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comfortcat 10-27-2013 09:34 AM

Tapered pin on nose gear...
I've deceided to use the tapered pin to attach the nose gear to the motor mount on my RV-9A. Low cost, well tested mod (Jim Ellis rules) that looks MUCH easier during installation than adding later. Note that the cost is low if you do not screw up the taper when cutting the hole!

BruceH in Ramona is my guide for using a hand tool, LOTS of oil and patience. Do you really have to push that hard to get it to cut?

I bought the #3 tapered reamer from A/S and will attempt next week-end.

Tips? Comments? Warnings?

Just in case I'm a glutton for punishment, do folks use a tapered pin in the mains as well?


bruceh 10-27-2013 09:57 AM


I think you start by drilling out to size "S" bit on the hole. That was the tough part. Almost burned up my drill motor on that one. The reaming can be done by hand. Once the reamer starts making chips, just keep it moving forward and it will go pretty easily as long as it is really oiled up. I helped another builder do his and it went MUCH easier than mine did. It helps to have a buddy and extra hands. Be careful when you get going not to go too far. It is easy to come up on the correct depth very quickly. We would pull out the reamer every few turns near the end, put in the pin and measure how far the threads on the pin were sticking out. Rinse (more oil), repeat as needed....

I think the main gear legs are fine with the provided AN5 hardware. Just be sure to measure the diameter of the bolts and use a correctly sized bit or reamer (not 5/32, which will be too big).

pilotkms 10-27-2013 11:02 AM

Do as Bruce says. He knows it well. He, with my assistance, did my nose gear. Came out perfect. Thanx again Bruce.

BSwayze 10-27-2013 12:33 PM

I followed Bruce's lead on my tapered pin installation as well. I bought a brand new "S" bit for the pilot hole, and I thought I'd never get that hole drilled. The material is VERY hard and it takes a lot patience, a lot of pushing, a lot of BoeLube, and a big powerful drill (I'd use the biggest electric you can get your hands on). But once the pilot hole is drilled, the tapered reamer takes almost no time, by comparison. I almost went too far! So be careful with the final reaming to depth.

NYTOM 10-27-2013 12:40 PM

S bit
Bruce do you know if the S size bit is needed for the 6A tapered pin install. My gear was already drilled from the factory so all I ordered was the pin and reamer. Never heard of having to drill out first unless this is something specific to the 7A or a un-drilled gear. :confused:

bruceh 10-27-2013 08:46 PM

If you have the tapered pin, take a measurement of the small side diameter at the point where it is going to exit the weldment. Add on the depth of the required washer and measure from there. You want to drill to that diameter (or less). Then you can start the tapered reaming. I followed the instructions online at the Matronics wiki.

NYTOM 10-28-2013 03:26 PM

Awwww now I got it. Thanks Bruce :)

marcnadine 10-28-2013 04:30 PM

Why does the gear leg bolt come from the bottom with the nut on top. I would think having the bolt coming from the top would safer. To me this just backwards.

Thanks Guys

grayforge 10-29-2013 02:01 AM

Maybe there's not enough clearance with the engine in to insert it from the top?

az_gila 10-29-2013 10:14 AM


Originally Posted by marcnadine (Post 820700)
Why does the gear leg bolt come from the bottom with the nut on top. I would think having the bolt coming from the top would safer. To me this just backwards.

Thanks Guys

I think it might be more to do with removal.

The pin could be tapped (or hit harder..:)..) downwards, but there is no room for a hammer or other striking device hitting upwards from within the cockpit through the firewall hole.

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