or won't be right for the job.
Emax ES08MD MA or A 3 gear hack (FAST SPEED MOTOR HACK)
I haven't done a hack on these yet.
Looking at the web drawings and gear photos I would completely remove the output spline and the next two gears and fit an axil in the third gear and move the pot and circuit board outside (has 6 gears total)
So it now has the motor pinion gear and two more gears only.
So all three servo cases have one side cut off just near the axil as needed.
The top servo case should be much lower in height now but needs a new piece added for the axil to run in (epoxy a piece of alloy or brass on top with the hole) and you will gain lots more space between the wheels for it in a small car. (Now 20mm)
From the axil center to the far side of the servo should be about 12mm.
So 20 x 12? x 11.5mm will fit most cars and have a stronger motor and it's geared fast.
Please post a report back here if you try this and its a good hack or not you guys.
Last edited by vtolman; Nov 22, 2016 at 10:04 AM. Reason: Update information
Mar 30, 2016, 10:33 PM
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Thread OP

DIY steering

I mostly used brass to make the steering.
Best to use K&S square tube 5/32 for the center box and 1/8 for the steering nuckles which fit together neatly.
Mar 31, 2016, 01:47 AM
Registered User
Wow really nice to convert thoses little car to RC
Mar 31, 2016, 01:58 AM
Registered User
Wow! That's so cool, if almost offer to buy one but I'd doubt that you'd part with one.
Mar 31, 2016, 02:51 AM
187trophy's Avatar
nice., gave me an idea on my next /1/64-1/87scales builds,good stuff with the servo drive gears,i like that .-thanks for an idea-/so what holds the gear to the shaft''axil'', form not slipping?.so just a tight fit or a little super glue does it? i think of useing mybe brass rods with some matel gear servo?then solder it.
Last edited by 187trophy; Mar 31, 2016 at 03:11 AM.
Mar 31, 2016, 05:39 AM
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Thread OP

These photos and info may help someone.

It's easier to make a 1:64 - 1:87 scale truck or bus but the cars are a bit tricky at first attempt.
Here is what I have built so far and how I made them work at scale speed and turn really sharp and have smooth accurate scale control ... unlike all the jerky coke can car toys.
Anyone please chime in when you have some good tips on design, small parts supplies or building ideas.
My converted 1:64 - 1:87 scale die cast cars cost $30 - 40 each complete with 2 servos, RX, LiPo battery, car body, switch, wire, plugs, metals, pins etc.

Auto World make nice 1:64 scale models with scale rubber wheels.
Die cast models from Hot wheels are also rather cramped when full of components, but I like their American muscle cars and land Yachts.
Some Majorette die cast models 1:61 are slightly bigger so easier to fit components inside ... Especially the bigger models like BMW X6 SUV (glue the doors shut) or their Chevy Silverado with a longer wheel base would both be good for someone's first attempt.
Also the Majorette's Mustang Boss is 1:61 scale and still looks similar in size to Hot Wheels but it has that little extra space you need for parts and a bigger LiPO and they have more scale narrow width wheels.
I grind down the inside of the hotwheels wheels to a narrower more realistic usable width.
To remove the bodies simply drill out the rivet heads holding it to the chassis then grind off all unnecessary metal tabs inside the bodies which clutters up the space.
Bevel or dremel the inside of the die cast wheel arches for tyre steering clearance.
I seperated the wind shield and back window from the one piece clear plastic and glue them in place to save on head room under the roof for the steering servo.
My DIY bodies for trucks and buses were made from plain electrical circuit board (1/16 thick 1.5mm) soldering the corners on the insides and sanding and covering the outsides in colored contact film to get pin strips and avoid messy paintwork (grind off some excess copper inside for better RC radio reception if you have an internal short antenna as I did.

