Jump to content

Entry for February 2020's Guitar Of The Month is open - ENTER HERE!

Prostheta

The Lancaster

Recommended Posts

Hi all - this is the beginning of what should be a long-term project going through many stages. The guitar will be a fairly standard two-humbucker superstrat, however the point of the design is to document the process from beginning to end.

Part of this will hash in with the CAD series of articles I'm penning whilst other bits will be the basis for various how-to articles. A productive design despite being more or less a standard. Essentially, a guitar that anybody can build. Depending on the availability of time, I will try and make this using the most basic of tools and equipment. A simple everyman's build.

The name "The Lancaster" comes from the planes that a family ancestor in the RAF flew in his final operations of WWII. I figured that a more vintage "slow looking" design seems to mate with the bomber theme. It's a tenuous link, but a good starting point nonetheless.

Share this post


Link to post
Share on other sites

The first step I take in any new design are the very basic specifications that define the instrument from the outset.

  • Bolt-on with vintage square heel
  • 25,5" scale
  • Original Floyd Rose bridge
  • 12" nut radius with 1,6875"/42,85mm width
  • Non-tiltback headstock

The less important specifications which don't necessarily drive the design process

  • Dunlop 6105 fretwire or "narrow, perhaps taller"
  • Rear-loaded electronics
  • Side-mounted jack
  • 6-in-line headstock
  • Radiused top/back
  • Arm and belly cuts
  • Ferrule-fitted hex bolts and threaded insert mounting

I'm open to opinions about the truss rod. In a perfect world, I'd like to use a Stewmac spoke wheel nut to adjust from either the heel end or in a slot between upper frets to get the best acting motion out of it. Alternatively, it might be a good opportunity to demonstrate a single-acting rod in a curved and filleted channel? I'm quite fond of U-channel rods myself, however I need to remember that as an "everyman's design" these aren't always easily available.

Share this post


Link to post
Share on other sites

Okay, starting a new file from scratch in TurboCAD. I set my space units as mm with a precision of 1, or tenths of a mm. I can still manually place items to tighter tolerances. I also set a default grid of 10mm purely as a visual sense of reference. This is totally unimportant once we get working.

Using Imperial matters here nor there since we're working in decimal rather than fractional. I'll do the necessary conversions either way so Imperial users can follow.

cad1.thumb.jpg.54f08724ea52a4076f526cf99

Share this post


Link to post
Share on other sites

I usually have all of my "standard" layers set up in a template, however I'm taking this from the top. My most important layer is one I call "guides" which I set up with a contrasting default colour. Anything that helps differentiate it from the rest of the drawing. The "0" to the right is that layer's Z order. Later on I might change the stacking order of layers for a bit of visibility.

cad2.thumb.jpg.05f7c80babd6c233413e18b22

Share this post


Link to post
Share on other sites

Next, I'll draw the first two important parts of our reference geometry; the centreline and absolute bridge placement which is perpendicular to the centreline. Both go through the XY origin (0mm, 0mm). This was done by selecting the GUIDES layer, turning on Grid in the snap palette and using the Line tool.

cad3.thumb.jpg.425deb48be1723821aaed090f

 

Et voilà. (I forgot....turn the layer colouration to "By Layer"! That means anything you draw uses the layer's set default)

cad4.thumb.jpg.07ec7d86719ee3975b7d563fd

Share this post


Link to post
Share on other sites

Okay, we have the basics from which everything else is built. The next step is to create a guides layer for our fretwork. Again a new layer is created and given a default colour:

cad5.thumb.jpg.a4a339f07ce12e8244945e66a

 

 

Share this post


Link to post
Share on other sites

We're going to cheat a little here. Cheat is a bit of a strong word because using geometry to your advantage isn't a shortcut in the negative sense! Grab your fret placement sheet, FretFind2D or alternatively use our basic fret calculator:

 

Inputting 25.5 calculates an even-tempered 12th-root-of-2 set of scale measurements. Here, we are interested in the values of the fourth column, "Distance from nut - Metric". Incidentally, TurboCAD happily accepts and converts values different to the current measurement system through manual input of 2in, 2", 2mm, 0.002m, etc.

cad6.thumb.jpg.849bb63c6c5bf927c5b5be3de

Share this post


Link to post
Share on other sites

By "cheating", I meant "using the measurement system to your advantage".

