Firewall Dimpling

On page 27-2, the plans call for using a female dimple die and a rivet (step 2) to dimple one of the holes. Using the shortest rivet I have, the rivet expanded, and I had to do some surgically precise drilling to remove the rivet without ruining the die.

Step 6 calls for dimpling with a modified dimple die set, or, once again, a rivet and a female die.

Not wanting to again risk ruining my dimple die, in what manner do the dimple dies need to be modified? What?s the purpose of dimpling like this? Is there another alternative?

Thanks.

I used a piece of square steel tube that was properly countersunk. It will accept any length rivet up to an about inch and has the feel of a bucking bar in hand - though much lighter.

The rivet method worked fine for me. Just make sure it is a short rivet that won't bottom out in the female die. It will also help to taper down the diameter of the shank.

C-Frame

I can't remember exactly what the issue is here or what I did, but if you have the cleaveland C-Frame, the bottom metal piece that holds the dimple die can be removed and used in your rivet gun. This might allow you to use the male dimple die instead of a rivet. ... Again, I can't remember exactly about these particular steps but I've used this method in many places successfully.

The purpose is that a normal dimple die won't fit in a hole so close to a flange. You can modify a die (or buy one already modified) that has a side machined off so it will fit. You may also need a short extension so your tool will also clear the flange. Another alternative is to not dimple and use an AN470 rivet instead - not as pretty, maybe, but these locations are not easy to view anyway. I don't recall having any difficulty dimpling the firewall with a modified die from Avery.

flion said:

The purpose is that a normal dimple die won't fit in a hole so close to a flange. You can modify a die (or buy one already modified) that has a side machined off so it will fit. You may also need a short extension so your tool will also clear the flange. Another alternative is to not dimple and use an AN470 rivet instead - not as pretty, maybe, but these locations are not easy to view anyway. I don't recall having any difficulty dimpling the firewall with a modified die from Avery.

Click to expand...

I did the same, by the time I completed my build, I had several dies that I had to modify by grinding down the side a bit to get them to fit in close quarters.

You have to choose which problem you want to manage. As long as you don't remove the dimple part of the die, it doesn't really effect long term usage of the die.