Shamelessly Copied from Andyjr - Semi Hollow Neck-Through

Andyjr1515

Andyjr1515 said:

I'll run through how I go about it if I get a moment tomorrow

I'm sure there are better ways but, for what it's worth, this is what I do nowadays:

-  I use a mm larger dia bottom magnet to the one on the lid.  For a light hatch, I might use 4mm bottom, 3mm lid.  For a heavier hatch, 5mm bottom and 4mm lid.  This gives me the working clearance without having to cut out a bevel, etc

- I also twigged that the magnets don't need to touch.  

- I start with drilling the bottom hole, using a decent bradpoint drill, to a touch over the depth of the two thicknesses of magnet I intend to use.  

- I then drop a spot of CA gel into the bottom hole and press the larger magnet firmly into the bottom of the chamber with a cocktail stick:


- I then cut a thin strip of emery paper (I use this as it is pretty non-absorbent) and concertina it so it fits into the remaining chamber.  I use enough emery packer to allow the top magnet to still locate in the chamber, but sit proud of the rebate :



- then pop the lid magnet on top.  It orientates itself...'cos it's a magnet.  I make sure that it is relatively level (if not, I level the emery packer a touch) and then add a drop of CA gel on the top face:



- then I position the hatch and hold it down firmly for a few minutes:


- then, with luck, when I lift it, the magnet is stuck fast.  Finally, I run a bead of thin CA around the hatch magnet to fully secure the join.  Then I winkle out the emery packer, move to the next one and repeat until they are all done.  No measuring required and no possibility of the magnets being the wrong way round!      :

MARVlN

Thanks @Andyjr1515 that's a really good guide. I remember reading that in your Trini thread, but I forgot some important details as it turns out. For example, I used the same size magnets top and bottom, which ended up making alignment incredibly crucial, and I'm having to faff about removing any and all tiny amounts of excess glue from both the cover and the cavity, adding chamfers etc.

Another learning point for the next build!

Andyjr1515

MARVlN said:

Thanks @Andyjr1515 that's a really good guide. I remember reading that in your Trini thread, but I forgot some important details as it turns out. For example, I used the same size magnets top and bottom, which ended up making alignment incredibly crucial, and I'm having to faff about removing any and all tiny amounts of excess glue from both the cover and the cavity, adding chamfers etc.

Another learning point for the next build!

Well, if it's any consolation, it took me quite a few builds and iffy hatches until I bumbled around enough to work out a method that gets round most of those challenges... 

WezV

I picked up some magnets for this a few weeks ago.   I was just going to inlay some metal on one side

Andyjr1515

WezV said:

I picked up some magnets for this a few weeks ago.   I was just going to inlay some metal on one side

Now there's a thought...

WezV

  I had a plan to use staples so i could mark either side before drilling  then thought" why don't i just put a bigger bit of metal on one side so alignment isnt an issue".

I was going to go with a simple brass shape a bit larger than the magnet.   Am i missing some reason this wouldn't  work?  I have 3mm  rare earth magnets

Sesh

It wouldn't work with brass,  it's not magnetic. 

Andyjr1515

As @Sesh says, not brass  but a bit of sheet steel from a baked bean can would be magnetic.

That said, magnet to magnet is a much stronger pull - depends on the hatch and how many magnets and their pull value, but 3mm onto steel might not be quite enough.  Worth an experiment, though.  If it's to fit to one piece of steel, all the magnets will need to be orientated the same way round.

Strangefan

Exceptional work

Roland

There is an easier method of locating the magnets. Drill 1mm into the cover, or whatever thickness the magnets are. Stick the magnets in with CA. Place a second magnet on top. Colour it’s top with a felt tip pen and, while still wet, press the cover in place. Then drill out the coloured spots. Put a small drop of CA in each hole and push the cover into place. If you make a mistake with too much CA, and the magnets get glued together, then you can tap the cover out with a pushrod through the volume/tone knob holes. Finish off by topping up the CA.

