my post has gone

hi guys,
i posted up my e-maxx build in the project x section.
now its gone has it been moved...or ?
chris

[suicideneil]

http://www.rc-monster.com/forum/showthread.php?t=21856

It's still there- you just have to select 'from the 'beginning' at the bottom of the page under Display options. :)

Glad you're still with us

oh yer cheers neil, i wondered why there was nothing there.
a blond moment i think....durrrrr
hows things ?
i have not been around for quite a while....what did i miss ?

[suicideneil]

Haven't missed too much- few new escs & lots of interesting motors appearing which is cool, and 1/5 scale electric models/conversions are really popular ( so too electric bike conversions ).

ahh..cool. i still got my old e-maxx, i took it for a spin last monday while i was at heliclub, pinion came loose again .
i need to replace that rubbish alloy pinion. the m3 grub threaded out...now i have drilled it out to m4, it will still come loose.
the pinion is so worn that it heats up in just a few mins of running and breaks off the locktite..., i need a steel one on there and a new spur gear.
any recomendations neil ?
chris.

[suicideneil]

Sure, for UK based options:

http://www.modelsport.co.uk/32dp/rc-...ID[41]=643

The RW ( 5mm shaft ) options would be great, as would the Robinson racing pinions. Mike's pinions are great but international shipping is killer as he needs to send recorded delivery- he may be able to cut a cheaper deal on shipping costs if you ask nicely though. Otherwise, try the list of Pinion gear suppliers here:

http://www.robotwars.00server.com/trucklinks.html

scroll down a little. Alloy pinions are hopeless though yeah, either the teeth wear out after a few runs or the grub screw strips too easily- hardened steel all the way

cheers neil
chris

seeing as i need a new spur and pinion i was thinking about fitting the newer e-maxx/revo slipper and spur neil.
only 3 things on my mind right now...

1. the newer spurs seem to only go up to 68 tooth as far as i know of... or is there bigger that i cant find?? current gearing is 70t and 18t pinion and i would like to stick to that as close as possible...

2. the newer spur is also a .8 mod. has anyone actually run a 32dp pinion on a .8 mod spur..i know its very close...but its not the same, do they wear out real quickly? noisier at all? i did not have much luck finding a .8 mod steel gear with a 5mm mount hole

3. the shaft...now there is no way i will bodge this with heat shrink, tape or any rubbish like that....
so its either make a new shaft complete, or buy the revo shaft and fit my gears to it, shorten it so it will fit inside my gearbox the both gears intact, (i know i will have to drill new holes for the gears and solid pin them), i want to keep my 2 speed for now.

anyway, i finally got round to flattening the bottom of the alloy gearbox on the milling machine...so it would sit on the chassis flat, and it is in there.
i did nothing with the motor plate locator and screws...i just wopped the motor plate on there.

first impressions is it is alot quieter i like that...means the idler gears are not moving around now ..so far so good.
so i turned up the power on the mm software to medium holy £$&*...bashed around the park showing mates what 6s will really do and shredded a rear drive shaft......apart from that the gearbox and motor plate held up fine for that run...fingers crossed.

thanks guys..
chris

[suicideneil]

1. Yeah, only goes upto 68tooth- 68 vs 70 won't make any real difference really, maybe one tooth up on the pinion but tire ballooning and ambient temp will make more of a difference to running temps and such.

2. The difference is so small it won't make a difference- different brands use different pressure angles on their pinions so that is more likely to cause premature wear if anything; just set the mesh correctly ( tiny bit of play but no more ) and it'll be fine. Any mod0.8 or 32p steel pinion with a 5mm hole will be fine - Mikes are great, if not the RobinsonRacing ones are great too.

3. I got someone to do that for me when I upgraded, but it looks simple enough based on a few guides:

http://www.rc-monster.com/forum/show...0&postcount=51

Seems like to keep it 2 speed, you'd need to buy the topshaft from the new emaxx/erevo tranny, remove the single gear, then drill 2 holes in the correct spots to install your original topshaft gears- just a matter of sliding them on and wiggling them about until the slipper is in the correct position and the gears line up correctly too, then mark & drill the holes to pin them in place.

my thinking exactly neil....i think i will just mod the newer shaft to fit my gearbox...sounds simpler to me than starting fresh.

gear class neil.....
the cogs we use on these cars are called an involute gear. dont mean to sound patronizing but im gonna educate you guys
to form a gear the teeth need to roll against each other (this im sure you allready know) so the teeth are shaped accordingly. if they where to scrape each other the gear would wear out in hours.

correct tooth form is made up of 2 arc's--- epicycloid ( the upper half of the tooth) and hypocycloid (the lower half of the tooth).
these two arcs are formed by rolling a smaller circle around the p.c.d of the gear where the line is a fixed point of the rolling circle, so as the circle rolls, an inner and outer arc would be formed. inner arc is lower tooth profile and outer arc is upper tooth profile.

the p.c.d of a gear is half the tooth height...or really the line of the 2 circles of the gear that touch (reffers to when drawing out a gear set. before the gears are drawn they start out as 2 base circles that touch, but the teeth will end up being longer to engage with each other)

epicycloid the circle rolls around the outside, and the hypocycloid rolls around the inside.
this will form a cycliodal gear tooth.

this is a very complex task...then transfer that to shape the cutter and away you go. well no not really, the cycliodal gear is very touchy about where it touches the other gear if the gear centres are off or move due to bearing wear the teeth will fail very fast.

so with that under our belt..i hope your still with me ....
a very clever guy came up with a new idea...involute tooth form the reason this is so good is 2 factors...

1. involute tooth is formed of only 1 arc, imagine a string with a pen on the end unwinding off a drum, as i unwinds it forms a single arc with a constant changing angle. so tooth forming and cutter shaping is much simpler.

2. involute gears are not so fussed if the centers are off...it makes no more friction from being .20mm off than being dead on centre.

pressure angle...this is the line of contact as the teeth roll over each other.
typically 20 degrees for an involute tooth form...no other angle has ever been used in industry except some old lathe change gears used to be cut at 14.5 degrees. changing the pressure angle changes the shape of the tooth...so different pressure angles could not be used together.

D.P...this means diametral pitch, the number of teeth per inch diameter of a gear

module..this is a metric way of quoting the size of the teeth or the pitch diameter in millimeters divided by the number of teeth.

so D.P is imperial and module is metric. a mod 1 gear is 25.4 D.P...mod 2 is 12.7 D.P so there is a tiny error there. this would cause excessive wear if a mod and a D.P gear are used together.
on a .8 mod i think the error is around .300inch / .75mm
not a great difference but approaching 1mm...

gear class over guys...i hope i explained this well.
phew...
chris

one more question.....using the revo slipper and spur, will my spur cover still fit ?

[suicideneil]

Not sure sorry, I've never ran the gear cover ( don't own one )...