Zachary;
Since you are only using the forms to look up the values in the tables, there is no need to bind the controls to the fields in the tables. An unbound form will do what you want so long as you create a query to look up the value you are wanting. In your db, I created a new form for Angles. It is unbound. I created a combo box but did not use the wizard. The source of the combo box is the table Angles. You can see this query if you open the form in design view, click on properties, data and look at the row source. You will note that I included all fields from the table. This is because you will need this information when you go to populate the specific characteristics of each type of product.
Next I created a control for each characteristic as you have done. Again these are unbound. In each of these controls I put an expression for it to populate it with the value from the query. Columns are numbered beginning with zero, so the size1 control would take its value from the third column but identified as column(2). Next in the after update event for the combo box, I put this code: me.requery. This tells Access to rerun the query when ever there is a change in the value to the combo box. Look this over. You will need to follow this procedure for all your forms to get what you are looking for.
BTW, it is not a good idea to update tables directly. You may want to develop some input form (or use the ones you have and delete the combo box) and create new search forms. Post back with any questions you may have. Attached is your db with only the Angle table and form included to keep it to an uploadable size.