Roland

Strangefan said:

Exceptional work

Yes

WezV

Well that is a good reason it wouldnt work    

I wrote that after a very nice 12.5% beer, and ive just had a bottle of bubbles.  I actually googled whether brass was magnetic and still read wrong.  Knowing i have brass, aluminium  or copper already.

I did try something a few weeks ago which was glueing a strip of a magnetic coffee can along the recsess, but it came loose to easily so i know i need epoxy rather than super glue if i do that.

But i think that a magnetic material inlaid will remove all questions of alignment 

WezV

Im just opening a 10% imperial stout, so answers may go down hill.

But im on holiday so its okay  

MARVlN

It's a good discussion!

You can buy sheets of self-adhesive magnetic material that's a lot easier to work with than steel. Wargamers use it for model transportation, they stick a decent magnet on the base of a model, then have a sheet of this stuff. They place the models on the sheet and the pull is much stronger than to a non-magnetised material. Means they don't need to use packing foam and so on, as the magnets just hold the models in place.

Something like this: http://https//www.greenstuffworld.com/en/magnetic-sheets/74-magnet-sheet-for-magnetic-trays-and-crafts.html

Just under 1mm thick, so doable, and could mean the alignment is significantly less important. I think my brother might have a sheet - could test the strength. Probably too late for this build though.

MARVlN

Another weekend gone, more updates. Very close now, just waiting on a few parts. Like more binding after it turned out the stuff I ordered wasn't long enough. Anyway, more on that later.

First off, I noticed a divot had formed on the ebony top, which I traced to a slight crack where the side wasn't completely level. I made a cleat/brace from a spare bit of khaya

Then clamped and glued it into place

This braced and slightly corrected the end of the crack, and then I wicked ultra thin superglue into the other end of the crack. The maple veneer didn't crack. After a few days, I then sanded the top down until the divot couldn't be felt any more. Still seems to be good a while later, so fingers crossed.

Next I finished installing the string clamps. Bit fiddly, not entirely happy about the high-E (which is where the screw broke earlier), but I'll fix that later if it needs it.

I ordered all new hardware (for anything but grub screws) in stainless with torx heads. Can't be arsed with the old easily-stripped Philips of questionable quality. I used Accu who seem to have excellent quality stuff in my experience so far.

Next up I removed the remnants of the old binding, recut the binding channels again and went with celluloid MoP bindiing this time. Paid particular attention to the neck join as that wasn't the best last time as I did final shaping after binding.

It was at this point that I realised I was about 20cm short. Almost cried. Touchstone must think I'm a complete moron (fourth order for 'some binding' in as many weeks). This evidence would suggest that they would have good reason to.

MARVlN

Whilst sulking about the binding (I had planned to really crack on with the finishing this weekend, but with the binding not done there wasn't much chance of that), I decided to crack on with the fret levelling, recrowning and polishing.

Kicked off with levelling. I leave the truss rod in its most-neutral position, used a marker pen to colour the top of each fret, then removed as little material as possible from the frets with the levelling beam. I removed material until even the tiniest amount of silver showed through.

Then cracked on with the tedium of reshaping the frets. After filing:

Then broke out the ultra fine sandpapers and #0000 wire wool. After that then polishing with Autosol:

Once I then cleaned the fret board (and all the remaining muck off the frets), and applied a coating of wax to the board:

Pretty happy with that! The ziricote is so lovely...

One last thing I could thing of before the enforced break was to soften the transition from the scratchplates to the centre block, and roundover the pickup cavities:

Coming soon: wiring. It's a complex one (four 4PDT switches, one volume, one tone). Can't decide where any of it will go yet.

Andyjr1515

It may be two steps forward one step back...but this is a top drawer build @marvin ;    It's looking splendid

downbytheriver

I am totally in awe of this build

MARVlN

Thank you both - kind words!

I'm trying to decide how to edge the scratchplates in particular. I quite like the squared edge, which I'll just soften with some sandpaper - much like the main edges of the guitar - but I'm wondering if something like a bevel would feel better.

WezV

I think a small bevel right on the edge will make it.  certainly no deeper than half the thickness, not a full bevel