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Tooling Up By John Siebold - firstname.lastname@example.org
Tool acquisition involves many and costly decisions at the outset of your first RV project. It is even a bigger deal than the other right-out-of-the-gate decision: to prime or not to prime (Go away! No primer wars today.) If you have bucks, order best quality everything that your heart desires, but keep in mind that some required tools won't be disclosed until the need arises, some common tools can be improved, and useless tools can befuddle.
Tool selection for first time builders raises profuse questions and, for most of us unsubsidized mortals, focuses on value, in consonance with Van's RV philosophy. Much time can be consumed evaluating and thinking ahead as far as inexperience allows. Still, critical, must-have-but-obscure tools can be overlooked until the need is apparent, perhaps stymieing progress while Fed-Ex empties your wallet. There are expensive tools, their value dependent on the eye of the beholder. When pros and cons of less obvious natures exist, a neophyte may not discern the differences.
I am riveting the wings on my RV-7, nonetheless I have tool observations that can help a newcomer through the maze, and save some bucks and time. Plus, I posit tool use Hints for encounters of the perplexing kind. Keep in mind that the RV-7, 8, and 9 are highly prefabricated with matched hole technology. This alone reduces tool variety and eliminates the need for forming machinery.
Tool Choices Are Affected by Not-So-Obvious Reasons
Van's web site has a "Required Tools" list, and Section 3 of the builder's manual discusses tools at length. The lists are comprehensive and do not compel you to mortgage the house, but with experience I discovered a few omissions and gained insight that, if known at the outset, would have saved some consternation and/or money. Many vendors offer "RV Builder Kits" that fulfill Van's lists, but you may wonder if you really need some of those other tools. Finally, armstrong tools and elbow grease can displace power tools for the same task, but take far longer, like deburring. In such instances, what value is your time?
Study tool supplier's catalogs. You will realize that they largely all sell the same thing for varying prices and to-your-door shipping policies and costs. Often, catalog order numbers thinly mask the tool manufacturer's part number and you can identify the same tool by similar number in other catalogs. Compare pictures and descriptions. Frequently they match, lifted directly from the manufacturer's literature! There are some in-house fabricated versions of the same tool, e.g., spring-back dimple dies. Shop price is my recommendation, especially if specifications are the same. I've found Aircraft Tool Supply to be least cost to the door for most tools unavailable at local big-box stores. Worthy proprietary tools I will mention by name. Van's estimates a complete set of (required) tools will be $1000 to $1500. I make it more like $1800 to $2000.
My View of the Absolute Truth
1. A pneumatic squeezer isn't worth its high price.
A pneumatic squeezer seemed like a great tendon-saving device, but I have abandoned mine. It isn't needed, and it has its own problems. Almost the first assembly is riveting the HS609's to HS603's using a lot of 470AD4's (1/8" rivet). At this point your muscles are not used to riveting with a manual squeezer, so the pneumatic seems a godsend. (I only buck when I can't reach a rivet with a squeezer.) But your strength will increase as with any repetitive exercise. The pneumatic is heavy and clunky. Just holding it in position is tiring. Because of its lumpy shape, there is no good sight line to aid in keeping the sets perpendicular to the rivet, a must-do for proper shop heads. Finally, the closure gap must be meticulously adjusted for each rivet size/length before production work; it's too easy to over squeeze because you can't stop in mid-stroke. I instead recommend…
2. The Avery Squeezer (or other similar) is mandatory and among the most-used tools.
Avery's squeezer, with its adjustable set holder, quickly interchanges between riveting and dimpling with easy closure adjustment. A salient feature is that the static handle is exactly in line with the sets' axis, making a wonderful visual reference for assuring perpendicularity to the rivet before, and during, squeezing. Avery's squeezer accepts standard yokes, but this has not proven a benefit as I've managed so far with just a 3-inch yoke, rather than buy a variety of expensive yokes. I do not like riveters that allow the yoke to rotate; it's another degree of freedom to control, and handle-to-workpiece interference has been too rare to justify hassling this largely unused feature.
Any squeezer's use is limited to just those rivets that the yoke can reach. A rivet gun and bucking bars is mandatory.
