Bob R Posted January 9, 2020 Author Report Posted January 9, 2020 2 hours ago, N201MKTurbo said: While it would be fairly straight forward to machine a set of these gears, install them and verify that they are running well. There has been 3 if not 4 different sets of materials used in these gears to get to the current material which lasts almost forever. It isn't easy to accurately determine which steel and heat treat was used and what yellow metal was used. If you do choose to produce your own parts, I would start with a 50 hour inspection interval until you determine weather they will last. I completely understand. My buddy who's actually makes them works for a company that does robotics and also does machining for NASA. I'll try and do the research with Mooney on the steel and the FAA, but if unsuccessful I will get the hardest steel known to man. By the way, have any of you guys out there with the 40;1 gears had to have your housing machined out? Quote
carusoam Posted January 9, 2020 Report Posted January 9, 2020 Going with the hardest steal known to man is not a viable approach to a materials challenge... Read up on tribology of metals... Matching the hardness in a proper range will keep things from wearing things out... Accidentally improving the gears could easily wear out what it is in contact with... Are you sure you want to approach this challenge this way? The last time somebody approached a gear material challenge in our Mooneys... they selected an aluminum gear to go with a steel gear... in every O360 engine on the planet... the aluminum one was supposed wear sacrificially compared to the steel one... sounds brilliant. selecting the hardness of the two gears properly leads to minimal wearing of both parts... Don’t feel bad, if not familiar... this is what materials engineers do for a living... PP thoughts only, I paid money to have to switch the aluminum gear out of my O360... not a materials engineer... Best regards, -a- 2 Quote
Bob R Posted January 9, 2020 Author Report Posted January 9, 2020 47 minutes ago, carusoam said: Going with the hardest steal known to man is not a viable approach to a materials challenge... Read up on tribology of metals... Matching the hardness in a proper range will keep things from wearing things out... Accidentally improving the gears could easily wear out what it is in contact with... Are you sure you want to approach this challenge this way? The last time somebody approached a gear material challenge in our Mooneys... they selected an aluminum gear to go with a steel gear... in every O360 engine on the planet... the aluminum one was supposed wear sacrificially compared to the steel one... sounds brilliant. selecting the hardness of the two gears properly leads to minimal wearing of both parts... Don’t feel bad, if not familiar... this is what materials engineers do for a living... PP thoughts only, I paid money to have to switch the aluminum gear out of my O360... not a materials engineer... Best regards, -a- I don't feel bad. You're right that's what engineers are for. Maybe he'll build them out of titanium like my new m20e door handle. 1 Quote
N201MKTurbo Posted January 12, 2020 Report Posted January 12, 2020 Worn out gear of current design. 1 Quote
EricJ Posted January 12, 2020 Report Posted January 12, 2020 37 minutes ago, N201MKTurbo said: Worn out gear of current design. Does the worm wear significantly, too, or just this gear? Quote
N201MKTurbo Posted January 12, 2020 Report Posted January 12, 2020 28 minutes ago, EricJ said: Does the worm wear significantly, too, or just this gear? I’ve never seen any ware on the worm gear. I replaced the ring without replacing the worm and they both still look brand new. The new ring has about 1000 hours on it. The wear was caused by an improperly installed actuator mount that was putting excessive stress on the actuator. 1 Quote
MikeOH Posted January 13, 2020 Report Posted January 13, 2020 9 hours ago, N201MKTurbo said: I’ve never seen any ware on the worm gear. I replaced the ring without replacing the worm and they both still look brand new. The new ring has about 1000 hours on it. The wear was caused by an improperly installed actuator mount that was putting excessive stress on the actuator. Would you please elaborate on the improper mounting and how you discovered it. I'd like to make sure nothing is wrong with my installation! Thank you! Quote
vik Posted August 11, 2021 Report Posted August 11, 2021 Anyone knows where to get the tool to undo the lock nut that secures the jackscrew bearing? This bearing is under the gear and mine needs replacement. Vik Quote
carusoam Posted August 12, 2021 Report Posted August 12, 2021 @N201MKTurbo Rich, Looks like a request you might be familiar with above…. See vik’s post… Best regards, -a- Quote
N201MKTurbo Posted August 12, 2021 Report Posted August 12, 2021 19 hours ago, vik said: Anyone knows where to get the tool to undo the lock nut that secures the jackscrew bearing? This bearing is under the gear and mine needs replacement. Vik It has been awhile since I took one apart. I don’t recall needing any special tools. Do you have a picture? Quote
vik Posted August 13, 2021 Report Posted August 13, 2021 (edited) Pictures of the nuts. Both needs to be taken out to replace the bearing. Edited August 13, 2021 by vik Quote
carusoam Posted August 13, 2021 Report Posted August 13, 2021 See if @N201MKTurboRich is around to see the pic… Best regards, -a- Quote
