how to machine a differential?

[theTman]

Around mid january i will most likely be starting a advanced machining class in school, and i was wondering if anyone thinks it is possible to build a differential within the means i have there. I have access to a manual verticle mill, lathe, horizontal and vertical band saws, hydraulic sheer, grinders, various hand tools, and a forge (not sure if it would be usefull). we also have a cnc milling machine, but they still need to string a power cord to it as osha would not approve of a perminant extension cord. It would be complex, and the teacher doesn't really have any lesson plans for it. if i can i would like to try to do this without it. come to think of it, a friend who took this class said the teacher has let guys build bikes and stuff before and earn credit in class for it. i have access to a stick welder, and possibly a mig. i am a decent stick welder, and mig is incredibly easy. now i just need to figure out how to make a differential, and get a job finally to fund it. so anyone who has any ideas or plans for this they are willing to share, post up please. oh, and i should add that i would like to ride in the winter, and i live in minnesota. i have 2 26" innova steel studded tires i would like to use. i would have a whole semester if needed.

[AtomicZombie]

Those large RC cars look so real...

http://www.klepprc.no/rogaland/klepp/krc.nsf/bilder/Marius-2_300x400.jpg/$FILE/Marius-2_300x400.jpg

Brad

[theTman]

i figured the spider gears would be a difficulty. i am not sure how to cut gears. also, heat treating is not an issue. we have an oxy torch, a forge, and other stuff too. i will have the capability, and know how to do so, i just need to look up the proper temperatures. you have to harden it, and then temper it. i have taken apart an rc diff before, i was into rc rock crawling for a while and ocassionally you would blow a diff in a solid axle. well, more like the diff would unlock if locked poorly and strip out. i'll look into that, as from what i've seen it should work. i decided to go for the D wolf over my previous plans for a meridian because i have more knowledge, and know now i am quite capable of this and more when i have the necessary tools. and also i have good bike building experience from tearing a bike down completely, repainting it 2 tone with a smoky fade between the 2 colors, and i regreased the cranks, headtube, and wheel bearings. didn't crack the freewheel open yet though. so the DW is well within my abilities now. and money may be limited.

[theTman]

i couldn't find any good 1/5 scale diffs. most of the stuff i find is replacement parts. any other ideas to get both wheels driving. in minnesota you encounter alot of ice, in fact the dirt road i live on becomes solid slick packed ice, so traction is a must. my mtb with studded tires handled it just fine, but it has problems, has crappy, energy sapping rear suspension, and has alot of excess weight for an upright weighing in at 41 lbs. also 3 wheels is alot more stable incase i get blown sideways by wind if i happen to encounter that kind of whether while out. also i could make a fairing to keep the wind out of my face.

i just had an idea. is there a way to drive both wheels seperately, and disengage one or the other when turning. like disengage the left wheels drive manually when turning left. maybe use a derailer to take the chain off the gear and onto a smooth drum or bearing.

[TheKid]

You could put a 5 or 6 speed freewheel on each axle and shift one or the other when turning. It works well if the roads aren't winding with lots of sharp curves. I had a setup like that on my quad, which was very heavy. The posi was great on straight hills, with both wheels driving the vehicle, and being able to shift the inside wheel to a lower gear made uphill turns a snap. It's kind of a pain to get used to, but it does work.

[theTman]

i have an idea based on the last 2 posts. i could make something like the picture posted, except each wheel would have a set of gears, and i possibly could have a derailer on the axle that converts from 1 chain line into 2. i would have to work out the gearing ratios to figure out how practicle it would be, and if i can find the right gears. that would yeild alot of gearing options. 3 rear derailers on one bike. one for adjusting the overall ratio, and one for each wheel to adjust for turns. that would mean 4 derailer levers on the handle bars lol. maybe i could omit the central rear derailer for simplicity.

[theTman]

hey Thekid, could you post up some pictures of your drive setup?
i also had another thought! is there a way to manually engage and disengage each wheel individually from the center drive axle with the rear derailer setup? like makeing a cable operated clutch maybe? any ideas?

[AtomicZombie]

Mark's trike is a very well built machine indeed. And, man does he ever look like George Carlin!!

Brad

[John Lewis]

Found this. Could be of interest. Differential about half way down page. Look at his Cheap Rod end bearings straight underneath the diff article too. Don't know how they'd last.

http://www.packratworkshop.com/trike8.htm

John Lewis

[bambuko]

interesting and practical solution, thanks John
BTW - this is not differential !
It is a ratchet drive and it has different action to differential (pardon the pun :)) see the discussion here:
differential and/or ratchet drive (http://forum.atomiczombie.com/showthread.php?t=198)

Chris

[John Lewis]

interesting and practical solution, thanks John
BTW - this is not differential !
It is a ratchet drive and it has different action to differential (pardon the pun :)) see the discussion here:
differential and/or ratchet drive (http://forum.atomiczombie.com/showthread.php?t=198)

Chris

Yes I realise that. It may however have its place.

Years back I had a motor scythe and it had big external pawls and rachets on the two drive wheels so I have a pretty good idea about how they work.

Glad I could help.

John Lewis

[Ten80]

John, would that have been an Alan Sythe by any chance? I ask because I was recently given one by the bloke who's farms I work on. It's a fantastic bit o' kit, and i was lucky enough to find both a manual and original sales pamphlet for it. The latter is fantastic, pictures of grounds keepers wearing suits and ties mowing brambles on embankments, or using the syther as a power plant to pump out pools, trim hedges and shear sheep with various attachments!

[John Lewis]

John, would that have been an Alan Sythe by any chance? I ask because I was recently given one by the bloke who's farms I work on. It's a fantastic bit o' kit, and i was lucky enough to find both a manual and original sales pamphlet for it. The latter is fantastic, pictures of grounds keepers wearing suits and ties mowing brambles on embankments, or using the syther as a power plant to pump out pools, trim hedges and shear sheep with various attachments!

Yes I believe it was. Painted green. Two fairly large narrow wheels with Alan (or was it Allan?) cast into the rim and picked out in yellow paint. Two stroke motor started with a separate pull cord. It's so long ago the details are becoming a bit vague now.

John Lewis