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Europa #435 G-RODO Build Journal - 2022 06

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4 Mark inner face of starboard door for centre of door lock mod access hole, 60mm up and 102mm in from aft bottom corner, and lightly centre-pop. Drill 2.1mm. Using that pilot hole, make access hole with 40mm holesaw. Check the drawing on the SM10297 mod document for the dimensions of the aluminium sheet reinforcement. Based on the dimensions, the drawing is 80% full size; scaling up the sizes on the drawing gives 40mm x 44mm for the aluminium piece. Mark out and hacksaw to size 2 pieces off the 19" rack front panel offcut of aluminium previously identified for this purpose. Clean up edges and check that they will slide into the access hole. Using 3 pieces of wood in the bench vise, put a slight bend in one piece. Check against outside surface of door and the bend is far too much. Hammer it flatter in stages on the vise anvil with the hide mallet, checking until satisfied with the curve. Slight twist also needed; do that with the pipe pliers and adjust it until the part lies evenly on the outside face of the door opposite the access hole. Abrade the outer face of this piece with emery cloth to remove all the paint. 3618.4
13 Abrade the area inside the starboard door frame for the door lock reinforcement plate. Degrease that area and the mating face of the aluminium plate with acetone. Mix 5g + 2g Redux (Araldite 420). Add a small amount of flox to thicken it slightly and make it less inclined to drip. Apply to both bonding surfaces. Offer up the plate through the hole in the door frame and place in position. Clamp in place with a SpeedClamp and leave to cure.

In the composites offcuts box, find the piece cut out of the fuselage floor for the tunnel, which should be good for making the cover plates.		 3619.4
14 Redux sample cured hard. Remove clamp from starboard door frame.

Tidy up under fuselage and roll it out onto the drive for access to the port side. Mark port door for lock access hole, centre pop and pilot drill 3/32". Open to 40mm with holesaw. Smooth off edges of hole with emery cloth. Clean off the paint from one side of the remaining piece of aluminium plate and abrade thoroughly. Try it for fit against the outside of the door - seems fine without any bending as the starboard one needed, sits well with no rocking. Abrade bonding area inside door frame, degrease that area and the aluminium plate. Mix 5g + 2g Redux (Araldite 420) and add a small amount of flox to thicken it to non-drip state. Apply Redux to both binding surfaces. Slide plate through access hole and place in position inside door frame. Clamp in place with SpeedClamp and leave to cure (in the sunshine!).

Remove handle cover plate on starboard door. Temporarily assemble the aft shoot bolt to the inner handle with a 10-32 screw and hold inner handle in place on the square of the outer handle. Hold the assembly in the closed position and mark on the shoot-bolt actuating rod the edges of the access hole with a pink felt-tip pen. Hold in open position and mark again with green felt-tip pen. Remove shoot-bolt and handles.

Pause for a while to let the Redux cure.

An hour or two later, the Redux sample in the mixing cup has cured quite hard. The Redux squished out around the aluminium plate is still a bit tacky, but it looks safe to remove the clamp at least temporarily. As for the starboard side, assemble the handles and shoot-bolt and mark on the actuating rod the extent of the access hole in both closed and open positions. Remove handles and shoot-bolt (latter is quite stiff to extract, not sure why). Re-clamp aluminium plate.

Tidy up tools and roll fuselage back into garage.		 3621.6
16 Check measurements on SM10297 Mod drawing. Lock barrel centre to roll pin centre is 16mm; radius of outer part of hook is 27mm, but these are at 80% full-size, so true distances are 20mm & 33.75mm. Thus true radius of inside of hook will be 20 - (3/2) = 18.5mm. The hooks are shown as about the same thickness as the original lock lever (2mm x 12mm). The spacers will need to total 5.5mm thickness to place the hooks 7.5mm apart (thickness of reduced area on pushrod). Check diameter of aft shoot-bolt actuating rod - about 10.2mm. Also check that it will be possible to position it on the mill table and clamp in the vise with 1 or possibly 2 VEE-blocks for support. The bolt end needs to be towards the wall; there is not enough room for it the other way around.
17 Spend some time trying to draw up the hooked lock plate for SM10297. Scaling it from the drawing in the mod document doesn't work as things don't line up properly.

