3 - Coil Assembly


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Post Fri Dec 01, 2017 6:36 am

3 - Coil Assembly

Unpack the case piece bag and separate the laminate parts for sanding. Spending some time here wet sanding with fine emery paper will give a *much* smoother rounded finish and if you're really patient the bakelite top can be polished to a gloss finish with a fine polishing paste such as car paint restorer.

Carefully sand the case top and bottom panels making sure not to scratch them, the side rings will be hidden so scratches aren't so much of a problem but they are fragile so don't put too much pressure on them.

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The coil consists of a former made using a stack of four paxolin laminate pieces. The coil itself is wound from 0.2mm silver plated copper wire, enamelled with a clear lacquer for insulation. You'll need to make this to test the clock PCB and before moving onto the case assembly instructions.

Start with the case base panel and insert the 2x M3 bolts into the holes at each side. Make sure the holes in the panel face the way shown in the pictues.

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Site Admin

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Joined: Tue Jul 24, 2012 8:05 pm

Post Fri Dec 01, 2017 6:43 am

Re: Coil Assembly

Now place the 0.8mm laminate piece as shown with the notch to the top left:

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Joined: Tue Jul 24, 2012 8:05 pm

Post Fri Dec 01, 2017 6:44 am

Re: Coil Assembly

Next one of the 2 'narrow, shaped' loops:

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Site Admin

Posts: 937

Joined: Tue Jul 24, 2012 8:05 pm

Post Fri Dec 01, 2017 6:45 am

Re: Coil Assembly

Finally the 'wide, shaped' loop:

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Site Admin

Posts: 937

Joined: Tue Jul 24, 2012 8:05 pm

Post Fri Dec 01, 2017 6:47 am

Re: Coil Assembly

Bolt the stack together - if you have a couple of spare M3 bolts it will help to use them in the end holes:

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Site Admin

Posts: 937

Joined: Tue Jul 24, 2012 8:05 pm

Post Fri Dec 01, 2017 6:47 am

Re: Coil Assembly

Now feed a couple of inches of the silver wire through the hole made by the notched piece and wind 26 turns (that is 26 times around the laminate former) of wire onto the groove formed by the 'thin' laminate loop in the middle of the stack. Trim the wire leaving a few inches spare then feed it through the notch hole again. Run some superglue into the hole to keep the wire in place and around the inside edges of the strips, making sure you don't glue the bolts in.

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It will really help if you unwrap the twist of wire first and rewind it onto a spool or roll of some kind.

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Remove the bolts and tin the wire ends - the enamel insulation will melt easily in solder so you won't need to scrape it off first. You now have a completed receiver coil assembly ready to build the case and PCB onto.

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