curtisa

Variable coil tapping is an interesting idea, never heard of it before. As far as I can tell your scheme will work. My only comment is that the way you've wired up the push-pull switch on the lower pot will mean that the coil tap selection on the two humbuckers will be the opposite for each pickup (up = bridge pickup outer coil & neck pickup inner coil, down = bridge inner and neck outer). Not sure if it was intentional, and it will still work, but if it isn't an issue for you then by all means build it up and try it out.

Prolly not such a good idea to throw a handfull of fine sawdust into an open fire. Fine airborne particles can be quite volatile when exposed to open flame. Maybe save aromatic wood shavings for potpourri uses? Saving sawdust from various timbers when sanding may be useful if you need to mix up sawdust with glue to create colour-toned wood filler?

On re-reading my earlier comment regarding using a variac, I think I need to clarify a little: "Despite what EVH may have done with his variac, you should never run a tube amp flat out at reduced mains volts for any length of time in an effort to reduce volume to apartment levels. Premature failure of the tubes is likely." (emphasis mine). Using a variac to lower the mains voltage by no more than 10-15% from nominal is actually perfectly acceptable, and is exactly what Mesa do with their "Tweed/Spongy" switch on a few of their amp models. Flicking this switch reduces all voltages in the amp by the same percentage and is technically no different than running your amp from a variac and winding it down by a small amount. However the volume drop is inconsequential and will still result in a nasty phone call from the neighbours or cops - the variac in this case is acting more on the tone of the amp than the volume. Depending on where you live you may find that reducing the mains voltage by a small amount is actually a good thing. You may have an old vintage amp of some kind that was originally designed to operate on 110VAC from the wall, and your local supply is closer to 120V. Reducing the mains voltage to its original spec will have a positive effect on tube life and other voltage-sensitive components in the amp. The real danger is just winding down the variac willy-nilly without paying attention to what effect it has on the amp as a whole. Reducing the mains voltage also reduces the filament voltage. Reduced filament voltage also reduces emission in the tube, which in conjunction with lots of plate current for long periods of time results in cathode stripping of power tubes (which I will admit is probably not going to cause the end of the world, but does mean you'll have to replace your power tubes more frequently). As Keith mentioned above, raising the variac above nominal is most definitely asking for trouble. Any device that has such an drastic effect on the operation of an amp should be treated with caution - it's easy to accidentally set it to a wrong value and not realise until the smoke comes out. In short, I guess unless you know exactly what you're doing with a variac it's probably best you find a different way to tame that Plexi.

Careful with that axe, Eugene. Removing one tube in a pair *may* work, but the results can be unpredictable. Even assuming you can get a 50% reduction in power, a 50W amp running at 25W output power in a small room is still going to be ear-shatteringly loud. It's not just a simple case of reduced power either - bias changes, tone changes, reduced load on the power supply may mean that components are run above their voltage ratings...the short answer is "it depends". A variac should most definietly NOT be confused with an attenuator. A variac is a variable transformer used to raise or lower the AC mains supply coming out of the wall. An attenuator is a device used to reduce a signal output down by a certain amount. The former is (allegedly) what Eddie Van Halen used to create his Brown Sound by changing the voltage his Marshall ran at. The latter is what you'd stick in between the amp and speaker to bring the volume down to a more managable level. Despite what EVH may have done with his variac, you should never run a tube amp flat out at reduced mains volts for any length of time. Premature failure of the tubes is likely. Whichever way you look at it any attenuation method will introduce tonal foibles of their own. Reducing the master volume, installing an attenuator on the speaker or in the FX loop, modifying you amps' circuit topology to use a more elaborate volume control or whatever will all change the sound of the amp. Trying to micro-size a 100W Marshall down to an iPod will always be a trade-off in some way or other.

Yep, most definitely. Most people probably haven't heard what an actual ground loop sounds like. Hums and buzzes in a guitar are often mis-labelled as a ground loop when it's more likely to be induced noise, either through poor shielding or something inside the guitar cavity being grounded poorly. A true ground loop will have a fundamental tone of 60Hz (or if you live in the UK, Aus, NZ etc 50Hz). Anything that sounds buzzy, raspy, hissy, squealy, static-y etc is not due to a ground loop and is far more likely to be caused by a wiring or shielding issue in the guitar. If you can change the buzz by moving around the room, or turning something off, or playing in a different house it's not a ground loop. The oft-touted star grounding method in a guitar does not guarantee noise-free operation of the instrument. Diagrams that show all grounds returning to the case of the volume pot as "star grounded" are not done because it IS star grounding, but because it's a handy central place to attach the many points in a guitar circuit to ground. The fact that it is star grounding is just a happy coincidence and probably only adds to the confusion.

