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We replace a few split or broken pyramid bridges per year, so have a few jigs that make turning out semi-finished bridges using tablesaw and jointer quite easy and consistent. Once the milling is done, the rest of the process goes quickly, and decisions on drop-in vs. through saddle and hole spacing can be addressed with a saddle mill and the usual pin layout process.

I should mention that I fabricated several bridges using just hand tools to get the feel for what time was saved by jigging up. For a one-off bridge, I think it is faster to use the Frets.Com (Mr. Ford's site) hand tool and sander technique which he illustrates so well. For multiples in a variety of woods (we mill them in Gabon and Macasser ebony, BRW, African blackwood, and curly maple), jigging up does help speed the process.

I spent a few days on fabricating belly and pyramid bridges for current projects, as well as a number of semi-finished BRW blanks for Mr. Morelli. I thought some shots of the jigs and some process description might be of interest.

The process begins with milling up the blanks plus some dummy bridge blanks in maple used for fine-tuning the fence settings and bit depth...we usually make up 3-4 dummy blanks. We mill to the nominal 1" x 6" x 0.450", but can always narrow the bridge a bit with some file work when matching a vintage example.

The first jig rides against the tablesaw fence and mills the angled faces on the ends of the bridge. Cutting these faces first avoids any possibility of blow-out. Our jigs are set for 25 degree faces, and the angled stock holders allow the tablesaw blade to be set square.



The second jig also a tablesaw fence-referenced jig - mills the front and rear faces at each end, with the numbering on the jig avoiding any blowout. With the 60 tooth Diablo 7-1/4" blade we use for this work, cleanup is usually just a light pass with P400 and buff.



The final jig mills a 1/4" wide round-bottomed channel between the body and wing of the bridge, which is then finished with a 3/8" chain saw file as part of the hand tool cleanup process. This jig is used on the router table, and is fence referenced like the other jigs.





Shaping the top radius is roughed on the disk sander and finished with a 10" mill bastard, while the front and rear radii are cut with an 8" mill bastard and scraper. The wings are finished with 4" mill bastard and scrapers, then the bottom of the bridge is radiused as necessary.

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For the times they are a changin'

- Bob Dylan

Awesome, thanks!


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Good judgement comes from experience. Experience comes from poor judgement.

I just did a pair by hand. Great to see these jigs, for future reference. How about the fourth (inside) face of each pyramid? I assume that part is done by hand, using the files, rasps and scrapers you have mentioned?

I tinkered a bit with making some jigs like this, but for the small number of parts I want to make, I found that it was easier to drill the round bottomed channel with a 3/8" Forstner bit (scrap held against the show face of the bridge, so the bit is biting into wood all around) and then just cut the pyramid faces with my Dragon rasps. It went surprisingly fast, and I had a lot of control. I worried that the jigs would take some trial and error to set up properly, but maybe that was an overblown worry.

All I ever made were pyramid bridges. Problem with jigging them up was that there were lots of different sizes and styles. I always cut them by hand, and after a time, got pretty good at making them fast.
The photos are pretty self explanatory.

Note the V's started on the bandsaw and finished with a rat tail...


















My favorite was the offset pyramid below...

Impressive stuff.

With the idea of making light bridges to reduce damping what do you guys thing of the idea of all that mass on the ends of a pyramid bridge. Is it counterproductive to what we are trying to achieve?

I use that hypothesis to rationalize my laziness in using tapered ends on my 1X6” Bridges

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It's not what you don't know that hurts you, it's what you do know that's wrong.

I made some simple jigs for making the Martin type pyramid bridge that allowed me to rough out the bridge with a band saw and 1 inch wide belt sander, but still left about half the work to be done with a file and sandpaper.
As to what effect the pyramids and trough have on the sound your guess is as good as mine. Some might argue the same merits as the high points on scalloped bracing and the potential to adjust the stiffness of the wings by changing the depth of the trough, but I think it is mostly a looks thing. Classical builders seem to be more in tune with what adjusting the wings does for the guitar, but that design is a little more straightforward.

Thanks Woody

Opened up a topic that I need

Ed

Thanks! These jigs are likely of interest for those that don't have a steady diet of restoration or early 20 c. repro work as their primary workshop task. All three jigs might consume 20 minutes or so of time to fabricate, so not a bad trade for eliminating much of the more tedious roughing tasks. We have a similar set that handles the Chicago-style Lyon and Healy-made bridges found on some Hawaiian-style Martins, but more common on other contemporary instruments from the early part of the century...same general approach as shown.

Mr. Parker - the inner radiused face is shaped with a small mill bastard file after roughing with a safe-edged 8" mill bastard...the process is very quick, as the bulk of the material has already been removed.

Re: mass... there's actually not that much more material in a 1" x 6" pyramid than the usual classical bridge, and if the pyramids are stripped away, there is a nicely radiused wing with long end bevel hiding underneath. The boss is deep into Fusion 360 these days modeling the range of bridges we produce - I'll have to see if there are some better graphics to illustrate this observation.

And let's be honest...pyramids are so much cooler than belly bridges on traditional pre-1930's guitar designs. Never underestimate the cool factor!

