Taigh Ramey wrote:
Hey Rich,
Do you have any special tricks for Dzus removal?
We have always just cut them off but I would prefer to remove the collars and keep the studs intact. Barring this I will cut the studs with stainless steel protection plates for the cowl panels.
We have so many to do I really need to tool up for a proper production run. I was thinking about making a custom mill to fit over the stud and cut the collar.
How did you do it on your big 1000 Dzus job?
Thanks,
Taigh
That was over 3 different A/C, 2 P-38s and a Mustang plus a bunch on other warbirds. I also put Electroless Nickel Plated dzus's in Big Beautiful Doll after the soft chrome was flaking on the ones put in when it was restored.
I had set up a big C Frame rivet squeezer with some tooling to do the collars on the cowls on the 38. Set the collars by hand and I always have pushed on the head of the Dzus carefully with a hard plastic/teflon set that just fits the dia of the dzus whether done by the squeezer or by hammer to install the dzus The instructions show the outer skin and head on a plate with impact on the inner side collar. I found that tends to spread out the energy making you hit harder and often mars the skin around the dzus. I also neck the tools down at an angle. They typically have a large OD with a large flat area with a countersink type cut in the middle for the collar side. That large flat area doesn't work on curved skin and you only need to have contact on the collar to set it.
Does the PV-2 have alum or SS collars? If SS it makes it a bit more of a pain. IIRC the P-38 was mostly SS on the orig installation.
For removal of the FA6 1/2 I have a 4 flute 11/16 od Hole saw cutter on a mandrel. The pilot is removed and the ID is maybe +1/16 larger than the body of the dzus. I use a battery powered drill but an air motor will work as long as you got real good control of the speed. High speed all the way isn't what your looking for. I will push down straight some and then angle the cutter slightly and walk the angle around 360 degrees watching and seeing if an area needs more and then not touching an area that is real thin.
If you break through tilt away to the thicker area. If you get the whole thing thin or part through and thin a tap with a hammer will usually knock the old dzus out. If the dzus is decent you can cut the remainder of the collar with dykes and have them cad plated and baked.
Otherwise the hack and cut the collar and/or dzus will be the order of the day.
I'll see if I can get a pic or two.