Edge distance, Please educate me....

[JoeB]

Been doing some reading on standards ect.

I understand the concept of why edge distance for rivet and bolt holes are important, but I am a bit lost on how to gauge it.

How do you determine required edge distance?
How do you measure your distance from hole to edge to ensure you have it?

Example for the slow minded builder please?


Joe B


RV-10
Tail kit
.............saving money for the rest....... lots and lots and lots of money.....

[fatherson]

Unless the plans call out a larger edge distance, the minimum edge distance from the edge of the material to the center of the rivet hole must be two times the diameter of the rivet shank. So, for example, for a rivet with a 1/8" diameter shank, we use a #30 drill to put a hole centered at least 1/4" away from the closest edges on each piece of material we are riveting together.

When checking a hole that's already been drilled, you can use a micrometer to verify that the closest side of the hole is at least 1.5 times its diameter away from the edge (since measuring to the center of the hole isn't possible, but we know the center of the hole is one radius or half the diameter away from the side of the hole). Using the same example as above, we would require the closest side of the same #30 hole to be more than 3/16" away from the nearest edge of each piece of material.

Hope that helps.

--
Stephen

[JoeB]

Yes, actually that helps
thanks

Joe

[Andy Hill]

Joe...

Having been educated, don't always be obsessive about it There are places in the kits, especially the older ones, where ED is not maintained / achieved, and the aircraft will not spontaneously self destruct as a result

An appreciation of what forces / directions will be applied, and what is structurally important (and not) will develop as you build. If in doubt, a post on here will get someone knowledgeable to advise.

[airguy]

Originally Posted by Andy Hill

Joe...

Having been educated, don't always be obsessive about it There are places in the kits, especially the older ones, where ED is not maintained / achieved, and the aircraft will not spontaneously self destruct as a result

Correct. Spontaneous self-destruction only occurs if you don't prime the surfaces.

[Mike S]

Originally Posted by airguy

Correct. Spontaneous self-destruction only occurs if you don't prime the surfaces.

But, only on a slider.....

[rv8bldr]

Originally Posted by Mike S

But, only on a slider.....

...with a nose wheel...

[sprucemoose]

Joe,

The 1.5X rule of thumb is just that, a rule of thumb. While it will get you in the ballpark, if you are going to be measuring edge distance with a micrometer, you really need to look at the Milspec and know what you are measuring against. The Milspec can be downloaded on Vans website. There are quite a few thousandths between the rule of thumb and the actual Milspec, and thousands of perfectly good rivets have been drilled out because of an incomplete understanding of this issue.

http://www.vansaircraft.com/public/Specs.htm

[airguy]

Originally Posted by rv8bldr

...with a nose wheel...

Be fair now - that only applies if you're going to use it for hard IFR flight.