Nuts and Bolts

[Tracer]

Hi Guys,

A bit of a technical question, but maybe someone has the answers, or someone may be able to point me in a direction to get the information...

I want to do a comparison between the following, quality/standards of bolts:
1. AN bolts
2. 8.8 bolts
3. Stainless Steel bolts

What I want to compare is the maleability, shear strenght etc.....

I take it that the AN quality bolts are best, but there aren't many "Trike"manufacturers that use AN quality bolts, throughout the trike. They generally use 8.8 bolts. Are stainless steel bolts not better than the 8.8 bolts?

Thanks.

[Morph]

you might find something here

http://www.boltscience.com/pages/references.htm

[wiskeyfoxtrot]

Hey Tracer,

You have to much time on your hands,
Stop playing with your nuts and do some work for a change !

[Tracer]

Hey Tracer,

You have to much time on your hands,
Stop playing with your nuts and do some work for a change !

It's called Time management

Oh yeah, about the cost of those rubbers you wanted...

[Le Pou]

Hi guys,
I strongly support Tracer's call for help. I have the same problem and have asked around and have not been able to get a straight answer.
Can no one give us an answer? Surely there are some engineerig types on this forum who can? The boltscience website is far too advanced for for a simple oke like me.

Le Pou

[wiskeyfoxtrot]

The only place i know that might be able to help with technical info on bolts & nuts is a place called J K M Engineering supplies. They are based in Oxford road in Randburg. Dont have the number with me now but will post it on Monday

Later guys.

[grostek]

Hi Tracer,

AN Bolts are made from 4037 or 8740 Alloy Steel
Heat treated to 125,000Lbs Tensile strength
Then Cadmium plated.

Have a look here
http://assist.daps.dla.mil/quicksearch/ ... _query.cfm

The Document you probably need is
MIL-DTL-1222J
In it you will find the specs for what used to be known as AN Bolts.(B7(4037) and B16(8740) or ASME A193 for both types )

Its plenty of pages but all the info you want is in there.

A Tip AN (Army Navy)designation is no longer used in Industry has been Superceded by the above as far as I can tell.

Unfortunately if you want info these days you have to do your research carefully.

Have tried to attach the PDF file here but it is too big so you will have to download it yourself.

Hope this helps

Kind regards,

Gunter Rostek

[Kingfisher]

I buit a VP 2 a while ago and came to the same question. Anton Maneschijn and his late father was still actively involved in experimental aircraft.
According to them using 8.8 bolts & nuts are acceptable as a metric replacement for AN bolts & nuts , as long as the threads are rolled.
Have them cadmium plated and heat treated , as they usually come unplated.
Also make sure your shaft lengths are long enough , you don't want any thread carrying load. Space up with washers to make up any extra bolt length.

Here is a rough calculator to ascertain the thread length of bolts ;
Bolt lengths up to 125 mm
M6 (6mm) Diameter x 2 + 6 mm (18mm thread)
M8 (8mm) Diameter x 2 + 6 mm (22mm thread)
Bolt lengths 125 - 200 mm
Diameter x 2 + 12 mm
Work out your shaft length , add the thread length & buy the closest one ( a bit longer if needed) You could cut the extra thread length of before the plating & heat treatment.

[Le Pou]

Hi Kingfisher,
Thanks for the info. Would you know where we could get cadmium plating and heat treatment done in the JHB area?
Any comment on stainless steel bolts?

Thanks,
Le Pou

[Arnulf]

8.8 Bolts have a tensile strength of 8N/mm2, with a yield stress of 80%

Stainless steel bolts are generally of substantially lower tensile strenght:

Stainless Steel
Stainless steel is an alloy of low carbon steel and chromium for enhanced corrosion characteristics. Stainless steel is highly corrosion resistant for the price and because the anti-corrosive properties are inherent to the metal, it will not loose this resistance if scratched during installation or use.

It is a common misconception that stainless steel is stronger than regular steel. In fact, due to the low carbon content, stainless steel can not be hardened. Therefore when compared with regular steel it is slightly stronger than an un-hardened (grade 2) steel fastener but significantly weaker than hardened steel fasteners.

Stainless steel is also much less magnetic than regular steel fasteners though some grades will be slightly magnetic.

18-8 Stainless
18-8 is a specific grade of stainless steel, and is the most common grade used in fasteners. For those familiar with the 300 series of stainless steel 18-8 is similar to 304 stainless. For more specific information on 18-8 stainless steel please see our Material Grade Identification and Properties Chart.


Be aware of stainless steel bolts and nuts galling, or cold welding. Use a lubricant, otherwise nut and bolt can seize.

Regards,
Arnulf

[Kingfisher]

I used African Electroplating at the time , Tel 011 474 8767.
Don't know if they still operate but the service was good , otherwise talk to the bolts & nuts suppliers , they can usually put you onto someone.
Arnulf pretty much summed up the stainless steel issue , if it was a good idea I think the
aviation industry would have used it long ago.
Make sure the nuts are also 8.8.
The bolts can be cross drilled for safety pins as well before
plating. The engineering guys should be able to help with this.
Cap screws (allan key heads) could also be used as are seen on many propellers and Windlass.

[Le Pou]

Thanks Arnulf and Kingfisher, that has certainly cleared up some misconceptions on my part.
Regards,
Le Pou

[Tracer]

Thanks for all the input guyd, great.

One last question though, which is more brittle? 8.8, 10.9, 12.9 or stainless steel? So what I'm wondering is, which will actually snap-off, and have limited stretch capabilities?

[Kingfisher]

The bolts with the harder temper are less able to stretch than the softer temper.
If you stay with the 8.8 you should be safe. I also heard of cap screws popping their heads
off but have no info as to the actual size , application & torque used when this happened.
Some are made with a square shoulder where the cap meets the shaft , some are rounded a bit.
The rounded ones are the ones you want to use if you decide to go that way.
8.8 & 12.9 bolts and cap screws are used extensively on car suspensions etc. , proof that they are more than strong enough for our average use.
What sets the AN bolts apart is the multitude of special shapes and sizes it comes in.

[Tracer]

Thanks Kingfisher. You confrimed some of the info I had and cleared up some contradicting info I had.