Fry Jig Instructions

I bought a used Fry jig for my RV-3B fuselage. This one is nominally an RV-4 jig so I'll need to tweak it a bit to work for this plane. I'll document the jig itself here, and things particularly pertinent to my RV-3B in that blog there.

Here are the instructions for the use of the Fry Jig for an RV-4. Please remember that I'm building an RV-3 so I'll be tweaking the jig to suit. Thanks to David Howe for the instructions.

Here is the catalog for the Fry Jig product line.

The jig folds and is slightly under 8' long when folded. My pickup truck as a topper and I can fit the jig in folded and on its side. Here it is in the truck right after I got it home:



I slid it out of the truck put one end on the ground. With it half on the truck, I could rotate it upright. Incidentally, this was the reverse of loading it- I'd put it half on the tailgate, rotate it sideways and slide it into the truck. Here it is halfway out:



The feet have wheels and also threaded adjustable feet so that when it's opened up and leveled, it'll be straight and won't wander all over the shop. Now it's inside the shop.



There are a number of smaller pieces that came with it.



and



Have to say that the shop was much more convenient with the jig folded. Now it's open:



Missing from the photos is the wooden spar center piece, a nicely-made spacer for the spar bulkhead. Since it's the wrong size for the RV-3B, I left it back in the hangar.

The photos are also hosted
here,
here,
here,
here,
and here.

Dave

Leveling the jig took an hour. The instructions say to adjust the leveling posts so that you start with the wheels about 3/4" above the ground. That worked out to about 3 1/8" to the bottom of the jig's feet, a handy dimension since the aft-most two feet have no castors to set their height to. The jig is stiff enough that most adjustments affect more than one area.

The adjustment posts have locking nuts and 1/4" adjustment holes so that I could easily use a screwdriver to turn the posts. The locking nuts take a 1 1/8" wrench, I think it was.

Dave

The aft bulkhead support post on the jig is low enough that it clears the tailspring for the RV-4 and even the smaller RV-3.



The yellow cross-bars that are the longeron references have a top surface that's 2 1/8 inches above the jig frame. But the aft centerline block's top is only 2.00 inches. So I taped a piece of 1/8" scrap for the string to start from.

The yellow cross-bars have 1/4-20 threaded inserts for the longeron clamps. These are positioned for an RV-4. For my RV-3, I've simply drilled holes where I need them and used sheet-metal screws. In the photo, there's a green circle on one of these RV-4 clamp locations so you can see what to look for. I've moved the cross-bars around so that these inserts, which protrude slightly, don't interfere with the RV-3 I'm building.

Incidentally, I didn't use the centerline block in the front. Instead, I located the center of the firewall and made a #40 tooling hole there and stretched the string from that point.

Dave