MK-319-BS rivets and 7/64" holes

Hi, all... am I the only one having problems getting the MK-319-BS rivets into 7/64" holes? Everything I've read says drill to 7/64", but it looks like I'll need to use a #34 or maybe even #33. I've tried multiple 7/64" bits with the same results. Am I missing something?

Thanks...

-Rob

#33

Jekyll

#33 should do it....

RV10Rob said:

Hi, all... am I the only one having problems getting the MK-319-BS rivets into 7/64" holes? Everything I've read says drill to 7/64", but it looks like I'll need to use a #34 or maybe even #33. I've tried multiple 7/64" bits with the same results. Am I missing something?

Thanks...

-Rob

Click to expand...

A copy of the rivet specs are here...

http://rapidrivet.thomasnet.com/ite...pop-rivets/open-end-rivets/mk-319-bs?&seo=110

The rivet size is a nominal 7/64, but the recommended hole size is given as 0.113 to 0.117

This puts the #33 at the lower end at 0.113 and a #32 near the upper end at 0.116.

Since the holes are usually hand drilled for these rivets, and are a little larger than the drill size... the #33 fits right in with the specifications.... If it's tight, then use the #32.

For reference, a 7/64 drill is 0.1094... giving a hole a few thousands tight as you found out....
The folks using their 7/64 drills are probably drilling sloppy holes.

gil A- reading those specs. again...

ADDED

This web site looks better for specifications, including hole drill sizes, for commercial pop rivets.

http://www.hansonrivet.com/w18.htm

Instructions call for a #33.

Thanks, all... that's what I figured--the spec for the rivet is bigger than the hole, and my micrometer told the same story. I was just confused since *every* place I've looked says 7/64" (including the -10 plans where I'm working now).

-Rob

Looks like the process for MK-319-BS holes is drill/ream #40, dimple, then drill/ream #33. For the RV-10, step 3 on page 22-8 says to final drill those holes using a #33 (this is after drilling/reaming with #40 and dimpling on page 22-5).

I see that the MK-319-BS rivets are also used on the elevators and ailerons, but there is no instruction to final drill those holes using a #33 for the elevators, and for the ailerons, a #34 is specified (page 21-08 step 2).

To the OP

If you don't have them, buy a set of drill bit gauges.

Non-aerospace grade pull rivet tolerances seem to be a bit loose. When similar issues with any fasteners pop-up in the future (and they will), drop the butt end of it into the drill gauge. You can drop down one size to account for the tolerance of a shop drilled hole. It may/may not be your ultimate bit size choice but least you'll have a starting point.

I had success with #34 reamer after drilling #40 - nice snug fit. #33 is also fine. Reamer makes hole a little cleaner than a drill (and rounder).