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This chapter shows the extras you will need; surveying instruments are useless without at least some of them. Other accessories are shown in Sections 1 - 3.

Instrument Stands. These instruments will fit on different stands, some of which can be made on site. All the instruments have mountng holes with 6mm. (1/4 “) Whitworth nuts - usually T nuts - so they can be bolted to any of the stands shown here, or to most camera tripods.
A sighting instrument should be at eye height. This can be as simple as sitting it on something flat, and levelling it by putting a nail or pencil under one end. Another way is to bolt or screw it to a stake - O.K. if it only needs to look one way, as when levelling a trench. If the instrument must turn, one of the stands shown here can be used. They provide either a vertical post with horizontal mounting hole (e.g. pipe stand) or a flat top plate with vertical mounting hole (e.g. the simple tripod ).
The first stand is made from plastic or metal pipe, 25 to 50 mm. diameter and about 1.5 M. long. A length of wood, of square or rectangular cross section and with the edges taken off to make it an easy turning fit in the pipe, is screwed or bolted to the instrument, and sits in the top of the pipe, like this:-

A metal pipe can be driven into the ground, or held up by guy ropes; toggles help to set the pipe vertical. The instrument can be held still by jamming a wedge between the wood block and the inside of the pipe.
The stand can be made firmer by putting it over a ground stake long enough to bring the top of the stand to eye height. Drill a few 6 mm. holes through both the bottom of the pipe and the ground peg, and put a 100 mm. nail through one of them as a pin. Like this :-

With this stamd, the instrument level must be checked each time it is turned. The guy ropes can be adjusted to make it level in all diections, but this is a long job.
For long instruments (or short ones resting on a flat board), make a triangle of stiles to sit it on. Each stile is two stakes and a top plate just below eye level, which should be about half the length of the instrument and have a narrow top face. Put up one stile, level the top, then use this as a reference to bring the others level, both lengthways and across the ends. Like this :-

An old builder once told me another way to do this. He piled up a mound of earth in the middle of the site, put a triangle of three bricks flat on top, then levelled the bricks and rested his sighting level on them. But what happened when it got in the way ? !

Or rest the instrument across the top of a small drum - like a paint drum - which has a rim on the bottom and isn’t bent. Fill the drum with water, and using the water surface as a level reference, make the top rim level all round by putting a stick under the bottom, like this:-

This may not look very stable, but the drum rests on three points, and with the weight of water is very firm.

The top of a short stepladder makes a good platform, especially if it is drilled with a 6 mm. (1/4 “) hole to take a bolt.
A camera tripod with a hole to take a 6mm. (1/4”) screw or bolt makes a very versatile stand because the head can be turned in all directions. However many camera tripods are not very stable, and are hard to adjust
The dumpy level can be floated in any water container, provided the float has clearance. If a reasonably level platform can’t be found, try a bowl with a rounded bottom, on an improvised tripod or trivet, like this:-

A simple tripod is shown in Fig.7-1. It isn’t the world’s best tripod, but it is easy to make, and the top plate provides a stable platform in both smooth and rough ground.

Make the legs from round or square section aluminium tubing or timber, light gauge pipe, bamboo poles, electrical conduit (at least 20 mm. diameter) or even angle iron; make sure they don’t flex much. A full tripod can be a large and heavy thing to transport, but a possibility with this one is to pack only the top plate in the tool box, then cut legs on site; drill a 6 mm. hole in one end of each, and make a point at the other end, with a hose clip or a screw for your foot, to push the point into the ground. Like this:-

The legs can be used either crossed and tied together, or splayed; when tied, the tripod is very firm, but may be harder to use on sloping ground. When splayed, it works well on sloping ground, but may shake a little; it depends on the stiffness of the legs. An instrument is held by a 6 mm. eye bolt and wing nut, screwed in to the instrument from below, and the wing nut tightened. This bolt is stopped from falling out when loose, by panel washers above and below the top plate, and a locknut 10 - 20 mm. below the end of the bolt, leaving enough thread to screw into the instrument base.

The Permanent Tripod is intended for use with dumpy levels, but can be modified to take other devices - the builders’ level, the dumpy plummet or the crevel - by adding a right angle bracket. It needs time to make, and is a little more expensive if all new materials are used;. But it compares well with commercial models costing much more.

It is based on three tee hinges bolted together in a triangle; slackness in the hinge pivots is taken up by three friction pads which bear on the centers of the pivots and make them stiff in action; the pad pressure can be varied by adjusting a screw.

The long arm of each hinge is screwed to a telescopic leg, with height locking screw and ground spike. A round flat top plate is both the mounting plate for the instrument, and holds the pressure pads in place. Each leg is long enough to bring the top plate to comfortable eye level, but may be shortened to make the tripod easier to transport if desired.

