Building Ronja 10M 130mm Tubular Optical Head

We are going a tubular head consisting of hollow tin tube, two tin caps (the front one with embedded lens and heating resistors) and a tin hood attached to the tube by bolts.

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3D model

Slide covers, bolts and nuts are not in place in this model.

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3D cutaway model

Slide covers, bolts and nuts are not in place in this model.

Cutting pipes

Cut (115mm+focus) long piece from the 145mm smoke pipe using a hand saw.

Postscript / PDF / EPS / BIG png / DXF (qcad)

Slide cover template

If you have accurate printer, print out 2 of these 16 templates and glue on a piece of tin for slide covers.

Postscript / PDF / EPS / BIG png / DXF (qcad)

Making slide covers

Cut and drill two slide covers

Postscript / PDF / EPS / BIG png / DXF (qcad)

Hood template

If you have accurate printer, print this template, cut out and glue on the hood tin (it must have precise dimension of the shorter side already).

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Hood model

Postscript / PDF / EPS / BIG png / DXF (qcad)

Making the hood

Cut and drill the hood.

Bend the tin into

this shape (ignore the paint and bolts).

Postscript / PDF / EPS / BIG png / DXF (qcad)

Heel template

If you have accurate printer, print out this template and glue it on the steel 25x25x2 U section and 20x4 flat steel bar.
The template is from two pieces because it doesn't fit A4 paper.

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Heel model

Postscript / PDF / EPS / BIG png / DXF (qcad)

Making the heel and it's flange

Drill out the steel sections for the heel and heel flange

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Pipe model

Mark the wider end of the pipe as front and the narrower one as back.

In the next, we will describe coordinates on a cylinder - by angle and length from one edge. The angle is measured in grads, 400 grads form complete circle.

Postscript / PDF / EPS / BIG png / DXF (qcad)

Grad gauges 450-458mm circumf.

If you have accurate printer and the pipe end has diameter from this set, print out this gauge, cut the gauge for the pipe diameter, remember that grad is a unit of angle where full circle is 400 grads, and skip to "Drilling out the pipe", where you use the grad gauge to mark angles around the pipe.

Postscript / PDF / EPS / BIG png / DXF (qcad)

Grad gauges 459-467mm circumf.

Postscript / PDF / EPS / BIG png / DXF (qcad)

Rulers

If you have accurate printer, print out these pipe marking rulers.

Making angle marks with a sheet of paper

Preparing marking paper sheet

Use a sheet of paper wrapped around to measure the angle. Wrap the paper around and make a circumference mark where the edge is. Then put the paper on desk and divide the circumference by 400 using a calculator and make marks at 25, 75, 125, 175, 225, 250, 275, 325, and 375 times this distance. Mark them 25grad, 75grad, 125grad, 175grad, 225grad, 250grad, 275grad, 325grad, and 375grad. Wrap the paper around the pipe again, the seam of the paper on the seam of the tube, and copy the marks from the paper onto the tube as necessary.

Drilling out the pipe

Angle	Axial Offset	Hole diameter	Purpose of the hole
75grad	11mm from front	4.3mm	Holds front cap
175grad	11mm from front	4.3mm	Holds front cap
275grad	11mm from front	4.3mm	Holds front cap
375grad	11mm from front	4.3mm	Holds front cap
75grad	11mm from back	self-cutting screw predrill diameter	Holds rear cap
175grad	11mm from back	self-cutting screw predrill diameter	Holds rear cap
275grad	11mm from back	self-cutting screw predrill diameter	Holds rear cap
375grad	11mm from back	self-cutting screw predrill diameter	Holds rear cap
125grad	(focus-20mm) from front	4.1mm	Slide path
325grad	(focus-20mm) from front	4.1mm	Slide path
125grad,	focus from front	4.1mm	Slide path
325grad	focus from front	4.1mm	Slide path
125grad	(20mm+focus) from front	4.1mm	Slide path
325grad	(20mm+focus) from front	4.1mm	Slide path
125grad	(31mm+focus) from front	4.1mm	Slide path
325grad	(31mm+focus) from front	4.1mm	Slide path
125grad	(51mm+focus) from front	4.1mm	Slide path
325grad	(51mm+focus) from front	4.1mm	Slide path
125grad,	(71mm+focus) from front	4.1mm	Slide path
325grad	(71mm+focus) from front	4.1mm	Slide path
25grad	65mm from front	7.0mm	heel
25grad	135mm from front	7.0mm	heel
25grad	205mm from front	7.0mm	heel
25grad	275mm from front	7.0mm	heel
25grad	345mm from front	7.0mm	heel
225grad	40mm from front	4.3mm	hood
225grad	80mm from front	4.3mm	hood

Filing out focus slide paths

Connect holes in each group of three holes marked for future sliding path together to form a sliding path for the screws. Use a tiny file or fret-saw to accomplish this. You can also horizontally vice an iron bar or pipe, and chisel the paths out against it.

2 caps

We are going to manufacture two caps: front and rear.