Firstly, activate the Select tool. Second, right-click in the workspace and activate "Make Copy":

cad7.thumb.jpg.fd41fcd33c79ed4d81104152a

Share this post


Link to post
Share on other sites

The process from here might seem a little confusing in how we're doing it, but it saves us a bit of calculation and simplifies things. We're going to repeatedly copy existing guides to create a separate set of fret guides.

Firstly, select the vertical guide placed at x=0mm;

cad8.thumb.jpg.1689c9f899748417e834db4ea

 

The object will change colour and transformation nodes and the centrepoint will appear. Next, in the Inspector Bar change Size Y from "600mm" (or whatever height your vertical guide is) to something slightly wider than the neck will be. I chose 100mm. Without pressing Enter, click into Pos X and input the first fret location. Now press Enter.

cad11.jpg

Share this post


Link to post
Share on other sites

cad11.thumb.jpg.ca955e641c4b203e8b73b197

This duplicates the selected object with an exact copy, including the parent layer and appearance values. We made two changes ("transforms") simultaneously; the Y extent (from 600mm to 100mm) and X centre (0mm to 36,35mm). Doing these transforms individually (pressing Enter in between) would have created two objects with each individual transform.

We want to place this new object onto the Fret Guides layer. Simply double-click "Fret Guides" in the Design Director. The green tick will change to signify which layer that object exists on.

cad12.thumb.jpg.4a9fb44d0b9ba3f868d9c2d8

You might have noticed that the Inspector Bar says "36,3mm" rather than the value we inputted. TurboCAD internally located the object at 36,35mm but displays the measurement according to the chosen tolerance. It's all good.

Share this post


Link to post
Share on other sites

The process from here is more or less identical to copying the initial guide. Ensure that you are using the Select tool and that the new fret guide is currently selected. One by one, type in the fret location values in the spreadsheet column, pressing Enter after each one. I went up to 24 frets even though I have not decided how many frets the finished design will have.

You should end up with an array like this:

cad13.thumb.jpg.29488a31dda441cf5bb99623

Share this post


Link to post
Share on other sites

I find it logical to work on guitar designs as I would look at them from the front. What we've done here is to place fret locations using absolute placement. It's better than relative placement ("distance from last fret") since any rounding is no issue, avoiding compound tolerance errors (±1% + ±1% + ±1% + ±1% + ±1% +....) which can play havoc with intonation!

The shortcut is that I temporarily used the X coordinate as a way of placing the frets. The fret locations are the wrong way around (left to right) and in the wrong place! We'll place one more guide and then flip the lot left to right. That will put things right.

Firstly, use the Select tool. Right click in the workspace and check that "Make Copy" is still active. Now, select the vertical green guide. In Pos X, input either 25.5in or 25.5" (the scale length) and press Enter. We are using the original Imperial measurement since that was the original value and the spreadsheet doesn't convert that value anyway. We'll now have this:

cad14.thumb.jpg.3a4a923ad6931aef1fd7f4db

Share this post


Link to post
Share on other sites

Zoom out a little if you need to. Click and drag a selection box around the vertical guides only, not the horizontal guide:

cad16.thumb.jpg.bf3a5fddf4433ad9946b9e03

You can do multiple selections with Shift and Ctrl if you need to add or remove anything from the selection.

 

Next, input "-1" into the Scale X transform box in the Inspector Bar:

cad17.thumb.jpg.787e34549d70ed4dae759943

 

Press Enter:

cad18.thumb.jpg.e8ac350fa33f7849ebfd25b6

Share this post


Link to post
Share on other sites

And there we have it. Everything that we need to build the rest of the geometry from! I think at this stage I'll save my work....

In reality, I have this basic scale template already saved for use in different designs. By using it as a group including the bridge point at nut point I have an object which I can shrink or stretch to specific widths corresponding to a scale length. Since each fret is at a point correlating to a specific percentage between the nut and the bridge, the scale calculation holds true.

Let's make a couple of tweaks. These are simply visual aids to highlight important places later on.

Select the 12th fret (count them along and check the Pos X value in the Inspector Bar against the spreadsheet). Adjust it's Size Y to 150mm. Do the same for the 24th fret.

Share this post


Link to post
Share on other sites

The next step that I like to take is to figure out the neck taper and string locations. The width of the neck affects how the body's heel is dimensioned, so we need to do this first.

