The most common problem with pneumatic riveting tools is low level or contaminated hydraulic oil.
If the stroke of the gun is short or it is taking two pulls where previously the rivet could be set with a single action it is likely that your tool needs priming.
Most pneumatic rivet tools have a cap screw located on top of the tool for priming.
It is important to prime your tool properly, this is just a guide, you should consult the manual or take the tool to a competent repairer if you are at all unsure.
Rivet tools are quite simple. Compressed air pushes a large diameter piston in the base of the tool upwards, a smaller diameter oil piston mounted centrally on the air piston runs up inside the handle of the tool. This piston pushes hydraulic oil into the head of the tool causing the jaw casing to move backwards or stroke.
The air is vented so that the tool sets the rivet and returns to the ready position with the jaw casing in its forward position.
Take your time to oil the tool properly. With the air line disconnected the air cylinder should be at the bottom of its stroke, the jaw casing should be forward, you can check that the jaw casing is forward by removing the nose housing, whilst you have that off its a good time to clean and check the jaws.
Disconnect the air line. Remove the cap screw from the top of the gun, have a rag handy, fill the priming syringe with hydraulic oil and gently inject oil into the tool. Stop as soon as you feel resistance.
Leave the syringe in the tool, it should have some oil left in, you will probably see bubbles rising into the syringe. Now go and make a cup of tea! Drink your tea, check your email, call Dafra and place an order for some rivets.
When you return the oil in the syringe should be clear as the air has risen out of the oil in the piston. Get your cloth, remove the syringe, clean excess oil and replace the cap screw. Check that the tool is complete and safe to operate.
Don’t over oil the tool. Stop as soon as you feel resistance.
Take your time; let all the air rise out of the oil.
Happy maintenance.
