Scotts2000's 20 MCS bumper

[Jarhead ☠]

So I was lent a bumper from scotts2000 for my saw so I could get it cast by one of my customers.
Well after several attempts it appears that shrinkage is an apparent problem 🤔
Unbeknownst to me that after the material is poured it gets smaller and thus all the holes don't align.
Now I'm sure I could spend money to have the calculations figured out but I was doing this cheap(like me)!
Either way I'd like to thank Scott for lending and then giving me the part, what a generous gesture, he also included an original fuel cap for my C series saw he noticed was incorrect.
I'd like to say thank you to all the members here that donate both their knowledge and parts that make this hobby more exciting!
Again thank you Scott👍

Al D.

[sweepleader]

I don't know right off where the holes are in that part BUT, could you have it cast without any holes and drill them later (in the right places)? Would it fit that way? Would it be obvious to everyone that it was too small?

Using the original for a pattern is always very iffy, a pattern maker would have all the shrinkage rates for different materials and would enlarge the pattern accordingly. The old guys used different rulers to measure the patterns for different metals, one for iron, one for brass, one for aluminum, etc.

Yeah, there are a lot of really great people here who often go way out of their way to try to help. Thanks to all from me too.

[undee70ss]

How many did you make, how much smaller are they really?

[Jarhead ☠]

I attempted 2 but the dimensions were noticeable even if I drilled my own holes as suggested by another.

[sweepleader]

There is a short description of pattern making/shrinkage for castings on this video:

www.youtube.com/watch?v=jr6HsOongdA

It starts about 4:15 but I really like the whole video and the entire series.

[scotts2000]

Oct 8, 2019 9:05:43 GMT -5 Jarhead ☠ said:

So I was lent a bumper from scotts2000 for my saw so I could get it cast by one of my customers.
Well after several attempts it appears that shrinkage is an apparent problem 🤔
Unbeknownst to me that after the material is poured it gets smaller and thus all the holes don't align.
Now I'm sure I could spend money to have the calculations figured out but I was doing this cheap(like me)!
Either way I'd like to thank Scott for lending and then giving me the part, what a generous gesture, he also included an original fuel cap for my C series saw he noticed was incorrect.
I'd like to say thank you to all the members here that donate both their knowledge and parts that make this hobby more exciting!
Again thank you Scott👍

Al D.

As a homelite enthusiast I am always happy to jump in and help... additionally I will contact one of my customers custom casting and see if they can pull it off.. if i am successful i will share these parts as well.. scott