Dissenting opinion filed by Circuit Judge DYK.
DYK, Circuit Judge,dissenting-in-part.
I agree with the portion of the majority opinion holding the claims of the '283 patent invalid on the ground that the disclosure of the provisional application did not support the claims. However, I respectfully dissent from the holding of invalidity of the claims of the '743 patent. Affirming a *1300grant of summary judgment, the majority holds that the '743 patent claims are invalid on grounds of public use under 35 U.S.C. § 102(b) because the use was public and the use did not qualify for the experimental use exception. I suggest that the majority is incorrect on both grounds.
First, the majority holds that the use was necessarily public because it took place “at a commercial jobsite on public land on the side of an interstate highway.” Ante at. 1298. The use actually took place under public land, hidden from view, and there has been no showing whatsoever that the use was anything but confidential. In order to understand the method of using the drill bit a person at the job site would have to view the drill bit or see it in operation, and this was impossible to do while the drill bit was underground.
Cox recognized that to obtain data about the use of the prototype drill bits he needed Earl Freeman to test the bits in the field. The only person with access to the prototype drill bits and who actually used the bits before the bar date was Freeman. Cox could not control when and where Freeman tested the bits because Freeman could only operate his drilling rig with the approval of an inspector. Thus, as the majority points out, Cox was correct to admit that he “did not and indeed could not control the actual drilling activities Freeman performed (because he was using the bit at commercial job sites)....” That Cox could not control the time and place the bits were used does not mean their use was public. Freeman’s use of the prototype drill bits was conditioned on keeping information about the bits and their method of use secret, and Freeman was under a duty not to disclose any information about the bits or how they were used underground. Indeed, Cox testified in the very next sentence after the one quoted by the majority that he “[felt] certain Earl Freeman understood from our conversations that his activities were part of an experimental program and were not to be considered either commercial or public in nature.” Further, there was evidence presented that among those with knowledge of the drill, “[t]here was no one of us that did not understand that this was supposed to be secret.” There has been no showing by Vermeer or Earth Tool that the method claimed in the '743 patent was used by anyone not under a duty of confidentiality before the bar date.
The decision here is contradicted by our decision in Moleculon Research Corp. v. CBS, Inc., 793 F.2d 1261, 229 USPQ 805 (Fed.Cir.1986). There, we held that the open, non-secret use of a claimed method was not a barring public use because the inventor expected knowledge of the method to remain confidential. Id. at 1265-66, 793 F.2d 1261, 229 USPQ at 807-08. In Moleculon, the patentee invented a three-dimensional puzzle capable of rotational movement (similar to the familiar Rubik’s cube, the accused product in the case) and obtained a patent containing both method and apparatus claims directed to the puzzle. The apparatus claims were directed to the puzzle itself while the method claims were directed to methods of manipulating the pieces of the puzzle. The district court found that although more than one year before filing his application the inventor “explained his puzzle to a few close colleagues,” he “at all times retained control over its use as well as over the distribution of information concerning it. He never used the puzzle or permitted it used [sic] in a place or at a time when he did not have a legitimate expectation of privacy and of confidentiality.” Id. at 1265, 793 F.2d 1261, 229 USPQ at 808. Under such circumstances, we held neither the apparatus nor the method claims were invalid under § 102(b). Id. at 1266, 793 F.2d 1261, 229 USPQ at 808. Here also, because Cox never used or permitted the drill bits to be used in a place or time in *1301which he did not have a legitimate expectation of confidentiality, the drill bits and the method of using them were not in “public use” before the bar date.
The majority suggests that a use of an invention is an invalidating public use, even though secret, “if the inventor is making commercial use of the invention”. Ante at 1299 (citations omitted). The asserted commercial use here results from the payment to Eagle Pipeline by a third party for performing drilling that, incidentally, involved use of the claimed method. If the use of an invention is “commercial” that use may be deemed public even if secret. However, in order to be commercial the use must provide a profit or commercial advantage to the inventor. See Kinzenbaw v. Deere & Co., 741 F.2d 383, 391, 222 USPQ 929, 934 (Fed.Cir.1984) (“In using the machines to test them for Deere, the farmers served Deere’s commercial purposes.... [T]he testing of the machines was a commercial use by Deere of its patented invention.”); D.L. Auld Co. v. Chroma Graphics Corp., 714 F.2d 1144, 1147, 219 USPQ 13, 15 (Fed.Cir.1983) (“[T]he intent of [invalidating claims based on commercial use] is to preclude attempts by the inventor or his assignee to profit from commercial use of an invention for more than a year before an application for patent is filed.”); Metallizing Eng’g Co. v. Kenyon Bearing & Auto Parts Co., 153 F.2d 516, 520, 68 USPQ 54, 58 (2d Cir. 1946) (“It is indeed true that an inventor may continue for more than a year to practice his invention for his private purposes or his own enjoyment and later patent it. But that is, properly considered, not an exception to the doctrine, for he is not then making use of his secret to gain a competitive advantage over others.”). Here there is no evidence on summary judgment that the inventor profited from the alleged use or gained a commercial advantage. The mere fact that Eagle Pipeline gained a profit is irrelevant.
