I owned and was CEO of a Aerospace hardware distribution corporation...In my experience there is no way to really compare the two. The grade 8 hardware is inferior to Mil spec hardware in almost every application and certainly should not be used in an aircraft.. To summarize some of what has already been said... AN bolts are made from good alloy steel and basically derive their strength from that fact. They are produced under strict quality control and each lot has to be certified to the AN and Mil-spec and sample tested to comply.. You can check out the specs here..( http://everyspec.com/AN-SPECS/AN100-AN999/AN3_THRU_AN20_REV-12_6281/ ) Plated AN bolts are plated to the QQP- 416 spec which requires them to be baked at 400 degrees within 4 hours of being plated to relieve hydrogen embrittlement caused by the electroplating process... You can check out that spec here. ( http://everyspec.com/FED_SPECS/Q/QQ-P-416F_22867 ) Grade eight bolts are made from medium carbon steel and are case hardened to achieve their rated tensile and shear strength ... Quality control is no where near as stringent and the case hardening makes them brittle and subject to breaking due to vibration and other like factors. With out going into a lot of detail there is simply no comparison between the two and as far as practical applications go each has their own place. The AN bolt is far more ductile because of the better quality steel, They will stretch and bend considerably before failure.. This was stated earlier as well but If you want a bolt that will bring you home and back to the ground safely use an AN, MS or NAS bolt. There are Grade eight bolts that can be found in the Mil-specs but they are used in ground handling equipment, surface vehicles and like equipment. If you are looking for a particular AN bolt and are having trouble finding it message me I might be able to help you out.does AN hardware exceed grade 8 hardware ?
Are they actual commercial Grade 8 or European aerospace grade 8 metric, it starts to get messy once you add in European GA aircraft / Rotorcraft (the bolts come in the same horrible large steps in length as commercial hardware).Grade 8 hardware is being used in some aircraft, Tecnam is one I know.
I agree except that I don't believe common AN bolts need to be baked after plating.Plated AN bolts are plated to the QQP- 416 spec which requires them to be baked at 400 degrees within 4 hours of being plated to relieve hydrogen embrittlement caused by the electroplating process... You can check out that spec here. ( http://everyspec.com/FED_SPECS/Q/QQ-P-416F_22867 )
Having been a power train engineer at both Ford and FIAT-Chrysler, I can tell you that every bolted connection in the vehicle is engineered. Fasteners from internal specs, for hardness, strength, ductility, cleanliness, fatigue, corrosion resistence and quality control. These specs include SAE grade 8, but go beyond because Grade 8 by itself is usually not enough. Then all of the joints get specs for how they are torqued and the joints are analyzed and tested in the fastener lab. Almost all of them are applied by DC nutrunners. Some are torqued, some run to torque plus angle, some are run to yield, and it is all done based upon the joints. This goes beyond engines and transmissions, to axles, suspensions, wheel and brakes, seat mounts, restraints, instrument panels...In most of the world AN hardware is non existent making automotive bolts attractive.Impression is given that Automotive hardware is junk without quality.It is dubbed as Commercial Hardware store variety.Does Toyota make junk bolts ?
A minimax ultralight has about 2100 Lbs of lift force through the struts which is fed into a 1 inch steel tube through a 1/4 bolt in double shear. A 1/4" grade 2 steel bolt can take 2000lbs in single shear or twice in double.A grade5 bolt can take 3500lbs.
It seems if you can get an actual Grade5 or 8.8 metric bolt it can handle the loads .One can always go one size higher for a little weight penalty.
Culver, Performance Propeller, Sterba, Prince. Frank at Performance Propeller is widely regarded as the "go to" guy for half VW props. Half VWs need a skinny prop so they can spin up to the rpm where they're making the power.i think i will return power fin prop but i see tennesee props has closed its doors any sugestions
Dana:I got four props with my CB40 powered Fisher, the one that worked the best was a Catto 56x27.5 (I believe Catto no longer makes small wood props).
The standard for metric screws is a standard on how to specify screws, nuts and on. I do think there is some tables on preferred/recommended sizes or size and proportion. But the ISO metric screw standard is no specification of screws like the AN system with its tabulated sizes for a selection of screws. On the other side, any AN screw could be specified within the ISO standard framework.Are they actual commercial Grade 8 or European aerospace grade 8 metric, it starts to get messy once you add in European GA aircraft / Rotorcraft (the bolts come in the same horrible large steps in length as commercial hardware).