how to use a rivet shaver

[sglynn]

Please, could those who have successfully used a rivet shaver share some info? I have the little shaver bit from Avery and I've been testing it in the countersink cage on some scrap. Seems like it works okay but have a few questions: What speed should I spin this? 3000 RPM in my drill or 10,000 RPM in hand air grinder? What techniques are there for minimizing movement of the cage? Due to speed it vibrates a bit and moves on the surface. Which countersink cage should I use? The 1/2 inch mini or the really small micro-c'sink? Will turning my c'sink at 10,000 hurt it, if it is rated for only 3,000? I put a little Boelube on it. I'm planning to shave just a small amount of some rivets on the tanks and really they are slightly tilted so it is one side of the mfg head then needs a tweak. Maybe it's not worth doing. What are the dangers and how do you screw up using a rivet shaver. Thanks for the G2.

[f1rocket]

I've built 4 airplanes now and I still can't figure out how to use the shaver bit. I tried once but it horribly messed up the skin so I put back into a dark recess of my toolbox. In my hands, that tool can do way more harm than good. I'll be interested to see what others have to say who have used it successfully.

[Rick6a]

Steve,

This question comes up from time to time and I believe part of the confusion lies in this: You did not purchase a rivet shaver from Avery. What you really purchased from Avery is a rivet shaver BIT. A rivet shaver bit is designed to be used in a dedicated rivet shaver and a rivet shaver operates between 15000 and 25000 RPM depending upon the manufacturer.

Short of investing in a real rivet shaver motor and I might add, never having attempted the technique myself, I suggest you try fitting the bit to a die grinder. In any event, read the response of Michael Brown of Brown Tool in post #8 in this recent thread: http://www.vansairforce.com/communit...ad.php?t=35075

Good luck.

[RScott]

I used a rivet shaver bit in a countersink cage with good results. What I used is shown at http://www.browntool.com/productselect.asp?ProductID=99.

Here's what I did: First I put double sticky tape over the rivet area to keep the countersink cage from walking. I set the depth to be sure I was not contacting the skin--actually I intentionally set it high. Using my air drill motor, which runs at something like 2,400 rpm, I shaved off the top of the rivet, then reset the depth, and took off a little more, working my way down. I did not try to make it exactly flush with the surrounding skin, but left it maybe .001-.002" high, maybe more. That close & being proud will never matter & so far, no one notices. Haven't painted it yet.

I have done this on probably 50 rivets--I was having problems with my squeezer & ended up with a bunch of high rivets.

[rv7charlie]

I had relatively poor luck with the shaver bit in a countersink cage, so I tried another technique.

I've got some small Harbor Freight diamond wheels that fit a 1/8" arbor for a dremel tool. I found that if the wheel is held as close to flat against the skin as the mounting nut will allow, I could drag the edge of the wheel across the rivet (wiping motion, not shaving) & get better results than I got with the shaver. The face of the wheel, not the edge, is doing the work. It just takes all the fingers on all three of your hands to control the dremel. :-) I drag, shift the wheel sideways a bit, & drag again. Technically, this does create a bit of 'dish', but if carefully done my results have been better than my best efforts with the shaver.



Charlie

[sglynn]

Thanks for your notes. So I tried and the result is very good. Here is what I did from your advice and my trial and error. First I made a bunch of practice proud rivets and tried the shaver in my countersink cage. I tried various things. The best result uses the larger c'sink cage with the nylon no-scuff foot. I use it in my die grinder which spins up to 10k, but I turned it down to about 7000 RPM (guessing). My drill at 3k is not sufficient. My practicing helped me get the bit just flush with the bottom of the cage foot using average force. Then I hold the cage with left hand with palm against the object, and slowly push in the bit turning at top speed. When it engages the rivet the cage will try to move. You'll feel it. So I just used gentle pressure and I developed a feel for when the bit is shaving the rivet and when not. Your fingers learn to distinguish minute changes in shaving. I shaved a little then let up. Sometimes I tapped the bit down a little. But eventually I could feel the bit no longer biting on the rivet, and I could gently move around the cage within 1/16 in radius. Important to keep the nylon foot flat/flush on surronding area. (Although I practiced tiling it, and it didn't damage). Result was perfectly flush rivet heads and not a scratch on the surronding metal. But, I'm doing the rivets on the main spar flange that hold the platenutes under the Tanks. So this is very firm area. And rivets were only slightly slightly proud. I haven't yet tried it on a skin. But I will because a few tank rivets are tilted and proud. I'll post photos soon on www.mykitlog.com/sglynn. Bottomline is if you bought the shaver bit from Avery, it can be used successfully. I think the key is run it fast in a die grinder, put oil on your c'sink cage, and PRACTICE PRACTICE PRACTICE first to develop your technque and learn the 'feel'.

[Rick6a]

Originally Posted by sglynn

......I'm doing the rivets on the main spar flange that hold the platenutes under the Tanks.......

Steve,

I'm glad it worked out. A properly shaved rivet has a very smooth, pleasing and professional look to it. No doubt other builders will benefit from your trial and error experience and try using the bit in a die grinder.

I note you are doing the rivets on the main spar flange that hold the nutplate rivets. For virtually ALL nutplate attach rivets on RV's, I highly recommend you use NAS1097AD3 rivets. I do not call them "oops" rivets, as that is a mere marketing device used by Van's to describe the use of NAS1097AD4 rivets in oversize #40 dimpled rivet holes. Lumping them into one basket and calling them "oops" rivets tends to make the first time builder think that is the primary use. WRONG. The NAS1097AD3 is routinely used in the aircraft industry to install nutplates and you can too. For our purposes, the most commonly used length is 3.5. Pick up a bunch, you won't be sorry.

http://www.wicksaircraft.com/catalog...145/index.html

[JHines]

Rick,

To clarify, is the idea that the thicker shank will have increased bearing surface to resist shear better?

I would imagine this is the primary load on the nutplate attachment rivets when the screw is installed/removed, and that the possibly reduced tensile load capability (as compared to an AD426 rivet) is not of concern.

[Rick6a]

Originally Posted by JHines

Rick,

To clarify, is the idea that the thicker shank will have increased bearing surface to resist shear better?.....

Yes, the more bearing surface the better. A significant advantage using an NAS1097 is the rivet allows you to machine countersink thinner material than .032 and not produce a "knife edge" which by definition is no bearing surface at all. It is impossible to machine countersink sheet less than .032 to accept the head of an AN426AD3 rivet. Van's would have you use 426 rivets for nutplate attachment in thin sheet...Duckworks also comes to mind....and that is less than optimum from a quality standpoint. I'm told by an employee of Van's they routinely use NAS1097 rivets to attach nutplates in company built airplanes but why the rivets are not included in hardware bags or even called out for use has never been adequately explained.

[Andrew M]

on a piece of flat stock that is primed. Dial it down to where it just touches the paint then back it off 3 or 4 clicks. Spray some rattle can paint on the rivets you want to shave, run the tool full speed before you drop it in and go for it. Deepen the cut until you just start to touch the surrounding paint. This is for a rivet shaver with out riggers. I've done alot of this work cutting down shop heads that fill a 78 deg. factory countersink. I haven't figured out a way to control the micro stop countersink cage. Good luck!

Andrew

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