Figs. 6-2 to 6-6 are the parts and assembly. drawings. Begin by bolting the hinges together; since they must distort a little to make them overlap , use longer bolts to pull them into position, then substitute short ones. It may be necessary to grind a little off the corners of the overlapping plates, but try to avoid this - it cuts into the plating.

Next cut out and drill the top and spacing plates, from 12 - 15 mm. thick plywood or similar. These plates are under stress; avoid anything likely to warp or absorb moisture, like particle board. You may need to alter the hole spacings to match the holes in your hinges. Make the pressure pads from three 12 mm. (1/2 inch) hex head bolts. Cut the shaft lengths about 1 mm. less than the thickness of the top plate, to ensure they won’t protrude when assembled. File grooves in the hex heads (Fig.704). Paint or varnish the top and spacer plates before assembly.
Assemble the plates, hinges, and pressure pads, and check that the pads are over the centre of , and aligned with, the hinge pivots. If not, drill the shaft holes larger, to allow the pads to move a little. (Put washers under each pad head if the holes need to be very large).

Make the upper leg sections from 25 mm. hardwood dowel, & drill holes to match the holes in your hinges. Choose two hinge holes well apart; one or both may not be on the centre line of the hinge, but drill the leg holes in line; each leg may be a little out of line with its hinge, but if all legs are the same this doesn’t matter. Cut a diagonal on the dowel top to allow plenty of clearance when the leg is swung outwards. Bolt the dowels to the hinge plates with 5 mm. (3/16 inch) screws and locknuts, or use lockwashers or locktite solution. The screws in the lower ends of the dowels are to take up the gap between the dowel and the inside of the lower leg; leave their adjustment until assembly.
Cut the lower legs from a length of 32 mm. class B (orange) electrical conduit. Class A (grey) conduit has a thinner wall section, and is too shaky when extended. Heat one end by immersing it in boiling water, or carefully with a gas torch, flatten it in a vice for about 25 -30 mm., then bend the flat at an angle to the leg as shown in Fig. x. File the flat to make a neat foot on each leg, then drill and countersink a 7 mm. hole in the centre of each flat. Grind points on three 6 mm. (1/4 inch) csk. head machine screws to make earth spikes, and screw into place. Drill a drain hole in the bottom of each tube.

Make up three spacers from an offcut of 20 mm. conduit - preferably orange, then drill and file a 15 mm. diameter hole near the top of each leg; & in line with the feet. The spacers can be glued centrally over the holes with p.v.c. glue if desired; this makes it easier to assemble, but isn’t essential. Cut the three locking bolts as shown, from short eyebolts with thread up to the ring; if not the bolts stick out too far. Each locking assembly consists of a hose clamp, a spacer, a 6 mm. plain nut, 6 mm. washer, a locking bolt and 6 mm. fibre locknut. If locknuts are not available, a plain nut with Locktite solution may be used. (Just make sure everything is assembled and tested correctly before applying Locktite!).

Don’t tighten the hose clamps too much - it will distort the conduit. The locking screws will work more easily if the clamps are left a little slack. The locking bolts or hose clamps cannot come out or fall off if the locknuts are in place.

Before sliding the lower tubes over the dowels, adjust the height of the screws at the bottom of each dowel to make a smooth sliding fit in the tube, without any play. Apply grease to the screw heads before sliding them into the lower tubes.

Tighten the height locking screws, stand the tripod on its feet, and test the legs at different heights; the upper and lower tubes should slide easily in and out, without any rattle or play when the tripod is standing.

Attach a short length of leather strap to one of the legs to keep them together when being transported. The tube can’t be drilled at this point, so the method of attachment shown is recommended.

Now put the mounting bolt into place; 6 mm. eye bolts of this length are not generally available in hardware stores, but specialist bolt and nut stores sometimes carry them. Failing that, make up something from 6 mm. threaded rod, which is readily available. The thread must be long enough to engage the tee nut in the dumpy plate, with the dumpy legs fully screwed in, in the dry mode. The locknut serves two purposes - to keep the mounting bolt captive , and to stop this bolt from being tightened excessively, which could either puncture the saucer or pull the bottom plate out. Screw the mounting bolt gently into the dumpy saucer plate until it stops, then set the locknut to prevent the bolt going any further.

Last job is to screw the top plate screws tight enough to make the hinge action as stiff as possible. Fully retract one leg, then swing it up horizontally; the hinge should be stiff enough to hold it there without sagging. DO NOT use locktite solution on these screws and nuts - as the pressure plates bed in, the screw tension will need to be increased. Use locknuts or lock washers.

In these photos, the top leg joints are aluminium; these have been replaced with wooden dowels.

