finesse and a stupid move

Got into the shop for a couple of hours on Friday afternoon.  Busy week working around the house and cabin now that the nice weather is here.

First order of business was to finish making the new wing root rib for the 701 wing repair.  When I last left the shop, I'd prepared the aluminum rib cutout by placing it into the wood forms.  Now it's time to bend!  Tools of the day...  workbench board, plastic dead-blow hammer and fluting pliers.

Ron has made many wing ribs over the years and has developed some great ideas to make the work easier.  One of his ideas is a wooden two-by-four with a channel cut down the middle.  This workbench board is screwed to the tabletop and gives a great surface to bend against from many angles.

Next tools needed are a plastic headed deadblow hammer and fluting pliers.  The hammer is plastic coated to avoid damaging/scratching the aluminum and the deadblow properties (non bounce) prevent leaving tooling marks.

Fluting pliers are used to slightly crimp the rib edges to take up the extra aluminum that bunches up when corners are bent.  Pliers can be bought at a tool supply shop, but Ron prefers to make his own from re-purposed tools.

So lets bend!

Forming aluminum around a form takes equal parts of patience, gentle hammering and finesse.  Starting at one end I used the deadblow hammer to start bending the rib flanges over, a little at a time all the way along and back again. 

As the flange starts to conform to the curve of the form, fluting pliers are used to "take up" the extra aluminum in strategic locations.  This is more of a do as you go type of thing, adding a little crimp here and there.  The fluting pliers are just the thing:

Gentle pressure... making sure the crimps face the correct way...

Like with the deadblow hammer, a little bit at a time as you go along is best. This picture also shows the modified jaws of the fluting pliers.

One nice thing about the Zenair plans is that they take some of the guesswork out of deciding where to place the crimps.  It still takes some experimenting to decide how much is required for each bend.

See the waviness in the rib flange? Careful adjustment of crimps helps straighten things up.

Once all the flanges are bent, the rib is removed from the forms.

Looks great....  until I laid it on the flat table!  That's not right.... hmm...

The cause?  Crimping depth wasn't enough.  Flipping the rib so the web side is face down and the flanges face up allows one to adjust the crimps slightly, completely flattening out the rib.  Perfect!

This was great to practice with and a big step to getting the 701 wing repair complete.  I'll have a ton of ribs and other formed parts to bend for my 750.

The next thing I managed to do was finish rivet the fuel bay rib cap repair.  Real happy with how good the repair looks:

In the closing moments of the afternoon, I started drilling apart the damaged slat ribs and brackets.  I wanted to get these done as they are the next repair up after the main wing.

The title of today's blog entry refers to finesse and a stupid move.  I've covered the finesse part with the wing root rib creation.  But no day is complete without a stupid move....

While drilling out the rivets on the damaged slat ribs, my smart brain apparently took a coffee break without the rest of my brain knowing.  Holding onto one the slat ribs in my left hand and drilling with my right I managed to remove the rivets fairly easily.  However, one of the rivets required more pressure on the drill.  Well...  too much pressure and yup...  through the rivet, through the rib and into the palm of my hand.

Ouch!  I immediately thought "oh-oh" but considering how much it hurt, there wasn't much needed to stop the bleeding.  Two days later, after much consideration about a weekend trip to wait in the understaffed ER, my hand is finally starting to feel better and I'm getting the flexibility back in my index finger.  Hopefully no permanent damage. No pictures either, too hard to hold the tablet camera and take the photo with only one hand!

Who knew building could be so much fun!