Front Gear Leg Bolt Hole Wear

[Noah]

Thanks Vlad. I think I'll pick up some 609.

Originally Posted by Vlad

I don't use nosegear on landings anymore.

Whudyado, put helium in your nosewheel? Hey, that's a good idea!

[Pmerems]

I installed a close tolerance bolt in this location. Have you experienced this play where a close tolerance bolt was used or just the standard ANXXXXX?

[FlyingArcher]

There's just another thread going on about using taper pins instead of this same bolt in order to prevent wear AND movement
http://www.vansairforce.com/communit...d.php?t=105870

[flyboy1963]

I am curious if anyone who experienced shimmy on a 'properly' torqued nose swivel has noticed any diff after taking the slop out of their socket?
....seems to me that the change in camber ( or whatever you want to call that axis) could allow, or even enhance an oscillation?

[Noah]

Originally Posted by Pmerems

I installed a close tolerance bolt in this location. Have you experienced this play where a close tolerance bolt was used or just the standard ANXXXXX?

I don't know about the other guys, but I believe I used the Vans supplied shoulder bolt, which is a close tolerance bolt, I think.

[RVDan]

I thought I might post this about retrofitting my 6A nose gear leg bolt with a taper pin. In general I like a good mechanical fit for longevity vs. the loose fit and locktite approach which was my original plan.

The only way to do this modification without removing the mount was to put the pin in from the top, reverse to the Ellis approach. This might make removal of the pin after time a bit harder but it will be possible. I also did not have to put a hole in the engine mount, but note that others might have to.

The original AN5 bolt was loose in the hole and with the nose wheel off the ground, I could rotate the gear leg in the mount an get some free play, which was bound to get worse over time. I decided to use a taper pin. I sized the taper pin based on the existing bolt size and used an AN386-3-12 pin. Unlike the Matronics/Ellis taper pin which is a -4 diameter, I sized the -3. The small end of the -3 at the OD of the tube is .318" and the large end is .3855", whereas the AN5 bolt is .309" to .310". The allowables for the AN386 pin are higher than the AN5 bolt and the 4130 steel engine mount becomes the weak point. Even so, the larger diameter of the pin should help the engine mount bearing loads overall.

Also, given the challenge of taper reaming the hole on the mount (see numerous other posts on this) , I didn't want to have to enlarge the holes all the way up to the -4 diameters.

The existing leg was already match drilled to the mount, and there was no obvious elongation of either hole so it provided a starting place.

I removed the gear leg, and carefully step drilled the hole using progressively larger drill bits so that the taper ream wasn't having to remove so much material (each larger diameter is drilled with less depth). Then reamed so that the pin fit to the proper depth (must account for the engine mount tube thickness, etc.) This took some real effort even with the step drilling. I started out by hand on a bench where I could apply my full body weight and eventually came to a stop. I decided to move to my 3/4hp drill press which I can get down to 120 RPM. Eventually cut the pin hole size to get the pin depth needed. Taper reaming the gear leg is not easy.

Then went back to the aircraft, using a short drill bit, enlarged the top hole in the mount close enough to the pin size to let the taper ream get a good start. Now it is impossible without a machine shop setup to enlarge the hole in the gear leg perfectly on center, but since we are enlarging the hole in the engine mount, I figured to let the gear leg keep everything aligned as the mount is reamed. Inserted the gear leg and aligned and reamed the mount.

Now the good news about the leg being so hard to ream, was that there was no danger of over reaming the engine mount leg combination while taper reaming by hand. Essentially when the reamer stopped cutting, I was to the same size as the gear leg with a perfect match.

After cleaning everything up, installed the gear leg, taper pin, washer and nut and voila', no play.

I have used taper pins for other applications and unless the bearing loads of the pin on the mount are to high, there should be no play forever, and I can remove the gear leg if necessary without having to deal with the locktite.

I hope this helps someone if they need to do the same thing. I don't have pics of this but not really much to show.

[flyboy1963]

Before I go drop $60 on a little bottle of loctite, how much have you guys really used???
there's 1 ml, 10 ml, 50ml, or 250 ml for only $223!!! ( acklands supply!!!)

where can you buy some at a reasonable price????

does a guy just put a thin film on, assemble, and hope you had enough?
can you inject more, or is it too thick for that?

I guess if some oozes out, you're golden.

thx

[Noah]

I bought a mL on Ebay for about $1.50. I haven't done mine yet so I can't tell you whether its enough. But its a small gap and it won't take much. Maybe buy 2 or 3 1 mL containers just to be safe. Or skygeek has 10 mL for $10.76:
http://www.skygeek.com/henkel-loctit...S7-2gDck_D_BwE

Just goop it on there and rotate the gear leg a quarter turn as you install it, like gluing PVC pipe together.