Sprokets and holes

been a tough and dishartening week, hoped to have the jack sahaft done and made a start on the SA by now as it is ive finaly maged to drill the 16 holes in the 2 sprockets! still that is progress can assemble the jack shaft at last, whilst waiting for parts ive been building the above recumbent trike for my nephews, but need to sort out some brakes before i let them lose as thers lots of hills here and this thing is fast!

English Wheels from farm yard scrap

couple of bits of esentialy scrap laying around out side top photo is an old center shaft belt drive i think, and above is the transmisson of a potters wheel, thourght the cast iron wheel would make a good anvil, and the frame of the potters wheel is cast iron and the perfect U shape, as a point of intreast the 2 drive cones the right hand one is steel but the left hand is paper!

Sprocket Carrier Casting

Not to bad, but thers some sand inclusions and porosity, and im not happy about the undercuts were i glued on the drive dogs, What i realy need is some kind of fairing compound to smooth out the transitons but will burn out cleanly with the foam.

ELF Upright

Lost Foam Casting Sprocket Carrier

Had a different day than planed, after boring the jack shaft tube i relised (you would think id of messured before starting!?) that it just wasnt wide enough to fit the sprocket bolts through, so i decided to quickly cast a couple of blanks.
But since i was casting i should also make the new sprocket carrier i need (to fit the smaller sprocket and run 10mm closer to the wheel) so i spent the day trying to cave pink foam into very complicated shapes. The stock item seen in the photo below is very light 660g with the 6 8mm studs. and as ive just worked out how to fit a R1 spindel to the wheel saveing 350g, and fiting the smaler alloy sprockt savein 1kg! i dont want to add it all back with a great big lump of alloy.

Brooklyn machine works Jack shaft

Thanks to them for esnding me this pic of a concentric SA jack shaft its like a inside out version of what im building
cheak out ther site for somw pedal powered beautys the Gangster is my kind of Pushy
http://www.brooklynmachineworks.com/site/bikesindex.html

Jack Shaft

Here is my rough arsed "engineering " drawing of the jack shaft along with the bearings and sprockets, since im haveing the jack shaft i decided to make it do 2 jobs and have 2 stage gearing which means i can drop the rear sprocket from 46t to 36t with a saveing in unsprung weight and lowering the chain line, im also useing a 28mm R1 rear spindel saveing a further 400g of unsprung mass.

Here im useing a dial gauge to center the block of alluminum this is esential since i will have to turn it round to machine the other side, with out the dial gauge the bearings wouldnt line up.

And finaly ive bored it out to 35mm to fit the needle rollers im then going to bore both ends out to 42mm for the ballrace and then drill it for the sprocket drives then cut it in half and turn down sholders for the sprockets.