Several of the pulled rivets that are used with RV aircraft and with the F1 Rocket are common to both. In particular the MK-319-BS and MSP-42 rivets. Recently I have been trying to find more information about these and have found very little. What I’ve been able to determine is the following and so far it seems to be working pretty good.
Cherry Rivets – “N” Type
Cherry N Rivets are called Break Mandrel rivets. These conform to MIL-R-24243 and IFI-114 Standards.
These rivets have some unusual features. The mandrel design is unusual (compared to other pulled rivets) as the design of the Cherry N Rivet holds the rivet and mandrel firmly together prior to installation. This insures positive mandrel retention in the installed rivet.
As the mandrel is drawn into the rivet, the end of the rivet sleeve closes in an ellipitical configuration, thus locking the mandrel firmly in place.
Cherry N Rivet Identification Code
First Letter is rivet materal:
- A = 5052 Aluminum
- B = 5056 Aluminum
- C = Stainless
- M = Monel
- S = Steel
- C = Copper
Second letter is mandrel material:
- A = 7178 Aluminum
- S = Steel
- C = Stainless
Third letter is head style:
- P = Protruding
- L = Large
- C = Flush
Note: The rivet manufacturer AVDEL has changed the mandrel design for some of their Cherry “N” Rivets. The change has not affected the strength of the rivet.
The MSP-42 is a pulled rivet made of monel, with a carbon steel mandrel. The head is universal with 1/8″ Diameter and Grip .063 – .125.
Researching this rivet there are several others that show up as alternate part numbers (interchangable). These are:
- MSP-42 (Cherry)
- 424BS (POP)
- CCC-42 (Cherry)
- SSK42SSDS (POP)
MSP-42 Installation Tips
As this rivet has a 1/8″ diameter, using a 1/8″ drill (.1250) results in a hole that is very tight. Again, you need to use a drill slightly larger to make the rivet installation a bit easier. I’m using a #30 drill bit (.1285) which seems to work well.
The MK-319-BS is a pulled rivet manufactured by Pop. This rivet is made of monel with a carbon steel mandrel and is completely zinc finished. The head is 120 Degree countersunk open end rivet with 7/64″ Diameter, Length .223, Grip .051-.090.
MK-319-BS Installation Tips
This rivet uses the #40 dimple, but requies a 7/64″ hole, however this combination results in a very tight fit. From what I’ve found on other builders websites and on the Van’s Air Force forum is that the general consensus is that a #33 (.1130) drill bit is preferred.
So the way I’ve been making this work is that I start by drilling the #40 hole, then dimple with the #40 dimple dies. Then I drill out the hole with the #33 drill bit to accept the MK-319-BS rivet.