3. A C-frame Tool (basically an arbor punch), Avery being prominent, is a necessity.
This tool conveniently dimples holes unreachable with the squeezer that is limited by its yoke throat depth (three inches is common), but sometimes surrounding material gets in the way of squeezer access, also. There are thousands (billions and billions it seems!) of dimples. (I wonder if some builder has or will become fed up with dimpling and Cessna-ize their ship with universal heads?). I don't use the C-frame for riveting because whacking rivets with a hammer is too subjective and variable force application. Don't even think of substituting "pop rivet" dimple dies for the C-frame Tool.
4. "Pop rivet" dimple dies are necessary.
Utterly impractical for anything but occasional close-quarters dimpling, like rib tails (see Hints), they afford access where nothing else will. The mandrel is a soft nail that is gouged by the puller, and so requires frequent redressing. These dies can be used in lieu of a C-frame tool, provided you will live to be older than Methuselah with the patience of a saint. Very, very, slow.
5. A blind "pop" riveter is necessary, and you must modify it.
Buy a style with the smallest diameter cylindrical "nose" possible. Examine it for a modification that cuts a flat on the side of the nose so that the axis of the puller is 3/8" or less from the flat. You need this clearance for riveting on the tank support angles and the flap reinforcement angle (there may be more applications I still don't know about). This mod should not weaken the puller so much that it can't be used extensively, nor risk having it break in the midst of closing the tank. Van's has more to say on this modification in the fuel tank instructions.
6. A great variety of bucking bars is not necessary, but you often seem to need one you don't have!
Any flat-faced, smooth steel blob two pounds or more will do when you can easily observe its placement and have uninhibited access. Problems arise when reaching into enclosed volumes and around flanges. There, the virtue of flat facets is most appreciated for judging placement of the bucking surface perpendicular to the rivet axis. My complaint with cast commercial offerings that I have seen is that they have large radii on supposedly flat surfaces, making their corners difficult to use, and it's the corners that frequently are the only part of a facet that can reach certain rivets. The oft-cursed aft rivets in ribs are impossible to set without a finely tapered bar that can squeeze in between the target rivet and one just above that you previously set. Then, the bar's c.g. should be as in-line with the rivet axis as you can achieve while keeping the bucking surface normal to the rivet axis. This all adds up to a good shop head, and reduces the propensity of longer rivet tails to heal over. Some personal favorites are Aircraft Tool Supply's AT750P, 148, and 142, plus a 1 x 1 1/4 x 6" hunk of steel that I polished.
Don't sweat the Rivet Police hauling you off if you use blind rivets rather than struggle trying to buck solids in confined locations. Only the most fastidious builder would care. It's your airplane and your time.
7. Few rivet set sizes are needed, but many lengths are convenient.
So far, I've used flat squeezer sets in 1/8, 1/4, 3/8, and 1/2-inch lengths, and 1/8-inch universal cupped sets in the same length combinations. Maybe I'll someday find a use for the 3/32-inch cupped sets that I bought.
Gun sets needed to my point in construction are few: 3-inch long, 1/8 universal straight; a 7 1/2-inch long, 1/8 universal, 10-degree offset; a swivel flush set, and …
8. A purpose-made back rivet set is just about a necessity.
The sliding sleeve lets you maintain the set's position with your fingers while the gun is firing. The sleeve is spring loaded to help clamp the work pieces together. This tool requires modification, see Hints.
9. Buy extra-long drill bits.
Have on hand 6" and 12" long bits in #30 and #40 sizes, and 3/32" and 1/8" sizes for drilling out tough-to-reach botched rivets. "Tough-to-reach" is a self-fulfilling prophecy for botching rivets.
10. Buy two 100-degree #40 countersink bits for microstop use.
Countersinking the main spars' flanges for the K1000-8 nut plates per Van's recommended technique abuses the bit's pilot. Mine broke unexpectedly weeks later. UPS was enriched unduly because this bit sees frequent usage.
11. Buy Cleaveland Aircraft Tool's tank dimple dies.
Sam Buchanan investigated the outcome between regular dimple dies and tank dimple dies with tank sealer under the rivet head. The regular dies resulted in proud rivets; the tank dies yielded flush rivets. I concur. Elsewhere, dimpling substructure with these dies and top skins with standard dies improves nesting of the dimples.
