The International Cessna 170 Association

I have a set of NOS solid aluminum axles I would like to install as part of doing my best to complete the list of suggested upgrades to my 170. My mechanic wants to use new bolts hardware and I agree however I have questions for the knowledgeable forum crowd. A few years back I installed a set of L-19 towing lugs on the main gear as I pull the 170 from the back into the hangar up a slight grade and wanted the pull on the main gear not the tailspring bracket. I really don't remember whether I replaced the top two bolts, or just the nuts? I had purchased a number of part items while my mechanic replaced a cracked tailspring bracket and spring stack and the four upper attachment bolts may have come from the L-19 supplier , just not sure. This brings me to my question. The 170 parts manual calls for AN6-24A Lower, and AN5-23A Upper bolts, and Optional Ski Plane using NAS146-42 Lower and NAS145-41 Upper bolts? (These seem hard to find) I may end up running skis in the next years , and right now would just like to run the strongest bolts for both landing and towing, any suggestions would be appreciated. "The Landing Gear Works" in Washington also officers a Main Gear bolt kits for 180/185 PN: BK 15 however not STC'ed for 170 I'm curious all bolts are NAS in this kit?
Thanks Mike

The NAS bolts are stronger than the AN bolts. Just be certain to have sufficient length to accommodate your tow-adapters also if you plan to keep them.
Aicraft Spruce and hrrp://www.gen-aircraft-hardware.com either should be able to ship the bolts and nuts to you.

Mike,
As you’re probably aware the NAS bolts have a radius under the head. Be sure to use chamfered washers rather than plain AN960’s under the bolt head. A quick search here will find several discussions about this. Considering the cost of eight NAS bolts I would measure the grip length required on your setup rather than trusting any IPC or bolt length suggested here. Genuine Aviation Hardware and Clarendon Specialty Fasteners’ catalog (formerly Coast Fabrication) both have a lot of good reference material to study when purchasing these bolts.

If you are going to use hyd wheel skis you need another axle inward. Then you need extra long bolts through both axle attach points. Might be cheaper to put ski axles on now with long bolts and be ready for skis. I think a set of 8 bolts/nuts for ski axles cost me over $800.00 a few years a go. They are left on year round .

Thanks George, Gary, Dogone for the advice, much appreciated. I will get the right grip length measured up and research the suppliers suggested. I had a set of Federal 2500A straight skis and we were just not getting enough snow here over the last years to hassle with them. I sold them to a fellow in Anchorage and he was happy with them. Hydraulic Federal AWB, or even Aero 2800 (if they get 170 approved) would be what I would like to get in the near future however a excellent set of 2500 AWB with all the parts (stub axles) included seems hard to find. Dogone, I sent you a PM as I would like to see your set up with the 180hp conversion and we're only an hour plus flight time away. Thanks again.