Spar Riveting with Harbor Frieght Press

by Rich Klee

Using a 12 Ton Press to Squeeze Your Spar Rivets.

If you have a shop press (the Harbor Freight $99 12 ton variety is just fine) you can, with minor modifications, squeeze your rivets very consistently and relatively quickly.

Modifications to the press - both dies must be held rigidly.

The bottom die ( 3/16" factory head rivet set) is held in a steel plate with a 3/16'" hole drilled in it. This is in turn clamped to the cross-member and finally the cross-member to the press structure itself. These presses are made pretty cheaply, so the clamps will remove any rocking out of the "base".

The ram (arbor) must also be steadied a bit - there is too much lateral motion - I used a 4x4 drilled with the appropriate hole for the ram and wedged it into the frame. The ram is just a mild steel rod about .75'' dia which is jammed into the existing tube of the press (see photo). It could just be free floating in the 4x4 hole with a return spring and a collar which would be pushed by the original press arbor. The only trick here is to make the hole in the 4x4 a snug fit on this .75" rod. Drill a 3/16" hole in the end of the rod for the flat rivet set.

It will help to have a pair tables (or rollers) to act as the infeed and out tables for the spar. Make sure that all the holes where the bolts will go are marked (I put the bolts in those locations to hold the flange strips rigidly together). The shop head of the rivet should be held tightly against the base rivet set (make the infeed and outfeed) tables tiny bit lower than the press base).

Now you only have to put together enough feeler gauges to get .094" (1/2 of 3/16") and start pressing away leave the feeler gauge right by the rivet (where the shop head will form) until it starts getting tight. Check you shop head for the proper diameter just to be sure. Gripping the jacks release knob in a pair of vise-grips will speed up the job because you don't have to remove the handle all the time to release the jack. The whole operation took me about 3 hours for each spar and everyone of the rivets came out perfect.

Send mail to Rich Klee

Go back to Hovan's Home Page

Comments or feedback, please send to