In many cases you don't get a choice. A humbucker with a 4-core shielded cable for example (4 signal wires and a 5th separate shield conductor) is technically only grounded at one end by deliberate action of the guy installing the pickup, ie by soldering the shield wire to the ground system in the guitar. The other end of that shield wire goes to the backplate of the pickup which is usually floating in mid air behind a scratchplate or screwed to a big lump 'o wood. By definition the pickup shielding is grounded at one end only. There's a lot of voodoo floating around regarding grounding and shielding in guitars. Probably the most important factors in grounding in guitars is not that you explicitly use star grounding or bus grounding or Eric Johnson's super-mysterious Alpha Centauri grounding system 5659-a rev 38, but that your work is clean and any grounds you use or make are low impedance. Chances are you'll probably settle on a wiring scheme for your builds that follows no rule in particular, but works every time and is easy for you to execute.

My personal situation is not so much that I couldn't afford a basic spray setup, but rather given my current rate of building I can more justify a simpler hands-on approach. Since my workflow is still a case of "do what I can when I can, or when I feel like it" wipe-on poly makes a pretty good alternative for me. The other factor in my chosing to forego a spray setup is my workspace simply doesn't lend itself well to a spray gun - I would have to be spraying outside, and would thus have to be battling the elements for most of the year to get anything finished. I can see that if you were in the business of turning around instruments quickly and consistently a spray setup is the way to go.

My last few builds have been wipe-on poly. Like you I'm limited by the equipment that's available to me (or rather the lack of it), so I have to use alternative methods of finishing. It's reasonably hard wearing provided you build it up, which will take much longer than spraying. It's not as hard as nitro, but a lot more durable than oil. I usually bank on two coats in 24hrs in warm and dry conditions. If it's cooler I'll do one coat a day. I'll generally aim for 12-14 coats total, and then leave it about a month to cure properly before polishing, assembling and playing. Use old cotton T-shirts or similar lint-free material as your application rags and expect to go through a lot of squares of rag material before you're done. Don't try to use the rag more than once. When the poly dries on the rag it will go like cardboard. Place used, wet rags outside laid flat on the ground when you're done applying a coat, as the poly is exothermic and can ignite a rag if it's screwed up and placed in an enclosed space. Wear rubber gloves too - since the poly is almost water-thin it soaks through everything. I use those disposable latex single-use gloves that Ansell make in boxes of 100 pairs. If you have the body mounted on a post in a vice, or suspended from the ceiling you can get away with only one glove and make the box last twice as long. I usually do light coats to start with, just placing the rag over the neck of the container and inverting the contents briefly to wet the rag enough to get the poly on the instrument. Doing heavy coats early on looks really good initially but seems to increase the drying time between each coat, and the finish devleops a rubbery feel that takes a while to cure out. Once I have about 4-6 light coats on I'll start applying heavier coats. I'll tip a small amount of poly into a small tub and soak the rag in the mix, squeezing the excess out before applying it to the instrument. Lightly kiss the instrument with 600-800 grit paper between each coat for the earlier stages, just enough to remove any surface imperfections and dust nibs. I've found that you can use much lighter grit sandpaper when you switch to the latter heavier coats, or even skip sanding between every altenate coat. Steel wool or scotchbrite saucepan scourers can work too if used lightly, just remember to go over the instrument with a clean cloth after sanding/scrubbing/scouring and remove any steel wool shavings, dust or scuzz before coating again. A light touch with the rag makes application relatively simple and foolproof. Aim for long sweeping motions in one direction only, overlapping each pass slightly as you go. When you hold the body up at various angles in the light you should be able to see how you're progressing and if you've missed any spots. If you can avoid it don't go over the same area more than once while wet, as it's difficult to get the edges to re-blend once the initial coat is down. If it looks like you've missed a bit or it's drying a bit patchy, just let it dry and fix it up in the next sanding/coating run. Depending on your timber choice you may find a couple of spots where the poly dries slightly differently to the surrounding areas (usually this shows up as a dull patch that suddenly appears when doing the sanding between coats). Again don't sweat it, as you build up the coats this will eventually blend in to the surrounding finish. Watch for runs as you apply the finish. If you do light coats early on runs probably won't occur. During the heavier coats you can get a run, but if you remember to squeeze out the excess and blend your edges as you go you should be pretty safe. If you do get a run just wait till it dries and take care of it when you do the next sanding pass. Conversely don't let your rag get too dry as you apply the poly, regularly "rejuvinate" your rag with more poly as you go. You'll feel it if the rag starts to dry too much as it will feel like it's dragging on the surface as you go, and the finish will start to look streaky when held up in glancing light. Satin poly is more forgiving in application and appearance than the gloss, but you can always steel wool the gloss to take it back to a satin appearance if you like. The satin poly also tends to build up to a semi-gloss look once you get above about 8 coats, so depending on the look you're aiming for you may need to re-introduce a bit of satin by buffing with steel wool again.

