Gluing the bridge

20210530
Finally the gluing of the bridge.
I measure the location of the bridge: 651mm at the treble side and 652 at the bass side.
The reference starts from 325 at 12th fret.
My saddle is about 3mm so I have enough saddle to cater for the rest of the compensation.
My nut end is inward by 0.5mm that's why the reference has to be at the 12th fret.

After drilling the locating pin with my 1mm drill bit, I tape the location on the top.
The tape also serves to remove the glue squeezed out.
Then I prepare the clamps.
For this build, I cant insert a bridge clamp as the tornavoz is taller than my usual, so the clamps are blocked.
But no matter I can reach the bridge from behind the end block instead.
Then I heat up my hide and glue the bridge.

Final weight of bridge

Measuring the location of the bridge

Heat up the hide glue

Prepare the gluing setup

Apply the glue

Glued and clamped

Close up of the squeeze out

20210605
The bridge was glued successfully and I managed to string it up.
But without the frets I can only hear the open strings.
I use a moveable fret and manage to get the top end trebles.
To be honest the trebles sounds great while the bass sound ok.
But it is too early to say for sure as the sound will develop further

The bridge glued nicely

Stringing up the guitar

18-hole bridge

Repair a guitar

20180801
I have a guitar coming in for a bridge repair.
Nothing too out of the ordinary.
But I did noticed that the top has some wavy curve across, but I did not see any damages to the butt area.
So I think the cause of the bridge coming loose is probably due to changes in RH.
Anyway for this bridge repair I use a caul underneath the top and clamp with 3 bridge clamps.
Before applying the glue, I clean the surface with sandpaper.
After that I applied the glue and clamp.

The gap developing at the back of the bridge. The top has a noticeable wavy curve.

Cleaning the surface with sand paper

Apply glue and clamped

Another view

Caul and clamp used

The bridge glued nicely

20180813
The guitar has been strung up for about a week and the bridge still stays strong.
I prepare a new nut for the guitar with a closer string spacing.
The maker has put a pin in the middle of the nut slot which makes the making of the nut a bit more challenging.
So I just make the nut to fit the slot and file the string spacing accordingly.

New nut with closer string spacing.

Guitar all strung up and ready to play.

Repair a guitar with bridge problem

20180417
a guitar came into my workshop for a bridge repair.
This is not the usually bridge lifting off problem, but the tie-block has came off.
Naturally I was surprised as this is the first time I have seen such a problem.
Anyway I thought the fix will be simple: to glue back the tie block
There owner wanted to change the whole bridge but I digressed.

• There were no missing pieces
• There was no problem with intonation / i.e. saddle placement

Hence I stick to my plan to glue back the tie-block
After gluing I strung up the guitar

Tie-block broken

Glue back the tie-block

Strung up

20140424
Unfortunately, after a few days, the tie-block came out again to my surprise.
True enough the glued joint is stronger than the wood itself, but the break as another layer in the tie-block
What this means was that the bridge wood has some sort of weakness in it.
So the solution now is to change bridge entire and build a new bridge.

Tie-block broke off again - different layer

Still with the strings attached

20180507
I began to remove the existing bridge.
Before that I scribed the edges to prevent the lacquer from chipping off as I remove the bridge.
I also took measurements of the scale length / compensation and bridge height.
To my surprise, the bridge began to crumble and broken in pieces as I remove it.
I followed my usual way of removing the bridge heating the platter knife and insert in between the bridge and top.
No heat was apply to the top
This was to ensure no excessive heat was applied to prevent other glued parts from coming loose from the heat
So the problem was with the bridge wood after all.
But I wonder what caused the wood to crumbled like that.

Finally after 45 minutes or so I manage to remove the bridge cleaning.
Surrounding woods are undamaged.

Scribing the edges to prevent lacquer chipped out

Heating and inserting the knife under the bridge. No heat was applied to the top. No water was used.

Done

20180531
I began to work on the bridge blank.
First by scraping and sanding the bottom arc to fit the top.
Also I sanded the top to remove the unevenness of left by the bridge removal.
Finally I sanded the bridge blank to fit the top.

Then I saw away the bridge wings and the bridge began to form in shape.

Scraping the bottom of the bridge blank

Sanding the top

Sanding the bridge to fit the top

Saw away the wing of the blank

Bridge taking shape.

