Date: Wed, 20 Jan 1999 19:02:14 -0500 From: Robin & Steve Subject: COZY: Threaded inserts For what it's worth, in some of the work I have been doing I have used what are referred to as "weld nuts". They are basically a tee nut without the gripping tangs, made from steel, NON-LOCKING, #8-32, #10-32, 1/4-20 sizes available. The base is 3/4" diameter X 0.04" thick, the barrel is 1/4" diameter X what ever thread and they come in varying heights (the ones I have on hand are 5/16" tall overall). Now, these are NON-STRUCTURAL, but they simplify mounting little covers and are nice when a nut plate isn't quite right. Did I say they were NON-STRUCTURAL? A box of 100 are less than $7 from McMaster Carr, I can't make 'em for that. Weight? 0.1oz each approximately. Guess I can add that to the two pounds I need to lose due to the landing light actuator, my buttocks is too large anyway. For what it's worth. -- Steven D. Sharp cozyiii@earthlink.net ICQ#: 9925394 From: cdenk@ix.netcom.com Date: Wed, 20 Jan 1999 20:56:36 -0600 (CST) Subject: Re: COZY: Threaded inserts If not locking, then you need to safety wire, cotter pin, or lockwasher the screw. Thats standard aircraft practice, and if ramp checked, a violation could be issued. Nut plates come in a variety of shapes, short and long ears, corner ones with ears at 90 degrees, and with both holes on one ear. I have many that are riveted with solid and avex (aircraft quality pop) rivets, riveted to aluminum, fiberglass, and steel, and floxed in with a ply or 2 of fiberglass on top. In 670 hours of flying I haven't lost one yet, and remember where the propeller is. When I started I bought a selection of #6 through #10 nutplates in the various shapes, maybe 6 or a dozen of each to start, then supplemented as time when on. For some lightweight covers none critiical location, its possible to drill an oversize hole, oil the screw, and flox; or drill and tap the flox with a machine screw thread. Also sheet metal screws work, but I didn't use any. Date: Thu, 21 Jan 1999 08:51:36 -0500 From: Paul Krasa Subject: Re: COZY: Threaded inserts A non structral mount that I use is a brass threaded insert that is made to be screwed into wood. They are available at any hardware store. To mount, I locate the hole for what ever I am mounting to the interior of the fuselage by screwing a short wood screw into the outer layer of fiberglass. Once all mount holes are made, I oversize the holes at approximately an 1/4 inch larger in diamater than the insert I am using, and I remove the foam until I reach the outer skin (a dremel tool and a small grinding stone works great). Fill the mount holes with flox and cover with a piece of peal ply to keep the flox from running out. After the flox pad has cured relocate the mount holes using the wood screw method above. Use the screw holes as pilot holes and drill a hole to screw the insert into. Screw in insert. Sometimes, I slightly over drill the hole then cover the outer threads of the inserts with flox, and finally screw in the insert. I feel this method produces a mount with greater torsional rigidity, but I have not tested it to see the difference. The inserts come in the same sizes as listed in the previous post which was sniped. The cost of the inserts is about a $1 apiece. Paul From: Cozy7971@aol.com Date: Fri, 22 Jan 1999 15:27:14 EST Subject: Re: COZY: Threaded inserts In a message dated 99-01-21 08:56:29 EST, p.w.krasa@larc.nasa.gov writes: << A non structral mount that I use is a brass threaded insert that is made to be screwed into wood. >> Paul's suggestion is a great way to attach stuff. I looked into this last year and, like Paul, found that the inserts run about a buck apiece at the hardware store. Being a cheapskate I came up with an alternative. Like Paul, I drill an oversized hole through the inner skin and clean out the foam. I then thread a nut onto a Vaselined screw. The nut (with screw) are then microed into the hole. After the micro sets up I simply remove the screw. It seems to work well and only costs pennies. Dick Finn Cozy Mark 4 #46 From: "Ugolini, Nick J" Subject: RE: