Flush Riveting

Are you using flush head rivets?

Flush head rivets is pretty much the only thing to go with.

The thickness of the three sheets together is a little over 1/8". I don't think you can really can countersink the material because the top sheet at least, won't have enough material left for the rivet to grab on too.

I've seen sheet metal work in a body shop where they drill the hole, make a dimple (dent) deep enough, around the hole, so the rivet head does not sit proud of the surface. The tool they used was a simple 'C' clamp with the pivoting foot removed, leaving the round part on the clamp. The stationary part of the clamp had a divot ground into it for the metal to form into. Hope this helps!

may-be with a counter bore or end mill drill down thru 1.2 m sheet half way and then drill 1/8 th or 3/16 ext

Howard huise did this to one off his air plains but not sure of spefics ?

I like the dimpleing methed if u can no lose of material good luck with this

If you are only doing a few fasteners in your shop, rather than a production setup, there are 120 degree flush countersunk pop-rivets available. Make sure the countersink is the right angle. Most CSK's are 118 degres and metric are 90 degrees. You need the shallow 120 degree. Most computer electronic enclosure have gone to rivets for joining 1 mm thick sheet metal and in some cases rivets are not used at all, but a rolled form using an extruded hole is the current method (see pictures) .

Guest, (how about registering so we know which "guest" you may be? its' painless and you don't have to worry about spam and junk with CR4.) you don't say what the riveted assembly is going to be used for but if it sees any kind of stress or movement at all I wouldn't waste my time with pop rivets. they are going to fail in a very short time. Counter sinking by cutting isn't practicle in the sheet thicknesses you stated. Coin dimpling is the way to go. Dimple dies are fairly cheap but you have to use the correct die for the rivet you using. So decide on the size of rivet first. Since you are riveting steel I would avoid aluminum rivets so you don't set up a condition for dissimilar metal corrosion and see the heads of your rivets pop off. Steel rivets are available but hard to set. I would probably go with a Monel rivet, they are harder to set than aluminum but won't corrode. Is this a one time project or small production run or what? Some hand tools can make this go easier but if it is a one time or Home project it can be accomplished with a piece of flat steel plate and a hammer and punch if you can access both sides of the assembly. If only one side can be accessed there are blind fasteners that if you are using a small enough diameter can be set with a hand puller. Google Cherry Max Rivets.

Hi,

Your Solution (if one side can potrude).

Place your sheets on top of another, clamp (steel clamp) or otherwise hold in place very rigidly. Drill your hole size through all (keeping it no larger than 1/8" will help). The counter sunk height portion of a pop rivit is in relation to its body size, and you want to keep the drill diameter low.

After your sheets are clamped and supported such that you can push on the assembly you are ready for counter sinking, use a good three fluted counter sink with a steep positive rake angle and countersink angle to match the rivet head sinkangle. The positive rake will assure the metal cuts rather than deforming. Use a lot of pressure (arm pressure if using hand held tools) and perhaps 150 RPM air tool maybe an option. Once you counter sunk through all, rivet. If you need to be flush on both sides then use a smaller diameter, special rivet and counter sink both sides.

Mirco

Limits beyond imagination.

Use Aviation rivets they are 100 degree countersunk. If your top sheet is too thin to countersink again there is an Aviation sheetmetal dimple tool that will work great. You can get all you need through any Aviation supply company. And use they do come in "pop Rivets" (Cherrymax rivets)

Have you considered "Grub Screws" http://www.modelfixings.co.uk/stainless_grub_screws.htm

or maybe spot welding?

http://en.wikipedia.org/wiki/Spot_welding

http://www.efunda.com/processes/metal_processing/welding.cfm

You need to use a solid rivet. Countersink the metal side that needs to be flush (standard rivets are 100 degree) 100 degree and the diameter about .2mm to .3mm larger than the flat head of the rivet to be sure it sits flush when installed. Make sure you have a solid steel backing on the head of the rivet when you buck the other side over.