[Notice in passing while checking the geometry, that the design could have been even more robust against forcing by making the locked position of the original tang parallel to the pushrod, instead of at about 32 degrees. That would mean zero rotational force on the lock barrel if the handle is tried. Of course that would have required a more bulky hook and might not have fitted into the available space.]

Eventually manage to create a drawing that honours the actual dimensions of the lock tang, pushrod, etc and also looks very like the sketch in the document. Dimension it and print out; now all I have to do is to find some 2mm steel plate and make 4 off hooks.

I think I have enough firm data now to determine the position and length of the flats to be milled on the pushrods. Yes, I could file the flats, but milling will give a much better result (dimension accurate, faces truly parallel and flat) without any danger of stress-riser scratches.
18 Compare the drawings and the felt-tip pen marks on the shoot-bolt pushrods and mark in blue felt-tip the required extent of the flats.

Set up the starboard pushrod in the milling vise, ensuring that the tang and slot at the ends are vertical, with card softening on the jaws and VEE-blocks for support at each side of the vise. Fit 16mm end mill and mill flats on each side of the pushrod, about 45mm long and 1.3mm deep, to produce a flat section 7.5mm thick. Repeat operation on port pushrod.

Find an offcut of 2mm steel plate about 40mm x 200mm which will be plenty for making 4-off hook plates.

Duplicate the hook plate drawing in CADintosh onto layer 2 and remove surplus construction lines and dimensions etc. Duplicate 3 times and print as template to stick onto the steel stock for the 4 required hook plates. Try it on the piece of steel plate, but the templates are too far apart and will cause a lot of waste. Edit the drawing to close up the spacing and re-print. Spray the plate with 3M PhotoMount and wait for it to part-dry, then stick the row of templates onto it.

Remove the SpeedClamp from the port door.		 3624.1
20 Hacksaw off the 4 pieces of 2mm steel plate with the hook plate templates. 3624.2
21 Hacksaw off a bit more waste from one workpiece then file down the top edge of each hook plate to the marked line. Hold the stack of plates in the milling vise within card softeners, supported on the filed edge by wavy parallels with a thin flat interposed to keep them all level. Mill the opposite edge down to the marked line with the 16mm end mill. Transfer the resulting parallel-sided stack to the drill vise, template face up, held on the now parallel edges with card softeners and supported by a sacrificial wooden strip. Ensure ends of workpieces are aligned before final tightening of vise. Centre-pop the 3 marked holes. Pilot drill 5/64" then open to 3mm. Tap 3mm x 12mm roll pins into the 2 screw holes to preserve alignment. Hacksaw off the forward lower corner (as seen in locked position) of the stack. Mount at an angle in the milling vise and mill down to the template line for the forward lower edge. Hacksaw off the forward upper corner of the stack. 3625.1
22 Set up the workpiece stack at an angle in the milling vise and mill down to the marked line for the forward upper edge. 3625.3
23 Rough out with the hacksaw the hook shape at the upper aft end on the workpiece stack. 3625.4
24 Set up the workpiece stack in the milling vise at an angle such that the upper straight part of the hook recess is horizontal. Mill down to the line on the template and across to touch the tip of the curved part of the hook, exposing part of the 3mm hole for the locking pin location.

Remove the stack from the mill and file the curved part down to blend with the hole. File off the sharp corners and smooth all over with the ScotchBrite wheel. Drive the roll pins out with a pin punch, separate the 4 hooks and remove the remains of the paper templates on each. Deburr the holes and file off the sharp edges.

Find from stock 4 off M3 x 16mm CSK screws and nuts to match. Countersink the hook plates, taking care to get them correctly handed.

Remove the tangs from the lock barrels. Find that one tang can be used as a parallel against the bottom edge of the hook plate for scribing the required angle cut on the other tang. Clamp (with some difficulty) the 3 pieces together in 2 different combinations and scribe lines.

Hacksaw off the angled end of the starboard tang where marked and smooth down to the line with a file. Clamp the other tang to the starboard inboard hook plate, aligned with the bottom edge, to act as a locator. Position the cut tang against it and scribe through the hole in the hook plate onto the tang. Centre-pop in those marked circles. Drill 2mm and open to 3mm. Deburr holes. Temporarily assemble the hook plate and tang to check the potential location for the roll pin in the pushrod - looks OK.

