5th scratch build

[Rabbit]

My pickups arrived, but it looks like the pole pieces are a lot further apart that I expected. the spacing is even too far for my 34 inch basses, unless used as a bridge pickup. The upshot is that I will be de-constructing them, making new bobbins and re-winding.

I have however done the base blank for the fret board.:



I used the CNC router at the mens shed to mark the fret slots and centre line. Since you have to baby sit the machine while it does it's thing I had Rush bluetoothing into my earmuffs

To cut to final depth I used this contraption:

[Rabbit]

Using the violin bass as a template for string spacing at the nut and bridge I did a bit of a mock up with twine, put a pice of flat aluminium under the twine where the pickup goes, and sprayed some black paint over the strings and aluminium:



I used this to create a file for the CNC to carve out the flatwork from some rock maple I thinned down with the correct spacing for the pole pieces. Since the wire on the pickups I bought was so thin, I broke it several times trying to unwind it. The upshot being that rather than buying cheap pickups, I ended up with expensive pole pieces .

Since I kept breaking the wire, I can't re-use the windings. It appears to be 42 AWG based on the micrometer reading.I ordered some wire, thinking 1km should be enough. I should have looked up the resistance first :\ . Turns out 1km aint enough for 1 pup, let alone 2!. Now this instrument will probably be for the most part a wall hanger, so details like how the thing sounds probably don't matter. But for some sick reason I felt compelled to do a little research on what the specs for the '51 telebass pups were..

Next step will probably be a mix of working on the fretboard and building a winder for the pups. My partner in crime at the shed seemed enthusiastic at the prospect of me building something so he can use it to wind pups for his 6 strings.

With a bigger budget I'd love to explore the differences between pups with the same resistance but with different number of turns. Like because the pole pieces are closer together, the new pups will have more turns, since each turn will be shorter than the pups I had bought.

[Trevor Davies]

I love the fret sawing contraption - it looks great.

Also, shame about the pup wire breaking! I had not given it much thought- but more than 1 km of wire! Wow.

[Rabbit]

I love the fret sawing contraption - it looks great.

Also, shame about the pup wire breaking! I had not given it much thought- but more than 1 km of wire! Wow.

Thanx

Yeh, enamelled copper wire specs resistance per km. 42 AWG specs out at about 5.8k/km... which is about the spec for the original '51 pups. Modern replacements are about 6k for the cheap Chinese ones and 7k for some of the others. In my case I have made the first spindle. it's a bit wider than the original and because the pole pieces are closer a bit closer together. Should hold bout the same as the original. I'm just going to stuff as much on as it will hold and do the same number of turns for the second one.

The motor and speed controller for the winder have arrived, the counter is in the country, as is the 3.5km of wire. Should have the winder made some time in the next two weeks. Hehe any bets on how many winds I mange to get before I put too much tension on the wire or wind too fast and snap the wire?

[Rabbit]

It's been a while since I last posted. I'm currently working on making a new jig to radius fretboards, but as with most of my endevours, it tends to be akin to "there was an old lady who swallowed a fly".....

As for the pups, I used the CNC router at the Men's Shed to make some of these:



it wasn't until I had assembled two with the pole pieces, that I realised... "um... dood....how am I supposed to mount these?" These are a custom size, so unlike the strat/jazz pups I pictured in my head, there is no cover with mounting holes! So I made a couple of these:



I didn't do the mounting holes cause I don't know what size screws I'm gunna use. The 5mm hole in the centre is an index hole. After marking the centre of the underside of the pup flatwork I glued this new piece to the underside of the pup.

I also made a winding machine:





This is the Mk1 version. It's a little rudimentary but it should do the job. It uses a magnetic sensor to count the number of winds (the white display at the top). When I turned it manually the counter worked just fine but stopped working with the motor running. At first I thought it wasn't fast enough to keep up[ with the rotations, but in the end I worked out the motor's magnetic field was interfering. When I re-positioned the sensor just a smidge it worked fine, si I glued in a baffle between the motor and the sensor just to be sure.

I recently was assessed to use the metal work lathe at the Men's Shed, so I was able to use that to make the part to connect the shaft of the motor to the winding wheel. I also machined a part to epoxy into the part with a short 5mm shaft to centre the pup spindle, which is attached with double sided tape.

I use a couple of nuts bored out to 1/4in on a 1/4 rod to set the width of the wire path to the boundaries of the inside of the spindle so I can apply tension and move the wire from side to side as the spindle turns. I believe they call that scatter winding. If I ever do a Mk2 it would have a guide that moved the wire from side to side automatically, much like the fishing line on a bait caster reel.

Setting the speed to about 10% seems like a nice comfortable wind speed. I think I worked out that it will take me about half an hour per pup to wind.

The speed controller has a nasty action where it starts the motor as soon as you connect power. There is a switch on it but that's connected to the electronics so you can't turn it off till after it's powered. I put switch between it and the motor so that you can mechanically switch it off before you supply the controller. Motor direction is also controlled by this switch, just in case it works and at some point it gets used to make a humbucker.

[fender3x]

That's an impressive machine. You'll be able to open your own custom pickup shop. No one can accuse you of not taking this "scratch build" thing seriously!

[Trevor Davies]

Wow. I'm super impressed with the winding machine as well. This looks great! Definitely next level for scratchies.

What voltage is this running on?

[Rabbit]

Wow. I'm super impressed with the winding machine as well. This looks great! Definitely next level for scratchies.

What voltage is this running on?

Thanx trevor and fender3x

Trevor, it runs off a 12v power supply. I picked a motor limited to a max of 6000rpm (these suckers can do over 20k rpm unrestricted.)

I found that 8% power is enough to turn the winder with an initial nudge, 9 and it will move on it's own from a standing start. Speaking of witch, with a few manual turns and 10000 turns later, I ended up with this:



I was using my fingers as both tensioner and leveler. I would get a few winds by hand just to secure the wire, then start at 8% power and slowly build to 17%. I didn't dare go faster for fear of snapping the wire...pretty sure with a tensioner and experience the process would tolerate double the speed. I got about 500 winds my first attempt before pinching too hard and snapping the wire. I got 1000 turns on the sencond try, but the wire got caught on a rough spot on the lip of the wire roll. 3rd time was the charm.

[Trevor Davies]

The pup wiring looks great. Really love the blue enamel coating!

So, is this going to lead a new business venture? And where do I place my order?

[Rabbit]

The pup wiring looks great. Really love the blue enamel coating!

So, is this going to lead a new business venture? And where do I place my order?

Hehe no, this is just me being batsh*t crazy and deciding that since no one makes 4 pole pups for the string spacing of the Adventure Time axe bass, I was going to have to make them myself. I'm also making a bridge for the same reason. A brass nut has started being formed. the strings and the tuners will be the only thing on this not bespoke.

After watching all 10 seasons of Adventure Time "for research purposes", I did not notice any physical frets in side profile. Now I know, it's from a cartoon...a very stylised cartoon, but....if they can manage to show that Marceline is ambidextrous by playing the bass both right and left handed, and flipping the side the controls are on. Given that attention to detail and she *is* a musician, she would not play an instrument that makes no sense. In addition her fingering suggests that perhaps the instrument is actually fretless, and the 13 frets are just markings.

So.. after I get the fretboard radiused I'll fill in the fret slots with black epoxy and it will be a fretless small scale bass.