Somebody school me. My prop instructions say to torque in three stages to 55#ft. Simple enough, except invariably 5 of the 6 bolts will have the safety wire channels pointed in an impossible direction to wire. On the first bolt I'll turn the bolt back to pull the wire, re-torque, measure and twist to the second bolt, turn that bolt back to pull the wire, re-torque, then finish the twist and tuck the pigtail. Sound easy enough but it's a sucky job to do in the restricted space around the hub. What do you other guys do? Any hints to pass along? Do you manually twist the second bolt or are you using LH twist pliers?
Hartzell-Style CS Prop Bolt Safety Wiring
- Thread starter stewartb
- Start date
skywagon8a
MEMBER
SE Mass MA6
Welcome to the club. Other than what you've done, you could press the bushings out of the crankshaft, rotate them to the desired position and reinstall. It's a case of the threads in the bushing not matching the threads on the bolt when it is at the desired torque while at the same time placing the safety holes where you want them.
frequent_flyer
Registered User
Arizona, USA
What gauge safety wire are you using? I was surprised to find that CubCrafters used a thinner gauge on my Trailblazer prop than I used on my fixed pitch prop on my PA-28. Perhaps the thinner gauge makes it easier. I hope I don't have to pull the prop and find out.
behindpropellers
Registered User
NE Ohio
Interesting... 040 typically is used for propeller safe tying.
Kid Durango
FRIEND
Rangely, Co
Your explanation of things is exactly what I experienced! And more directly, I twisted left hand manually. It sucked
wireweinie
FOUNDER
Palmer, AK
Was anyone else here, taught safety wire by John Steer? No safety wire pliers allowed, ever. Manually twisted, pigtails finished with duckbill pliers, and cut to length with side cutters. And, he ALWAYS caught any shortcuts or cheats.
Any way you could change out the prop bolts for ones with heads drilled three ways instead of just one way? Might help out with getting wire started at least.
Web
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Is it acceptable to cross-drill additional holes as a local shop procedure?
bob turner
Registered User
Doubt it. And why is .040 so important? Once those nuts start backing out you are in trouble no matter what size safety wire. The wire is not designed to maintain torque.
wireweinie
FOUNDER
Palmer, AK
'Cuz loose is better than gone.
Web
Web
RaisedByWolves
FRIEND
Tx
Recent MT install called for 32. I was happy to use that.
This tool works great too
https://www.aircraftspruce.com/catalog/appages/wrench05-12375.php?clickkey=67780
I'd be lost with out my reversible pliers
https://www.aircraftspruce.com/catalog/topages/milbarwiretwister.php?clickkey=3009235
First shop i worked at used duckbills and dikes. Sure is nice with reversible pliers
bob turner
Registered User
If something happens to allow a nut to shear .032, I doubt that .040 will stop it. I agree, loose is better than gone, but there are places where if loose happens, something else is already broke. I forget the spec, but these are not torqued lightly, as I recall.
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
"Doubt it." What basis? Seems to me that drilled is drilled, but??? Of course it would take appropriate machinery to get the additional holes located and aligned per spec.
Edit: I'm thinking about bolt heads; maybe you guys are referring to something different - I'm not the least bit familiar with the application y'all are discussing.
Edit: I'm thinking about bolt heads; maybe you guys are referring to something different - I'm not the least bit familiar with the application y'all are discussing.
Grant
FRIEND
At Work.....
These Props use.032 wire. The "Nuts" are captured in the hub. You cannot "Drill" the heads. I use two tools for this...
The Anti-Splat Wrench (same as the one Tom mentioned) - Use it and you'll never use a normal wrench for this again... its the fastest way to remove and install these props.
And the Saf-T-Cable Tool - Another tool worth the money - Watch ebay for them. I got all of mine for less than $150 each.
I get the nuts snugged and thread the saf-t-cable then using the Anti-Splat prop wrench I torque. The wrench is thin enough that you do not touch the wire when torquing. It works nice. We have about 40 Aztecs (80 props).... We change them alot.
The Anti-Splat Wrench (same as the one Tom mentioned) - Use it and you'll never use a normal wrench for this again... its the fastest way to remove and install these props.
And the Saf-T-Cable Tool - Another tool worth the money - Watch ebay for them. I got all of mine for less than $150 each.
I get the nuts snugged and thread the saf-t-cable then using the Anti-Splat prop wrench I torque. The wrench is thin enough that you do not touch the wire when torquing. It works nice. We have about 40 Aztecs (80 props).... We change them alot.
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Grant
FRIEND
At Work.....
Because its not a bolt like you are thinking. Its a bolt with a special head that is installed in a captured way then securred with a roll pin.
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Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Ah, I see. Thank you for that. It DOES look like a major PIA!:-?