12. Buy a bench grinder and six-inch Scotch-Brite wheels, plus a die grinder and mandrel for small wheels. With these, I have not wanted a belt sander.
You will want both. A die grinder is hard to control, and the little wheels wear quickly. Inside lightening holes and skin edges is where it shines. The bench wheels really speed up deburring thick or stiff parts, but not thin skins. See Hints.
13. I've no desire for these possibles mentioned here and there. Not that they aren't useful and nice. My time's cheap compared to what time they might save me for their price.
· An angle drill attachment. Thank goodness, as they tend to be spendy.
· Drill stops (I wrap tape around the bit when necessary).
· Right and left snips - straight, yes.
· Rivet spacing fan (use your brain and a ruler) when the kit's pre-punched.
· Plate nut drill fixtures (use a plate nut for a guide as need is rare).
· Bandsaw (don't let fabbing the HS610 and 614 deceive you that it's needed).
14. So far, I needed a few items that weren't emphasized or on Van's lists:
· A #10 screw dimple die set for the holes attaching control surface counterweights.
· A # 6 screw dimple die for wing access covers.
· #27, #19, and #12 drill bits (these are for screw-sized clearance holes).
· A 37-degree tubing flaring tool. There is a Parker-Hannifin tool sold by most vendors for about $70. Aircraft Tool Supply sold it cheapest.
· A tubing bender. There's a swell $20 unit. The spring things are good for free-form bends.
Some tools need modification. Others can find application beyond their intended use with some kinky ideas.
1. The back rivet set (from ATS, but I believe common among all suppliers) must be modified to function correctly. The problem is that the set's face is convex, so it will immediately slide off the rivet tail until restrained by the sleeve. You cannot hold it in place with your fingers - trust me! Rivet tails are formed canted and healed over. The simple fix is to disassemble the unit and polish the set face flat.
2. Microstop countersink holders do not need the silly nylon foot. It likes to break off, chips embed in it, and it's tough on the fingers. Pull it off and polish the cage end. There won't even be a buff mark if you stop cage rotation with your fingers.
3. "Pop" rivet dimple dies can be made more useful by fabricating a short mandrel with length equal to the two dies closed together. It serves to guide the two dies together from either side of the work piece as the dies are squeezed together with vice grips.
The outside of one vise grip jaw should be cut back so that it better can reach into confined areas (rib tails, again). Van's instructions illustrate this and other ideas for dimpling in close quarters.
4. The leading edge cradle suggested in Van's instructions is a tool that you fabricate. I recommend altering dimensions to keep the bottom of the rib-contour cutout at least five inches above the table top. Also, if you notch the rectangular panels to receive the 2 x 4, rather than set them on top of the 2 x 4 as the drawing depicts, the jig will not be tippy. With these mods, you will have superior access and stability for clecoing and riveting.
Kinky Tool Uses
1. To squeeze 3/32 flush rivets in really tight quarters (rib tails), try removing the anvil set and place the small flat area around its hole in the yoke on the rivet tail. Put on your best spectacles for this operation, but I've made it work instead of firing up the gun to buck two rivets. You can create more clearance by cutting back the outside tip of the yoke.
2. Sheet edge polishing is easy with this trick. Using some scrap sheet, wear a shallow groove in the face of a 2" Scotch-Brite wheel turned in a die grinder. Skin sheet metal edges will stay in this groove as you move the wheel along the sheet edge, smoothing the face while simultaneously breaking and rounding the edge. Trying to use the flat wheel face across an edge requires much greater attention to position and often induces chatter, and it's slower progress. You can increase edge radius by first drawing a v-notch deburring tool along it. This will help prolong the life of the wheel.
3. When back-riveting control surface stiffeners, you can't easily get the gun directly above the aft-most rivet. Consider using the next larger angled cupped set to buck tails. Try a 10-degree offset, 7 1/2-inch, 1/8 universal cupped set. The concave cup self-centers on the tail and won't have a tendency to walk off, and the offset length positions the gun away from bad interference with the opposite skin surface. The shop head is convex, of course, which isn't pretty, but still fits the min/max height specification of MIL-R-47196.