Bruce bars question

[Flying B]

I'm thinking about using embedded brass bars aka Brucebars in my current p-bass build. I've tried the search function but it's failing me, what size stock are you all using? I'm looking at 8mm square stock, sounds about right? Can I go thinner, as this is hopefully a lightweight build? (Will defo drill some weight relief holes).

 

[MPU]

Im using 10mm square bar. I want long threads. If you want lightweight, drill the bars full of holes.

 

[ardgedee]

Bruce posts pics of inserts in this thread with a discussion about them.

 

[Bruce Johnson]

I'm thinking about using embedded brass bars aka Brucebars in my current p-bass build. I've tried the search function but it's failing me, what size stock are you all using? I'm looking at 8mm square stock, sounds about right? Can I go thinner, as this is hopefully a lightweight build? (Will defo drill some weight relief holes).

I normally use 3/8" square brass, which is about 9.5mm. And I'm usually using 10-32 stainless neck screws. 8mm square stock would certainly work, and have enough length of threads for strength. I prefer the larger size so that it has more footprint area, pressing down on the neck wood.

Yes, I normally drill 1/4" holes in the middle to reduce weight. I don't drill those lightening holes all the way through the bar, only about 5/16" deep. The undrilled side faces down, for that footprint area.

You can also make the neck bars from 6061 aluminum, if you want to. Lighter weight and cheaper than brass. There's plenty of strength in the aluminum threads, but you have to be more careful when assembling them not to damage the threads.

 

[Flying B]

Thanks guys, looks like 10mm is the way to go. I'll hold off on ordering until I check what size router cutters I have at work, if I have exactly the right size cutter for either 8 or 10mm that will be a deal breaker!

 

[Bruce Johnson]

Thanks guys, looks like 10mm is the way to go. I'll hold off on ordering until I check what size router cutters I have at work, if I have exactly the right size cutter for either 8 or 10mm that will be a deal breaker!

When I rout for the bars, I'm usually using a 1/4" bit, smaller diameter than the width of the slot. I'm using a template and a collar on the router base. Sized with an offset to end up at the right width. Routing a slot with a bit that's the exact width that you want the slot gets troublesome, because wood chips can jam the collar within the template if there's no clearance.

Plan your operation to use a bit smaller than 10mm. Like, 1/4".

 

[Flying B]

I think I would just use a fence on my router running against the edge of the neck rather than make a template with a guide bush, although this requires a straight parallel edge, so I'd need to do it before shaping the neck. I suppose it's not too much effort to make a template. There's more than one way to skin a cat!

 

[Bruce Johnson]

I think I would just use a fence on my router running against the edge of the neck rather than make a template with a guide bush, although this requires a straight parallel edge, so I'd need to do it before shaping the neck. I suppose it's not too much effort to make a template. There's more than one way to skin a cat!

Sure, there's many ways it can be routed. Probably the simplest is if you have a 1/4" top bearing pattern follower bit. Then make an MDF template with both slots, to exact size width and length. Then one clamp down on the neck blank, and rout both slots to 10mm deep in 2 or 3 depth passes. And save the template for future necks.

Then use a transfer punch at the ends of the slots to locate the holes for the screws.

By the way, the slots don't have to be a perfect fit. It's cool and professional to have the bars slide into the slots with no clearance, but it really doesn't matter if they are a little loose. A drop or two of Titebond will keep them from rattling around. And once the neck screws are in and tightened, they aren't going to move.

 

[Flying B]

Sure, there's many ways it can be routed. Probably the simplest is if you have a 1/4" top bearing pattern follower bit. Then make an MDF template with both slots, to exact size width and length. Then one clamp down on the neck blank, and rout both slots to 10mm deep in 2 or 3 depth passes. And save the template for future necks.

Then use a transfer punch at the ends of the slots to locate the holes for the screws.

This is most likely the route I'll take. I much prefer using bearing guided cutters to guide bushes. As you say, you can then make your template the exact dimensions you need instead of taking the offset into account

 

[NKBassman]

By the way, the slots don't have to be a perfect fit. It's cool and professional to have the bars slide into the slots with no clearance, but it really doesn't matter if they are a little loose. A drop or two of Titebond will keep them from rattling around. And once the neck screws are in and tightened, they aren't going to move.

So you don't epoxy the bars into the neck heel or anything like that? They're just friction fit and then engaged by the screws when everything is assembled and tightened up?

 

[Bruce Johnson]

So you don't epoxy the bars into the neck heel or anything like that? They're just friction fit and then engaged by the screws when everything is assembled and tightened up?

I don't do any separate gluing operation of the bars. But the bars are fitted flush with the neck top surface, so when I glue the fingerboard on (usually with epoxy) some of that will stick to the bars.

It doesn't really matter if the bars are free to move around a little bit in the slots. They might rattle when the neck is off, but they will be clamped down tightly when it's bolted up.

 

[Bruce Johnson]

I don't do any separate gluing operation of the bars. But the bars are fitted flush with the neck top surface, so when I glue the fingerboard on (usually with epoxy) some of that will stick to the bars.

It doesn't really matter if the bars are free to move around a little bit in the slots. They might rattle when the neck is off, but they will be clamped down tightly when it's bolted up.

By the way, when you glue your fingerboard on, I recommend threading bolts into the bars, to keep glue from pushing into the threads. Turn the bolts in so the tips are just flush with the top surface of the bars. This also serves as a check-fit, to make sure the holes in the neck line up correctly with the threads in the bars. I usually glue my fingerboards on face down on top of a neck beam. I leave the bolts in the bars during the clamp-up and while the glue cures.

If your slots are a little loose, this is when you can add some glue to fill the gaps. With the bolts in place, squirt some glue down into the gaps along side the bars, right before flipping it over and clamping it down onto the fingerboard.

 

[NKBassman]

Makes sense to me. Thanks Bruce