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Front cap model

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Rear cap model

Drilling out front cap rim

Take one cap and mark it as front.
Insert it into the front of the pipe, cap seam at 200 grad. If it won't go, cut V-shaped slits into the rim at 25, 125, 225, 325 grad.
Drill through one 4.3mm hole with 4.3mm bit. Insert some M4 bolt and drill the hole on the opposite side. Do the remaining three holes and always insert a bolt.
Mark which side of the front cap is down (at the heel) with a permanent marker. Remove the bolts and the front cap.

Drilling out rear cap rim

Take the other cap and mark it as rear.
Insert it into the rear of the pipe so that cap seam is at 200 grad. If it won't go, cut V-shaped slits into the rim at 25grad, 125grad, 225grad, 325grad.
Drill through one self-cutting screw predrill hole and insert some pin or nail to keep it in place. Do the remaining three holes, inserting a pin or nail every time.
Mark a bottom mark on the cap at the heel holes.
Remove the pins/nails and the rear cap.
Drill through the four holes at the rear of the pipe with self-cutting screw through-hole diameter.

Postscript / PDF / EPS / BIG png / DXF (qcad)

Cutting out front cap: option 1 (template)

If you have a calibrated printer, shear out this template. Glue the template inside the cap, with regard to center. Put a block of wood horizontally into a vice and the cap over it and hew out the appropriate circle using cold chisel and hammer. Use hammer again on the wooden block to repair face of the cut.

The round piece that falls out is called thermal shield.

Cutting out front cap: option 2 (hand)

Take the front cap. Make a mark in the center of the outer side using the hard stylus and hammer. Measure exactly the lens diameter with slide gauge. Set pair of compasses to (lens diameter/2)-1.5mm. Draw a circle. Make the circle more visible by redrawing it using the marker pen. Put a block of wood vertically into a vice and the cap over it, the rim down. Use cold chisel and hammer to chisel out the curve. Then the round piece will fall out. Collect it, it will be the so called thermal shield. Use the hammer to repair the face of the cut on the wooden block.

Cutting out front cap: option 3 (mechanized)

Take the front caps and mark the inside center of them with a marker. Take a nail and with a slight strike mark the center with it (you may even drill there a 2-3mm hole). Set the pair of compasses to (lens diameter/2)-1.5mm and draw a circle. Mount a jig saw on the underside of a wooden board, so the blade would come out of the top of it. Take the cap and drill 3 to 5 holes (depending on your blade dimension) on the circumference of drawn circle. Put the cap on the board so the blade would poke through drilled holes. Adjust the position of the cap, so its marked center would be ortogonal to the natural path of the jig saw on the beginning of the blade. Now take a nail and hammer it through the center of cap deep into the wooden board. Nip off the nail header, so you can remove the cutting (future thermal shield) easily. Turn the saw on and pivot the cap. When the hole for the lense is complete, clean the impurities with a hand file.

Postscript / PDF / EPS / BIG png / DXF (qcad)

Rear Cap Template

If you have accurate printer, print out this template:

If your terminal pitch is 9.96mm or 11.53mm instead of 10.11, use these templates.
You will need only one from the 2 presented
Glue it on the inside of rear cap, with regard to the center
Drill out and skip the next box ("Finishing rear cap drilling")

Finishing rear cap drilling

Place a 8-terminal wire nut on outer surface of the rear cap in position shown shown in the drawing. Drill a 3.1mm hole between terminals 1 and 2, insert an M3 bolt, drill a 3.1mm hole between terminals 7 and 8, insert a bolt, and do another two holes between terminals 2 and 3 and terminals 4 and 5. Drill one 8.5mm hole above the wire nut and four 10.5mm under the wire nut.

Postscript / PDF / EPS / BIG png / DXF (qcad)

Thermal shield drilling

Drill out the thermal shield according to the drawing or template possibly glued on the shield.

Postscript / PDF / EPS / BIG png / DXF (qcad)

Silicagel boxes

Print out these 4 templates, cut out and glue on 92x67mm boxes lids (leave lids on boxes)
Punch all unmarked holes with an awl and drill out the 4.3mm holes

Parts to be washed

Pipes
Caps (front, rear)
Heel, heel flange
Thermal shield
Slide covers
Hoods
Lenses

Cleaning

Fill a bucket with hot water and add detergent, for dosage see the bottle label
Throw all pieces with templates into the bucket and let the templates soak off.
Use emery paper to remove noncohesive rust from pieces where templates weren't used.
Wash parts to be washed plus parts already in water in the bucket using a brush or sponge to get rid of all grease
Place everything wet on a rag and dry with hairdrier while turning around.
Now remove noncohesive rust from pieces where templates were used.

Placing the sealant

Place a fair amount of the sealant inside front cap into the corner but not on the edge on which the lens will sit.