20180619
Half way I decide to use pre-made bridge as I can complete the process faster.
And the fit was quite good.
So I use epoxy to glue the bridge.
Not my usual habit to glue the top but in this case as there were some gaps in the surface, a epoxy glue will be a better guarantee.
So I fitted the bridge and applied the glue to both surface, followed by clamping.

Bridge glued.

20190620

Next I removed the clamp and make a new saddle, change the tuning machine and string up the guitar.
The bridge glue job looks good.
And the guitar sounded nicely.
I touched up some of the finishes but they certainly don't look perfect though.

Bridge glued nicely, new saddle made.

Tuning machines changed

Gluing the bridge

20160506
Next is to locate the position of the bridge and drill the alignment holes.
This time round I double check and triple check just to make sure it's correct.
If not I will be force to remove the bridge like in #5 haha
Then I heat up the hide glue and glue the bridge.
The usual bridge clamp cannot be used due to the tornavoz so I just 3 cam-clamps instead.
The top usually is able to support the bridge and I use very little pressure for the clamping so no worries during the clamping.
Next will be to hear how it sound!!!

Locating the position of the bridge

Drilling the alignment holes

Bridge glued.

Apply the clampes

20160509
After the bridge is glued I string it up to see what the resonance is like.
All are within my expectations / prediction.
Though I kind of hope the air resonance will go down a bit more.
But still it's within range.
I temporary use some of my existing nut and saddle (not optimised) and string it up.
I also use my temporary fret to fret the high notes and hear it sounds.
Not bad at all :)
The bass notes are deep but yet controlled.
Definitely have a deeper tone than my #3 but not as deep rumble as #5 (this is due to the bracing).
The treble notes are all very even as expected of the Bouchet bar.

The guitar strung up temporarily

Closer view of the bridge

Back on the bench.

Making the bridge

20160418
While making the fingerboard, I also began on making the bridge.
Choosing the right material is important for the bridge.
Although some luthier believe the damping is not important only the mass (weight) is important.
Well I still think both are important.
So I between IRW and CSA-RW, I choose the latter as it has better tap tone.

So I began by cutting to the length, and square up the sides.
After that I marking the centre line and the position of the tie block.

Choosing the bridge blank. IRW or CSA RW?

Matching the color of the blank to the rest of the body. Both blank looks oK

Matching the color of the blank to the rest of the body. Both blank looks oK

Squaring up the edges

Scraping the under surface to match the top doming.

Check the doming fit. This is not final though just rough matching.

Marking the centre line and tie block and wings lines.

20160422
I routed the saddle slot in the blank.
For this bridge I make the saddle lean backwards by a little.
This will help in the structure for the top I think.
It's done by adding shims below the template.
The route are guided by the aluminium rails and the rails are adjusted to fit the slot marking.
I took several passes to reduce the chances of tearout.
After the slot is routed I began to reduce the thickness of the wings.
I saw multiple saw cuts and remove the waste with chisel.
Finally I smooth them with files.
So far the original blank weight is 50g and I reduced it to be about 30g.
Some more to go.

Router set-up

Another view; Close up view.

Saddle slot routed

Sawing cuts at small intervals for easier chiselling and to prevent big chunk of chip out / tear out.

Removing with chisel

And rebate plane.
The block of wood besides to hold down the blank but also to prevent accidental damage to the saddle block / tie block region.

Current weight about 33g

Preview of how it will look; Looking quite nice.

20160429
After thinning the wings, I began to carve the saddle block and tie-block.
In my previous method, I actually route 2 channels, one for the saddle one in between the 2 blocks.
But this time I only routed one for the saddle.
So for the between, I use my saw to start the cut and chisel / plane away the rest.
The weight after carving ends up about 24 g.
I probably need to remove more to cater for the bone inlay weight.

Saw a cut between the 2 blocks

Using rebate plane to remove the waste.

Using chisel to remove the waste.

Weight of bridge 24g

A look before gluing.

20160506
I finished up the bridge and glued it.
After much pondering I use the MOP as the tie-block inlay because of the weight.
The full bone was just too heavy.
After gluing the inlay and I drill the 12-holes.
The final weight is about 24 g.
It's slight heavier than I expected but still within the usual range.

Gluing the tie-block inlay

Drilling the string holes

Weight is about 24g

12-hole bridge