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love of Ampeg and other Scroll Basses, Part 2

Discussion in 'Basses [BG]' started by smperry, Jan 9, 2014.

  1. jumbodbassman

    jumbodbassman Gold Supporting Member

    Dec 28, 2009
    Stuck in traffic -NY & CT
    Born Again Tubey
    Beat me to the post. Just saw that
  2. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Interesting. Miami? I wonder if this guy bought the leftover stock from that guy in New Jersey, who was selling it a decade ago?

    They do appear to be original parts, with all the usual factory pinholes and casting flaws. It could be a box full of seconds, leftover from the factory. They are cast from black-tinted epoxy.

    Yes, they are the size that were used on all post-1961(?) Baby Basses and all of the Scroll Basses. The early semi-Zorko Baby Basses used the larger size inserts.

    My replacements are cast from black polyurethane, and are crisper and neater looking. And quite a bit cheaper. But hey, real NOS Ampeg parts if you really want them!
    Last edited: Aug 24, 2018
    ICM, JimmyM and farace like this.
  3. bluesblaster


    Jan 2, 2008
    Maybe same guy I got the AMB-1 bridge cover from some years back.
  4. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Yeah, that's the guy. I forget his name. He and some others bought the building that Ampeg was last in, in Linden NJ. When they cleaned out the attic, they found several boxes of misc parts. He got in touch with me and sent me lots of pictures, hoping I'd pay big bucks for this goldmine! Unfortunately, the parts weren't nice NOS parts. It was mostly leftover samples, seconds, handmade prototypes, junk.

    The most valuable things were (6) unplated AMB-1 bridge covers. He figured that they were worth at least a couple hundred bucks each. He didn't understand how limited the market is for rare Ampeg bass parts. I offered him a fair price for them, and he was insulted and pissed at me. He went ahead and got them plated and listed them on ebay. I think he sold one for about $300, then the price kept coming down over time as they remained unsold. It took him about 2 years to sell them all, and I think the last one went for $75.

    There was also one bare NOS SSB neck, probably a sample from the outside company that was making necks for Ampeg. I think he wanted $1000 for it and was pissed that I didn't immediately find a collector buyer for it. He was just into that Antique Show Barn Find mentality, and thought he had struck gold.

    Other than that, there wasn't much of any value to us Scroll Bass owners. A bunch of Baby Bass parts. A few tailpieces, some pickup coils, and a bunch of scroll inserts.

    I gave up trying to deal with him. I assume he kept trying to sell the stuff. That was back in the late 2000's? So I guess he finally sold the batch of Baby Bass parts to the guy in Miami. I think I know who that is.
    JimmyM likes this.
  5. Bass 45

    Bass 45 Supporting Member

    Jun 23, 2011
    Tempe, Arizona
    Were the unplated bridge covers bare brass? One of those tarnished and antiqued would be stylin' on one of my well Walnut stained AMB-1's.
  6. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Yes, they were bare brass when he originally showed them to me. I think they were actually stamping test samples, and may not have been exactly to spec. But he had them all plated, and sold them that way. There were only six of them.

    I've always been hoping that the press dies would show up for sale somewhere, but I'm sure they wound up in a dumpster. That was 51 years ago.
  7. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Too many people watching American Pickers and thinking they struck the gold that Mike and Frank very seldom do :D
    Gilmourisgod likes this.
  8. Gilmourisgod


    Jun 23, 2014
    Cape Cod MA
    10 minutes after viewing those Ampeg headstock end caps, EBay emails me to ask if I’m “still interested”? Just shoot me now, please. Big Data Never Sleeps.
    ICM and JimmyM like this.
  9. jumbodbassman

    jumbodbassman Gold Supporting Member

    Dec 28, 2009
    Stuck in traffic -NY & CT
    Born Again Tubey
    Usually just fools gold.
  10. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Meanwhile, work goes on here in the Lab. I'm behind in posting, as usual. These are from several weeks ago.

    I'm going take you all through the process of building the new second neck for Jim's (formerly) hornless Devil Bass #1116. If you remember, it is originally a fretless Devil Bass, which is quite rare. However, Jim thinks he would get more practical use out of it if it were fretted. I could convert the neck to fretted, but we hate to do that to a rare original neck like this, which is actually in pretty nice shape.

