DannyC
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That's how I made my 2WD for use with a mid-drive 8-speed.
Running something up the flagpole to get opinions please.
- Thread starter DannyC
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DannyC
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Agreed, the idea is to do "spot-welds"/"tacks" separated by time and cooling action. The cassette in the picture has the first 3 "plates" all connected with metal spacers and I am expecting the heat not to go up into the area with the plastic separators.
On the other end (the single speed) I do have the option of marking out the "ring" where the 60mm tube ends up and I can just slice off the excess metal like cutting a hexagon shape and just welding it at those 6 points like you would weld an outside corner. Again, one weld at a time and plenty of cooling off to prevent the grease all melting away.
How does that sound as a plan of attack?
Popshot
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It's a chance.
I would use as long a length of box spanner as possible along with as long a nut or hexagonal shaft inside it as possible to give the biggest drive area to reduce wear. Box spanners are rarely hardened in my experience, having bent a few so consider a 6 wall drive socket as the drive rather than the box spanner. The 6wd socket has the advantage of driving on the wall rather than the corners of the nut / hexagonal bar and is going to be very hard. I've never rounded a nut with a 6wd.
Just as a point, a multispeed will typically last 3000 to 6000 miles and changing this means cutting, replacing and rewelding once worn. You ideally want any driveshaft mating wear to match or exceed that to avoid rebuilding more than necessary.
I would use as long a length of box spanner as possible along with as long a nut or hexagonal shaft inside it as possible to give the biggest drive area to reduce wear. Box spanners are rarely hardened in my experience, having bent a few so consider a 6 wall drive socket as the drive rather than the box spanner. The 6wd socket has the advantage of driving on the wall rather than the corners of the nut / hexagonal bar and is going to be very hard. I've never rounded a nut with a 6wd.
Just as a point, a multispeed will typically last 3000 to 6000 miles and changing this means cutting, replacing and rewelding once worn. You ideally want any driveshaft mating wear to match or exceed that to avoid rebuilding more than necessary.
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DannyC
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As an update (of sorts), I made enquiries of those 'in the know' and they confirmed that the units currently in use all have a fairly small hex end to the axles. Bizarrely, one is slightly smaller than the other.
The left drive shaft has a 1/2" af hexagon .
The right drive shaft has a 7/16" af hexagon.
So my guess at a 12mm hex end being adequate was pretty good.
The axles are all just Silver steel.
So Lathe-boy purchased an expensive 12mm hex-broach to go in his wobble-broach.
Game on!
The left drive shaft has a 1/2" af hexagon .
The right drive shaft has a 7/16" af hexagon.
So my guess at a 12mm hex end being adequate was pretty good.
The axles are all just Silver steel.
So Lathe-boy purchased an expensive 12mm hex-broach to go in his wobble-broach.
Game on!
Thanks good luck it takes creativity make a low tech no lathe differential, will be much appreciated by all home builders.
DannyC
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While the main thrust is to make a cheap "Boy Scout" achievable 2WD unit without resorting to and sophisticated tooling; there is also some interest in a more sophisticated unit that does require some lathework and precision manufacture.
So, lathe-boy escaped when he heard some steel tube arrive today.
Today's cast of players in order of appearance (L-R).....
Mr. Cheap screw-on freewheel.
Mr. Tube
Mr. Screw-in 10Spd cassette carrier with internal freewheel and pre-formed 12mm AF internal keyway.
Mr. Tube got told to square up and then had a little recess cut in the top end that the base of the cassette-carrier fits into perfectly.
This means that the cassette carrier can be welded to the tube at several points around its base with no impact on the cassette carrying capability.
Similarly, Mr. Cheap Screw-on freewheel will be inserted into the other end of the same tube once the tube has been shortened and then bored out so as to be a tight fit over the free-wheel's outer case. An appropriately threaded metal slug with a 12mm hex hole broached in it will go into the screw-on cup of the freewheel to become the interface for a LH axle.
Clearly I can just weld the sprocket teeth of the freewheel to the tube too. "Job-done", OR I could make a pair of metal "rings" to go round the tube and also on the outside of the freewheel sprocket and make it a bolt-together 2WD that can be separated for lube & service (new balls please).
Costs so far:
So, lathe-boy escaped when he heard some steel tube arrive today.
Today's cast of players in order of appearance (L-R).....
Mr. Cheap screw-on freewheel.
Mr. Tube
Mr. Screw-in 10Spd cassette carrier with internal freewheel and pre-formed 12mm AF internal keyway.
