Re: Broken Starter Motor ends

Posted by John Wogec On 2019/2/14 12:17:17

Hi again,

I just finished restoring my starter a few months ago so I am familiar with that starter end cap. It fit a little roughly in place and I remember wanting to hit it with a hammer to have it seat completely. Thankfully I resisted that urge because that 90 year old casting may have reminded me of its age. Perhaps someone forgot that lesson at some time in the past and cracked the specimens in the picture then just put them back together in pieces? I don't have any other thoughts on why the end caps would fracture like that. They seem pretty heavy duty, but I am a novice at material science, so there may be some aspect of old, dirty castings that makes them give up the ghost after 90 years of stress, heat and oil impregnation.

As for the cost associated with casting versus 3D printing: I researched 3D printing for my footrest brackets and some guy in the midwest wanted $1,500 to reproduce them using 3D printing then CNC milling. He explained that the cost came from the milling which would take about 8 hours of machine time...at $150 an hour. My final cost for both castings was less than $400, then a few hours of time for a machinist to clean up the precision spots. The other huge benefit of using someone with casting experience is that they can recommend what type of metal to use. I remember my machinist commenting on how impressively hard the bronze was that Alcast used, which was intentional, to help them survive another 90 years.