And however carefully you have worked out your invention on paper you will find that when you come to make a model, or have one made, you will have to change it not once but many times, that is if it is a machine in which a number of parts are made use of and you may have to re-design it and re-construct it several times.
For this reason it is a waste of money to build a fine appearing and costly model in the beginning but what you should do is to make one that will work without regard to its looks so that you can experiment with it, overhaul it, tear it down, build it up again and so on until you are satisfied with it and the results it produces, if such a thing is possible, before you even begin to talk to a patent attorney about applying for a patent on it.
Nearly every _tyro_ inventor seems to believe that the only way to keep honest folks from stealing his invention is to apply for a patent on it immediately. You will remember I pointed out in the first chapter how to protect your first idea by signatures and _affidavits_ and protection of this kind is just as good, and in my opinion just as safe, and in every way better than to rush off and apply for a patent and--though of course money is of no object--it is cheaper by at least $35.00.
Again as I stated in the preceding chapter if you apply for a patent before you have made a working model of it you will find when you finally get your model finished it will be so at variance with what you have written in your specification and claims that you will hardly be able to recognize it as being the same invention; and besides there will be the trouble and the expense of changing your drawings and specification and claims.
On the other hand when you have finished your model to the point where it will do the work you want it to do you are in a position then to make a new and accurate set of drawings, to write a clear description of how the machine works and to draw up your claims with the certainty of knowing just what you have and what you want to ask for--in a word you are ready to do business with the patent office.
~Ways to Make a Model.--~The way in which you get your model made depends on several things and over these you will have little or no control.