The only time I have ever done blind routing was to add a wiring channel around the side of a battery box cavity, but that was using a 4mm x 4mm slotting bit with a bearing. It's not something I'd want to be doing too often. Anything bigger is going to raise all sorts of issues with practicality and safety that I personally wouldn't feel comfortable going ahead with: A bigger undercut requires a bit with more "reach", so how do you get a wide bit down into the cavity to start with (bit may be wider than the opening you're trying to put it into)? How do you stop it getting away from you if things go pear-shaped (can't just simply pull the router away)? How do you safely finish the cut and the bit is still spinning inside the hollow you've just created (can't just simply raise the router)?

Yes, the Wilkinson posts have the set screw inside the post to help lock it into its chosen height. And no, I wouldn't recommend using any kind of threadlocking compound/tape to secure the posts either. If your posts have so much wobble that you need to use glue or tape to secure them you should be replacing them outright.

Good points and comments, all. I have destroyed several horn tips because I was attempting to go around the body in one direction only. At best I was able to salvage what I had done by sanding the affected area down. At worst I had to trash the blank (and change my trousers!). The most common offenders are the tips of the horns around to the outer edge of the horns. I should probably clarify that at no point in my method am I employing a climbing cut. I have never felt safe or comfortable using climbing cuts on the table with such large bits. Even though I am always routing downhill, by flipping the body over for each alternate curve I ensure that the direction of cut is always into the bit rather than away from, and at the same time the cutting blade only removes material in such a way that doesn't try the push the grain back up into itself and cause a grab.

If it encourages constructive discussion, then all is well in the world. There is no doubt that the router is one of the most dangerous pieces of kit in our workshops, and talk of safety around them should be encouraged. When I'm using them it's safety specs, earmuffs and dust mask time. And unless I can see an air gap between the plug and wall socket, my hands don't go anywhere near the collet to change the bit. In regards to Chris' video, I had seen it earlier and a lot of what he discusses is what I've used in my methods too. The thing that strikes me as different is that it appears he cuts the body in one direction only. At 2:04 for example, he's cuting a section in a direction that is flowing uphill against the grain, wheras I would flip the body over and cut downhill into the "valley". IME depending on the timber you're working with, the cut that Chris does in that video increases the chance of tearout, especially in areas where the curve is even tighter such as inside cutaways and tips of horns.

I voted for psikoT this month. Most definitely a deserving winner IMHO.

The final pass with the router gives the following results: In the last shot you can see where I proceeded slightly past the middle of the cut on the blackwood body and some of the grain has fuzzed-up. If I had continued around further this would have undoubtedly resulted in destructive tearout because the cutting action of the bit at that point would have been violating the "slice-cut" or "downhill-cut" rule and was starting to move into the "tearaway-cut" or "uphill-cut" zone. However, the myrtle top at that point where there is a lot of knots and inclusions shows no sign of tearout.

The body is flipped over and the bit is then cranked up so that the shank-side bearing rides against template. If using the two-bit method you'd swap for the bearing-on-shank bit at this stage: With the body flipped over it is now possible to trim the remaining curves while maintaining the "slice away" cutting rule. Marking the sections to cut shows the following. Essentially all you're doing is just routing away the leftover bits so that all the previously routed sections are all joined together. Top of the players' armrest to the middle of the waist: Outer edge of the bass-side horn to the tip: Middle of the bass-side cutaway to the middle of the heel: Middle of the treble-side cutaway to the tip: Outer edge of the treble-side horn to the waist: Outer edge of body curve to strap button position:

After firing up the router and cutting only the marked sections, you should end up with something like this. Each cut only goes as far as halfway around the curve:

