How to Build 767 YOKES Part1

7/24/2019 How to Build 767 YOKES Part1

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How to make a 767 Yoke

Given that there are not many commercially available yokes for hobbyists, and those that are available

are either very expensive or not particularly rigid, I decided to make my own, as shown here. As I

needed something which is hollow for the cables but also rigid. Ive used copper pipe and fittingswhich are standard U metric si!es and when coated with glass fibre are exactly the right si!e.

If you decide to have a go at making some yourself you will need the following "to make # yokes$%

&'''##mm elbows

#'''()*()*mm reducing +ee pieces

#''')*(##(##mm reducing +ee pieces#''')*(# reducers

#''')*(##mm reducers

- metre ##mm pipe#'''wooden block for the centre"or nylon or similar$

-g glass fibre resin "activator$

- s/uare metre glass fibre clothGas blowlamp

0older1lux

2ire woolA rough half round rasp or file

3ipe bending spring

*44g Automotive body filler- small tin 1ine filler"stopper$ to fill fine scratches

Abrasive cloth(paper -#4 grit down to &44 grit e.g -#4(#&4(&44 5wet6dry7 grades are best

- can Aerosol 3rimer- can Aerosol paint

# lots 8 core cable for the switches

Good /uality dust mask." your health is worth more than a dust mask9$:isposable plastic container to mix resin0mall stiff brush for the resin

0mall plastic syringe "-4cc$to measure activator "normally available where you buy the resin$.

;ubber gloves+hinners or paint solvent to clean up

I bought the switches from Arcolectric as they are a perfect fit.

All the materials cost me ots of patience9

+his drawing shows the si!es


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1irst ?ob is to soften the copper pipe by heating it with the blow lamp until it is red hot thenimmediately /uenching it in cold water. +his will make it easy to bend the pipe as the handles are

curved.

Assemble the fittings loosely as shown below, cutting and bending the pipe using the bending springinside the ##mm pipe to prevent buckling.

@ut pieces of pipe about 4mm long and split them lengthwise and flatten the pipe out to give arectangular flat pieces of copper. end and cut these to form the housings for the multi'com switches at

the rear as well as the thumb grips.

2hen you are happy with the dimensions and positions, clean all of the fittings and pipes where they are

going to be soldered with the wire wool.

Apply the flux and solder the fittings together. It should look something like this


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+he wood block has a hole at the rear which goes down to the bottom centre for the cable, block is

approx #mm thick.

+he block should also have a -4mm hole drilled from the centre to the bottom to allow for the cable.

Install the cable now.

:rill through the pipe and screw the pipe to the wood block. # screws are enough as the fibre glass will

hold it all together. +he holes will be covered by the glass fibre later. +his block can be used for fixing

the front label holder later.

and of course make a mirror image for the 1B side


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Using the rasp, roughen everything to give a 5key7 for the glass resin to get hold.

Cix the resin(activator at - D activator i.e -44 grams of resin -cc of activator, this allows about - hour

before hardening "dependant upon temperature, greater than - @ is re/uired$. I used the wifeEselectronic kitchen scales to weigh the resin accurately.

Beware! the resin stinks so dont do it in the house!

Apply a light film of the resin over all, then wind the glass fibre tape(cloth around, using a stiff brush toforce more resin through the cloth(tape, donEt worry about getting it all right as this is only the first coat.

+ry to avoid air bubbles by forcing resin through the cloth, you may need to tie some wire around loose

ends of the tape(cloth to hold until hardened.

2hen dry PUT O YOU "#$% and a pair of gloves, and use the rasp to remove the strands of glass

that are sticking up."these are really sharp so take care$ Use the rasp to shape the glass fibre roughly toshape as re/uired.

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:U0+ I+ 2I>> 0;H: BU; >UJG0 AJ: AI;2A0. Alternatively buy 3olyester matting but still

avoid inhaling the dust.


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If you use a power sander to do the shaping make sure you have a good mask and some form of dust

collection(extraction available, but it is safer to do it by hand albeit slower. Using a power sander alsorisks sanding flat lines into the curves, whereas your hand can curve round the yoke to get the re/uired

shape.

Cix more resin and apply as many layers of glass fibre as re/uired to give the desired shape and si!e.

Use the rasp in between coats to continuously shape the glass to the desired profile. Use -#4 grit

abrasive to get in the curves.

2hen you are happy with the overall shape, mix some automotive body filler and coat the whole yoke

with it as this fills in all the sanding marks and holes and dents in the glass fibre, like this

you can see I remembered the cable9

Jow using abrasives sand the yoke down to get the right shape and work down in abrasive gradeschecking between grades for any holes which may need re'filling with the body filler. 2ork down to at

least &44 grit abrasive as this will give the smooth finish re/uired for painting. Use 5wet and dry7

automotive abrasives with slightly soapy water as this keeps the dust down and gives a better finish as

well as prolonging the life of the abrasive by preventing clogging. Use the tips of your fingers to feelhow smooth the yoke is, as your fingers are incredibly good at feeling small dents(lumps(holes. our

target is a finish which is smoother than a babyEs bum9

How to Build 767 YOKES Part1

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