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View Full Version : How many shims is too much?


TwinTurbo95
04-26-2010, 12:05 PM
Ok, last week I landed a little too hard and I had to replace my feathering shaft. No biggy, I got this bird used and I noticed that the parts used in the feathering shaft were not quite what I've seen in some pics. But, my bird flew great, no vibes, great blade tracking. So I replace the shaft and install all the washers, shims and bearings just like the 400 bible shows. It really hasn't been the same since I did it. It's got 6 shims on each side and it doesn't seem to be enough. The o-ring can come out a bit and that causes the blades to be woobly. The blades in one spot track, but if i look on the other side they don't track, what gives? Should I add enough shims to make it tight enough that it's not wobbly?

TwinTurbo95
04-26-2010, 01:00 PM
I've looked at some pics and the ones I've seen there aren't many shims being used. What gives? Why do I have to use so many?

Also, I used the Align feathering shaft. I remember it came with little collars, I didn't use them, was I supposed too? And of so where?

Sky1trek
04-26-2010, 03:48 PM
I believe the align feathering shafts need to be grinded down slightly to fit properly.

jcarne
04-26-2010, 06:06 PM
I don't know about the align feathering shaft but I replaced my feathering shaft a couple days ago and did a lot of research on this matter. what it came down to for me was first determining if your orings need replaced, mine did so I just went to Lowes and got 10 of them for a couple dollars. these new orings coupled with 4 shims per side really seemed to do the trick. ultimately what I ended up doing was just adding shims one by one until I got the grips nice and snug, it took a heck of a lot of time but now I know the right combo for my heli. generally what I have seen around the web is people are using about 4 per side, but it really depends on the condition and stiffness of your orings. hope this helps

TwinTurbo95
04-26-2010, 06:53 PM
do have the specifics on your o-rings from Lowe's? part number?

Sky1trek
04-26-2010, 11:10 PM
go to home depot or lowes or similiar and get #60 orings in oring section, plumbing etc. direct replacement .... from Londo HF member.

I've never been able to find them myself but if you do, please ship some my way:-)

jcarne
04-27-2010, 07:57 AM
ill go ahead and check when I get home after work, but I couldn't find anything at home depot (what a surprise) Lowes seems to never fail tho.

Larry227
04-27-2010, 08:31 AM
If you're using 6 shims per side and still have slop the shaft must be too long. Get the proper B400 shafts and go from there. Four shims + the step washer per side should be plenty.

TwinTurbo95
04-27-2010, 11:00 AM
yeah, that's my only conclusion, the shaft must be too long. I ended up putting one extra cup washer on each side and use just one shim next to the o-ring and she is good to go now. No notchy in the grips.

I know i'll get flamed for not using the right parts, but hey, it works. ;)

Larry227
04-27-2010, 02:20 PM
No flame from me. As long as it's working and the heads not going to fly apart you're good to go. Just make sure you locktite the blade grip bolts.

jcarne
04-27-2010, 09:14 PM
for future reference if you still need it, I got the orings at Lowes, brand is Danco and look for 1/4"OD x 1/8"ID x 1/16"