Mr. Tube got told to square up and then had a little recess cut in the top end that the base of the cassette-carrier fits into perfectly.
This means that the cassette carrier can be welded to the tube at several points around its base with no impact on the cassette carrying capability.
Similarly, Mr. Cheap Screw-on freewheel will be inserted into the other end of the same tube once the tube has been shortened and then bored out so as to be a tight fit over the free-wheel's outer case. An appropriately threaded metal slug with a 12mm hex hole broached in it will go into the screw-on cup of the freewheel to become the interface for a LH axle.
Clearly I can just weld the sprocket teeth of the freewheel to the tube too. "Job-done", OR I could make a pair of metal "rings" to go round the tube and also on the outside of the freewheel sprocket and make it a bolt-together 2WD that can be separated for lube & service (new balls please).
Costs so far:
- Cheap Chinese 12T screw-on freewheel £7.39
- Screw-in 10Spd cassette carrier with internal ratchet £13.99
- 300mm of precision 42mmOD, 36mmID tube £21.66 (sufficient to make at least 4 such units) so in effect about £5.20.
- Lathe-boy time.... £priceless ..........................because it is so much fun.
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DannyC
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Lathe boy was at it again today and the other end of the tube got trimmed and counterbored for the small freewheel.
This is what the finished item will look like. Not too shabby is it?
Total length end to end is 93mm. The cassette carrier can accommodate 8..10 speed cassettes.
A bolt is holding it all together for the picture as it is yet to be welded at either end.
The weight (excluding the bolt) is 697g so that's pretty good IMHO.
I fluffed the counterbore for the small freewheel and it is just a tad oversize, but some shimstock placement before welding it up will sort that out. So about £26 and my time (2 hours at £37.50/Hr ... as per my last job). It is still a very cost-effective 2WD unit.
This is what the finished item will look like. Not too shabby is it?
Total length end to end is 93mm. The cassette carrier can accommodate 8..10 speed cassettes.
A bolt is holding it all together for the picture as it is yet to be welded at either end.
The weight (excluding the bolt) is 697g so that's pretty good IMHO.
I fluffed the counterbore for the small freewheel and it is just a tad oversize, but some shimstock placement before welding it up will sort that out. So about £26 and my time (2 hours at £37.50/Hr ... as per my last job). It is still a very cost-effective 2WD unit.
DannyC
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Having been gently reminded by the Northern chapter of the "Hell's Pedal-car-ista's" that allowing "Lathe Boy" to run riot and steal all the limelight was not actually making a "lathe-free" 2WD that even boy-scouts can make, it was time to let "Tig-Boy" loose to see how much damage he could do to a screw-on cassette freewheel.
I am pleased to report that he was very gentle and used shims on 3-lobes of the 6 welding positions (to centralise the tube that joins the two outer races together). He then welded up the 3 un-shimmed lobes, then pulled out the shims and welded up the other 3. He also put a paper insulator on one side of the piece in the vise to prevent the welding current flowing through the bearings of the cassette freewheel.
Adequate cooling-off time and prayers in various languages (mostly Anglo-Saxon) were used between each individual welding operation.
When all done it looked like this....
Now as luck, and careful product selection would have it, this tube that fits "INSIDE" the cassette cluster also fits nicely "OUTSIDE" the shell of the other freewheel. This will have the sprocket sliced about like an old UK thrupenny-bit (ask your Grandad) to provide readily accessible places to weld the joining tube to the sprocket flange of this second freewheel.
Before joining the second freewheel to the tube, a bearing cup with a 12/13mm deep socket welded into it will be screwed into the cassette-freewheels screw on sleeve to act as a receiver for the RH half-shaft.
It will look a bit like this from the outside (simulation, not welded or sprocket cut yet).
The completed unit should be very small and neat (IMHO).
I am pleased to report that he was very gentle and used shims on 3-lobes of the 6 welding positions (to centralise the tube that joins the two outer races together). He then welded up the 3 un-shimmed lobes, then pulled out the shims and welded up the other 3. He also put a paper insulator on one side of the piece in the vise to prevent the welding current flowing through the bearings of the cassette freewheel.
Adequate cooling-off time and prayers in various languages (mostly Anglo-Saxon) were used between each individual welding operation.
When all done it looked like this....