Original wheels from Hot Wheels and Majorette (slippery plastic) were used (width modified narrower) and covered with black heat shrink rubber tube on the tread areas to add traction and sanded for more grip I'd needed.
Another suggestion is liquid electrical tape but I haven't tried it yet.
I read that some people are using dental rubber bands stretched over the slippery plastic wheels and maybe glued on if needed ... coloring both tread methods with permanent ink pen if they are not black should work.
Auto World die cast have nice thin scale rubber tires on their cars ... Apparently ... but my country doesn't have them so I can't truly comment.
I glued very small pieces of tube or bushing (from WD40 or CRC spray can tubes or the inside of old disposable cigarette lighters) inside the hot wheels where they have the recess hole on the outside for the axil ends ...... Because when I grind down the inside of most wheels to get them to a more usable width size (around 4-5 mm wide) it also removes the wheels inside nipple and now the wheel may have excessive wobble on an axil as it has so little meat left to spin on.
New out of the box all these die cast model wheels wobble on the original axils as they really are too loose to start with in my opinion.
This tinny tube I fitted in the outside of the wheel was only about 2mm in length and adds back the stability on the axil needed.
I have also drilled a 2mm hole right through the front wheels (only 2.5-3mm wide) and press fitted the WD40 tubes into them ... the piece is about 4mm long.
My DIY truck and bus tires were made from small rubber fuel line (approx 11mm O.D x 5mm I.D. ) stretched over thin plastic tubes (whatever I could find) for the wheel centers. (I never did find the perfect piece for the wheels)
Do 1:64 slot car parts help anywhere I wonder ?
I found truck van and car wheels and tires on the web also but they will cost you.
For trucks and buses my DIY tires finished approx 12 - 14 mm in diameter and about 2.5 - 4mm wide depending what vehicles.
I heated pieces of rubber fuel line in boiling water and slipped them over plastic grommets or tubes which I then spun up in a drill and dremeled off the wheel widths as needed.
The wheels internal centers for the axils (sometimes are too big) were sometimes made smaller using the thin plastic tubes (or K & S brass tube) to match the axil sizes.
Front AXILS for these DIY wheels were sometimes small screws and nuts often used by optometrists etc.
Front Axils to suit the Hot wheels or Majorette cars were either original axils cut in half or sewing pins or needles or spring piano wire with jewelry glass beads glued on to the ends to keep the wheels on.
Fallers Car System and some others have attractive detailed tires and wheels and complete front steering axils etc which can avoid the hassle of making all this ridiculous fiddly stuff if the size works and that's what you prefer.

(Update see posts #20 21 etc for a different steering method with servo between the wheels)
Basically copy the Faller Car System type steering but have the tie rod link on top and the box pivots on a piece of horizontal wire glues to the car chassis.
The Centre pivoting axil section is 0.5mm thick (20 thou) brass sheet folded into a square U-shape but its much easier to use the K & S square brass tube 4mm (or 5/32") but once again my country doesn't have that stuff.
The outer two pieces (steering knuckles) use 3mm (or 1/8") square brass tube which neatly fits inside the center pivot section and pivot on sewing pins ... drill with 0.5 - 0.7mm bit and a little glue on the pin head for easy service and removal.
My first models all had small screws from the optometrist but it's a waste of time taping for all those silly threads (you can tap threads using these stainless screws into the softer brass) when you can use simple smooth sewing pins with small metal heads.
The connecting tie rod link was a flat piece of 0.5 mm brass about 1.5-2mm wide.
My tie rod lengths from hole to hole centers match the length between the Knuckle King pins .... I experimented with some cars having a shorter tie rod (1-1.5mm shorter so the inside wheel turns sharper) and a small Ackerman angle but it makes little or no difference (too much Ackerman angle and wheels skid and don't turn at full lock and/or the inside steering knuckle is overlocked and the servo binds)
Basically make EVERYTHING parallel and plumb and square and equal lengths so all your pivot points viewed from the side or top or front are forming equal sided rectangles .... No toe in ... No camber ... No castor ... No angles anywhere etc and it will still work fine.
The hole centers on trucks are approx 18 & 6mm and 16 & 5mm on the cars.
Careful the knuckle lengths are not too long and catch on the mudguards when turning.
It is hard to get it totally perfect without some accidental slight angles and or free play slop but it will still work ok .... all my vehicles are far from perfect but they all work fine.
You could probably connect the tie rod to the knuckles (I never tried) if you epoxy or solder pins in place instead of screws (Or use a plastic tie rod link and screw into it instead of brass)
The steering arm push rod linking the brass servo arm to the tie rod is made up from a sewing pin (flame heat first makes neater right angle bends and you could glue some jewelry beads on it for lock collars to stop it undoing off the tie rod or from binding up. (I did tiny balls of solder on it sometimes and only U-bends other times)
DIY SERVO CONTROL ARM HORNS are cut from 0.5mm brass sheet as space is very limited inside the cars and you need it cranked forward and I also used a smaller head screw (or grind it) to hold it on as it's usually right up near the windshield.
I sometimes use tiny little glass jewelry beads (approx 0.8mm inside and 1.5mm outside) on the sewing pins for .... axil wheel nuts if needed ... Ball Bearings ... thrust bearings ... bushes etc.
Washers ... I found some small plastic cheap jewelry discs about 3mm and 4mm round and rather thin with center holes under 1mm.
The main center pivot point is approx 1.2mm piano spring wire and the steering box axil is held on this wire with the cigarette lighter plastic tubes which is easily to press fit on and off when setting up the servo linkage.
This 1.2mm spring wire is attached to the aluminum chassis with epoxy.
Design the vehicle track width of the two front wheels about 1-3mm narrower than the overall outside width of the mudguards on the vehicles (example my hot wheels Cadillac / Riviera wheels are about 27mm overall but the die cast measures 30mm at top and 26mm near the lower rocker panels ... Most trucks and buses are about 31mm wheels overall with a 32mm body but have more height clearence.
Most cars front and rear wheels only clear the die cast mudguards by about 0.5-1mm when turning and pivoting. (The higher the body is above the wheels the wider the wheels can be placed apart if you prefer)
The rear axil has no differential so one rearwheel has to either drag or spin faster which fights the steering but only noticeable if you have a slippery road or slippery front tires and it then plows straight ahead the tighter the steering is turned.

