HOLE LOCATOR TOOL By JOHN AMMETER EAA 286081 3233 NE 95th St. Seattle, WA 98115

'. The RV-6 canopy has a 1/2" tubing across the front of the frame with an aluminum sheet riveted to it. The problem I saw was how to locate the hole in the aluminum sheet so that it was exactly on the top of the tubing; if the hole was slightly off to one side or the other the hole would not align on the tubing properly. At first I thought of measuring very carefully but knowing the possibility of error, after all, there are several holes to be drilled, I determined that the best course was to make a guide for the drill bit. With a few scraps of aluminum I found around the shop, I fabricated up this device - it is not critical that you make your guide of the same exact material but you should be sure that whatever you use is not likely to scratch the soft aluminum skin. Round and smooth all the corners. Also, the space is labeled as .040 stock, it can be whatever you find necessary in your particular situation. After making this device and using it on the canopy, I found that it can also be used wherever you have two skins to be riveted together and the distance from an edge is critical. I have used it to locate holes in the front spar of the new right elevator I am making for my RV-6. It would be possible to make it adjustable or maybe you could make one with several holes in it for different edge margins. In use, you carefully slide the device over the aluminum skin until the lower bar contacts the tube (or lower skin). The hole in the top bar locates the hole for the rivet. This hole should be as small as practical; I aluminum sheet

*^

\

i/8" pop rivet

P /

used a 1/16" drill. The resulting hole is a pilot hole for the rivet hole. How To Rivet In Tight Places Several of the flush rivets near the trailing edge of the control surfaces are very difficult to set - there is not room to use either a rivet gun and bucking bar or the conventional rivet squeezer. Some

strik* with hammer at this point

\ bar of 1/2 x 1/2 x 6 stetl

Rivet Set Tool Elevator Tip Detail

builders have taken a vise grip pliers and ground the jaws flat to use as a rivet squeezer. This is entirely adequate but, with the price of even the inexpensive import pliers nearing $5 or $6, there has to be a cheaper way. Even on the RV-6, which is almost all aluminum, there are less than 50 (out of 12,000) rivets that are located in such tight quarters. Since most of the control surfaces will have been back-riveted, it is likely that you will have a large heavy flat piece of steel around the shop some place (if your shop is as organized as mine, take a few days off and find it; it is sure to be somewhere logical, like under the scrap aluminum pile). bolt together \ 1/8"X3/4"AL \ "\

1/16"

L^———————rr ^\ .040 AL

1/2" tubing

Canopy Bow Tubing

Put the flat steel plate on the bench and carefully place the control surface (with the rivet in place in the hole) on it; you will probably have to block up the far end so it will sit flat on the plate. Now take the square bar and carefully put the formed end on the working end of the rivet. The other end of the bar will sit on the flat plate. At this point you have just realized that you are about to use a hammer in close prox-

\

3/8" X 3/4" AL

Hole Locator

|| 25

imity to the piece of aluminum you have just spent 2 weeks building. This is not the time for shaky hands; if you value your airplane parts as much as I do there is a very simple way to shield the control surface from harm. Either place your extra hand (whichever is not holding the hammer) on the control surface to act as a cushion in case you happen to come too close to the aluminum (this is guaranteed to increase your anxiety and make you even more shaky) or place a large piece of wood over the aluminum. Personally, I prefer the use of wood over flesh; so does my wife and dog, less sound effects when I slip. Now, very carefully strike one blow with the hammer on the bar near the aluminum. If all went as planned you now have a perfectly formed working head on the rivet. This is a very simple solution to a very vexing problem. I want to credit this idea to Mike Adams of Vancouver, WA. He and his friend, Russ Parr, who are both interested in RV's, stopped by my shop recently and, seeing that I was building a new elevator for mine, mentioned this method of riveting. Thanks to both of you, my rivets turned out perfectly. (Continued on next page) SPORT AVIATION 79

EPOXY CLOSET TEMPERATURE CONTROL By Steven Willhoite EAA 359601

2916CalleDerecha Santa Fe, NM 87505 One of the first construction projects I undertook before starting my Cozy Mark IV composite airplane was to build an insulated closet for my epoxy ratio pump. Ideally, the epoxy and pump should be maintained at a constant 90 degrees F. temperature for the proper viscosity. I put a 60 watt light bulb inside the closet attached to a light dimmer for adjustment, but soon found out that I was constantly making minute adjustments to the dimmer control to maintain the desired temperature. My next stop was at Radio Shack where I picked up one of their digital temperature control modules for $20 (P/N 273-123). The digital temperature control module is powered by a single AA battery and has a large LCD display which displays the current temperature at the connected probe with a 0.18 degree F. resolution. With three normally open pushbutton switches you can display and set a minimum temperature which the module will regulate via a control line to an external circuit. For the external control circuit I used a 12 Vdc power supply (P/N 2731652), 12 Vdc relay (P/N 275-248) a 2N222 transistor and a 1K ohm resis-

Epoxy Closet Temperature controller Module

- 90.OF

tor as depicted in the schematic diagram. Mount the loose parts on a small pre-drilled circuit board and then mount the circuit board and the temperature control module in a small box which can be attached to the top of the epoxy closet. Mount the temperature sensor probe inside the closet at about the same height as the bottom of the epoxy reservoirs and the light bulb to the top of the closet to keep it out of the way. Use wire nuts inside the temperature control enclosure to

join all the 115 Vac wiring. I have been operating my closet for over a year now and the temperature inside the closet never varies by more than 2 degrees F. (unless I leave the door open) despite the fact that the temperature in my garage varies by 40 degrees F. on some days. Due to the 0.75 inch Celotex insulation on all sides of the closet, the 60 watt bulb is on only a small portion of the time, making the closet very economical to operate.

Readers are invited to submit entries to EAA, Hints For Homebuilders, Art: Golda Cox, EAA Aviation Center, P.O. Box 3086, Oshkosh, Wl 54903-3086. Entries will be reviewed by a panel of EAA judges. Readers whose hints are published in any EAA magazine will be awarded one of three monthly prizes by Snap-on Tools - a 3/8" Drive Socket Wrench Set, a 1/4" Drive Socket Wrench Set or a Nine-piece Long-Handle Combination Wrench Set. Members are also invited to submit hints of an electrical nature. Any hint used will receive a Fluke Model 23-2

Multimeter with Holster from the John Fluke Mfg. Co., Inc. The contest will run from August through July of each year with a Grand Prize of a Snap-on Tools KR657 Roll Cab and KR637 Top Chest

being awarded the best entry for the year. A Grand Prize will also be awarded by the John Fluke Mfg.

Co. These awards will be presented during the EAA Convention. Our thanks go to Snap-on Tools

and John Fluke Mfg. Co. for providing these awards. 80 APRIL 1992

(RS 277-123)