    So, we've agreed that I'm going to build a new fretted neck from scratch, matching the dimensions, shape and finish of the original. I'm also going to put my standard brass insert blocks in the heels of both necks, so the two necks can be switched back and forth easily. Jim will be ready for any gig calling for some Devilishness!

    I've made a few full replacement Ampeg necks before. A few years ago, I made a new one for Devil Bass #317. The new neck will be almost the same in design and construction as one of my AMB-2 necks. Same lamination structure, truss rod, general headstock layout, etc. The only real differences will be the shape of the hook on the back of the headstock, and a few slight differences such as the position of the zero line. I'm also going to shape the back of the neck to match the original neck. My AMB-2 neck profile is a little more modern shape than the Ampeg profile. We want #1116 to feel and sound original, with either neck on it.

    So here we go. I was actually just getting started on two new AMB-2 necks, for instruments #018 and #019. So, I'll be doing all the operations on the three necks at the same time. You'll see them in many of the pictures. Towards the end will be where the Devil Bass becomes slightly different.

    The first step is picking three good strips of hard maple from my rack. I pre-cut strips of maple and walnut to 1 1/4" square x 34" long, and store them in a rack for a while to let them dry out and stabilize. At least six months, sometimes many years. They are matched as sets and dated. I also cut 3 1/4" x 1 1/4" x 18 1/2" blocks from the same boards, which will become the headstocks. In most cases, the picked set all came from the same board.

    Here's the set I picked out for the Devil Bass neck. A nice old set. They all came from 2012, sawn and stored back when I was in Burbank. They are a matched set, and they've stayed nice and straight over the years. They are done drying out.


    Here are the three sets of strips for the three necks. #018 is walnut; #019 is maple. I've rotated and flipped the two outboard strips of each set to put the growth rings into the correct symmetrical V orientation. The center strips are straight vertical grain (quartersawn), and will end up at 3/4" wide. The sets are marked for the orientation.


    The strips go into my special long routing fixture, to cut the gluing surfaces perfectly straight and flat. The fixture holds the strip by the sides in an un-sprung condition while the router cuts the surface flat to the rails. These are the two side strips of the Devil Bass neck. I'm cutting the two inboard surfaces at the same time.


    Then the center strip goes in the same fixture. I flatten one side, flip it over, and flatten the other side, bringing it to 3/4" thickness.


    And there's the sets of strips, ready for gluing. They are cut to fit tightly together with no spring or gaps. The clamping should not be bending them or forcing them flat, or putting in any kind of internal stresses. This is how to build stable necks. And note the orientation of the rings on the ends.


    Glue up! I use West Systems epoxy, the slow 105/206 mix. I daub it onto both surfaces of each joint, let it soak in for 5 minutes, then clamp them up. They are stacked sideways on my neck beam gluing fixtures. The quick grip clamps hold the three pieces approximately in alignment. The glued up lamination is still oversize, and will be trimmed down in the following steps. The point is to glue them together solidly, with no internal stresses. So the whole lamination never moves or warps or comes apart, no matter what weather it eventually sees.

    Last edited: Aug 31, 2018
    nouroog, BassHappy and Gilmourisgod like this.
  11. Gilmourisgod


    Jun 23, 2014
    Cape Cod MA
    I see what you mean about the growth rings set as opposing direction on either outer lamination. Does it matter which of the faces is the fingerboard side of neck back side as long as the Q-Sawn (maybe more like rift on those pieces) oppose?
  12. jumbodbassman

    jumbodbassman Gold Supporting Member

    Dec 28, 2009
    Stuck in traffic -NY & CT
    Born Again Tubey
    i am feeling a bit devilish.. some more Bromberg big band tunes in my future...

    walnut neck.... always loved the 81 fender walnut precision special bass ( i have 2 of the ash CAR models - weigh about 100 pounds - northern ash) but very few long scale walnut necks out there IIRC.
  13. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Well, yes, it does matter. When you look at a strip of wood from the end, the portions of the rings are curved. You can picture where the center of the log was by the circles.