_________________
For the times they are a changin'

- Bob Dylan

Terry, I never put much stock in weighing things. Anyone who has seen my tops with BRW laminations. square tone bars and maple UTB's combined with a thicker top than most knows that I didn't take weight "lightly". AFB isn't one of the lightest woods anyway for bridges.
As far as the mechanical/theoretical side of it all, well, I never speculated much.
You know what my instruments sounded like...

Thanks pal!!! I'm always looking for an easier way. The couple I did were early in my building and they looked a little like pyramids after 2000 years of weather and sandstorms, somewhat lacking in the crispness of edges.

I dug my jigs out of the dust bin and found a bridge blank that was drilled a little too close to the ends ti demonstrate the set up.
The first thing I do (not shown)is drill the "troughs", either by starting out with a piece I can cut down the center for two blanks , or by clamping two blanks together and drilling in the center as Don described. I then use a couple of simple jigs on the bandsaw to rough out the pyramids. I then use the same jigs (not shown) on a 1X48 inch beltsander to smooth them . I sometimes round over the front and back of the center section with a router or sometimes just break the edge with a file and sandpaper. The forth side of the pyramid for the Martin style bridge is rounded with a file (not shown). Drilling pin holes I sometimes do before or after shaping the bridge and cutting saddle slots I do after gluing the bridge on the soundboard.
The first jig is cut to the angle of the end and slides along a piece of scrap clamped to the table. There is a small "stop" that it rests against and it is held in place by hand. There is a recess in the jig to allow for the sawblade.
The second jig also slides along a scrap, but there is a recess cut in the scrap for the saw blade. The depth of cut is adjusted by moving the scrap closer or further from the blade.You can slide the jig or slide the blank.
To cut the angle on the opposite side of the blank the jig and scrap is moved to the opposite side of the table.

Charlie Hoffman uses jigs with a shaper to make his.
Sort of like killing a mouse with an elephant gun....

He shows it on his website.

Lots of ways to kill a mouse

In the interest of full disclosure I do mine like Hans, by hand. If I had to do several I would probably make a jig.

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Steve Smith
"Music is what feelings sound like"

When it comes to power tools, I don't scare easily. Charlie Hoffman's approach is SCARY. DAMHIK

Mr. Hoffman's technique could be made relatively safe by fencing off most of the cutterhead making it less likely that in a moment of inattention the cutter could grab the work and pull the clamp (or hands) into the cutterhead. Two things I do like about his process are that the jigs are simple to make and they produce a finished surface which only requires minimal work. I may try to refine and adapt my jigs to use with a router table.
As Steve said - lots of ways to kill a mouse, and at least 4 are shown here.

I bet Hoffman's jig has the guard removed for clarity - looks insane as it is. Although I have seen plenty of people put something through a table saw with no fence.

Ed

Don't know if Charlie is building much anymore. Think he's within a few years of me.
I guess it mostly depends on how you like to build. Some folks probably could figure out how to CNC pyramid bridges. I can see where folks that build in batches would jig up for it like Olson, but that was never my style. I'd hate the thought of making a dozen of anything. Only thing I ever jigged was kerfing and I could kerf 4 at a time on the bandsaw.
That said, I could make a pyramid bridge plenty fast enough. A couple of good extremely sharp chisels and a couple of Grobet Vulcrylic Swiss pattern files made it easy along with some wide sanding sticks took care of the the rest. Nice thing about building them individually (besides not having to build bridges all day) is that they had an individual look, and usually looked a little more handmade along with the rest of the instrument.
Guess that all depends on how much of a perfectionist you are. I learned long ago that perfectionism is a dream, most all handmade instruments have a flaw or two and you develop your own "look" by the imperfections that you have allowed when you have found your groove...

Anyone know how the factories did these bridges back in the day? They must have had some kind of jigging.

The basement of Charlie’s shop where the power tools were was dark and dingy and felt medieval.

_________________
It's not what you don't know that hurts you, it's what you do know that's wrong.

I don't know for sure how Martin made pyramid bridges "back in the day," but my copy of "Martin Guitars: A Technical Reference" puts the main period of pyramid bridge use on Martins between 1867 and sometime after 1900 (page 38). I doubt Martin was engaging in any sort of Henry Ford type assembly line mass production during that period. I allow for the possibility that they just had a group of guys who were really adept at building pyramid bridges by hand, because they did it a lot.

When we say "factory," that tends to make us think of extreme mechanization, like what the factories have now. 100 years ago, there was a lot less of that.

But, I'm not a Martin historian, so I could be wrong about how much they relied on jigs during that period.

Jigs need not confine you to one size or style of bridge. The jigs I use allow both the size and proportions of the bridge to be changed. They are used to eliminate some of the milling and add consistency to the final product. The final shaping and fitting is still done by hand.
I like to rough out some things in batches -linings, necks, bridges, blocks, etc.. Even joining and gluing center seams of tops and backs I often do in batches. Having a number of parts that have some of the initial shaping done at the same time helps me avoid doing additional setups each time I need a part.

Think Charlie had a moat down there...

My set up for pyramid bridges:
I use these 2 to rough cut on the bandsaw

Then finish on the router table with these,




Inner angle gets cut with a chisel.

Bob