I cut up 0.5mm thin aluminium box sections 25mm wide on most cars which is easily cut ground and shaped but some die cast models are only 23mm wide inside the body.
Thin brass or aluminum folded up would also work ok.
The 25mm wide chassis overall requires cut outs for the rear wheels to fit.
I epoxy the rear servo drive motor and switch and or charge socket onto the chassis after all is tested working.
The body just lightly press fits onto these aluminum chassis and no need for screws (pack the gaps with foam or tape etc)

I have noticed a few others have done tall spring suspension and wide track widths on their Table Top Trucks and rock crawlers or monster trucks but then added the smaller HO scale body on the top.
But for attempting a scale like suspension hidden underneath a small 1:64 scale body in the tight spaces I experimented with neodymium magnets (ebay again) and had success with tiny 3mm diameter and 1mm thick magnets. (4 x 2 mm should work better )
I extended a piece of brass on the front pivot box axil forward about 3mm and glued a magnet each side on the top and then glueing another two under the hood area directly above them.
You can add more magnets onto them (without glue) for more strength to tighten up the suspension.
They start to repel about 10-12mm apart and are firm about 3mm apart.
Without this front suspension for off road driving or non level ground when tilting the vehicle 40 deg or more definitely helps stop the vehicle from rolling over too easy because it is only relying on the rear fixed axil for stability.

I have only used the 8mm wide EMax ES9251 0.27kg torque 4.8v (Turnigy MX-96E is the same servo) for the steering on ALL vehicles and cut off the side tabs to fit them in most cars (sometimes I sanded off the sharp corners also to fit snugly into the curved roof area)
Hobby King HK-5320 (max 4.2v) have thinner 6.2mm wide servos (14x16-18mm) with the 1.25mm micro JST plugs to suit the VD5M FrSky
This servo could better fit some small cars but it states only 0.075kg torque. (Maybe ok for steering .... but will need testing for the drive motor)
The HK-5330 looks better for a drive motor power servo (4.8v max) at 0.17kg and it's 20 x 13 x 6.2mm
Please post here if you try any of these out.

MOTORS and ESC control (see How To servo hacks above)
These are all made from modified servos.
On the small cars I used the ES9251 and some use the original 6 gears and some use only 4 gears.
I used 4g EMax ES9051 for medium size vehicles
I used EMax ES09MD (or ES09A) for the trucks and buses - it's way overkill with lots of power (a bit tricky to modify as you cut them in half and remove the last output shaft)
Spare 4, 6 and 8mm diameter Motors are on ebay for a $1- $4 each if they eventually burn out.
Also I noticed some micro receivers have a built in forward/reverse ESC to control brushed motors supplying low milliamperes.

BATTERIES eBay again (I'm still testing all the choices here)
Smallest cars used 3.7 volt 150 mah lipo (22 x 20 x 3-4mm)
Medium size cars and SUV's and pickups used one 3.7 volt 240 - 300 mah lipo (30 x 20 x 5 or 7 mm) these just fit down low between the longer wheel base length vehicles and still allow steering to clear them. (Minimum 46mm wheel base centers)
NOTE the die cast vehicle wheelbase often determines the battery size you can fit between the wheels.
Some of my vehicles used 3 x 1.2 volt 250-400 mah nimh 1/2AAA cells (each cell was 22mm long x 10.3 mm diam) so assembled it is big at 31mm long by 22 wide by 10.3 high battery pack or I used the 30 x 20 x 7mm lipo
The biggest batteries I used are 3 or 4 cells AAA 900 mah nimh in the drab green riot vehicle and low loader tow truck and the bus but they will run for a long time)

