MKB Forum

Forum Information => Questions and Queries => Topic started by: Jamieg285 on April 24, 2013, 11:51:43 am

Title: Stainless fasteners - advice required
Post by: Jamieg285 on April 24, 2013, 11:51:43 am
I know there some engineers on here that can probably answer my question.

I added some crash bars to my motorbike and had to buy some longer bolts to make them fit.  I went for stainless cap heads, but found them very soft - 1 rounded out and will need to be drilled out when the time comes.

I want to know what grade of stainless would be more suitable, something that's more comparable to steel than butter.
Title: Stainless fasteners - advice required
Post by: F Body on April 24, 2013, 12:02:27 pm
Sounds like Chinese Stainless ?

You'll be wanting something with a higher tensile strenght, not my area of expertise, but would it be 8.8 (http://www.mkb.cc/forum/smileys/chiny.gif)
Title: Stainless fasteners - advice required
Post by: Andy on April 24, 2013, 12:06:19 pm
Doesn't sound very much like stainless steel, or if it is, its a chiwanese version.

I have been this week, just making some M16 bolts for a customer from 316 (1.4404 - new grade spec), its pretty tough stuff. Its got a higher nickle content iirc which makes it a lot tougher on our tools. This also makes it far better when it comes to polishing up and surface finishes.

http://www.themontrosegroup.com/Products/MONTROSE_SOCKET_CAPSCREWS
Title: Stainless fasteners - advice required
Post by: VIPER on April 24, 2013, 12:06:56 pm
get yourself down to allfast in luton ...Great guys and very helpfull.Just got some Black SS allen bolts this morning...
Title: Stainless fasteners - advice required
Post by: Roadkill on April 24, 2013, 12:11:22 pm
Was you using A2 or A4 stainless fixings ?

Stainless is simply not as strong as an alloy bolt.

An 8.8 grade alloy fixing is comparable (but still stronger) than even a A4 stainless fixing, so if you had A2 you were way-off 8.8 alloy steel.

If you want tensile strength in stainless it HAS to be A4 to compare to 8.8, alloy.

EDIT -

Here you go - this sums it up quite nicely :

http://www.volksbolts.com/faq/basics.htm

:mrgreen:
Title: Stainless fasteners - advice required
Post by: Jamieg285 on April 24, 2013, 01:03:32 pm
I've looked up the ebay ad. They were from Falcon Workshop supplies, supposedly A2 304.

Looking at the torque guides on that link from RK, it looks like it may just be me putting too much effort into them.

I have a couple of spares left over, so maybe I'll try one of them with a torque wrench and see how they behave.  I just hope drilling it out isn't too difficult.
Title: Stainless fasteners - advice required
Post by: Roadkill on April 24, 2013, 01:18:31 pm
Quoting: Jamieg285
I just hope drilling it out isn't too difficult


Unfortunately Stainless is quite hard due to the Chromium content so you'll find them harder to drill than normal steel.

Make sure the drill is sharp and "peck" with the drill (to create small swarf chips) as opposed to just leaning on the drill - this'll likely just destroy the drill bit.   Use a lubricant when drilling stainless, too - spit works on steel but you may need something more on stainless.
Title: Stainless fasteners - advice required
Post by: art b on April 25, 2013, 07:20:55 am
Quoting: Jamieg285

I added some crash bars to my motorbike



(http://www.mkb.cc/forum/smileys/pics.gif)
Title: Stainless fasteners - advice required
Post by: EDGE on April 25, 2013, 09:06:10 am
A2 is akin to play dough :(
Title: Stainless fasteners - advice required
Post by: F Body on April 25, 2013, 11:43:37 am
Quoting: Jamieg285
Looking at the torque guides on that link from RK, it looks like it may just be me putting too much effort into them.


Just thinking about the application, it may well be that they are designed to be both not that tight or strong (http://www.mkb.cc/forum/smileys/dontknow.gif)

If they are bolted tightly to the motorcycle frame, you could bend the frame with a minor spill (http://www.mkb.cc/forum/smileys/chiny.gif)

Didn't think that they still made crash bars other than for aventure/off road bikes nowadays ?

I have the crash bungs/mushrooms on mine (http://www.mkb.cc/forum/smileys/wink.gif)

Mind you there is a much simpler and cheaper solution (http://www.mkb.cc/forum/smileys/dontknow.gif)

Make sure you don't fall off in the first place  (http://www.mkb.cc/forum/smileys/rofls.gif)
Title: Stainless fasteners - advice required
Post by: Jamieg285 on April 26, 2013, 12:49:51 pm
Quoting: F Body
Just thinking about the application, it may well be that they are designed to be both not that tight or strong  

If they are bolted tightly to the motorcycle frame, you could bend the frame with a minor spill


The bars are mounted in 3 places on each side. These particular ones are the mounting points for the footpegs.  Don't know if that has any bearing on the what's needed or not.


Quoting: F Body

Didn't think that they still made crash bars other than for aventure/off road bikes nowadays ?


Maybe, but then the bike is 13 years old!