HeadSmess
Well-Known Member
- Local time
- 10:20 PM
- Joined
- May 17, 2010
- Messages
- 3,048
right! the scrap yards open after the break, ive been paid for the last week of slavery, the pile of bills has shrunk, i can return to this project!
purchased, after much scavenging...one piece of brass (grrrrr, there wasnt any copper i could see that was suitable, alloy would have possibly been better anyway- and cheaper!) cut as a 8 " or so disc. there was a whole stack of them. i think theyre rejects because of the small nick in one edge (opposite my thumb) due to bad cutter programming...
also scored a nice 1:1 right angle drive
anyways! the plan!
bore hole in centre, trim edge, balance using a whipstick. (a long mandrel, held in chuck, disc at far end. mandrel rides in tailstock centre. spin it up with crayon held just off disc edge, back off tailstock centre just a touch, and disc will "wobble" and be marked at the heaviest point. drill out small spot of material, retest, repeat till perfect)
machine that alloy thingy as a hub with bearings. bolt to disc. probably better to balance it after all that, rather than just the disc. im planning on running this straight off the crank now
then get a steel plate, set it up on a bush so it can be slide back and forth along the shaft. cover the thing in neo magnets and by decreasing clearance between magnets and disc...achieve adjustable eddy current braking.
may end up silver soldering some brass strips to the back, to make a rudimentary fan. possibly two discs with the strips in between for a "slotted" rotor... getting too far ahead of myself now!
the disc with the magnets will be the stationary "torque" member.
yay. lenz law
now where to find some big neo magnets that are fairly cheap...
wow. a 4" X 1 " disc has 262 kg of pull! and costs about that much too! (oh yeah... one place i worked at, a client bought in his "fishing" magnets. they needed a permit because they CAN KILL YOU! "fishing" as in fishing out the auger that just fell apart 2 km down in a sand and water filled hole)
or a 12x5mm with 4kg of pull...20 pack for $42 sounds betterer...thats 240 kg or so of pull for $120
purchased, after much scavenging...one piece of brass (grrrrr, there wasnt any copper i could see that was suitable, alloy would have possibly been better anyway- and cheaper!) cut as a 8 " or so disc. there was a whole stack of them. i think theyre rejects because of the small nick in one edge (opposite my thumb) due to bad cutter programming...
also scored a nice 1:1 right angle drive
anyways! the plan!
bore hole in centre, trim edge, balance using a whipstick. (a long mandrel, held in chuck, disc at far end. mandrel rides in tailstock centre. spin it up with crayon held just off disc edge, back off tailstock centre just a touch, and disc will "wobble" and be marked at the heaviest point. drill out small spot of material, retest, repeat till perfect)
machine that alloy thingy as a hub with bearings. bolt to disc. probably better to balance it after all that, rather than just the disc. im planning on running this straight off the crank now
then get a steel plate, set it up on a bush so it can be slide back and forth along the shaft. cover the thing in neo magnets and by decreasing clearance between magnets and disc...achieve adjustable eddy current braking.
may end up silver soldering some brass strips to the back, to make a rudimentary fan. possibly two discs with the strips in between for a "slotted" rotor... getting too far ahead of myself now!
the disc with the magnets will be the stationary "torque" member.
yay. lenz law
now where to find some big neo magnets that are fairly cheap...
wow. a 4" X 1 " disc has 262 kg of pull! and costs about that much too! (oh yeah... one place i worked at, a client bought in his "fishing" magnets. they needed a permit because they CAN KILL YOU! "fishing" as in fishing out the auger that just fell apart 2 km down in a sand and water filled hole)
or a 12x5mm with 4kg of pull...20 pack for $42 sounds betterer...thats 240 kg or so of pull for $120