I have only used the FrSky VD5M 5 channel 3 - 7.2 volts (22 x 18.5 x 5- 9mm) NO telemetry or fail safe (I think it still works down close to 2.8 volts but thats not good for LiPo's)
I have a Taranis TX for flexible programming like slowing down the jerky steering movement with servo slow and or time delay and smoothing out the stop and goes.
SPEKTRUM compatible ... Other people have used the smaller size ....... 5-7 channel receivers for these tight spaces and good if you have a Spektrum TX (or Taranis with external Spektrum module) so you could drive 3 cars all with separate steering and throttles or 6 cars with all their steering working full time (WHY drive 6 cars you ask ... because we can
The VD5M have mini 1.25mm spaced pins JST style 3-pin plugs so I ordered a bag of 10 pairs male plug leads about 150mm long from ebay (comes with matching female socket with no wires) and soldered them onto the servos *ONLY buy them prewired as they are impossible to do yourself without the expensive tool.
Some sell these servos with the 1.25mm plugs but the leads are alway too long anyway (cut and join is the solution here)
I used the female socket they come with for the charging sockets on the cars (5.5 x 3.5 x 4.5mm high)
Cramped for space we could also use the 2 pin version I guess.
Any smaller charging socket ideas are welcome ???
If you are really limited for space you can hard wire solder the servos to the VD5M receiver if you remove the cardboard cover and white plugs off the receiver and desolder the pins (5mm smaller in height one end and a bit thinner - 22 x 17 x 3.5mm)
I have only just managed to avoid this hack so far which means I can still easily swap things about and unplug as needed.
It has a short 30mm antenna wire which easily fits inside a car.
Note that 4 (or more) receivers can bind to the one transmitter if all done at the one time together (most other 2.4ghz brands will do this also)
Then you can have the throttles on each car plugged into a different channel on their receiver and use the flight mode switch to quickly change between cars for their different throttle.
With the 4 cars (all with the 5 channels RX in each) I have all their steering acting full time all plugged into channel 1 - however the flight mode switch also changes their respective center position or offset or reverse and travels etc to customize each vehicle steering variances when in use (warning - I set all their steering up very similar to begin with to prevent the other vehicles servos from binding or over travel etc)
Side note Idea - micro reed switch in vehicles to stop the steering servo so when you park all the vehicles over some neodymium magnets under the road the steering stops working. (The reed switch / magnets have many other uses)
Side note of interest to some ... I noticed someone put magnets in the back of their Faller bus and trucks and reed switches in the front (to cut the motor) and it works as a collision avoidance system.

The red circuit board mounted style DIP switches come from eBay (10 mm long x 7mm high x 4.5mm wide) and they can be ground down on each dimension about 1-2mm if needed to cram them in somewhere.
They are surprisingly big for the small cars.
Are there smaller switches available anyone ???
Or another idea for on off.
I prefer not to unplug the receiver battery all the time because it's a fiddly pain in the ....

Some German business sells the laser cut (steel ?) blanks so you can fold up tiny universal joints all from a small flat sheet and silver solder ? them together I assume.
I see some plastic universals for HO trains but they still look too big to fit into a HO scale 4WD front steering .... but I may be wrong.
As for mine I used the 0.5mm sheet brass again and cut 3mm strips then drilled a hole to match the drive shaft and folded it into a U shape about 3 x 3 x 3mm overall.
Then I drilled the pivot holes 0.7mm ready for the next center + cross piece.
Now grind away the excess brass around those 0.7mm holes like a v shape as close as you like or the universal joint will bind up and not work if it's still a chunky 3mm wide on the ends .... Each U ends up about 2 x 3 x 1.5mm after grinding down.
For the center piece then cut a + cross from a piece of any thin mesh (mine was steel 0.7mm welded mesh with 6mm square spacings approx)
I then opened the U into a V and fitted the + and closed it back up into a U on both pieces.
Then you can fold the extra tails of the + cross over (center of cross must be central)
This keeps everything in central alignment otherwise you could build up a small ball of dental floss in the middle of the + cross and zap it on.
My universals were about 3mm in diameter and about 6mm long overall finished.
Universals only work up to 30-35 deg angles from straight before they start to bind so this will limit the steering angles.
Cheap NECKLACE CHAIN is even better but only the ones which look like 4 sided little boxes all strung together ... It's 1.5mm square and bends tight into a 90 degree 5mm radius with only a 7mm length so a 4-5mm length should be enough for the front steering universals to swivel 45 deg in theory.
I electrical soldered the necklace chain ends to pin heads and 1mm wire for testing.
Should be silver soldered not electrical solder as it's a bit weak. (Jewelry work etc)
All of the above universals tested fine turning smoothly in my drill but I am yet to make up a front end to test any on a 4WD model until I order some micro worm drive gears similar to the Faller gears.
Tip ... Re-drill the drive shaft holes in the U after it's folded up (they distort when bending) and then tapper the drive shaft end slightly in your drill and dremel the tapper so it only just neatly tap fits in flush and tight into the holes of the U metal and no further .... then its much easier to handle when soldering.
Or use long large pins for drive shafts with the pin heads inside the bottom of the U and then epoxy or solder on the outside or the U.
Tip ... leave a long tail on one end of the + cross so it's easier to handle when wrapping the floss/thread around and or assembly etc.
Tip ... every piece of the steering parts brass should be left longer than needed for handling all the drilling etc then trimmed to length only is done last.
Tip ... I often have many steering pieces all marked out together on one piece then drilled first then filed and lastly cut up into their little pieces with a dremel.
(beats fiddling about with tiny little brass pieces and trying to drill them square is almost impossible)

