Im not sure if its the right video, but you can do this with an AfterUpdate event

I tried to explain in this screen shot what I am trying to do Adam.  Do you think it is possible?
Wayne

Sure, put the after update event on the inches field, say you added a field called NewCalcField

Just make the after update event something like

If ComboBoxName <> "" Then
  NewCalcField = DLOOKUP("ContactsPerInchField","TableName","ContactID=" & ComboboxName) * InchesFieldName
End If

Actually you could do

If ComboBoxName <> "" and InchesFieldName <> ""

and than you could put it in both fields after update events

This is related.  The previous never worked for me.  I am getting very frustrated.  This should not be this difficult.  What am I doing wrong.

I notice that MaterialNumber is a ShortText field. Is this by design, or an oversight?
Assuming MaterialNumber is supposed to be ShortText, Try this:

If MaterialNumber <> "" then
   WeightProduced = DLookup("PoundsPer", "FGTBL", "MaterialID=""" & MaterialNumber & """") * QuantityProduced
End If

DLookup

MaterialNumber is a short text.  It is in fact a PartNumber but I could not use that here.  I'll try this Kevin, Thank you.

Wayne, I see that you're getting frustrated. Keep in mind, this stuff can take years to learn. You're still in my Expert classes. I teach VBA properly in my Developer series. If you want to start seriously learning VBA, I'd recommend my Access Developer 1 lesson to start.