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General control line discussion => Open Forum => Topic started by: bob whitney on August 31, 2016, 10:10:55 PM
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just a reminder ..a 4 way is not the best tool to tighten a carbon prop.it is best to use a Box wrench long enough to get some leverage on it
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Just a caution a box end wrench is not for a lot of people, many will break off the crankshaft end with this type wrench. I have seen it done many times, plus stripped prop nuts
Randy
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Aren't Grip Washers sold in USA?
Aki
http://www.shop-online.jp/mnti/index.php?body=spec&product_id=955518&category_id=88711&PHPSESSID=416abb6fb4d5da5a249e42b8c9bf474e
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Just a question on this has anyone established a proper amount of torque for different types of props . Is the old keep tightening until it doesn't come loose still valid ? Maybe one of those inch pounds torque wrenches will find its way into our pit boxes .
Brad
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Jus' torque it!
w. y1
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Just a caution a box end wrench is not for a lot of people, many will break off the crankshaft end with this type wrench. I have seen it done many times, plus stripped prop nuts
Really? I have used about a 10" ratchet for about 40 years now, and while I can imagine that getting grossly excessive torque would be physically possible, I would be amazed that you can pull a 5/16" hardened steel crankshaft in half by accident or without realizing you were overdoing it.
I have seen aluminum prop nuts damaged, but that was from galling and lack of lube rather than excessive torque. I have also had to use a Zona saw to cut off someone's spinner nut for the same reason.
Brett
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Really? I have used about a 10" ratchet for about 40 years now, and while I can imagine that getting grossly excessive torque would be physically possible, I would be amazed that you can pull a 5/16" hardened steel crankshaft in half by accident or without realizing you were overdoing it.
I have seen aluminum prop nuts damaged, but that was from galling and lack of lube rather than excessive torque. I have also had to use a Zona saw to cut off someone's spinner nut for the same reason.
Brett
Brett, you, like most modelers have a "feel" for the tightness, but there are many who don't
So, indeed it does happen ,I have seen in person, more than a few times, most are 1/4 inch shafts, but people like Bill R . can wring your car lugg nuts off with a 4 way modelers wrench !!
I Also replaced dozens of popped Super Tiger drive washers split in half from being run down too tight, these were all later model parts
DO NOT even think about using a box end on a FOX 35 , OS 35, Tower 40 etc.. unless you have a feel for how much "crank" is going on.
I have also seen this happen to ST 60 and 46... many 35s STs launch themselves !
Randy
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Aren't Grip Washers sold in USA?
Aki
http://www.shop-online.jp/mnti/index.php?body=spec&product_id=955518&category_id=88711&PHPSESSID=416abb6fb4d5da5a249e42b8c9bf474e
Well, apparently not. Perhaps some industrial supply place might have them. I tried Central Hobbies in Billings, Montana, thinking that they would be a most likely source, but with no luck. Using their website's search function for "grip washers", OK Model products, "abrasive washers", etc. No luck! If anybody can find them at McMaster-Carr or someplace like that, please post! I just emailed Central Hobbies to see if they might bring them in or maybe find a domestic source.
I rather like a "stubby" box-end wrench from Craftsmen to tighten props, but often use the standard box-end wrenches. A Machinist's Handbook (I think I burned mine!) should provide torque specs for any given sized screw, but IIRC, you'd need to know what grade the bolt/nut are. Should be some help, if you decide to make the plunge for an inch-ounce torque wrench. I'm sure Tim will be along in a minute with a chart. ;)
On the various OS and Magnum engines I've run, most got a spinner attached. If I want to run without a spinner, I throw the OEM nut away and install a 1/4-28 Grade 8 nut from the local hardware store. No reason to have a UNF thread with a metric hex. I'm fine with the French system, but can't abide mixing the two systems together. n1 Steve
EDIT: I already got a reply from Central Hobbies. They don't seem interested and say the abrasive washers are not available. I can't think of another hobby shop that imports stuff direct from Japan, or that would be interested in doing so. Shazbot.
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I personally saw one fellow who shall remain nameless break a Fox and an Enya crankshaft with an 8 inch crescent wrench in the same day. From watching this "bruiser" operate I would guess he inflicted about 100+ ft lbs of torque with that wrench. Being a sit on my Butt most of the time engineer I can tell when to stop from the pain inflicted on my soft hands. <= LL~ LL~
I use a small 4 inch box end wrench and can get even carbon props tight enough to not come off or pop loose on backfires. I've turned a lot of torque wrenches in my motorcycle racing days so I do have some feel for tightness. I recommended to the Bruiser mentioned above that he get a torque wrench and he gave me a look that said he might try to use a wrench on me! LL~ LL~ LL~
Randy Cuberly
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people like Bill R . can wring your car lugg nuts off with a 4 way modelers wrench !!
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Randy
I can attest to what Bill Rich can do with a prop nut. After the team trials in 2013, I was an intermediary in purchasing one of Bill's stunt ships with a PA 75 and a carbon prop for another person. I needed to remove the engine. Almost was a big mistake because I could not loosen the prop nut until a put a long handled wrench on it, and then it was not easy to loosen. I would not bet against him in an arm wrestling match.
Keith
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I personally saw one fellow who shall remain nameless...
C'mon, Randy, cut out the namelessness.
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Blue lock Tite and 320 grit black wet or dry are great things to use TOO, use a little Blue on the threads and cutout a small sandpaper Doughtnut for the backplate or prop
Randy
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C'mon, Randy, cut out the namelessness.
Uhhh He still lives around here and doesn't really like me very much anyway. This guy may have played linebacker for the Packers! He's a plumber now. I can take care of myself but I'd rather not have to! I'm too old to run very fast anymore. LL~ LL~ LL~ <=
Randy Cuberly
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My Dad used to tell me when tightening nuts, bolts and screws, go until tight and then a half turn more. Have stripped out those aluminum prop extensions.
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The Rossi .15's were famous for having the cranks snap off when tightening the prop. One of the "tricks" is to put a 1/64" or 1/32" plywood washer under the prop washer (front side of prop for most of us, but apparently not all?). n~ Steve