Dear George, Walt, Rich, Loran and Ron, This input is so appreciated. I am going to take the gear train fully apart, clean everything and make a close check of all issues brought out here.
Please add any and all other thoughts, you experts out there. I have been told by several that noisy is just the Model A Homes have to be, and that they don't significantly quiet down with most applied heroics. I have a hard time believing they could have been so commercially successful in that were the case. I surely appreciate you Loran and all out there in Phono-L land. Happy New Year to you all, Dr. K. ----- Original Message ----- From: "Walt" <[email protected]> To: "'Antique Phonograph List'" <[email protected]> Sent: Tuesday, January 02, 2007 11:25 AM Subject: RE: [Phono-L] Re: Noisy Home Rich is correct...It is simple Mechanical Engineering 101. The primary reason that a low viscosity lubricant is applied to a gear train in which one of the dissimilar metals is steel/iron (like in a phonograph) is to reduce corrosion. Surfaces that corrode lose smoothness and that will increase friction. Also, the corrosion itself is accelerated by the abrasive action of the oxides in steel (or iron) combining with lubricants. Brass does not readily oxidize like steel or iron. So, by making the mating gears out of dissimilar metals, the coefficient of friction is reduced. Decreased friction is related to the molecular [lattice] structure of metal atoms. When the structures are different, the mating surfaces cannot fit together perfectly (at the molecular level, that is), the result of which is that there is less surface contact between the two mating/rubbing surfaces which correlates to reduced friction. Brass with iron/steel designs have much lower coefficients of friction than steel on steel or brass on brass (or iron on iron for that matter). Correct me if I am wrong, but in order for there to be something you might call self-lubrication, the brass would have to have been formulated with a something like lead in the alloy to reduce friction; that is, the lead molecules actually transfer from the alloy and act as a lubricant to some degree? I didn't think that Victor or Edison used lead in their brass gears? I might be off on that point but I think it is correct. I am not sure that self-lubrication is a true term or not, but I studied electrical engineering not mechanical engineering. Brass (and I mean the mating surfaces of the gear, not the sides or bushings) is highly resistant to corrosion because during use the surface forms a fairly pure layer of copper along with zinc oxide which also helps to protect the metal. (That is also one of the reasons that metal parts for outdoor use are zinc coated-plated.) Iron oxides associated with steel/iron do not protect metals like the zinc oxide does on brass, so any corrosion will just get worse, especially if the humidity is high. Lubricants, especially high viscosity lubricants like grease, collect the iron oxide and far from the lubricant serving to protect the surfaces like you think it should, it actually works as a medium to suspend and distribute the iron oxide in a degenerative manner during operation of the motor. Theoretically, no lubrication should be necessary between brass and steel gears, but the problem with "theory" is a thing called "reality", and what plagues it the most are the iron oxides which spring forth their miserably destructive traits because of humidity. So, by applying a thin film of lubricant (I am a fan of synthetics myself) the hope is that you will eliminate or reduce potential oxidation of the steel/iron and thereby reduce friction/wear. Most manufacturers of motors even going way back before Edison and Eldridge Johnson, etc. to the first clocks, understood the inherent advantage of using dissimilar metals in a gear train, and because it was already a long-ago proven design by the year 1900, they simply practiced it as any good engineering firm would. It wasn't a cost issue at all; it was just good engineering practice. Walt -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Rich Sent: Tuesday, January 02, 2007 12:00 PM To: Antique Phonograph List Subject: RE: [Phono-L] Re: Noisy Home Brass gears meshed with steel gears should never be greased or heavily lubricated. They are self lubricating. Any extra lube will hold dirt which will imbed into the brass which will result in excessive wear on the harder (steel) gear. If you van see of feel the lubricant then there is way too much. Rich On Tue, 2 Jan 2007 10:46:15 -0500, Ron L wrote: >How are the rubber mounts between bedplate and motor, and between upper >works and bedplate? Are the gears lightly greased or just oiled? Have the >conical bearings on the mandrel shaft ever been disturbed, especially turned >and/or moved in or out? _______________________________________________ Phono-L mailing list http://phono-l.oldcrank.org -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.409 / Virus Database: 268.16.2/613 - Release Date: 1/1/2007 _______________________________________________ Phono-L mailing list http://phono-l.oldcrank.org