We're planning for an Original Floyd Rose here, so referring to the specs sheets we find that we have a string spacing at the bridge of 10,7mm between strings. That said, there seems to be some variance....anywhere from 53mm total spread, 10,8mm and other values! A tenth of a mm isn't going to cause problems so we'll stick with that consistently.

Change to the Line tool and change the active layer to GUIDES. Change Snap Mode to grid only:

cad19.thumb.jpg.c60a85ebfef43fbef804bb49

Share this post


Link to post
Share on other sites

Zoom in fairly closely to the bridge area:

 

cad20.thumb.jpg.41a161fc7b71825402f42fcb

You'll find that as you move the cursor around the drawing area it is followed by a magenta diamond showing the snap point. Currently mine is snapping to every 10mm. If yours isn't, right click on the grid button in the Snap To selector:

cad21.thumb.jpg.a8f0f1a221eccab5b6601630

...change it to 10mm

 

 

Edited by Prostheta

Share this post


Link to post
Share on other sites

Change from the Line tool to the Select tool and drag a box around all six of these lines.

cad24.thumb.jpg.afb922479ab1f1275441628c

 

We're wanting to space these out equally according to how the strings are spaced over the OFR. Since we're looking at 10,7mm over six strings; 10,7 x 5 = 53,5mm. In the inspector bar, input that size into the Size Y box and press Enter. The selected objects are then stretched to that height, automatically spacing them 10,7mm each.

cad25.thumb.jpg.27375d921e696c6c4e6a78e8

Share this post


Link to post
Share on other sites

We're now wanting to locate these guides at the bridge point. These will serve to tell us exactly where the saddles should be located at their furthest-forward mark.

Firstly, in the Snap To palette select Intersection and deselect Grid:

cad26.thumb.jpg.6cbc6f296f5d252018407eb9

 

Click the yellow dot in the centre of the six selected lines (if they are deselected, drag a box and reselect them) to pick the objects up and hover the cursor over the point where the vertical guide meets the horizontal guide. The cursor should snap and a magenta diamond showing the snap appear. Click to drop the objects.

Alternatively, you can simply select all six lines and change the Pos X and Pos Y values in the Inspector Bar to 0mm.

cad27.thumb.jpg.21f98eca0bca43d5fc4b6eba

cad26.jpg

Share this post


Link to post
Share on other sites

State of play:

cad27.thumb.jpg.e05d9a5c8dab5aecc47d85ca

 

The next job is to do almost the exact same thing at the headstock end. Firstly, select the six lines and Edit > Copy them. Zoom out and zoom back into the headstock end before Edit > Paste:

cad28.thumb.jpg.15f7c55dad45c3b5cad507e2

Share this post


Link to post
Share on other sites

Referring to the specs for the type 3 OFR locking nut, the E-E string spacing is 35,95mm. Change the size of the six line object group to this, and place over the nut-centreline intersection as previous:

cad29.thumb.jpg.4e79d873af5a91a9952313aa

 

Finally we want to place guides showing the absolute width of the nut unit. Firstly, left click anywhere away from an object in the workspace to deselect everything. Next, click the top line of the set of six. Then - holding down shift - click the bottom-most. Right-click in the workspace and select "Make Copy".

cad30.thumb.jpg.1519925f4cd0fb87fdf7f49a

 

The nut specification say that the unit measures 42,85mm wide. Enter that into the Size Y value and press Enter. Deselect "Make Copy" in the right-click menu and left click in empty space to deselect all objects.

cad31.thumb.jpg.3697a6489530d092277d511e

 

So this is what we now have (zoom out):

cad32.thumb.jpg.e2ab1804bfc9d2a7d4de9d97

Share this post


Link to post
Share on other sites

Before I knock off for the day, we'll add in the strings provisionally. Create a new layer called "Strings" and assign it a colour such as a mid-grey. Change the Z-order from 0 to 10. As we work, layers will be re-ordered and strings tend to be on top.

cad33.thumb.jpg.c01977b18678e65085abf5fc

 

Change to the Line tool and ensure that Intersection is the only active tool in the Snap To palette. Select Strings as the active drawing layer:

cad34.thumb.jpg.8260fce2efa04c7c4247c28a

Share this post


Link to post
Share on other sites

Carefully click at each bridge location point to start a line, before moving the cursor over to the headstock to finish it at the appropriate end point. Use the mouse wheel to zoom in/out as you work:

cad35.thumb.jpg.3909fe2edb0f0d88625afa5ecad36.thumb.jpg.c26679c93478dfb28cd55840

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...