minimum thickness between holes in aluminum plate

[ebegt]

Is there a guideline for the minimum distance between holes bored into a given thickness of aluminum plate?

We have a 1/16" thick plate that is ~7" diameter round of aluminum that requires 12 holes. It was suggested:

12X diameter 1.350"+- .005" thru, equally spaced at 30 degrees apart located on a diameter 5.400" BC.

So the hole centers are located radially from the center of the plate, but at these dimensions, the thickness between the holes is quite small. I want to stagger the holes, but was wondering if there is a rule for wall thickness between holes in this situation.

Thanks.

 

[ctopher]

There are specs for what you need depending on the product. I don't remember the spec no's.
But usually you can't miss making the mtl between the holes the same as the radius of the holes.
Maybe others here know what those specs are.

Chris
Sr. Mechanical Designer, CAD
SolidWorks 05 SP1.1 / PDMWorks 05
ctopher's home site

 

[Dennyd]

ebegt,

A lot of the answer depends on what you need and how you plan to achieve the holes. From my aircraft days we used an edge distance of 1.5t (t=material thickness) between the edge of a hole and the edge of the part (or in this case another hole of appreciable size). This was for pullout reasons. Other reasons for edge distance would be the method of manufacture. Edge distance requirements for punching would be different from drilling and laser cutting.

In order to give you a meaningful answer you'll need to tell us a bit more about the application (loads, life expectancy, environment, what's in the holes, etc.) and the method of manufacture. It sounds like you have a bit of decision lattitude still since you mention staggering. How fixed or flexible is your design?

- - -Dennyd

 

[arto]

Try the Industrial Perforators Handbook:

http://www.iperf.org/perfhand.htm

 

[IFRs]

The Aluminum Association has a design handbook that covers hole spacing, both in the direction of the load and perpendicular to the load. Try

http://www.aluminum.org/Template.cf...e=/Ecommerce/ProductDisplay.cfm&Productid=563

 

[vonlueke]

ebegt: Try thread725-35803.

 

[diamondjim]

I think 1.5D is the generally minimum
distance between holes where D is the
diameter of the bolt or hole. The
other consideration would be to check
out the wrench od to make certain you
have the clearance for a wrench and
the bolt head with washer. This assumes
materials are similar.

 

[Tofflemire]

Hi Ebegt

Are you putting nuts, washers and bolts in these holes or is this plate a location device for D-cell batteries?

You hardware will overlap in the current configuration.

Tofflemire

 

[ebegt]

Thanks everyone. More detail: this is a center plate used to orient cells (close in size to d-cells). We will use epoxy to keep the batteries in place. We do have flexibility in design/manufacture. We're planning on machining out thru holes.

ebegt

 

[Cockroach]

There is no rule. You need to understand the circumstances to loading, then push the pencil a little to calculate stresses. In your case, you need to worry more about stress concentrations between holes on the bolting pattern. Obviously your stresses need to be below material yield, typically a design would call out for a reasonable factor of safety that would address concerns on variance of material properties, ultimate acceptable load and worst case scenario(s).

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada