03-11-2018, 07:11 PM
Made a hub for the concrete flywheel and welded some bar onto it for reinforcing and to increase weight near the perimeter
and cast the concrete, it was cast on a plywood disc laid on a nice level section of the floor and the shaft plumbed to the vertical to minimise runout.
When the concrete was firm, I removed the shaft so I could cut the keyways.
I used my not-quite-finished sharpening jig to sharpen a 1/4" x3" side and face cutter to put a keyway in the 25mm shaft, first time I've had a chance to make a cut with a cutter dressed on this jig, very happy with the result, the cutter was cutting on all teeth and made a nice job, although it was actually .235" wide at the cutting edge so I had to take an extra pass on each side of the cut.
I made a test assembly and gave it a run, I added the seat mount to the frame and attached the chain derailer / tensioner from the bicycle.
Had a couple of issues to sort out; there were a couple of tight spots in the bevel gears, I did some dressing with a file but couldn't get rid of the tight spots completely. I set the gears up so there is minimal clearance at the tightest teeth. The bevel gears are quite noisy under power, I think this is inherent in the parallel-tooth bevel, just have to live with it.
The drive works well and the ratio of the bicycle sprockets I used seems spot-on, I pedaled it up to speed and used my analogue RPM gauge on the throwing head which showed 250 rpm, exactly what I had aimed for after my pottery research. The flywheel stores a lot of kinetic energy and keeps the wheel spinning for a long time once pedaled up to speed.
There was a distinct wobble from imbalance in the flywheel. I decided to approach it like a big surface grinder wheel.
There was a definite heavy point that the wheel kept settling to, I tried removing weight by drilling holes near the perimeter but that was a very inefficient way to remove mass so instead I added weight to the opposite point by glueing some 6mm steel offcuts to the underside, there's about an inch of clearance to the frame under the flywheel. Didn't take too much to get it to the point where there was no consistent point that it wanted to settle at.
I disassembled and gave the frame a coat of paint- Ford tractor blue.
All assembled ready for handover. Six adjustable feet so the throwing head can be leveled. The yellow masking tape is there to protect the enamel which is still soft. Seat height and pedal height are adjustable, once it is all adjusted to fit the owner, I'll cut the chain to length and get rid of the tensioner.
I presented it to my daughter last night, only 4 days late for her birthday. It's going to have to be dismantled again to transport it to her place, getting that 90kg flywheel into her garage and assembled again might be interesting. Anyway, a fun project, a lot of hours in it, I was worried it might turn out to be a white elephant but the end result is very functional and she was ecstatic.
and cast the concrete, it was cast on a plywood disc laid on a nice level section of the floor and the shaft plumbed to the vertical to minimise runout.
When the concrete was firm, I removed the shaft so I could cut the keyways.
I used my not-quite-finished sharpening jig to sharpen a 1/4" x3" side and face cutter to put a keyway in the 25mm shaft, first time I've had a chance to make a cut with a cutter dressed on this jig, very happy with the result, the cutter was cutting on all teeth and made a nice job, although it was actually .235" wide at the cutting edge so I had to take an extra pass on each side of the cut.
I made a test assembly and gave it a run, I added the seat mount to the frame and attached the chain derailer / tensioner from the bicycle.
Had a couple of issues to sort out; there were a couple of tight spots in the bevel gears, I did some dressing with a file but couldn't get rid of the tight spots completely. I set the gears up so there is minimal clearance at the tightest teeth. The bevel gears are quite noisy under power, I think this is inherent in the parallel-tooth bevel, just have to live with it.
The drive works well and the ratio of the bicycle sprockets I used seems spot-on, I pedaled it up to speed and used my analogue RPM gauge on the throwing head which showed 250 rpm, exactly what I had aimed for after my pottery research. The flywheel stores a lot of kinetic energy and keeps the wheel spinning for a long time once pedaled up to speed.
There was a distinct wobble from imbalance in the flywheel. I decided to approach it like a big surface grinder wheel.
There was a definite heavy point that the wheel kept settling to, I tried removing weight by drilling holes near the perimeter but that was a very inefficient way to remove mass so instead I added weight to the opposite point by glueing some 6mm steel offcuts to the underside, there's about an inch of clearance to the frame under the flywheel. Didn't take too much to get it to the point where there was no consistent point that it wanted to settle at.
I disassembled and gave the frame a coat of paint- Ford tractor blue.
All assembled ready for handover. Six adjustable feet so the throwing head can be leveled. The yellow masking tape is there to protect the enamel which is still soft. Seat height and pedal height are adjustable, once it is all adjusted to fit the owner, I'll cut the chain to length and get rid of the tensioner.
I presented it to my daughter last night, only 4 days late for her birthday. It's going to have to be dismantled again to transport it to her place, getting that 90kg flywheel into her garage and assembled again might be interesting. Anyway, a fun project, a lot of hours in it, I was worried it might turn out to be a white elephant but the end result is very functional and she was ecstatic.
Lathe (n); a machine tool used in the production of milling machine components.
Milling Machine (n); a machine tool used in the production of lathe components.
Milling Machine (n); a machine tool used in the production of lathe components.