Question for the mechanical engineers amongst us.
Discussion
I have had some brackets machined which hold on the brake calipers. The bracket can be seen inside the disc in this photo.
I have been told by the guy who made them that now he knows the use case he is not sure the material the brackets are made from has the correct properties. They are made frpom MIC 6 for which is a cast tooling alloy. The properties are as follows:
|http://thumbsnap.com/oSnHCp5i[/url]
The bracket bolts to two lugs on the upright (each lug has a csa of around 300mm² - small compared to the csa which would have to shear on the bracket, which is about 100mm² csa at its narrowest point). The upright is sand cast from LM25. ML25 Spec is below:
Sure neither of these alloys have the tensile strength of 6061, but given the lugs to which the bracket is bolted has material properties similar to the MIC 6 (from what I can work out)is there likely to be an issue here?
I have been told by the guy who made them that now he knows the use case he is not sure the material the brackets are made from has the correct properties. They are made frpom MIC 6 for which is a cast tooling alloy. The properties are as follows:
|http://thumbsnap.com/oSnHCp5i[/url]The bracket bolts to two lugs on the upright (each lug has a csa of around 300mm² - small compared to the csa which would have to shear on the bracket, which is about 100mm² csa at its narrowest point). The upright is sand cast from LM25. ML25 Spec is below:
Sure neither of these alloys have the tensile strength of 6061, but given the lugs to which the bracket is bolted has material properties similar to the MIC 6 (from what I can work out)is there likely to be an issue here?
Edited by IBDAET on Friday 29th August 10:54
Tensile strength of T6061 is around 270Mpa so compared to your MIC6 it is roughly 1.6 times stronger number wise.
The acting forces are nearly radial so only shear on the bolts and "butt tension" in the bolt holes.
The bracket material where the bolt sits at the lug hole from the upright seems a bit thin on the photo.
Normally for cast alloys I take a minimum of 1.6x the bolt diameter.
Possible long term failure could arise on the sharp edges where the thicker area goes thinner.I would have liked a bit more radius on that spot.
You could still solve that with a slight undercut radius in the thicker part Shouldn't be a problem strength wise, but would improve possible fatigue issues.
All said, from the photo it looks stronger then the lugs from the original mountings.
The acting forces are nearly radial so only shear on the bolts and "butt tension" in the bolt holes.
The bracket material where the bolt sits at the lug hole from the upright seems a bit thin on the photo.
Normally for cast alloys I take a minimum of 1.6x the bolt diameter.
Possible long term failure could arise on the sharp edges where the thicker area goes thinner.I would have liked a bit more radius on that spot.
You could still solve that with a slight undercut radius in the thicker part Shouldn't be a problem strength wise, but would improve possible fatigue issues.
All said, from the photo it looks stronger then the lugs from the original mountings.
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