Sealing in the lens

Put the lens into the place from inside the cap and shape and finish the sealant in many gentle circular motions with your little finger so that it becomes smooth and flawless. Take a great care not to smudge the lens. If you have smudged the lens and decreased clear aperture, wait until the sealant partly solidifies and then remove it mechanically and clean the remaining haze with a rag and acetone. Removing the hardened selalant is not easy and must be done using a razor blade, without scratching the lens.

Sealing rear cap grommets

Put cable grommets into the holes in rear caps: 6mm grommets into 8mm holes and 8mm grommets into 10mm holes. Seal them all against the cap from both sides with the sillicone sealant.

Warning

If you don't seal the optical head properly, water will probably get inside. The link may stop working and the electronics may be irreparably destroyed. See a video.

Installing heating on front cap with lens

Wait until the sealant solidifies on front cap. Cut four small pieces of PCB blank and cut the copper on one side of one piece into two pieces insulated by a gap. Solder these pieces regularly on the outer rim of the lens, on the tin. Solder the 8.2-ohm resistors there as specified in the drawing, connecting them to the rim with pieces of thin bare wire. Check that there is no short circuit between the network and the metallic cap itself using a multimeter. Wash the cap again with detergent, warm water and dry them into the clean dry rag. Cut a 0.65m piece of two-conductor 1.5mm^2 insulated cord. Solder two one-inch pieces of 4mm^2 hard copper wire on one end of the cord and insulate the solder joints with duct tape. Solder the other end of the cord one on the terminals of the heating network.

Painting

We are going to paint all the stuff. First look what the painted things will approximately look like. Some parts on the photo (rear cap outside, front cap outside) are not painted althought they should be.

Warning

Failure to paint the optical heads correctly can result in peeling of the paint under the silicon sealant and water getting into the pipe, which will render the link inoperable and destroy the electronics. See a video.

Primer painting

Paint with water-soluble primer. Paint only those parts of the specified list which are able to corrode, i. e. they are from raw steel or iron and are not galvanized nor tin-plated. Paint caps, pipes (including inner surface), hoods, slide covers, and thermal shields with water-soluble primer. Adhere to manufacturer's datasheet for recommended procedure.

Black painting

Paint with water-soluble matte black top coat. Paint inner sides of the tubes, inner sides of the caps, inner sides of the hoods, and the thermal shield. Adhere to manufacturer's datasheet for recommended procedure.

White painting

Paint all remaining surfaces that are not already black (including those that do not corrode) with the water soluble white (matte or glossy) top coat. Paint caps, pipes, hoods, and slide covers. Adhere to manufacturer's datasheet for recommended procedure.

Fixing holes clogged with paint

Prick out paint from all holes.

Installing wire nuts

Screw the 8-terminal wire nut into its apropriate place using the M3x15 screws, M3 nuts, and M3 washers.

Attaching heel

Attach heel to the pipe using 5 M6x14 bolts, 5 M6 (6.2mm) toothed spring washers and 5 M6 nuts. Tighten firmly. Seal with silicone sealant: around bolt heads, around the 20x4mm flange, around the heel and also cover the nuts, spring washers and bolt tips.

Note: the photo is of smaller head, and of later assembly stage.

Attaching front cap

Screw the front cap in using 4 M4x8 bolts, 8 M4 (4.2mm) washers and 4 M4 nuts. Seal the joints from outside with silicone sealant. Seal the gap between the pipe and the cap with silicone sealant from outside.

Detail of joint between center of the hood and the pipe

Attaching hood at it's centre

Mount the hood's central two holes on two holes on the top of the pipe using 2 M4x15 bolts, 8 M4 (4.2mm) washers, and 6 M4 nuts. Tighten firmly. Seal the joints from inner side carefully with silicone sealant. Press the hood against the pipe firmly and drill through the remaining holes on the hood with 4.3mm bit.

Detail of joint between hood's side
and the pipe

Attaching hood's sides

Mount the hood sides using 4 M4x8 bolts, 8 M4 (4.2mm) washers, and 4 M4 nuts. Tighten firmly. Seal the joints both from inner and outer side with silicone sealant. Put also some sealant between the tins before you assemble them together.

Preparing silica gel

Put the silica gel into the two boxes (200g fits into two 92x67 boxes and 100g into two 67x46 boxes). Screw up using M4x25 countersink head bolts and double M4 nut. Tighten the nuts one against the other.
If the silicagel is not 100% dry (usually shipped in airtight containers), put the bag into oven (at minimum heat) for two hours. Gas oven to minimum setting, electric to 150degC. Do not use microwave oven. If you were so stupid you bought the blue one, be sure not to do that in a kitchenware and destroy the vessel safely after usage because it will be contaminated by the cancerogenous dust. Store the dry silica gel boxes in airtight jars or plastic bags.

Grinding paint off positioning-critical joints

Use emery paper to grind off the paint from around the six holes on the heel.

Postscript / PDF / EPS / BIG png / SVG (Inkscape)

Save for future

Save the slide covers and 4 self-cutting screws and 4 M4 washers for mounting electronics inside and closing the rear cap. The washers should be put under heads of the screws.