After doing several bodies in the last couple of years and researching the topic a bit, I think I've finally settled upon a method for routing body shapes on the router table that appears to work everytime with next to no tearout. I'd seen mentioned in several places to always "route downhill", but it was never entirely clear to me at the time what exactly "downhill" was in relation to a body curve. Hopefully the following post(s) will clear that up for anyone else who, like me was confused by this terminology, and also give a pictorial guide to shaping a body blank to a template without the router destroying your work. The bit I use is one of these bad boys: It's a 3/4" diameter CMT flush trim bit with 2" long downshear blades. I've modified it with the addition of an extra bearing on the shank to make it a dual bearing unit. You can probably buy these things with the dual bearings already installed. I just had the extra bearings in my toolkit and fitted it. The dual bearings are necessary, and will become clearer on their function further on. As an alternative you can use two separate bits - one with the bearing on top and one with the bearing underneath. It will have the same effect, only you'll need to swap bits halfway through the procedure. Whatever bit(s) you end up getting, make sure they're quality ones with enough blade length to cut the full thickness of your body blank. The size and duty of the bit probably necessitates the use of 1/2" shanks - a 1/4" shank bit will likely break when used in the following application. In this example I'm trimming a figured top wood down to a precut blank, but the procedure is the same if you're trimming a blank down to your template (in fact this is exactly what I had done earlier with my blank in the pictures). The body in this one is Tas blackwood (unfortunately easy to burn, so please 'scuse the visible scorch marks!) and the top is Tas myrtle burl with a fair bit of figure and knotty sections: I've cut the top down with about a 1/4" overhang, but in practice the smaller this oversize cut is the better - less timber to route, easier on the bits, less chance of tearout. Nevertheless, trimming the overhang down from 1/4" works OK with a soft timber like myrtle with only 15mm of timber thickness to deal with, especially in multiple small passes: The bit is installed in the router and cranked up so that the top bearing rides on the template (or in this case the body). If you were to use the two-bit method you'd install the bit with the bearing on top in the router. With the bit at this height we're going to route half the body curves in a particular order: The next trick is to work out and mark which curves shall be tackled with this bit. The idea is to have the bit attacking the workpiece in such a way that the rotating blade wants to "push" the grain of the wood back onto itself as it cuts, rather than try to lift the grain away. This "lifting while cutting" is what causes the tearout in the first place. Imagine routing an edge across the endgrain of a block of timber from right to left with the workpiece facing away from you. As the router starts the cut on the righthand edge everything starts fine, but as the bit finishes the cut on the left it breaks out a piece off the edge perpendicular to the cut. A similar thing happens when routing curves depending on which direction you attack it from, and (what I now realise) is what is referred to as "downhill routing". The next series of shots hopefully explains this better. I've marked in pencil the start and end of the cuts. With the bit rotating in an anti-clockwise direction this satisfies the "slice-away" cutting action for each curve. From the bottom of the control cavity to the waist: From the top of the arch where the players arm rests to the strap button position: From the outer edge of the bass-side horn to the waist: From the middle of the treble-side horn to the tip of the treble-side horn: From the bottom of the treble-side cutaway to the middle of the heel: From the outer edge of the treble-side horn to the tip:

If guitar headstocks were jazz musicians, we'd all be "paying homage". Liking the progress of this one so far!

From memory the Wilkinson studs have about 3/4" of thread on them, so unless they're already backed out of the inserts more than about 10mm I can't imagine adding a couple more turns on them will affect the operation or stability of the trem. You can even just back out the bass-side stud a bit if all you need is a bit more height on the E/A/D strings. I've done exactly this on my last build and I have no issues whatsoever with the trem.

Interested to see how the Hannes bridge goes for you. Was considering trying it for a future build myself. It's got that all-at-one-level, no-pointy-bits-sticking-out thing that looks extremely comfortable. Same reason I like the Hipshot bridges too.

Good to see a return to form this month with such a large collection of entries to choose from. I went with the Spalted Maple Singlecut this time round. The combination of black hardware and the spalted top sit nicely together. Job well done to all entries this month!

Lots of examples floating around where builders have carved a top where the carve goes all the way through to the body, either by design (after a particular look) or necessity (top was too thin to retain a binding edge). No reason you couldn't carve it if that's the look you want, or even just stick with a shallow carve. http://projectguitar.ibforums.com/topic/47054-guitar-of-the-month-for-february/?p=519875 http://projectguitar.ibforums.com/topic/46381-guitar-of-the-month-for-may/?p=506608 http://projectguitar.ibforums.com/topic/46055-guitar-of-the-month-for-february/?p=500930 http://projectguitar.ibforums.com/topic/45572-guitar-of-the-month-for-september/?p=493138 http://projectguitar.ibforums.com/topic/45271-guitar-of-the-month-for-june/?p=488693

Ouch on the CNC! Can your CNC be fitted with some kind of supervision that looks for these kinds of failures? At least then if something decided to go fizzle it would shut the system down rather than continue on and destroy your work. Do Hipshot offer those headless systems commercially yet? I've only seen the 6 string version on their website.

I've just bought a batch of the Allied rods. Up till now I'd been using the Allparts wrapped-in-blue-plastic generic double action rods, which have all been perfectly serviceable. As Scott mentioned there's no real difference in terms of size between LMI and Allied, and based on the Allparts ones I've been using they're all probably the same dimension-wise. The Allied ones certainly look prettier, and they have finer pitched threads which allow more turns for a given amount of "bend", which gives it a nice quality feel. The supplied allen key is certainly better quality too. I still had a couple of rods in my batch where the threaded block had been welded slightly off-centre on the flat bar. Not enough for the rod to be unusable, but enough for me to think that although the rods are probably some of the better ones on the market, they're still prone to the same kind of assembly faults as the cheaper Allparts ones.

Some really nice work you have there. Particularly like the 4th one, the Baritone DC.