anchor.diff:  	if(D.make_reagents.len)
   		return 0
   
  -	var/build_amount = 1
  +	var/build_amount = 0
   
   	for(var/mat_id in D.materials)
   		var/M = D.materials[mat_id]
  
positive.code: 		if(!M || !redemption_mat)
  			return 0
  
  		build_amount = min(build_amount, round(redemption_mat.amount / M))
  
  	return build_amount
  
  
negative.code: 	if(exchange_parts(user, W))
  		return
  	if(default_pry_open(W))
  		materials.retrieve_all()
  		return
  	if(default_unfasten_wrench(user, W))
  		return
  