Rooks RCA-4!!!

[rook]

SHIM MAKING

After a bit of searching I found a hardware store nearby that sold maple veneer for about 7 bucks for an 8ft roll.
Maple Veneer:


First I traced the neck heel onto a piece of paper to create a stencil. I transferred the outline to the veneer and started cutting. The veneer is really easy to work with. Cut very well with scissors and was kinda fun so I ended up making a bunch while watching a movie. After cutting I needed to sand the sides a bit for a perfect fit, but all in all it was simple and fun.

Making template:


I assume I will need to glue two or three of these things together to get the thickness I need, so I cut them in alternate directions of the grain. Which I think is the right thing to do...

Still need to shape the top of the shim that protrudes from the pocket, but they are basically done.

semi-completed Shims:


@pablopepper gave some advice on how to come up with a tapered shim without many tools. And I might go that route.

HIS ADVICE:

I would suggest getting some wood veneer and playing with layers. Wood veneer is usually 0.6mm thick, so start with a piece about a half to two thirds of the length of the pocket, place it at the back of the pocket, clamp your neck in again and check action. If that's not enough, cut another piece half the length of the piece before, stack, clamp and check again. Repeat until mostly happy.

When you are done, glue the stack of veneers together, flip it and give it a rough sand to smooth the layers out a bit. This should give you a workable shim with little to no power tools used.

But I am wondering if there is any disadvantage to simply using a flat shim.
I googled around and can't seem to find any reason a flat shim is a bad idea, but if anyone here has an opinion, I'd love to hear it.

Thanks!

[Simon Barden]

With flat shims, you need a much thicker shim to achieve the same amount of extra height at the bridge. O those Ric style neck joins, you haven't got a lot of direct contact area for gluing anyway. The more flat shims ypu put underneath the join, the less actual neck wood will be glued at the sides.

Lets say the heel join that's 6cm long and you have a shim that tapers from nothing at the headstock end of the heel to 1mm high at the body end. Lets say the bridge is about 25cm from the far end of the shim (measured on a Peavey bass so it won't be far off your kit measurements). That means that you will have gained (25/6) x 1mm = 4.1mm of string height at the bridge. With a flat shim, you'd need 4.1mm of shims underneath the neck joint. If the shim went from nothing to 1.5mm high, you'd have gained 6.25mm of height at the bridge. That would be a lot of flat shim!

So you don't need much of a shim to make a lot of difference. Also you keep the heel to body joint looking normal which is important if you are staining rather than doing a sold paint job on the bass. Otherwise you've got a lot of obvious ply sticking out either as part of the heel or if cut back flat, as part of the body under the heel.

Now making a shim that delicate takes a lot of doing and you'd probably be best sticking the shim on the heel first and then sanding the angle in rather than doing it to a thin bit of veneer and then sticking it on. I've never made one so I really can't comment on the best way to do it.

But that is why one small angled shim is a better solution than a lot of flat shims. You can probably work out how much extra height you need at the bridge to allow the saddles to be raised a bit and also get a low enough action. You'd probably want a minimum of 4mm extra height to be sure, so a shim that gained 1mm along its length would be enough. Plus if the shim didn't taper to nothing but had a finite thickness at the thin end and was 1mm thicker at the other, then you can add that finite height to the extra string height at the bridge.

So basically just divide the distance from the start of the shim to the bridge by the length of the shim, multiply by the height gain along the shim and then add on the initial shim height, and you'll have the height gain at the bridge.

[rook]

@SimonBarden You have been a great source of help and info for me on this so far. I cannot say thanks enough, it is sincerely appreciated. Your write-up above is very helpful.

For some reason I couldn't comprehend why an angled shim offered more bang for the buck. I'm starting to understand the math behind this a bit better and it has become clear that building an angled shim is the smartest option.

I am still worried that a shoddy uneven shim might lead to a twisted neck, but I'll face that hurdle when I get there.

Thanks again for the info, Simon!

[Simon Barden]

No problem at all, Rook.

It's one thing to talk about the math behind an angled shim, it's a bit harder to make one well and as I've never had to make one yet, I wish you the best of luck.

[Andyxlh]

I must admit my RCA4 kit could have used a shim. I didn't consider that, I measured the position of the bridge correctly but found to get a nice action I had to make a mod on the bridge to lower the strings. So the shim is the way to go! Might be worth contacting Adam so he can let the factory know to alter the CNC settings slightly as I'm guessing that all of the RCA4 kits have the same issue.

