KIS-List Digest Archive

Wed 08/31/16


Total Messages Posted: 1



Today's Message Index:
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     1. 02:40 PM - KIS TR-1 Nose Wheel Axle Stack (Owen Baker)
 
 
 


Message 1


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    Time: 02:40:42 PM PST US
    From: "Owen Baker " <bakerocb@cox.net>
    Subject: KIS TR-1 Nose Wheel Axle Stack
    8/31/2016 Hello Steve, Your question is so far removed from the original subject line of this thread (Belleville Washers and IO-240 Oil Drain Plug) that I think it is a good idea to start a new thread. If the new subject line that I picked does not really follow your concerns feel free to create a better subject line. First some generic guidance regarding use of washers extracted from: << http://www.faa.gov/documentLibrary/media/Advisory_Circular/Chapter_07.pdf >> =9C7-86. PLAIN WASHERS (AN960 AND AN970). Plain washers are widely used with hex nuts to provide a smooth bearing surface, act as a shim to obtain the proper grip length, and to position castellated nuts in relation to drilled cotter pin holes in bolts. Use plain washers under lock washers to prevent damage to bearing surfaces. Cadmium-plated steel washers are recommended for use under boltheads and nuts used on aluminum alloy or magnesium structures to prevent corrosion.=9D You wrote: A) =9CAre there washers on the inside of the nose gear axle?=9D Not in a well designed and built up stack. See below. B) =9COr just on the outside where the carter pin goes through?=9D Definitely need one on the outside to protect the soft aluminum under the steel nut as you tighten the nut. And maybe more than one washer to get the tightening effect that you need or to properly space the hole for the cotter pin. (What is this carter pin that you keep referring to? Are you from Boston?) Now as to your specific question =93 in order to answer it correctly I=99ll need to know more about your nose wheel, its axle, and the bearings. But what I can do is give you a description of my KIS TR-1 Kit #116 Matco nose wheel stack up and why it is stacked up that way. Understanding this stack up should also answer your question about washers on the inside or outside of the aluminum shoe. 1) The nose wheel and its mounted tire is supported within a U shaped aluminum shoe or cradle that is in turn mounted to and swivels about a vertical portion of the nose landing gear weldment. 2) Each half of the split nose wheel contains a two part bearing that is press fit into its half of the wheel. The outer part of each bearing is intended to rotate with the wheel, the inner part of each bearing is intended to remain stationary and not rotate with the wheel. So the design of the stack up is intended to clamp and support the inner part of each bearing while leaving the outer part of the bearing free to rotate with the wheel. 3) Here is how that is accomplished: a) A long 1/4 inch diameter bolt goes completely from one outside of the aluminum shoe to the other outside of the aluminum shoe. This bolt is the true axle for the nose wheel. As described in 7-86 above one or more cadmium-plated steel washers are placed under the head on one end of the bolt and under the nut on the other end. More about these washers later. b) Surrounding the bolt in a) above is a long thick walled bushing sized in length so that it just fits between the two inner walls of the aluminum shoe. The bushing is sized with an inner diameter of a 1/4 inch clearance hole for the axle bolt in a) above and an outer diameter so that it just fits through the inner diameter hole in the inner part of the two part bearings that are pressed into the wheel halves. c) Two short thin wall bushings that will slip fairly easily over each end of the long thick walled bushing in b) are also used. More about these short thin wall bushings later. d) Now comes time to assemble the nose wheel aluminum shoe: d1) The tire and wheel are completely assembled. d2) The long thick walled bushing from b) is slipped through the inner diameter holes in the two bearings. d3) The two thin wall bushings are placed, one on each end of the thick walled bushing. d4) Place the three above assembled items between the inner walls of the aluminum shoe so that the long 1/4 inch diameter axle bolt with a washer under its head will go through all of the above as well as through the two holes provided, one one on each side of the aluminum shoe. d5) Now put a washer on the threaded end of the bolt, thread the castle nut onto the exposed threads of the bolt, tighten down the nut and you have a perfectly put together nose wheel assembly. d6) Wait!! It did not work as designed because something: the inner portion of the bearings, the long thick walled bushing, the short thin wall bushings, or even the long 1/4 inch diameter bolt are rotating with the wheel and they are not supposed to. Remember only the outer portion of the bearing, the wheel, and the tire are supposed to rotate. d7) So how do you stop this unwanted rotation? Maybe just put another washer or two under the nut on the long 1/4 inch diameter bolt and retighten it. If that does not stop the unwanted rotation try making the two thin bushings a bit longer so that they are more readily clamping the inner portion of the bearings when you tighten the nut on the 1/4 inch diameter bolt. If there is excess space between the ends of the long thick walled bushing and the inner sides of the aluminum shoe try slipping a washer into that space. d8) With everything rotating or not as desired and tightened as desired install the cotter pin. Any questions? OC ============ From: pastormac@comcast.net Sent: Wednesday, August 31, 2016 1:05 PM Subject: Re: Belleville Washers and IO-240 Oil Drain Plug Hi Owen, Are there washers on the inside of the nose gear axle? Or just on the outside where the carter pin goes through? There was not a clear drawing anywhere I could find. Thanks, Steve Sent from my iPhone




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