|
Riveting Tips
To post your comments please scroll to the bottom of this article
Riveting is an essential building block of aircraft assembly. This is a very time consuming process, as there are thousands of rivets to squeeze and buck. Here are a few preparation steps to follow to make your flush riveting work a little less tedious.
The first step of riveting, is to prepare your work pieces. Mark out where you are going to be riveting on your framework, as well as on your sheet metal. An easy way of doing this is to use a rivet fan spacing tool. This tool maps out and spaces the rivets easily and with great accuracy.
After marking where you will be riveting, drill out the holes using the bit size specified for your rivet. When drilling the sheet metal, a good rule of thumb is to drill through the sheet metal into a block of wood to keep the metal from bending, or creasing. Now you are ready to countersink.
When dimpling, you must countersink into the frame to keep the skin of your aircraft aerodynamic. The easiest way to countersink that I have found, is to use an adjustable stop countersink cage and a 100 degree pilot cutter. Thread the pilot cutter into the countersink cage and adjust it to barely cut into the frame. This leaves you with a countersunk hole, which the dimple will fit into later when riveting your sheet metal onto the framework. You must experiment to get your adjustments correct on your countersink cage, so I would suggest you practice on a few pieces of scrap material first. Also, make sure that when you drill your holes, that you de burr them. Otherwise the rivet will not seat correctly when it is set into the hole.
At this stage, your surface has been properly prepared to use your dimple dies. Actually, you can dimple at any time during this process you just cannot attach the sheet metal to the frame before countersinking the framework. This is because the dimple will actually fit directly into the countersunk hole, causing the sheet metal to naturally lock into place. In this way, it helps to make the skin more durable and less likely to peel back under extreme conditions.
There are two different types of dimple dies that you can use. There are regular type dimple dies, and spring back dimple dies. The difference between the two dies is the design of the face. The spring back die is more precise as its face compensates for the deflection of the sheet metal. This will give you an exact 100 degree dimple. The regular type die does not compensate for this deflection, which leaves you with a less precise, less than 100 degree dimple. This is very important if the aircraft is to be aerodynamic.
To use a dimple die, simply insert them into any .187 shank rivet squeezer, making sure to align the punch/male die in through the hole that was just drilled. Pull the handles together, being careful to leave a little space between the dies when you clamp down. If you do clamp down all the way, your dimple will be too large. This will cause the rivet to sit too low in the dimpled hole, possibly causing the sheet to deform. This may keep the sheet metal from sitting completely flat. The rivet should sit slightly above the skin, so that when you actually buck the rivet, it pulls the sheet down, while pulling the frame up, leaving the rivet flush.
At this point you are ready to insert your rivet and either squeeze, or buck it to install it. Make sure that your rivet does in fact sit above the sheet about one to two thousands of an inch. This compensates for the indentation you just formed with the dimple dies, along with the countersunk hole.
Pre SpecialSpecial made
Got any comments or better Tips reply to this article! Click on the link above.
|
Reply to this Article