Sharp Rivet Heads

[mike newall]

Just started our 2 12's.

Having issues with some sharp finished heads when pulling with an ATS pneumatic puller.

Have no issues when using the Cleaveland offset adapterator, so wondering about making a better mandrel for the puller.

Any thoughts ?

[Gandalf]

What do you mean by "sharp finished heads?" Is the steel mandrel not breaking properly or is there a round mark on the rivet head. Most rivet pullers come with a set of nose pieces and if you do not use the correct size, it makes a round mark on the rivet head. I also spray WD40 through the nose of my rivet gun.

[madmaveric]

Check you have the right head in it puller (has it been swapped over by mistake), the rivet mandrel should be a snug fit in the gun.
If the inside diameter is too large when the rivet is pulled you can get part of the rivet pulled up between the mandrel and and the gun.

Telltale sign is a lip round the hole in the rivet where the mandrel pulls out.

I get this sometimes when I use the angle wedges on tight rivets as the hole is slightly larger than needed to go over the rivet mandrel.

Normally there should be no sharpness to the rivet at all.

The other option is a broken mandrel, is the mandrel breaking off proud of the surface and that is what you feel. This can be down to air pressure being used so you can try changing it to see if that helps.

Just noticed you say it is the second RV, could it just be worn out after the first one (the rivets are soft but the mandrel is steel so could have worn the head a bit).

It took me so long to reply I got beaten to it while writing the post lol.

[mike newall]

You are right - think it is the wrong size mandrel.

I have now tried drilling a smaller mandrel out to .070 which seems to be the correct size for the rivet.

Will polish the front of the mandrel as well.

No steel coming through, just a bit of distorted head causing the sharpness.

Not second 12 - we are building 2 together......

First time with pulled rivets.

[bobnoffs]

i couldn't find a mandrel that was snug enough so i took one to a welder and he added material so i could redrill from gun side and mandrel would end up with a snug hole. then ground and polished face of mandrel. a lot of messing around but i've got 12000 good looking Rivet heads, better than what i would had with my stock mandrels.

[RFSchaller]

I pulled some 1/8" rivets with a 3/16" nose piece that extruded the rivet head into the nose piece of the pneumatic puller. Quite a pain to drill them out and replace.

[Alex Edwards]

I don't know what you pneumatic rivet gun is like but mine cam with instruction on how to adjust it internally When I first used it, thing were ok but after a short time it didn't do a good job and was jamming a little. A few of the rivets the mandrel broke off and was sticking up. I adjusted it according to the instructions and it now works perfectly....