Now as luck, and careful product selection would have it, this tube that fits "INSIDE" the cassette cluster also fits nicely "OUTSIDE" the shell of the other freewheel. This will have the sprocket sliced about like an old UK thrupenny-bit (ask your Grandad) to provide readily accessible places to weld the joining tube to the sprocket flange of this second freewheel.
Before joining the second freewheel to the tube, a bearing cup with a 12/13mm deep socket welded into it will be screwed into the cassette-freewheels screw on sleeve to act as a receiver for the RH half-shaft.
It will look a bit like this from the outside (simulation, not welded or sprocket cut yet).
The completed unit should be very small and neat (IMHO).
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Well done that man.......
“Any sufficiently advanced technology is indistinguishable from magic”. [ A.C Clarke ]
Now ain't that spooky you share the same surname ? and you may actually become more famous in ' pedal car circles ' than your namesake ![ before you puff out your chest the circles are quite small ]
Paul
“Any sufficiently advanced technology is indistinguishable from magic”. [ A.C Clarke ]
Now ain't that spooky you share the same surname ? and you may actually become more famous in ' pedal car circles ' than your namesake ![ before you puff out your chest the circles are quite small
]Paul
DannyC
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I confess that the tube welds are NOT the tidiest but I can see full penetration inside the tube on each of the 6 welds and I was trying to start there and encourage flow across to the tabs on the cassette. This will use up all my "spare" bearing cups, and I will also have to buy some 12/13mm sockets. I have told the Pedal car forum page that it is a free giveaway to a team willing to deploy & test it.Well done that man.......
“Any sufficiently advanced technology is indistinguishable from magic”. [ A.C Clarke ]
Now ain't that spooky you share the same surname ? and you may actually become more famous in ' pedal car circles ' than your namesake 
One for doing Hex forms on the end of round bars, and one for doing squares.
This will be used for cutting the hex-keys onto axles.
The quality of these is stunning as they are only £14.99 each and I already own an ER35 collet set for my Micro Mill.
Didnt know machining was getting affordable
Congrats on tig welding without bearing melt down, hope to see the end result soon
Congrats on tig welding without bearing melt down, hope to see the end result soon
DannyC
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Here are the 3 2WD units I am making/prototyping.
They are all just 2 independent freewheel units linked together, there is no "magic" involved.
Left to right they are A, B & C
A is a 7speed "simple-tools" version with 13mm AF sockets as the interface to the axles, Overall length is 95mm. This is something a suitably supervised boy scout team could probably make without resorting to lathe-work.
B is a 10Spd cassette carrier and some simple lathe work and its axle interface is M12 Fine L & R hand threads, overall length is 103mm.
Again, this could be made by any team with access to a mini-lathe and everyone can find a mate/club locally I bet.
C is based on a screw-in Freehub 10spd cassette carrier, axle interfaces are 12mm AF hex., overall length is 90mm.
B, could be made the same overall length as C.
So B & C need access to a mini-lathe or similar.
B does also need some M12 fine taps & dies to make the axle interfaces etc.
C needs a wobble-broach or similar to cut a hex keyway.
So you choose your level of complexity, but I believe that they are all achievable. I am clearly making one of each to prove my point.
They all cost <£50 in parts to make. Time to make varies of course.
Option "B" is probably the easiest of the 2 more advanced options because drilling holes and tap's and dies are readily available whereas "wobble-broaches" and bits are a bit more "nerdy".
They are all just 2 independent freewheel units linked together, there is no "magic" involved.
Left to right they are A, B & C
A is a 7speed "simple-tools" version with 13mm AF sockets as the interface to the axles, Overall length is 95mm. This is something a suitably supervised boy scout team could probably make without resorting to lathe-work.
B is a 10Spd cassette carrier and some simple lathe work and its axle interface is M12 Fine L & R hand threads, overall length is 103mm.
Again, this could be made by any team with access to a mini-lathe and everyone can find a mate/club locally I bet.
C is based on a screw-in Freehub 10spd cassette carrier, axle interfaces are 12mm AF hex., overall length is 90mm.
B, could be made the same overall length as C.
So B & C need access to a mini-lathe or similar.
B does also need some M12 fine taps & dies to make the axle interfaces etc.
C needs a wobble-broach or similar to cut a hex keyway.
So you choose your level of complexity, but I believe that they are all achievable. I am clearly making one of each to prove my point.
They all cost <£50 in parts to make. Time to make varies of course.
Option "B" is probably the easiest of the 2 more advanced options because drilling holes and tap's and dies are readily available whereas "wobble-broaches" and bits are a bit more "nerdy".
