Carbon Props

[bob whitney]

 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

[RandySmith]

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

[Akihiro Danjo]

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

[Brad LaPointe]

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

[Ward Van Duzer]

Jus' torque it!

w. 

[Brett Buck]

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

[RandySmith]

    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

[Steve Helmick]

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.      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.

[Randy Cuberly]

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.   

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!   

Randy Cuberly

[Trostle]

(Clip)

people  like Bill  R .  can wring your  car lugg nuts  off  with a  4 way modelers  wrench !!

(Clip)

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

[Howard Rush]

I personally saw one fellow who shall remain nameless...

C'mon, Randy, cut out the namelessness.

[RandySmith]

 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

[Randy Cuberly]

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. 

Randy Cuberly

[john e. holliday]

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.

[Steve Helmick]

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?).    Steve