Rule of thumb of placing a center of a bolt hole from the edge of steel
Rule of thumb of placing a center of a bolt hole from the edge of steel
(OP)
I had drilled a bolt hole of 8mm diameter into a solid steel that was so close to the edge (around 2mm to the edge) of the steel. After sometime, the steel had fractured across the bolt hole. Does anyone know a rule of thumb of placing a center of a bolt hole from the edge of steel? Is there any reference standard or specification?
I have done some research online and some of the articles stated the rule of thumb would be placing the center of the hole 1.5*Diameter from the edge? Does anyone know if there is any reference for this rule from any metal handbook or standard?
Many thanks.
I have done some research online and some of the articles stated the rule of thumb would be placing the center of the hole 1.5*Diameter from the edge? Does anyone know if there is any reference for this rule from any metal handbook or standard?
Many thanks.





RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
Ted
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
distance from edge rule of thumb 1.5 times bolt diameter.
“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
A quick google shows that it apparently is based off of: http://www.boltcouncil.org/files/2004RCSCSpecifica...
However, it depends on your context. I can tell you that these numbers do not hold true in tooling design and machinery. They have much different considerations and "norms" that allow for ignoring those numbers found in the RSCS Spec.
The structural connections are likely based upon the assumption that one is using A36/A500 type steels, for one. Plus, you're unlikely to see anything thinner than 1/2" thk being used in any ply. Additionally, there are much different load considerations. Different grades and types of bolts, and I would guess the structural steel erectors are more likely to properly, fully torque a bolted connection than any typical machine/mechanical application, unless specifically controlled.
I expect you won't find much help with a "rule of thumb" unless you are working to a particular industry standard, company standard, or design manual. In the tooling/fixturing world, most major companies have design manuals/standards that will specify PREFERRED fastener spacing, or MINIMUMS, and almost always include exceptions are allowed as needed, if justifiable.
Plus, as an educated designer/engineer, you should be able to evaluate the special cases to decide if they are adequate or if they will fail so quickly.
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
But, in any load bearing case, I always analyze the tear out strength of the material when I'm that close to the edge.
--Scott
www.aerornd.com
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
drawings, pictures, intended use, etc, etc, etc
It may be your design was fine, but the bolt(s) were not tightened adequately.
Or, something else altogether
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
It's also situational. If the bolt is loaded in bearing, 1.5 x hole diameter is the absolute MINIMUM I would accept. Depending on loading I might still be uncomfortable at that number.
If the assembly load is taken up by shear force between the faces of the two parts or in tension parallel to the bolt axis (as in a flange connection) then distance from the edge matters less, in my opinion. You'll see a LOT of flanges in various applications where hole distance from the flange OD is less than 1.5D.
As with everything else... the rule of thumb only applies in the right situations.
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
They can mostly save young/inexperienced people from completely boggling up simple stuff, though, and the young/inexperienced likely aren't being charged with very critical responsibilities yet, anyways. Otherwise, I'm sure we all develop our own 'habits' or 'idiosyncrasies' when applying typical placement. To write out calculations for allowable edge distance for common situations would be a waste of time. Rules of thumb, when intelligently applied, save time, money, and allow for more focus on more important things.
I find edge-distance of fasteners to be one of the most fundamental basics, though, personally.
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
To get back on topic... a star for J.
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
- For tear-out area (A), use twice the product of the total link thickness and the dimension from the edge of the hole to the outside of the part.
- For bearing area (A), use product of the bolt diameter (I prefer 75%) and the link thickness.
If both of these check out in less than the diameter of the bolt, use the bolt diameter as the distance of the edge of the hole to the edge of the link. See Norton, Machine Design.I used to count sand. Now I don't count at all.
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
The 1.5 x dia are a standardized design criteria to achieve a maximum transmissible bearing stress for a given fastener. If this is not the guiding value, one could go down to 1.2 x dia.
But nevertheless: There's no design w/o specific analysis
Roland Heilmann
Lpz FRG
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel
thread725-267581: Welding between a thick plate & a thin plate
This is discussion of lifting lugs, but the David T. Ricker reference discusses the thickness of flanges next to screws. To heck with rules of thumb.
R.I.P. unclesyd
--
JHG
RE: Rule of thumb of placing a center of a bolt hole from the edge of steel