Drill with sharp chuck jaws that close tight for small drill bits.
(Or wrap your small drill bit shafts in cello tape to build up size so they tighten in drill chuck)
Drill bits 0.5mm, 0.7mm, 1mm, 1.5, 2, 2.5, 3, 4mm
Dremel type of tool.
Dremel type grinding cutting Discs ( I make stronger spare discs by snapping them off a large 1mm thick x 100mm diameter industrial cutting discs and punch a center hole and mount them in 3mm x 40mm high tensile hex bolts with cello tape around the thread (1/8 size is probably a better fit) these discs are much stronger, last longer, and cheaper than those brittle thin dangerous ones which come with the tools (wear safety glasses regardless of what cutting discs used as they can still fly to pieces if they jamb in the metal)
Various dremel rotary burrs and sanding and grinding drums and diamond burrs.
Exacto knife, small long nose pliers and large pliers, tin cutter snips, side cutters, micro screw drivers, soldering iron and work station clamps and magnifying glass, hammer, ruler, small file set.
A Vice and Dial calipers and a mini drill press would be very helpful but I have managed without them so far.
Last edited by vtolman; Jun 16, 2016 at 10:40 AM. Reason: Corrections and updates
Apr 02, 2016, 02:32 PM
Registered User
This is fantastic! , this is what the hobby is about, making things solving problems yes yes yes

I do like your servo/rear axle invention!, very nifty , I think I might adopt the idea in the future!

I would use tine ball bearing whereever possible
Apr 02, 2016, 07:33 PM
Registered User
Thread OP

Parts and tools

Note the BMW is bigger - good to use a slightly bigger car like this for a first attempt.
The drift car is extremely cramped inside and has a 30 x 20 x 7mm 300ma LiPo.
Wheel base is only 44mm but it's a real jigsaw.
Lots of speed and wheel spin.
The drill bits are 0.5mm and 0.7 and 1mm (I don't use 0.5mm)
Axil and pin and all steering joints use 0.7mm
Axil is No. 5 needle
Neodymium magnets and NC/NO reed switch.
1.25mm lead and plugs.
Apr 03, 2016, 01:34 AM
Registered User
These are so darn cool. I wanna make one!
Apr 03, 2016, 03:08 AM
Registered User
this is really crazy cool.
Apr 04, 2016, 03:10 AM
Registered User
Thread OP

Steering and gears photos

Inner workings photos
Apr 17, 2016, 11:34 AM
I'm BIG on micros
JSS4's Avatar
Excellent work! I finished my first 1/87 RC in late March using German components. A good compact gearbox to use is the M400G8 from kkpmo or mcc modelcarparts. I use Deltang receivers, they go down to 12x12 mm for super compact use and they have some slightly larger that control driving lights

The servo as an ESC is something I need to try, my ESCs now are 20 EUR each but they are excellent for low end control

As for the axles, have you tried Faller axles, for 1/64 they are small so try the truck or bus axle which may be the right sze. Sometime I should try to do an awd Expedition with the U joints.

The German company making the U joints is MZR-online, by Andreas Rackel
Apr 18, 2016, 05:47 AM
Registered User
Thread OP
Good info.
Yes I've found most of that stuff you mentioned thank you.
I messed with the Faller car system years ago in RC trucks but I like to build my own steering as it often needs special design and sizes etc.
I'm now working on a convertible mustang but I'm waiting on stocks of 6mm thick servos for steering.
It's rather tricky as I need to mount a tiny servo between the front wheels and fit under the hood height .... Looks promising so far ..... It should work ok.
I geared it on the 5th gear this time and it's working nice also.
Last edited by vtolman; Apr 19, 2016 at 11:39 PM. Reason: Add photo

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