Edit: So Grant, as I'm getting schooled here - - at the top of your pic I see left-twist safteying, with the attach geometry suggesting a left hand thread. Is that a rule? i.e. left thread, left twist? I've never encountered left hand threads on a plane.
Edit: So Grant, as I'm getting schooled here - - at the top of your pic I see left-twist safteying, with the attach geometry suggesting a left hand thread. Is that a rule? i.e. left thread, left twist? I've never encountered left hand threads on a plane.
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Grant
FRIEND
At Work.....
Thats the Tail of the wire.... you cant see that from the picture but its cropped from a larger picture.
The "twist direction" of the wire has more to do with how it "lays". Getting the wire to lay down around the head and not "Pop" over the top is solved by the "twist direction" - This is the value of the reversable safety wire pliers. The "pull direction" has to do with the left or right threads.
Left threads are pretty rare - Turnbuckles come to mind. Some Flying wires too.
The "twist direction" of the wire has more to do with how it "lays". Getting the wire to lay down around the head and not "Pop" over the top is solved by the "twist direction" - This is the value of the reversable safety wire pliers. The "pull direction" has to do with the left or right threads.
Left threads are pretty rare - Turnbuckles come to mind. Some Flying wires too.
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
Thank you!
frequent_flyer
Registered User
Arizona, USA
skywagon8a
MEMBER
SE Mass MA6
You have given me another thought of how to "move" the hole. These bolts are actually studs with a castle nut held in place with a roll pin. The safety wire goes through the roll pin. Stewart could pull the roll pin, reposition the nut one castellation and reinstall the roll pin. This would change the relationship of the nut to the threads like adding or subtracting a washer. That is if there are additional castellation in the nut. The ones in the pictures above don't have extras.
frequent_flyer
Registered User
Arizona, USA
I was not aware that "roll pins" were used but I enlarged the photo I posted earlier and I do see one.
I searched the Hartzell owners manual for "roll pin" and found nothing. I then found "spring pins" specified for the R flange. (I'm used to calling these "tension pins").
I need to get more familiar with exactly how the prop is fitted on my airplane and will be taking a closer look next time the top cowling is off.
BTW 0.032 wire is specified for R flange props.
I searched the Hartzell owners manual for "roll pin" and found nothing. I then found "spring pins" specified for the R flange. (I'm used to calling these "tension pins").
I need to get more familiar with exactly how the prop is fitted on my airplane and will be taking a closer look next time the top cowling is off.
BTW 0.032 wire is specified for R flange props.
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Removing-reinstalling these props is an exercise in patience. Prop bolts need to moved a little and all the other bolts moved equally, then start the progression again. Otherwise you jam the bolts against the hub. All while (during removal) oil is running out. Good times when the only helping hands available are your wife. Reinstalling requires care not to pinch the O ring and getting bolts started in places not easy for a guy on a ladder to reach while holding an expensive prop at the proper angle. And when all that fun is done? Safety wire. I hope the bolts are replaceable because next time I do it I’d like to torque bolts that aren’t rounded from the torque wrench slipping off. All this fun resulting from the curiosity about clocking it 180° to see if it smoothed it any. It didn’t. In fact it needed to go back to original, so it was a two episode program. Yep, good times.
Which brings into question… the Whirl Wind spinner backing plate is indexed to blades 1 and 2. The spinner and fillers are indexed as well. I didn’t re-index the backer when flipping the prop but did follow the blades with the spinner and fillers. Everything fit perfectly. Which begs the question, why is the backer indexed? Probably to assure spinner fit given how the spinner is fitted to the hub. I doubt there’s any balancing done on the backer-spinner assembly. Or is there?
frequent_flyer
Registered User
Arizona, USA
It appears your installation uses bolts rather than the stud+nut+pin assembly shown in the Hartzell manual. Why the difference?
The only reason I can see for using the stud+nut+pin assembly is that it allows the prop to be positioned on the studs before the nuts are started. Is that a real advantage in practice?
For those familiar with the stud+nut+pin assembly - At what stage in the installation is the pin inserted?
frequent_flyer
Registered User
Arizona, USA
Ok, think I understand now. When you say "bolt" you are actually referring to the stud+nut+pin assembly.
Hope I don't have to pull my prop. If I do I'll try to remember to mark where each stud was fitted and photograph how they were all wired.
RaisedByWolves
FRIEND
Tx
With the tool posted it’s not bad to torque them all, back off run the wire one at a time and torque. Usually only have one or two that has to be loosened and the wire run through. That tool is nice, one end the jaws are shorter acting like a ratchet almost, for quickly tightening them
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spinner2
MEMBER
Montana
I’m wondering what the hex size is on the Trailblazer? I’ve got one ordered for a project and thought I’d get one of these wrenches before it came. They offer a 5/8” and 3/4” size wrench.
