Assemby mates question

[dabiz7]

new user to SolidWorks 2012...this is really ticking me off !!
I have two cylindrical parts, each has a circular bolt pattern I am trying to mate up, all the axes are square, the bolt circle diameters are the same, I can concentric mate the parts on the OD's of the two parts, but when I try to apply concentric to the mating bolt holes, it says "Over defined" and won't work. SO, I tried just making the hole ases coincident, same thing... What am I missing here?

 

[ctopher]

Are you mating two flat surfaces together? They may not be square.

Chris, CSWA
SolidWorks 13
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[dabiz7]

I did not apply a mate to the flat surfaces, but I am sure everything is square.
I wonder if there is a rounding error in how far out Solidworks calculates the dimensions for sketch features?
Does it calculate out to 13 places or where does it cut off in checking two different dimensions, in this case,
the bolt circle diamters of the two sets of bolt holes I am trying to align?

 

[Updraft]

First, verify that the bolt patterns are indeed identical. This does not mean equivalent, it means they must be identically defined. They should be defined the same way for each part such as having a seed hole a specified distance from the center axis and the hole patterned, OR if all the holes are put in in one feature then the other part must use the same definition, i.e., if you define the holes with a radius and angular spacing in one part and an equivalent center-to-center distance in the other part then SWX will see the spacings as being different between the parts. (Since SWX is a double-precision system the hole spacing could be off by .000000000000000000000001 and SWX would see them as different.)

If you are dealing with any imported parts then you might also check for the parallelism of axes. You can query this in the part by turning on the temporary axes and picking two axes in question and then selecting measure. The first line in the measure dialogue box will say if they are parallel or not.

If these are parts you modeled in SWX I would be willing to bet you have your holes defined differently between the two parts. Also, make sure your sketches are fully defined.

- - -Updraft

 

[DanStro]

This may be a stupid question but did you remove the concentricity mate from the OD's and just mate up the holes in your pattern?

Han primo incensus