COZY: Threaded inserts Date: Mon, 25 Jan 1999 07:55:20 -0500 I take two layer of wetted glass (between clear plastic) cut into 1" squares, and place the glass squares wherever I want an attaching point. When hardened, I drill a hole and just use a rivet nut. Works great. The rivet nuts in two layers of glass sometimes pull out, but work well in 4 layers. I guess you could go a step further by putting a small piece of Al between the wet glass and the surface. -----Original Message----- << A non structral mount that I use is a brass threaded insert that is made to be screwed into wood. >> From: "Jim White" Subject: COZY: Screw Attachment Points Date: Mon, 1 Feb 1999 20:30:38 -0800 Todd Morgan taught me this trick for creating lightweight attachment points on fiberglass. It is simply a nut plate floxed beneath the fiberglass. I use it for attaching my armrests and any other place (within reason) where I want to attach a screw into a fiberglass surface. I'm NOT recommending they be installed in place of aluminum hardpoints called out in the plans. Apply a light coat of oil to a screw and screw it into a MS21047 (K1000) nut plate. Drill a hole in the fiberglass where you want the screw to reside. Elongate the hole to the shape of a bowling pin. Fill the hole with flox and insert the nut plate center and one half of the nut plate in the elongated part of the hole. Rotate the nut plate 180 degrees to get the other half of the nut plate beneath the surface of the fiberglass. Now rotate it back 90 degrees and let it cure. Works for me. Jim White N44QT .__ ..\ \ ...\ \ .....\ \ l l l_l ......\__ l l_ < _ ..... ___ )_ > ...l l / l l ...../ / l l ..../ / ._/_/ Date: Mon, 29 Nov 1999 20:56:25 -0500 From: Neil Clayton Subject: COZY: Question for A&P's When safety wiring a nut or bolt-head and there isn't another nut nearby to use, what's the accepted method of anchoring the other end of the safety wire? Thx Neil C From: "Russ Fisher" Subject: Re: COZY: Question for A&P's Date: Mon, 29 Nov 1999 22:51:50 -0500 -----Original Message----- From: Neil Clayton >When safety wiring a nut or bolt-head and there isn't another nut nearby to >use, what's the accepted method of anchoring the other end of the safety wire? Neil, I'm no A&P, but two editions of Standard Aircraft Handbooks each show the wire fastened to a frame member or nearby hole as long as your bolt is not too far away from such a structure. If it is a nut you're fastening, personally, I'd use a castellated nut with a cotter pin. Russ Fisher From: cdenk@ix.netcom.com Date: Mon, 29 Nov 1999 22:54:27 -0500 (EST) Subject: Re: COZY: Question for A&P's On 11/29/99 20:56:25 you wrote: > >When safety wiring a nut or bolt-head and there isn't another nut nearby to >use, what's the accepted method of anchoring the other end of the safety wire? > >Thx >Neil C > I'm not an A&P but, wrap the wire around/through anything nearby that won't move is usually acceptable. A cotter pin or safety wire and castle nut and drilled shank is ok, and numerous other methods. 2 references that cover the subject in detail are "Airframe & Powerplant Mechanics General Handbook" and a very thick FAA publication "Accepted Practices ..." These should be a references that all builders have readily available, and good reading material, not to read every word, but know whats there and where to find when needed. There are a wealth of details that should be used in building that are very well described and illustrated. From: JHTanstaaf@aol.com Date: Mon, 29 Nov 1999 23:18:46 EST Subject: Re: COZY: Question for A&P's In a message dated 11/29/99 10:58:47 PM Eastern Standard Time, cdenk@ix.netcom.com writes: << a very thick FAA publication "Accepted Practices ..." These should be a references that all builders have readily available, and good reading material, >> a wise man once told me to get the book (AC43.13-A, about $15 from spruce/wicks/etc.) and let the kids play with it even if you don't want to actually use it. then when the faa comes over to sign-off on the project he sees this dog-eared copy of their bible & it warms the cockles of his heart.