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Nosegear Service Bulletin Compliance Trick

JDeanda

Well Known Member
Old A&P here. My buddy has a -12 and I helped him drill thru the firewall and the new nosegear attach plate yesterday. We're both too old and lazy to get on the floor to hold the drill bushings against the firewall while drilling. We came up with a stratagem to make it easier. We got a piece of ~5/16" I. D. aluminum tube that was about an inch shorter than the distance from the drill chuck to the base of the bushing, slipped it over the drill, then put the bushing on the end of the drill. Now we could use the tube to hold the bushing in the existing hole in the bracket and firewall while sitting in the seat. Works on both the #30 drill and the 1/4" drill. We vacuumed after drilling the #30 hole and the 1/4" hole to get the chips out of the hole so the bushing would fit properly. We also put wet paper towels on the floor inside the console to minimize how much swarf* stays down there so vacuuming was easier.
I hope this helps, you RV-12 folks have enough extra work already. Great, sweet airplane, though, totally worth it.

*It's a real word... go look it up. :)
 
Old A&P here. My buddy has a -12 and I helped him drill thru the firewall and the new nosegear attach plate yesterday. We're both too old and lazy to get on the floor to hold the drill bushings against the firewall while drilling. We came up with a stratagem to make it easier. We got a piece of ~5/16" I. D. aluminum tube that was about an inch shorter than the distance from the drill chuck to the base of the bushing, slipped it over the drill, then put the bushing on the end of the drill. Now we could use the tube to hold the bushing in the existing hole in the bracket and firewall while sitting in the seat. Works on both the #30 drill and the 1/4" drill. We vacuumed after drilling the #30 hole and the 1/4" hole to get the chips out of the hole so the bushing would fit properly. We also put wet paper towels on the floor inside the console to minimize how much swarf* stays down there so vacuuming was easier.
I hope this helps, you RV-12 folks have enough extra work already. Great, sweet airplane, though, totally worth it.

*It's a real word... go look it up. :)

Hey JDeanda, Did you find it necessary to repeatedly add a cutting oil while drilling? Thanks.........Tom
 
I too took a different path drilling the holes in the new gear. I started the process Wednesday afternoon and was set up to start drilling when my hangar partner came in. I showed him all my stuff, long bits and bushings, and how I was going to have to lean/reach into the cockpit to keep the bit straight. I used a drill stop on the #30 bit and a piece on masking tape on the end of the bushing to hold the bushing in place before inserting the bit. The tubing over the 1/4 bit is a great idea to hold the bushing in place because this is where I ran into problems.

My hangar partner suggested since I could mark where to drill with the good set up of the #30 bit and drill stop to go ahead and mark or drill through with #30. Remove the gear leg and do all the finish drilling on a drill press we have in the hangar. So I did.

Well getting the gear leg set up in the drill press took some time to support and clamp everything to drill using the same progression of drill bits to finish with the 3/8 size. Two advantages were a nice straight hole and being able to apply cutting oil easily during the drilling process. Also I didn?t have all the drill shavings inside the tunnel.

Once drilled and deburred I reinstalled the gear leg and checked the fit pushing the bolts through. It worked well but again the set up in the drill press was something I really took my time getting it right on the marks made with the #30 bit.

I would be interested in selling my set of three long bits and the two bushing. If interested email me at pclaar at comcast dot net. I would like to get half my cost back plus shipping to you. Thanks
 
Etc.

My buddy Don had everything opened up, tailcone stand, engine hoist and nosegear in place when I arrived. Figuring out the tube idea, finding a piece of aluminum tube, drilling and deburring the holes and bolting the new nosegear in place took us about 5 hours. We?re slow.
Our cutting lubricant was Boelube, one application on the #30 hole seemed to be fine, 3 or 4 each for the 1/4? and 3/8? holes. Turn the drill a bit slower on the two bigger holes and push hard until you?re about to break thru. I like Boelube because it?s not nearly as messy as liquid cutting oils. Beeswax would likely work about the same.
Drilling the #30 holes and finishing up in the drill press sounds good, too. Maybe not quite as accurate, but plenty accurate enough and a lot less athletic.
BTW, getting those rubber isolators in place was a bit of a bear, too. Don put some beeswax on them which didn?t help much, and then some LPS 1 to ease pushing them into their holes. A long extension with a 9/16? socket on the end makes inserting the bolts easy. It?s a two technician job.
Confession... all we could find was some 5/8? OD aluminum tube, really too big. So we just mashed one end down with vise grips. Worked fine. My first thought wast to use a lloonngg spring, but we rejected that idea. I think a piece of fuel hose might even work in a pinch.
 
Came up with a similar strategy a little late

Old A&P here. My buddy has a -12 and I helped him drill thru the firewall and the new nosegear attach plate yesterday. We're both too old and lazy to get on the floor to hold the drill bushings against the firewall while drilling. We came up with a stratagem to make it easier. We got a piece of ~5/16" I. D. aluminum tube that was about an inch shorter than the distance from the drill chuck to the base of the bushing, slipped it over the drill, then put the bushing on the end of the drill. Now we could use the tube to hold the bushing in the existing hole in the bracket and firewall while sitting in the seat. Works on both the #30 drill and the 1/4" drill. We vacuumed after drilling the #30 hole and the 1/4" hole to get the chips out of the hole so the bushing would fit properly. We also put wet paper towels on the floor inside the console to minimize how much swarf* stays down there so vacuuming was easier.
I hope this helps, you RV-12 folks have enough extra work already. Great, sweet airplane, though, totally worth it.

*It's a real word... go look it up. :)

After doing a two-man acrobatic routine to hold the drill bushing in place and drill, knowing we need to do it again on some other RV-12's and RV-12iS's, I took a couple of 14" PEX tubes, which are slightly narrower than the bushings, reamed them out about an inch deep with an 31/64" bit, and press-fit the bushings in. The PEX tube will be easy to grab and force the bushing in place while drilling. If it works well, I'll let you know. If its a failure, I'll be quiet....
 
Don?t have my kit yet and haven?t even seen the bushings, but would it be effective to put a wad of modeling clay over them to hold them in place inside the engine mount backing bracket?
 
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