Universal Mount. The instruments in these notes will work on several different mounts, but if you do much surveying, it is better to put the instrument on a mount which fits between the instrument and a stand, and is able to do three things :-

1. It should let the instrument move a little in any direction without having to move the stand or tripod, so it can be accurately positioned over a ground marker such as a peg, and then be locked there.
2. It should allow the instrument to be levelled (or plumbed, depending on the instrument) and, again, locked there.
3. It must let the instrument turn to point in any direction, without disturbing either the position or the level.

Commercial instruments and tripods do these things well, but it is hard to make such a precise mount with hand tools. The Universal Mount shown in Fig. 7-2 is not perfect, but comes as close as it is possible to do with simple construction. It will turn a full circle, has levelling screw feet, and will sit flat on any horizontal surface through which a hole for a 1/4” (6mm.) bolt can be drilled, such as the top plate of the simple tripod, a camera tripod already fitted with a 1/4” mounting screw, or the top step of a short stepladder.

It supports the mounting bracket and instrument to one side of a stand; the base plate rotates around the top of the stand, a slot in the plate lets it move in or out, and a clamping block holds everything tight. The whole thing is guided into position by a plumb line hanging from the turning axle eyebolt, which is the instrument reference position. The line hangs down the side of the stand or tripod, but works just as well as the usual central mounting. Unless it is very carefully made, it may not keep an instrument exactly level as it is turned, but if the observer checks the level indicator often, and adjusts the screw feet if necessary, the bracket works well.. Like this:-

Construction. Make the five wooden pieces shown in Fig. 7-6. The mounting block is fastened to the turntable by two wood screws, from underneath. The block must be held very firm, to stop any instrument wobble, and two small shelf brackets should be added after assembly. They must not come high enough to stop the instrument from clamping flush with the block, so it is best to fit the instrument first, then cut some length off the shelf brackets if needed.

The front face of the block must sit on a line through the centre of the turntable, as shown in Fig. 6-7; then when an instrument is clamped in place, its reference point will be in line with the turning axle eye bolt, and with a plumb line hung from the eye.

The base plate can sit flat on the stand if necessary, but to stop wobble it is better to fit three small metal furniture feet or even three round head screws underneath, so the base is sitting on three points only. Don’t use rubber feet - they give too much.
The levelling plate sits on two screw feet and one machine screw; the holes for them in the baseboard have more clearance than normal, to allow the screws to move a little if the levelling plate and baseboard become out of parallel when the level is adjusted..Don’t set the locknuts too tight; allow a little slack so the levelling screws can move.

The turntable must turn smoothly on the levelling plate, so put three small plastic or metal furniture glides, or round head screws, underneath it.
The turning axle needs an eyebolt 85 - 100 mm. long, with at least 50 mm. of thread. To assemble the baseboard, levelling plate, and turntable, follow this order:-
1. Put the levelling screws and machine screw into the levelling plate, and tighten the top nut on the machine screw.
2. Put the top three locknute on these screws, but don’t put thescrews into the baseboard yet.
3. Push the axle eye bolt through the baseboard hole, and put on the lower locknut, and the panel washer. Run the locknut well down the thread.
4. Put the axle through its hole in the levelling plate, and at the same time put the feet into their baseboard holes, and put on the lower locknuts. Adjust all foot locknuts so there is a gap of 20 mm. between the baseboard & levelling plate when they are parallel.
5. Put on the top axle locknut, and set it so there is about 12 mm. of thread above it.
6. Screw the axle into its hole in the turntable., as far as the top locknut will allow, and screw it tight.
7. Using an open ended spanner, bring the lower axle locknut up until the turntable can just turn easily but without any play. Some grease on the levelling plate helps.

Lead Screw and Turntable Clamp. It is hard to turn an instrument by hand to set it accurately without a slow morion adjustment. Usually this is a worm gear, but that is beyond simple construction, and needs many turns to move through a large angle. The mechanism shown here is attached to the Universal Mount. In use, the turntable clamp is loosened to allow the instrument to be turned by hand, then tightened so it can be moved by the lead screw. It uses an eye bolt , or section of thread cut from a bolt, as a lead screw, a nut made from softwood , and a clamp made from two panel washers, two 6 mm. nuts, and two 5mm. screws and wing nuts.
Sometimes a problem with lead screws is that play betreen the nut and the screw causes backlash - that is, reversing the direction of the lead screw causes the nut to stop, before starting to move the other way. The nut used here is made of softwood, which allows the lead screw to wear a corresponding thread in the wood, without need of a tapping tool, and. can be adjusted to prevent backlash; if it is made carefully it works very smoothly.

Fig. 6- 8 shows the parts, and as an assembly attached to the Universal Mount.