Repeat tang cutting, marking and drilling on port set of parts. Roll pin location on port pushrod looks fine too.

Temporarily assemble hook plates and tangs to keep all parts together until ready to check what thickness of spacers will be needed.		 3628.8
25 Try the GoPro on the roof mount to check fit and field of view. Must have a built-in gravity sensor as the preview is right way up even though the camera is upside-down. All looks fine. Take some pictures to confirm how well the instruments are resolved.

Assemble the starboard inner hook plate to the tang with a scrap piece of 2mm plate interposed, to get the tang near the crest of the pushrod curve. Part-assemble the starboard door handle and pushrod. Holding door open above my head, hold handle in closed position and place the hook plate against pushrod face with tang against upper surface of pushrod. Mark through the square hole in the tang onto the reinforcing plate on the door skin with a long felt-tip. Centre-pop on that mark and pilot drill.

Note that the flats on the lock barrel are 0.5" and the threads are 0.575" OD.		 3629.8
27 Enlarge the hole in the starboard door frame for the lock barrel to 10mm in 1mm steps, then to 12mm with step drill (should have used that from the outset). Insert pushrod and temporarily fit to handle. With handle in closed position, place hook plate in position and mark against edges of lock tang onto inside of door for alignment of lock barrel oval hole. Start the oval shape with square file. On the outside of the door, place the toothed washer to align with the straight edges and mark the rest of the hole outline with a fine felt-tip. File out to that line with a round file. Try the lock barrel and keep filing in small increments until the barrel just fits. Place the toothed washer onto the barrel and secure it with the nut. Tighten onto the barrel so as to make witness marks from the teeth on the aluminium reinforcing plate. 3630.7
28 Use an 18mm box spanner to tighten the nut on the starboard lock barrel and ensure the points on the washer make witness marks on the aluminium reinforcing plate. Undo the assembly and centre-pop the 4 witness marks. Pilot drill those spots and then widen in stages with a snail countersink to achieve a reasonable fit for the points of the washer. Abrade around the hole in the aluminium plate with the powerfile (accidentally nicking the edge of the hole in the door inner skin in the process). Abrade washer. Mix a batch of Evo-Stik 2-hour Control epoxy and apply to both bonding surfaces. Grease the lock barrel and nut. Position washer against the oval hole in the outer skin and reinforcement. Insert lock barrel and fit nut. Tighten firmly with tube spanner, wipe off surplus epoxy and leave to cure. 3631.7
29 Undo the nut on the lock barrel and try to remove the lock barrel. It won't shift, even when encouraged by tapping on a 16mm box spanner used as a drift against the loosened nut. I guess that even if the epoxy has not bonded to the barrel because of the grease, it has been able to weep into the hollows of the thread and thus lock it in place. So, it can stay there - I guess there is no need to remove it. Re-tighten nut.

Check that the 3mm x 12mm roll pin will pass through the shoot-bolt bush - no problem.

Insert starboard aft pushrod and temporarily connect to handle. Remove circlip from lock barrel to allow offering up tang with attached hook plate. Try it, but a much bigger spacer will be needed. With depth stem on vernier caliper, measure from face of lock to inboard face of milled area on pushrod - 10.7mm.

Remove the inboard hook plate and fit the outboard one to the tang, without spacing. Try for fit; looks as though it might just be OK.

Sketch the arrangement in CADintosh. Inboard spacer should be 8.7mm thick. For the outboard hook plate, it needs to be on the inboard face of the tang but only 1.2mm thick. I guess it could be milled thinner on the mating area. More practical tests needed, including fitting the tang to the barrel without any hook plates, to check how it aligns with the milled part of the pushrod.		 3632.4
30 Remove inboard hook-plate from lock tang. With some difficulty and after several false starts, fit the tang to the lock barrel, retained by the circlip, in the open position. Turn the key to the locked position and it seems the tang actually goes very slightly down behind the pushrod. Measured with the vernier caliper, from the inboard face of the pushrod milled area to the inboard face of the tang is 9mm. That means there is 1.5mm clearance between the inboard face of the tang and the outboard face of the pushrod milled area. So, the outboard hook plate could be fitted to the inboard face of the tang if its outboard face were milled down by 0.5mm to make it 1.5mm thick where it abuts the tang. 3632.8
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