DannyC
0
We've all experienced the phenomenon where what appeared to be a simple job turns into something much more complicated haven't we?
Today was one of those days.
I have been messing around looking to see how I might more cheaply build 2WD units for Delta trikes and Quads with a mid-drive and RWD .
The last one I made used 2 single speed freewheels and a host of bolts.
The freewheels were not cheap One was a Sturmey Archer and the other a "Dicta". Both of these are around £15 new.
The good thing about the Dicta freewheel is that it has no internal shoulder on the threaded portion so it can be mounted round the "wrong" way and provide a forward motion freewheel for the LH wheel of your axle.
I thought I had found a much cheaper source of such an ambidextrous freewheel (£6.99) as all the pictures appeared to show a "through" thread with no visible shoulder.
They arrived today and well blow me down, while they are a nice smooth ratcheting freewheel (better than a lot of the junk that's "cheap") the threading does not however go completely through, they have left about 1mm of unthreaded sleeve. Rats!
So we need to gently and sensitively machine that off. Cue "lathe-boy".
But wait! the bit you need to remove can't be removed because the inner sleeve "freewheels" on the ratchets.
Ahhh... OK we'll run the lathe in reverse and attack it from the rear (oo-err missus).
But wait! Most of the tooling you have assumes you are doing "normal stuff" in the right direction so you have to get "tricky".
What A pain in the proverbial!
I tried several tools but effectively you are trying to use 12mm shanked tools inside a pipe and the tool's relief is such that the metal of the tool hits the wall before the carbide insert bites and you end up graunching up the tool holder.
I tried lots of different positions and insert angles but I just couldn't get my tool in there properly to get the job done (story of my life really).
VERY frustrating indeed. I got most of it removed but not enough to allow free threading all the way through.
In the end I chucked the freewheel round the wrong way and used a boring bar in reverse (working from the inside -> outside), working mostly blind and by feel/noise.
Hurrah! Job done. The freewheel on the right has had the unthreaded section machined away to allow it to thread on so it can be used as a LH drive in a ratchet differential. The one on the left is threaded on up to the stop and in use would be threaded on the RH side providing a RH ratchet freewheel of the 2WD.
I can now make something no-one has asked for or probably wants (except maybe the pedal-car folks) but it satisfies a curiosity "itch" and is half the price. The 2WD inserts for the axles would be in Aluminium with flanges to act as stops. No bolts between L & R sides this time, just a joining tube welded to each sprocket with 3 decent tack-welds.
Just something to stop me going crazy while my knee gets better.
Today was one of those days.
I have been messing around looking to see how I might more cheaply build 2WD units for Delta trikes and Quads with a mid-drive and RWD .
The last one I made used 2 single speed freewheels and a host of bolts.
The freewheels were not cheap One was a Sturmey Archer and the other a "Dicta". Both of these are around £15 new.
The good thing about the Dicta freewheel is that it has no internal shoulder on the threaded portion so it can be mounted round the "wrong" way and provide a forward motion freewheel for the LH wheel of your axle.
I thought I had found a much cheaper source of such an ambidextrous freewheel (£6.99) as all the pictures appeared to show a "through" thread with no visible shoulder.
They arrived today and well blow me down, while they are a nice smooth ratcheting freewheel (better than a lot of the junk that's "cheap") the threading does not however go completely through, they have left about 1mm of unthreaded sleeve. Rats!
So we need to gently and sensitively machine that off. Cue "lathe-boy".
But wait! the bit you need to remove can't be removed because the inner sleeve "freewheels" on the ratchets.
Ahhh... OK we'll run the lathe in reverse and attack it from the rear (oo-err missus).
But wait! Most of the tooling you have assumes you are doing "normal stuff" in the right direction so you have to get "tricky".
What A pain in the proverbial!
I tried several tools but effectively you are trying to use 12mm shanked tools inside a pipe and the tool's relief is such that the metal of the tool hits the wall before the carbide insert bites and you end up graunching up the tool holder.
I tried lots of different positions and insert angles but I just couldn't get my tool in there properly to get the job done (story of my life really).
VERY frustrating indeed. I got most of it removed but not enough to allow free threading all the way through.
In the end I chucked the freewheel round the wrong way and used a boring bar in reverse (working from the inside -> outside), working mostly blind and by feel/noise.
Hurrah! Job done. The freewheel on the right has had the unthreaded section machined away to allow it to thread on so it can be used as a LH drive in a ratchet differential. The one on the left is threaded on up to the stop and in use would be threaded on the RH side providing a RH ratchet freewheel of the 2WD.
I can now make something no-one has asked for or probably wants (except maybe the pedal-car folks) but it satisfies a curiosity "itch" and is half the price.
The 2WD inserts for the axles would be in Aluminium with flanges to act as stops. No bolts between L & R sides this time, just a joining tube welded to each sprocket with 3 decent tack-welds.Just something to stop me going crazy while my knee gets better.
