Thursday, May 22, 2014

RM90 machine repair

One of the school's RM90 cleaning machines stopped working.  I volunteered to fix the thing.   The problem was that the retract assist spring was broken (for how long I have no idea).  This put extra strain on the drive shaft that moves the cleaning platform up and down.
Due to this additional strain, the roll pin that tied the shaft to the gearbox had disentigrated.
To fix the problem I needed to remove the lifting wheel the unbolt the motor from the housing.   Once the supply wires were labeled and removed I could disassemble the motor and gearbox assembly.
The remnants of the original roll pin were hammered out, then I installed a new 3mm pin using a vice to drive the pin home.   Finally, after reinstalling the motor I lubricated the mechanism and installed a new assist spring.
The machine is once again in working order, hopefully my inexpert repair lasts the test of time.

Opened gearbox

Broken spring hangs from the upper right, the lifting wheel is disconnected on the left side

Output cog with remnants of the old roll pin waiting to be hammered clear

The new pin installed

Machine reassembled with new spring, ready for testing

Thursday, May 1, 2014


Today I passed my SAWTA 4 exam.  I'm now a SAWTA certified watchmaker!  The remainder of the year will be spent doing projects and prepping for the CW21 exam at the end of the school year in August.