KeithHowell

You can try asking Ken McKay at  www.upnorthstrings.com he was making them and also had some tutorials on using them to build laminated archtops. Also try http://acme-archtops.com/ and http://www.pacinfo.com/~sholst/laminatedplates.htm

44 minutes ago, Prostheta said:

...Yes...it's actually SUNNY! .  

I know....here in the middle of the UK.  Unbelievable!  I thought it was a UFO at first and it scared the cat for sure.  I passed some young parents down the street saying to their toddlers, "...it's called the SUN.  It's like the RAIN, but not so wet...."

The sun is a mythological character from the Kalevala. Don't try and convince me otherwise! 

Well here its actually raining. The sun has taken up permanent residence and has been beating down relentlessly for months with no respite. We have only seen a break over the last 10 days! Now of course with everything so dry the rain is causing havoc washing away topsoil causing potholes in roads etc.

Great guitar and especially your method of gluing the bindings. We used to use a similar method when applying veneer sheets to foam cores for making radio glider wings.

Have you looked at Trevor Gores neck joint method? It is a double tenon bolted in both planes.

In terms of string tension an acoustic archtop there is no exception. Acoustic archtops perform better when there is an optimum amount of down force on the arched sound board. This is directly proportional to the angle of the strings over the bridge.

Given the tailpiece height at the same as the bridge the force is all in line with the strings. Lowering the tailpiece (or raising the bridge) will create a vector of the force vertically into the sound board giving the required down pressure on the top.

A stretched string will, as far as I am aware, actually follow a catenary and also vibrate following a catenary which is close but not a parabola.

The neck under the influence of the string (and the counter influence) of the truss rod will form a far more complex curve as it will be influenced by the density of the material (wood) at each point along the length and the cross sectional area. Wood being what it is can have varying density and a complicated integral will be necessary to calculate it all.

If you are really interested I can get some formulas from a structural engineer of my acquaintance (my brother actually) and post them.

Keith

Have a look at: http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/u-turn-lift.html

It is really not difficult and I find it more controllable than the concave burs.

My technique is:

Mask the fretboard

Use a felt tip pen and colour each fret along its top.

Use the triangular file on each side and round the fret until you have a thin black line on the highest point of each fret. (Few strokes along each side should do it)

Polish the frets using your favourite technique making sure you polish off the last of the felt tip ink

and Done!

I cant find a good crowning file actually fits the fretwire.

Use a small triangular file. Grind off the sharp edges.

Mask the fret board and do it old school. (Like before we had all these fancy tools dreamed up by Stew-Mac to empty your bank account )

Have you tried changing the strings?

My friend and guitar teacher recently had his Telecaster upgraded with a compound radius fretboard. After re-fretting and restringing he also had what could only be described as a "horrible plinky sound" on the B and top E strings. Our first thought was fret buzz but after an hour of adjustment on the bridge we decided it must be the strings as there was still a peculiar ringing on the open strings. He restrung it and all went clear as a bell.

Unless the fingerboad was designed to float of the body (as on some archtops) I would glue it down

Yes most definitely glue it down. This ensures the stress on the neck and sound board are correctly coupled and the neck (and neck block) wont move(creep) towards the bridge.

Not sure if this is a problem in Ovations where the neck block is probably molded into the back shell, but it certainly is on conventional acoustic guitars.

You could also consider modifying to incorporate a bolt on neck.

A plucked guitar string is not a simple single frequency sine wave but a complex waveform with a fundamental and harmonics. The bridge is in effect a mechanical filter and damps various components of the waveform. A string also has a different tone depending on where it is plucked as well (Johnny Cash at times used to strum half way up the fretboard to get a different sound)

Keith

Have you thought of epoxying some mahogany to the sides (and back if its also tapered) then cleaning it up square with the router and straight pattern bit following the edge of the fret board, thereby giving a square neck then fitting it into you neck pocket?

Keith

Running a tube amp off of a variac and turning down the voltage is NOT a good idea at all!

While you are reducing the voltage on the amplifier tubes which will indeed give you lower output power you are also reducing the voltage on the tube heater supply which is usually designed to run at nominally 6.3 volts or 12.6 volts +/- 10 % depending on how the heater supply is configured. Reducing the heater supply below its lower limit will reduce your tubes life and accidentally increasing it above the upper limit will most definitely destroy the heater coil.

Ground loops inside guitars are somewhat overrated. Hum and noise are directly proportional to the current in a circuit NOT the voltage. In a guitar the currents are to low to really be a problem for ground loops. Amplifiers where you have several hundred volts (tube/valve) or lower voltages and lots of amps in the solid state case ground loops become much more important. A few volts potential difference between ground points will result in current flow and the resultant hum.

