Head & Tail Assembly: Thrust Bearings & Spindles

[cml001]

Thought I'd post up on a method I like to use. First I disassemble the head or tail.. Lay it all out in order of assembly.

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Pay attention to the thrust bearings... The race with the larger inside diameter goes inward.. Closest to the hub.. Then middle piece, bearings, needs to have the open/cup side inward toward the hub as well. This will help(as much as it can) keep grease from depleting as fast. The outer race of the thrust bearing, closest to the blade, will have the smaller inside diameter. GREASE THE PISS OUTTA EACH LAYER!

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Each manufacture has their own order of the assembly of bearings & washers into the blade grip... But they don't differ much. Once the thrust bearing is greased & assembled.. It's hard to get it along with the radial bearings & washer installed into the grip without getting the grease inside the spindle threads.. Which is a bad thing as you want the spindle bolt thread locked into dry threads. The last thing you want is to eject a blade & grip mid flight because the spindle bolt backed out. The best way I have found around this is to clog the spindle threads. On smaller 450 size birds you can use a toothpick.. On larger birds a Q-Tip(cotton swab) does fantastic. Depending on the size of the threaded hole, u can use the swab or cut the swab off & just use the stick of the swab. I do my best to clean the threads as well.. Dip a swab in alcohol, thread it in & out. Repeat with a clean dry swab. Let air dry for a bit.. Then clog the threaded hole with the swab, toothpick, or swab stick. Once spindle threads are clogged, the stick that hangs out can be used as a guide to assemble the grip, bearings, & washers. I regrease the spindle shaft after putting on each piece of the assembly as each piece drags the grease away... It gets real messy & slippery.. But that's good! After assembling the grip in order per ur manual, all that's left is to unthread the swab piece.. Leaving a clean & dry threaded hole.. Apply thread lock to the spindle bolt and tighten it down.. Repeat on the other side. You can also thread lock one side of the spindle and build out to the other side.. Here are some pictures of the process taken from various builds. This method makes for a clean (even tho it's the messy part of a build), fast, and SECURE build of head & tail assemblies. Hope this helps someone.

[Graham Lawrie]

Nice clear pictures:)

My only reservation would be that you could get a wood splinter in the bearing.I do something similar but with a metal rod. I hated getting grease on the bolt, more so on my 450, 550 and 600 were not as bad to work on:)

[Tony]

That's one big head...lol

[pvolcko]

I haven't had issues with grease getting into the spindle threads really. I usually swab them after I put the bearings in place just to be sure. My issue is always making sure I don't threadlock the bearings. I haven't done that yet, either. But it is what I really worry about.

[cml001]

Got a trick for that too... Toothpick! Get thread lock on a toothpick and insert it into the threaded hole and whirl it around... Then insert the bolt dry.

[pvolcko]

I do that on the smaller helis (300 and under). But on the 550+ size I feel like I can't get enough TL in there with a toothpick. What I've started doing is getting TL on the first couple of threads only. The extra collects at the junction and coats the remaining threads as it is screwed in. So far it has worked well. Maybe I'll try the toothpick stick on the 500 when I rip it apart and rebuild it.

[cml001]

Sometimes I'll add the thread lock before assembly as well... If it's a tedious spot that helps a bit. I find it hard to keep thread lock from pool'n up under the head of the bolt.. Usually a sign of too much... But I usually use too much anyhow I'm sure.