Construction.
1.Cut out and drill the bearing.block, and put the lead screw in as shown, tightening the lock nuts enough to stop any sliding movement in the block.
2. Cut the softwood block for the nut to size, and drill the clamping screw hole.
3. Drill the lead screw hole, making sure it is the right size; it should be no more than 5 mm. (3/16 inch).
4. Cut the nut block in half, through the lesd screw hole, as shown. Put the nut clamping screw through both halves, but don’t tighten it.yet.
5. Make the lead screw from a 6 mm. machine screw or bolt, and put a 6 mm. control knob (available from electronics stores) on one end. Or simply use a 6 mm. eyebolt of the right length.
6. Put the lead screw right through its hole in the nut, and gently tighten the nut clamp until the lead screw thread bites into the softwood a little. Now try turning the lead screw gently in the block; it should screw in and out like an ordinary nut. As the lead screw wears into the wood, tighten the nut clamp until the lead screw and nut work smoothly without any looseness between them. Let a few drops of oil soak into the nut.
7. Assemble the clamp and connecting rod, and attach them to the nut. The 6 mm. nuts used as spacers between the panel washers should keep the washers a little less than 12 mm. apart.
8.Drill a hole for the bearing block near the edge of the levelling plate, and screw the assembly in place.
9. Finally, make a small guard plate from thin sheet metal, and screw it to the edge of the levelling plate , to stop the clamp swinging away from the turntable when it is loose.

Targets, and Target Patterns. An improvised target may only need be a strip of wood, but there are times when something better is needed - on dull days, or when a clear mark standing out against a blank background is helpful. The target patterns shown here may be downloaded, printed, and taped on cardboard, wallboard etc.,or put on a wall or staff.

Target B2 is a bar pattern for bi-directional sights; mount the target so that the bars are parallel with the sight slots. Choose which bar is the best visual fit in the foresight slot - the longer the target distance, the wider the bar needed. Diffraction (bending) of the light rays in the slot may stop exact matching of widths, but doesn’t affect accuracy. The centre line of each bar is shown by the arrow points. A good target for a staff can be made by cutting out part of the printed sheet, and wrapping it around a round or square dowel, which can be turned to bring the needed line width into view.

Target E is a cross pattern, which will give the right answer even if it is tilted a little, as long as the sight line is on the center of the cross. It may be used with the cross square or diagonal. Like this:-

Target C and Target C2 are number scales for use when the observer can read the numbers. They are good for aligning instruments when you have only yourself. They can be cut out and pasted on stadium rods or staffs, and turned to bring the right scale into wiew.

A 'Knocking Board' is a stake, with a white target for good visibility nailed to the top. Cardboard is good, but translucent plastic -e.g. a margerine container lid - is better; if the sun is behind the target, it shines through and lights it up. Put a square black cross for v- notch sights, or a diagonal cross for a crosshair. Like this:-

Boning Rods are often used to guide excavations for drains or underground pipes. They are simply stakes with a board nailed across the top. All rods must be the same length. There are two types - ones with a point on the bottom end, and ones without, intended for use with separate pegs.The line of the excavation is first set out on the ground, then boning rods are driven in at intervals along this line, and their tops lined up with a string line or sighting instrument. Like this:-.

As soil is dug out, the trench goes only as deep as the point of the rod or peg. Which type to use depends on the situation; with the pointed type, you need enough rods to put one at each station; when you use separate pegs, you may only need one or two rods. A good idea is to have pointed ones at each end to fix the sight line, and only one more, plus pegs, for the rest.

Ranging Poles When setting out or measuring, ranging poles are used to mark boundaries, corners, etc.; each is a brightly coloured pole about 2M. long, with a spike for pushing into the ground. The pole is placed by an assistant, directed by the observer, and the assistant must know when the pole it is truly vertical,.to avoid errors.

The pole shown here is made from tubing, with a plumb line and bob hanging down the inside. Two holes in the tube at eye height allow the assistant to see the bob weight, and bring the pole vertical, so that the bob is hanging down the centre of the tube; this requires practice but is not all that hard to do.
The sketch below is self explanatory, and no construction details are given. Make sure the short plumb line is fastened at the top in the dead centre of the tube, that the long bob weight is straight, and that it hangs vertically below the plumb line.

Another way to use a range pole, especially when the ground is soft, is to hold it swinging in one hand like a pendulum, with the bottom point a half a metre or so above the ground. When the instrument observer signals that the pole is in line, let it go to make a hole in the ground,as in the right hand sketch..

Plumb Line Toggle.When hanging a plumb line from a tripod, it it often necessary to alter the length to suit the tripod; a quick way is to put a toggle on the plumb line. Like this:-

Make it from plywood, hard plastic, or aluminium. The free end of the line can be wound round the body of the toggle, and gripped in the slit.

This brings us to the end of the instruments; the rest of the notes are descriptions of test gear, and some theory.. If you make and/or use any of these instruments , or if you have questions, or good ideas you would like to share,please let me know. Many people have helped with these notes - more than I can thank here - and the notes will grow better if you share your knowledge with us.