DIMENSIONS: OD 1.89 INS/ ID 0.185 INS
Please note that the Meccano and the Mamod SP3 engines have a crankshaft axle width which is 0.156 INS. You will not have to overcome the problem of this flywheel's internal diameter being marginally too large because you will get also an i.d. spacer that takes up the slack well enough.