Mooneymite Posted August 13, 2021 Report Posted August 13, 2021 5 hours ago, vik said: Pictures of the nuts. Both needs to be taken out to replace the bearing. What grease are you using...the grease in my actuator is quite black after the 10% molybdenum is added... 1 Quote
N201MKTurbo Posted August 13, 2021 Report Posted August 13, 2021 6 hours ago, vik said: Pictures of the nuts. Both needs to be taken out to replace the bearing. I think I used a pair of snap ring pliers to take them apart. Quote
N201MKTurbo Posted August 13, 2021 Report Posted August 13, 2021 6 hours ago, vik said: Pictures of the nuts. Both needs to be taken out to replace the bearing. As @Mooneymite said, you have the wrong grease in there. The grease is mandated by AD. Quote
Mkruger2021 Posted August 13, 2021 Report Posted August 13, 2021 On 1/9/2020 at 5:14 AM, N201MKTurbo said: While it would be fairly straight forward to machine a set of these gears, install them and verify that they are running well. There has been 3 if not 4 different sets of materials used in these gears to get to the current material which lasts almost forever. It isn't easy to accurately determine which steel and heat treat was used and what yellow metal was used. If you do choose to produce your own parts, I would start with a 50 hour inspection interval until you determine weather they will last. Exactly what I was thinking....Nailed it!...I would be very hesitant doing this.....It all comes down to risk, insurance, and FAA!....As an A&P, I would not take the risk signing for it.....There just is not enough money in it for me to lose my house with a bunch of lawyers.....Just my thoughts! Quote
vik Posted August 13, 2021 Report Posted August 13, 2021 4 hours ago, Mooneymite said: What grease are you using...the grease in my actuator is quite black after the 10% molybdenum is added... Please, do not get me started! I just got this plane and did not even fly it yet. And I am not going to until I check everything personally and my IA gives his nod and other experienced A&Ps exhaust their sarcastic jokes aka critical comments. As for the grease in the actuator - I am going to report the IA who did last several annuals! That actuator has never ever been taken off the plane, but the genius IA somehow "complied" with AD. There are other issues that directly affect safety and do not look like mistakes, more like a pure negligence. And you are talking about using the correct grease! I was pleasantly surprised to find some grease inside at all! 2 Quote
vik Posted August 13, 2021 Report Posted August 13, 2021 4 hours ago, N201MKTurbo said: I think I used a pair of snap ring pliers to take them apart. Tried that carefully. Snap ring pliers are too weak for both nuts. Need better tools. Just do not want to ruin the expensive part. Quote
Mooneymite Posted August 13, 2021 Report Posted August 13, 2021 52 minutes ago, vik said: ... As for the grease in the actuator - I am going to report the IA who did last several annuals! That actuator has never ever been taken off the plane, but the genius IA somehow "complied" with AD. .. No molybdenum? Maybe why the gears are worn? Sounds like you're doing some catch up maintenance. Good luck. It'll be great when all this is in your rear view mirror and flying a pampered plane. Quote
vik Posted August 13, 2021 Report Posted August 13, 2021 10 minutes ago, Mooneymite said: No molybdenum? Maybe why the gears are worn? Surprisingly, the gears looks like new and pass the test specified in AD. It is the jackscrew bearing (in the picture) that does not pass my subjective smoothness test. To get to that bearing I need to remove the worm gear and undo the nut holding the bearing. Both nuts require special tools. Quote
tony Posted August 13, 2021 Report Posted August 13, 2021 why isn't the grease black? I think you're using the wrong grease. Quote
Guest Posted August 13, 2021 Report Posted August 13, 2021 3 hours ago, vik said: Tried that carefully. Snap ring pliers are too weak for both nuts. Need better tools. Just do not want to ruin the expensive part. Make a steel bar with two holes drilled to the same centres as the pin holes, drive two pins through the bar deep enough to engage the holes in the nut. Clarence Quote
N201MKTurbo Posted August 13, 2021 Report Posted August 13, 2021 4 hours ago, vik said: Tried that carefully. Snap ring pliers are too weak for both nuts. Need better tools. Just do not want to ruin the expensive part. You could use a sacrificial socket of the correct diameter and grind the end down until there are two posts left. I have found that making a wooden sled for the table saw that clamps the socket in place along with a breaker bar or T handle and then putting an abrasive cutoff wheel in the saw allows you to do precision grinding on a socket. Quote
vik Posted August 14, 2021 Report Posted August 14, 2021 18 hours ago, N201MKTurbo said: You could use a sacrificial socket of the correct diameter and grind the end down until there are two posts left. I have found that making a wooden sled for the table saw that clamps the socket in place along with a breaker bar or T handle and then putting an abrasive cutoff wheel in the saw allows you to do precision grinding on a socket. Will probably go that route. The large nut feels like tough to get out. So, maybe a tool with hardened pins will be needed. Quote
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