Create Planes parallel to each other that cut through the holes. Then mate the part between the planes.
Have you tried making planes where the holes are and use those for your width mate ?
How you want it to be align; inline or perpendicular?
Also make sure to include part files when uploading assemblies or drawings. Use pack and go from the file menu.
Please check this post for your future reference to get best out this forum
You could make planes at the center of the holes and them make a mid-plane between them. Make a plane at the middle of the gusset part and mate it to the mid-plane. If the holes move the gusset will move with it.
First, you're uploaded assembly doesn't contain your parts, (review "Pack and go") so I created my own parts.
I'm assuming you want to mate between the material left between the holes:
1) Create a ref plane connecting the two hole centers (so the final width mate aligns to the hole centers.
1a) View temp axes to select the axis of each hole (you don't need to create these).
1b) Create a ref plane by selecting these two axes.
2) Create ref planes tangent to each hole and square to the plane in step 1.
2a) Create hole 1's plane by selecting the hole surface (near the gap between the holes) and selecting the step 1 plane. Be sure to select Perpendicular,
2b) Repeat 2a for the other hole.
3) Mate the bottom of the block coincident to the face of the hole plate.
4) Mate the midpoint of the bottom edge (the mate will be a point, not an edge) on one end of the block coincident to the step 1 plane.
5) As in step 4, mate the midpoint of the other end of the block.
6) Width mate the ends of the block to the planes created in step 2.
By creating the first plane and mating the block midpoints mate to it, the block will remain aligned to the hole centers, whether the holes are vertical (to the plate edge) or not.
Step 2 planes are tied to the hole diameters, so a change in either diameter, updates the width mate.
I've attached my two parts and their assembly.
I hope this helps.
Lastly, you can right-click the planes in the feature and select hide if you don't want to see them when you're done.
You can also turn off view temp axes now, too.
MateBetweenHoles.zip 121.9 KB
As an alternative to creating extra planes, underlying sketches can also be used.
You hit the nail on the head Kelvin.....
All you need is two equal spaced lines from hole to hole and a center point in the top part and 3 mates (points coincident, face to face coincident and sides parallel)
Thanks for all of the suggestions. They definitely helped me get over that hump. I appreciate the feedback.
For future reference, I have found some video tutorials on how to do this as well.