Return-Path: Received: from sccrmhc13.comcast.net ([204.127.202.64] verified) by logan.com (CommuniGate Pro SMTP 4.1.3) with ESMTP id 2560333 for flyrotary@lancaironline.net; Wed, 27 Aug 2003 23:40:51 -0400 Received: from rv8 (12-225-206-211.client.attbi.com[12.225.206.211](untrusted sender)) by comcast.net (sccrmhc13) with SMTP id <200308280340430160055ogme>; Thu, 28 Aug 2003 03:40:43 +0000 Message-ID: <117601c36d16$277e42c0$d3cee10c@rv8> From: "kevin lane" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: roller bearings Date: Wed, 27 Aug 2003 20:40:38 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 thanks for your wisdom. when I think about it I realize that my "knowledge" of bearings came from adjusting, or attempting to adjust, the cones on my bicycle. Too tight and it was harder to pedal, too loose it was wobbly. from there I went on to build airplanes and even offer rides! Kevin Lane Portland, OR e-mail-> n3773@comcast.net web-> http://home.comcast.net/~n3773 (browse w/ internet explorer) ----- Original Message ----- From: To: "Rotary motors in aircraft" Sent: Wednesday, August 27, 2003 5:02 PM Subject: [FlyRotary] Re: roller bearings > In a message dated 8/27/2003 7:24:28 PM Eastern Daylight Time, > n3773@comcast.net writes: > > > Tom Green of Vans tells me that the main gear roller bearings like to be > > tight, that I could even run 4-6 in/lbs of torque on the nut. He says they > > are different from ball bearings. I have never heard such a thing and > > wondered what is the general consensus on this. My outside bearing races > > have worn after 1000 hrs. I always tightened then and then backed the nut > > off one face before cottering. > > Kevin Lane Portland, OR > > e-mail-> n3773@comcast.net > > web-> http://home.comcast.net/~n3773 > > (browse w/ internet explorer) > > > > That is correct. Tapered roller bearings can be damaged if run a bit > loose. They have preload figures for each size. The race car bearings are quite > large, and I tighten them to 3 foot pounds. I have never had a bearing failure. > These bearings have a system that allows for any preload and a positive lock > using two lock nuts. > You would always want the bearings loaded, so the wheel would track as rigged. > > After servicing a bearing, I reinstall it and torque the adjusting nut to 20 > foot pounds. > For smaller bearings, use less torque. This assures that the new races are > seated firmly in their wells. Then I turn the hub over a few times. Then loosen > the adjusting nut until the bearing set shows obvious play. Then tighten the > adjusting to whatever torque for your specification. > > If the nut is not in a position to install a cotter, think about a shim > washer between the adjusting nut and the "wear washer" between the nut and the > bearing race. Install a washer that will allow the correct torque and a cotter > installation. Only the hard "wear washer" against the inner race. The inner > races "walk" around the shaft all of the time. A thin shim washer will wear away. > The wear washer is usually pinned or keyed to the shaft, so it cannot turn. > Otherwise it would be trying to loosen the adjusting nut all of the time. > Another trick, is to buy a collection of nuts. The threads will seldom have > identical starts, so one, or another will come out just right over the cotter hole. > > Lynn E. Hanover > > >> Homepage: http://www.flyrotary.com/ > >> Archive: http://lancaironline.net/lists/flyrotary/List.html >