    The important thing is: when wood warps on its own, it almost always pulls toward the original center of the log. Look at the near end of the strip. From the rings, picture where the center of the log was. If the stick warps, the far end of the stick will be moving toward that imaginary center. If that's not clear, I'll make some sketches.

    When you arrange the sticks, you want the angle and curvature of the rings to be opposite and opposing and approximately equal. You also want the curvature facing up; the imaginary centers are above the neck.

    The reason for this is that, if there is any movement, it will be up; forward bow. If you put the centers down, movement would be down, resulting in back bow. Forward bow is always preferable to back bow, because that's the direction the truss rod is designed to handle.

    The V-shape of the rings on the outer strips should be opposing, equal, and facing up.
    ICM and Gilmourisgod like this.
  14. Gilmourisgod


    Jun 23, 2014
    Cape Cod MA
    Thanks Bruce! Now I gotta check the photos of my last build, can’t remember which way I did it, too late now either way, but you got me curious. I don’t think I’ve ever heard that addressed one way or the other, anywhere. Can’t overstate how much I appreciate your shared wisdom on such a wide range of subjects! Reading your posts always cuts through the chaff like a laser.
    BassHappy and ICM like this.
  15. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Here's a better look at how the strips and growth rings are arranged in the neck laminate.


    Notice how the rings in the center strip are nearly straight vertical. The two outer strips are curved, opposing, approximately equal in ring spacing, and angled upward into a V. The fingerboard goes on top. This is the ideal, the most stable way to make a neck.
    Last edited: Sep 1, 2018
    Michael Uhler, BassHappy, ICM and 3 others like this.
  16. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Back on those three necks, including the one for Devil Bass #1116:

    Next up are the headstock block laminations. Each headstock starts as a block of maple or walnut, 1 1/4" thick x 3 1/8" wide x 18" to 20" long. I generally cut them from the same 6/4 board that I cut the strips from. I also date them and store them to dry out.

    I forgot to snap a picture, but the first step is to put the headstock block into that same old routing fixture I was using above. I trim the thickness down to 1 1/8" and cut the top surface flat.

    Then I use this template to draw left and right hand block shapes on the board. The template is typical construction; MDF with three long steel dowels that stick out the front and back. I hold the template on the board, seating the dowels against the side and end of the board. Then flip it over to trace the reverse pattern on the other end of the board. I also use the transfer punch to spot the locations of the big lightening holes.


    At the punch mark, I drill a small pilot hole through the block, then plough in with a 1 1/2" Forstner bit, 3/4" deep. When the halves go together, this forms a big hollow chamber approximately centered between the scroll inserts. It's there just to reduce weight.


    Here are the headstock blanks:


    ...Which are then sawn apart into the matched halves:


    They are glued together in the same way as the neck strips. West Systems 105/206 (Slow) epoxy is daubed onto both surfaces and allowed to sink in for a few minutes.....


    And they are clamped up....

  17. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Continuing on with the three necks: I'm getting behind on my documentation; this is from about three weeks ago.

    Here are the three neck laminates, unclamped from the gluing bench. They are still oversized in thickness and width. The top one is the Devil Bass.


    Each blank goes back in the long router fixture, where I rout the top surface flat. Then I flip it over and rout the bottom surface flat, bringing it to a final thickness of 1.030".


    I draw a center line and place this template on the top surface of the blank, clamping it down. It's a Master Template, which has two accurately located drill guide bushings. I use them to locate and drill two small reference holes in the neck blank, one near the fork and one at the heel. You may notice an extra pair of drill guide bushings in the template, right on the centerline. Those are from an earlier model Scroll Bass neck.

    These reference holes are very important. Almost all of the fixtures that I'll be using to machine the neck have dowel pins that plug into those two holes. Almost all of the dimensions of the neck are established in reference to those holes. In maple, I drill them #30, which makes them a nice sliding fit on standard 1/8" steel dowel pins. To make everything fit together, I use the same Master Template to drill the holes for the pins in the fixtures.