Further, even if the majority were correct in finding that the claimed method was in public use prior to the critical date, the majority is incorrect in finding that the use of the method was not experimental. The majority’s theory appears to be that the inventor was satisfied with the method after tests in early January, and that further testing was designed only to test the particular bits and not the method. The majority states that “all of the testimony adduced by New Railhead indicates without equivocation that it was only the drill bit claimed in the '283 patent, and not the method of the '743 patent, that was being tested by Freeman.” Ante at 1298. The testimony does not in fact separately address the method and the bit. Nor could the two be separated. The method and the bit were inextricably intertwined. The claims of the '743 patent were specifically directed to “method[s] of horizontal directional drilling in rock.” '743 patent, col. 5,1. 18. Claim 1, the only independent claim, recites “[a] method of horizontal directional drilling in rock, comprising the step of causing a drill bit at one end of a drill string to intermittently rotate as it digs in, stops rotation until the rock fractures, and then moves after fracture in a random, orbital intermittent motion.” Id. at col. 5, 1. 18 col. 6, 1. 2. Drilling with the experimental bits was plainly a test of the claimed method. The method would not work if the drill bit did not work. During the experimental period both the drill bit and the method of using it were being tested.
After being generally satisfied in January with both the method and the bit, the testing continued to determine the durability of the bit. (Cox Dep. at 79-80) (stating that “[w]e would run [the bits] until they went down to figure out what footage we could get, the type of penetration and sometimes put them in some awful condi*1302tions to see if they could survive.”)- The question is whether such further testing was experimental. We have held in earlier cases that testing durability is an appropriate part of testing inventions where durability is an implicit feature of the invention, even if not claimed specifically. See EZ Dock, Inc. v. Schafer Sys., Inc., 276 F.3d 1347, 1353, 61 USPQ2d 1289, 1293 (Fed.Cir.2002); Manville Sales Corp. v. Paramount Sys., Inc., 917 F.2d 544, 550, 16 USPQ2d 1587, 1592 (Fed.Cir.1990). As we discussed in EZ Dock:
In Manville Sales Corp. v. Paramount Sys. Inc., 917 F.2d 544, 550, 16 USPQ2d 1587, 1592 (Fed.Cir.1990), this court permitted the inventor to test the invention for durability during winter although claims did not expressly mention durability or severe weather conditions. Instead this court reasoned that the nature of the invention (luminaires) required durability so that the claims’ reference to the subject matter placed that topic within the proper frame of experimentation. In this case, the '055 patent claims a floating dock. These floating docks, by them nature, must endure all kinds of water conditions, including choppy water created by weather and boating. The waters at Bass Camp, the location of Mr. Greden’s dock, were much rougher than the waters in Mr. Neitzke’s marina where he was testing other dock sections. Mr. Neitzke testified that he sold the dock to Mr. Greden to test how it would hold up under these more turbulent water conditions. In other words, Mr. Neitzke testified that he sold the dock to Mr. Greden to determine whether it was “capable of performing its intended purpose in its intended environment.” Gould, 579 F.2d at 583 [Gould Inc. v. United States, 217 Ct.Cl. 167, 579 F.2d 571, 198 USPQ 156 (Ct.Cl.1978) ].
Id. at 1353, 276 F.3d 1347, 61 USPQ2d at 1293. Here durability of the bit is an implied feature of the method claimed, as a method would not be found to serve its intended purpose if the practice of the method prematurely destroyed the tools used to practice the method. “When an evaluation period is reasonably needed to determine if the invention will serve its intended purpose, the § 102(b) bar does not start to accrue while such determination is being made.” Seal-Flex, Inc. v. Athletic Track & Court Constr., 98 F.3d 1318, 1324, 40 USPQ2d 1450, 1454 (Fed.Cir.1996).
Under the majority’s holding, Cox should have filed his application for the method patent within one year of beginning testing of the drill bit even if he had not completed testing of the drill bit used in the method for durability. We should not adopt so stringent a test for experimental use that we force prospective patent applicants to prematurely file with the Patent Office. Rather we should be faithful to our earlier eases, which apply a more sensible and realistic test.
For the foregoing reasons, I respectfully dissent.