Shielding inside guitars is more important than worrying to much about loops

I am finding this threads comments by "Stiffy" more and more objectionable as well as incoherent!

If English is not your native language then please say so. We then might be able to help you but you are coming across as a complete moron who looks like they are just trying to cause trouble.

"oh, everyone's getting rid of Horse Power, because its not an accurate measurement now. Everything's being converted to ccs."

What utter balderdash! Salesman will say anything.

Horse Power is a very precise unit of measurement it just that it's the old Imperial system or whatever you guys call it in the USA.

Watts is the correct SI unit for power and generally KiloWatts is used.

CC's is cubic centimetres a measure of volume which is also a bit archaic. The accepted measurement is Litres which is 1000 cubic centimetres.

Soundholes on acoustics are reinforced for practical reasons. Off the top of my head I think without it they introduce unwanted overtones and eventually crack from the vibrating air pumping in/out of them.

In flat top acoustics there is a component of the string force running longitudinally in the sound board into which a hole is then hacked. That's why bracing is then placed around the sound hole to distribute the forces around it and up into area under the fretboard and hence into the rest of the neck. Without it the sound hole will start to distort into an ellipse and crack as you correctly state. See Cumpiano and Trevor Gores books for detailed info on the subject.

I use a radial armed saw with a blade my local blade sharpener made for me for about R120 ($12USD)

Great blade no runout, wobble etc and cuts a perfect slot. He adjusted it to fit the sample of fretwire I supplied.

Works great very accurate (well as accurate as you position the board under it)

The saw is a DeWalt my Dad bought about 40 years back which I inherited along with his workshop.

Keith

Perhaps you mean barely?Either that or you are hungry?

Or thirsty? Want to brew some beer?

I've done this by first marking the new taper on the fretboard then using the edge of a file, at the end of each fret, to take the fret and the wood down to the taper line.

Once that is done a router or plane can be used to bring the rest of the wood down to the line, followed by re-beveling the frets.

As far as I understand, side bracing is purely to prevent splitting around the sides isn't it or am I thinking of something else very similar?

Yes, pretty much, however they do give more structural integrity to the sides which can be desirable on a 12 string. The more common method is cloth tape (Duck Tape works well) which also stops the splitting but has little structural strength. I have also used cloth impregnated with Titebond.

Keith

Make sure the the brace is the full width of the side. Don't trim them off to the linings. ie Do the braces first then fit the kerfed linings between them. See Bennedetto's book on building archtops for a good explanation.

Keith

Capacitors are notorious for having terrible tolerances! If you measure the three you will most likely find at least 10% or even as much as 20% differences although they are all marked 0.022uF. Caps manufactured back in the early days were very variable but modern manufacturing has tightened things up a bit.

I am pretty convinced the tone voodoo thing is a direct result of the different values, which you will hear, as various types have vastly different tolerances.

I am very suspicious of Chinese supplied parts for anything. If I can't see it, feel it and test it before buying I pass. Our part of the world (South Africa) is also flooded with cheap Chinese knock offs.

A colleague of mines company was commissioned to install some Chinese built Variable Frequency Drives in a production plant. He spent many hours fiddling with the electronics to get them up to spec and then many more hours with the horrible documentation to get them to run properly all of which the client ended up paying for.

The next set of drives they bought they went for a more expensive British built model and he had them up and running with no problems. The end result was the full cost of the British drives came to less than the cost of the Chinese stuff!

Keith

Humbuckers cancel the hum generated in the field they make (Same as two single coils with opposite windings). No pickup cancels out "external" hums, they actually will pick up the noise in proportion to their output (ergo, a humbucker becomes noisier then a single coil). The absolute best way to do this is to shield your pick guard and your guitar body with copper foil tape (best), graphite paint (expensive but easy), or aluminum (cheap fix).

No! Humbuckers cancel external noise NOT generated in the field they make. The external noise is induced in both coils but is 180 Degrees out of phase and hence cancels!

This principal is used in may areas of cabling. Cable pairs are twisted together to achieve the same effect. Open wire telephone routes we used to see alongside roads and railway lines used the same principal, the two lines of a pair of wires were swapped in a regular pattern known as a transposition scheme to reject external induced hum, usually from nearby power lines.

Yes shielding is also good: stop the noise getting in before it causes trouble.

Keith

are the rails stiff enough to hold the router without any bowing?

I would turn the rails through 90 degrees (ie stand then on their long edge). This will make everything stiffer all round.

I built a routing jig for bindings using similar rails and found them much more rigid in that orientation.

Keith