    After drilling the reference holes, I can easily plug the template onto the neck blank with two steel pins. I trace around the outside of it to give a rough outline of how it will be cut out later.


    Over to the routing bench! This template is clamped down, and I use a small plunge router to cut the pocket for the adjusting head assembly of the truss rod.


    Then this template fixture is used to rout the slot for the truss rod. The slot is curved in the vertical plane, so the template has raised side rails that the router base rides on. The router base has a collar which slides between the side strips of the template, to guide the router down the straight line. It's a 1/4" diameter bit, and it takes 5 passes to get the slot to the full depth.


    Here are the neck blanks with the truss rod slots all routed. These will get my normal single-rod double-acting style truss rods.


    I draw and bandsaw out the center of the fork end, undersize from the final dimension.....


    ...So I can pop the neck blank onto this fixture to drill the access hole for the truss rod. The neck blank is face down on the fixture, accurately located on the two dowel pins in the reference holes. This truss rod access hole needs to be drilled at a precise location and angle. This type of fixture is one way to do it. The long 1" diameter steel shaft has the drill bit mounted in the end of it. The near end is turned down to 3/8" so a drill motor can chuck onto it. The steel rod spins and slides in the two brass bearing blocks, guiding the drill bit accurately. Another good reason to own a metal lathe!


    Next up: installing the truss rod!
  18. Ed Bloom

    Ed Bloom

    Oct 24, 2017
    Yokota AB, Japan

    I go through and review the posts on this thread once or twice a week, if for no other reason than to vicariously experience your techniques in working on basses. After seeing the exchanges on Rocklike, I also want to let you know that I prefer a black Rocklike fingerboard on my fretless. We had a similar, shorter exchange last year when I ordered the bass and I was undecided. The combination of the Rocklike looking more similar to the fingerboard on Danko's original sunburst fretless and your engineering analysis has convinced me.

    While I appreciate the shared information from all the posters, I am amazed at the in depth knowledge and skill you share with us. I really enjoy playing my Ripper, but I am anxious to add the AMUB-2 to the arsenal.
    JimmyM likes this.
  19. dloase


    Jun 20, 2016
    Once again I am amazed by the precision that goes into your work.
  20. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Meanwhile, in other Scroll Bass projects, I just finished up Trussart SteelScrollPeg #004, an extensive rebuild on it. If you've been following this thread for a while, you've seen the pictures and story on the previous three. These are a special version of my AMB-2, all dressed up with metal plates and hardware. I build them and ship them to my friend James Trussart in this form: A complete bass, fully assembled, but in bare wood and with bare aluminum plates. James and his guys will now disassemble it, paint it, and cover the plates with elaborate etching. The finished bass is an art piece in James' unique style, but a fully playable AMB-2. He'll probably have it at the January NAMM show, if it doesn't sell before then. #003 sold at this year's Summer NAMM show for around $7K.

    If you've been following the story, I originally built #003 & #004 as special twin-pickup versions, with each having two of my 4-coil quad pickups. A bunch of R & D, and they sure looked cool. But they weighed 12 lbs. Just too heavy, and no real advantage to the twin pickups. So, I rebuilt them both to standard AMB-2 configuration, with new chambered poplar bodies and the single AMB-2 pickup. Same as #001 & #002. Now #004 weighs 9 lbs 1 oz. That's reasonable. A standard walnut AMB-2 is around 8 lbs 2 oz.


    The headstock has full side plates made from 0.040" 7075 aluminum. The scroll inserts are the same dimensions as my standard ones, but turned from aluminum.


    The front and back plates on the body are also made from 0.040" 7075 aluminum, about the same shape as my normal pickguard. They are recessed flush into the front and back surfaces of the body. That was a pain to do; a lot of hand fitting.


    The pickup is standard AMB-2, except with a perforated aluminum shell, rather than brass. The bridge and tailpiece are standard.


    I think this is the last one I'm going to build. At least for now. James asked about ordering a few more, but I'm so backlogged on orders for my own Scroll Basses, I don't need the distraction now. I need to concentrate on my own R & D projects, and get my other models into production. Maybe in the future we'll do some more.
    Leiria, Joshua, mapleglo and 5 others like this.

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