[Simon Barden]

The recent revelation from Adam in one of the Announcement section posts was that they don't use CNC machines in the Chinese factories, it's all hand-done with templates (which accounts for some of the variations we see in the kits). That surprised Adam as well. So they really need a new routing template for the RCA-4 kits.

[Gary B]

I must admit when I set everything out to position my bridge I didn't pay much attention to the action.
Looks like I will need to mock it up again before I commit to gluing the neck to see if I need to shim.
Great information on here again, thank you gents

[rook]

UPDATE:
Veneer layers are glued and I'm waiting for them to dry so I can sand them down to a smooth taper.

Made several shim versions to account for mistakes - which I plan on making.

SHIMS DRYING:


In the meantime, I went to a music shop and played a real Rickenbacker 4001. Playing may be an overstatement. I was like a forensic investigator studying the instrument in every detail. The dude at the shop asked me if I wanted a patch cord to plug into an amp and when I declined he stood 3 feet away giving me the stink-eye like I was gonna steal it.

In any case, I got to study the shape and I realized/decided that I wanted to revisit the belly-cut that I originally did.

As a whole, the real rick has a lot more rounded edges than I remembered. All the edges have a pleasing bevel to them. And the body cut is super angular. I did another sanding pass on my body - rounded edges, and tried to get close to the same belly cut...

I wasn't able to match the same "belly-cut swoop" as the real rick, but it's a bit more official. The bottom hip is the hard part to match.

Part of me wants to go further - the other part says leave it as is. What do you think? Keep going or leave it?

HERE'S HOW IT LOOKS NOW:


Next up, sanding and fitting the shims!

[rook]

LAST SHIM QUESTIONS - I (SORTA) PROMISE!

Hey everybody, I have a few more shim questions that I would love some help with.

I took pablopepper's advice on how to build a neck shim. (Thanks again, pablopepper!)

I found some maple veneer that was 0.03 inches thick. Stacked and glued it. I then sanded it to an even tapered wedge.
I now have a shim that is 1.5mm at it's thickest and tapers to almost nothing.

CURRENT SHIM:


When clamped in, it gives me a great string height to work with. It is invisible from the back.
And most importantly it allows the neck and body to connect where the shim ends.

Here's the problem -- my shim is only half the length of the neck pocket.


This means that there will be a small pocket of air - about the thickness of a single piece of paper - between neck and body for a short section of the neck join.

I will be gluing with Titebond wood glue. I assume the glue will fill this tiny gap and create a strong hold. But will it be strong enough?

I call this OPTION A - GLUE CONNECTION:


OPTION B would be to create a longer tapered shim that stretches the full length of the neck pocket and delivers continuous contact between neck and body for the entire length.

The drawback to Option B is that the entire connection between neck and body will be made through a piece of flimsy veneer.
I worry this will equal a weak connection.

OPTION B - VENEER CONNECTION:



I would love to hear some thoughts on which option will create the most sturdy connection.

I would also love to know what the other rick builders did?
I scrolled through nearly every RC-4 thread, but there wasn't a lot of detailed info on this specific problem.

Please help! I'm at a loss for what the best choice is here is. Any feedback on this would be great.

And thanks again to everyone who has taken the time to weigh in with tips and advice. It has been very much appreciated and extremely helpful to me. Thanks again!

[Simon Barden]

Nice shim work!

However, option B will make the better joint. With option A, the neck is only making contact with wood at two points, the rest is varying levels of glue, and the glue is strongest when there's not much of it and it's bridging a small gap.

It's never a good idea to have thick pockets of glue if you can avoid it. The strongest joints are made using the thinnest layers of glue. Why do you clamp pieces of wood together when you glue them? To both force the glue into the wood and to get the glue layer as thin as possible. Otherwise there wouldn't be any point in clamping joints and you'd just lay one piece on top of the other and wait for the glue to dry.

A good glue joint is stronger than the wood itself. Although your shim is thin, when glued between two other bits of wood, the result is still a strong joint.

It's something you can try yourself by glueing a piece of veneer the length of the pocket between two 25x50mm lengths of timber in an overlapping joint, clamp tight and let it dry for 24 hours. Then clamp one bit of wood and try pulling on the other bit of wood.