rear suspension casting

[HenryVIII]

Does anyone know why some castings have the oval hole in them and others do not?

The top one is an M3-75     Autocar MFG.
The next two are M2's        Both made by White

Henry

[spec4don]

If I had to guess, they figured out how much of a B I double itch to clean the mud and debris out of there and so they could work on it.

Don G.

[WayOffTrack]

If I had to guess, they figured out how much of a B I double itch to clean the mud and debris out of there and so they could work on it.

Gotta go with what Don said probably a design improvement to ease cleaning esp. snow and ice removal.

[Outsider]

I have looked over both designs of the castings and found they have the same part number cast into them.

Steve

[HenryVIII]

I agree with what Don said, It would be easier to clean out the debris. I did not think of that.

Something I did not mention before is that the top and bottom picture are from tracks with the larger, late style idler spring. The center picture is from a track with the smaller single spring. the other one I did not post a pic of has the single spring but no hole.

My thoughts were that maybe they were made by different subcontractors and each had different molds or casting processes but had to use the same part number as per the contract. The other thing I thought is that maybe there was a strength issue and the hole was eliminated. I have not noticed anything that would indicate one type was used early or later.

I am going to look for foundry or manufacturer symbols that might vary even though the part numbers are the same.

Henry

 

[HenryVIII]

On the castings with the holes I have found a foundry symbol that looks like an "S" inside of a backwards D. This is on 2 different vehicles, both with the same castings. The ones without the holes do not have any foundry symbols that I can find. The only markings I can find other than the part number is a D1 on one casting and a D2 on another one. All the castings have the same part number D48408. I have not been able to find what foundry used this SD symbol yet. I think there were multiple suppliers of the same components which might account for some of the differences. Has anyone found other foundry marks or symbols. I wonder how many different companies made the same parts?

Henry       

M3-75-1895 left side


M3-75-1895 right side


M2 halftrack


M2 halftrack


M2 halftrack