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I've been trying for a couple of weeks now to figure out a way to rout a clean saddle slot for my first build. So far I've wasted 2 rosewood balnks (I ran out of scrap) but on my third try I "came close." I have one more rosewood blank to use but I'm wondering if #3 is salvageable.

I've heard mention that sometimes clay is used to shim saddles when removing a pickup and I'm wondering if that can be applied in bridge fabrication as well?

FWIW here are the issues I've been having:

1: a friend loaned me his Stewmac saddle slotting jig with precision router base but I'm much too wet behind the ears to use it properly. My Dremel's vibrations kept loosening the fittings on the PRB.

2: unless I'm a complete idiot, the Stewmac PRB has no plumb function so I've had to be careful about the right angle to enter into the slot. I don't think it's been a problem but still something to keep in mind. I've tried to counter for that by drilling in the endpoints with a drill on its own "precision" base:



BTW, I ended up not relying on the Stewmac jig in favor of one I'd thrown together out of birch plywood scrap. It's not pretty, but I works to some extent.

3: Since I had issues with the Stewmac PRB I tried going back to the cone base that my Dremel 300 came with but it wasn't up to the task. That's when I saw on youtube that Dremel had its own plumb routing base, which I decided to invest $30 in. Even still, I had issues with the bit wanting to "wander" even if I tried doing shallow passes along the length of the saddle slot. That's when I jury-rigged a second angled guide to keep the base from wandering:



4: I also tried the "conect the dots" approach (as suggested by Stewart MacDonald) but still didn't seem to get a clean line. As the name implies, I plunged a series of dots along the line all the way down to the target depth determined by the stop on my Dremel base but when it came time to "connect" them I had issues. The "front" of the slot is clean, but the back is irregular, as if my base had shifted. I thought I'd taken that into account but apparently not. The bottom of the slot is also a little sloppy in places and I'll need to go back and clean it up, but I'm concerned that my slot will be even wider than the 1/8" I'd intended. Hence my idea about using clay.



BTW, I'd also had trouble drilling all the pin holes in a straight line but I decided to invest in a set of brad point drill bits which along with a digital caliper (IMHO) came out acceptible. After that I decided to move along with roughing out the shape of the bridge using my cheap little Ryobi bandsaw and a coping saw to shape the wings. I still have to angle the back of the bridge and clean up the rough edges and bevels but this is the closest I've come yet:





Anyway, I have one more blank - well actually I also have an ebony blank that I want to use for a future build - but how does this one look for a "third" try? Should I try again?

PS: what's a good "scrap" material to use that's similar to work like rosewood if you think I need to practice more? SPF from the big orange or blue hardware stores is way too soft and oak is way too hard.

For scrap materials similar to rosewood try maple, walnut, or oak.

Use a narrower bit, for a 1/8" slot use a 3/32" bit, and for 3/32" slot use a 1/16" bit... so on. Cut the initial in the middle and clean it up by moving it to one side then the other. I also had good luck chucking a small endmill in a drill press and milling it on it. I am not using any fancy jig, just enough guides to get the slot routed and I used a laminate trimmer to do the actual routing.

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Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

+1 to all that, especially minimal jigs & laminate trimmer. The bearings in most dremmels are too sloppy for real precision work.

edit: by the way, the saddle slot should angled back a few degrees, close to bisecting the breakover angle at the saddle.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

Really? Why is the saddle slot angled back a few degrees? I have not yet reached this point in my first build and am interested it this comment. I didn't realize this fact. What is the breakover angle?

To the original poster, I truly wouldn't trust my dremel used as a router in such a wide slot. It is asking a lot for such a underpowered tool especially in cases that require precision as well. If you don't have the ability to get a larger router then I would suggest using a smaller bit as well.

When you're looking at the bridge from the side, the strings make an angle when they cross over the saddle, that's the breakover angle. The strings push down on the saddle, and the direction of that force bisects the breakover angle. That means it's mostly down, but also a little foward. Angling the saddle back a little puts more of the force on the bottom of the saddle slot and less on the front edge.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

IMO, not necessary. If the bridge dimensions, the saddle slot location in the bridge and the saddle height are in the ballpark, the bridge will stand up to the stresses just fine. Many thousands of fine guitars have lasted decades with vertical saddles.

Pat

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formerly known around here as burbank
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http://www.patfosterguitars.com

Absolutely correct, angling the saddle back is not necessary, a vertical saddle will work fine. If you're using an undersaddle transducer, it might make a difference.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

Robbie O'Brien has a good YouTube video on making saddles which shows his slotting jig. I built a similar jig but I use double stick tape to hold the saddle in place.

Drilling pin holes in a straight line is easiest with a drill press equipped with a fence IMO.

Kevin Looker

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I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

angling the saddle back makes a great deal of sense, IMO, if you could be guaranteed to hit the ground running as far as action and intonation are concerned, but if you are doing a precision intonation/action set-up, it seems to me that the saddle would have to be really thick to allow for the subsequent adjustments ...

Yeah, I see that the Dremel isn't up to the challenge. I think I'm going to use it for inlay work only - when I get to that point. In the meantime I'll see if I can get access to a router.

As for angling the saddle back, I'm missing the point. I was always under the impression that it had to be vertical so that there is 100% contact between the underside of the saddle and the slot so that vibrations are optimally transferred. I also thought these vibrations were further optimized by the downward force of the string on the saddle which is determined by the break angle which is in turn dictated by saddle height and distance to the pin behind it. I can see that the saddle slot is thick, but that having a thicker saddle would give me more wiggle room to set intonation later on down the road.

FWIW I'm working directly off the OLF MJ plans that I bought from Stew Mac. I'm trying to follow his figures as close as I can.

A vertically angled saddle slot makes sense from a mechanical perspective but seems like a nightmare from a real world perspective. Does anybody do this?

Kevin Looker

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I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

Be careful following the Med. Jumbo plans, Neil. I am working from the same plans, and there are parts that are not to scale.

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

Builders who angle the saddle back, (and there are indeed some) rout the saddle slot at an angle as well, so that there is total contact between the bottom of the saddle and the slot.

ie the bottom of the slot is not parallel to the soundboard, it is angled back slightly.

I've never heard of tilting the saddle back before.

A couple of advantages. Helps to get closer to a downward force through the height of the saddle,making spliting of the forward section less likely to happen. Also gives an automatic adjustment for compensation when raising and lowering the saddle. There is a somewhat optimum angle but not sure what that is as I have never done these type of bridges myself.
Tom

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A person who has never made a mistake has never made anything!!!

Yes Neil, you have made the same discovery as all of us - dremel tools are not up to the task of routing a clean saddle slot. A laminate trimmer will do it well. But the best setup is one that allows you to plunge into the job, and a router is best for this. You have the right idea with your jig that places the bridge on a lower level and then runs the cutting tool on a solid surface above and parallel. You are also onto a good plan having a solid fence on both sides of your tool, so that it has nowhere to go but in a straight line. You can also set a stop at each end of the travel to avoid cutting too far (this can be as unsophisticated as a small nail partly driven into the end of your jig).

To cut a sloping slot just put a popsicle stick flat under one edge of the router/trimmer. It lifts it up about enough to slant the slot by 2-3 degrees towards the tailblock.

Its not that hard to do it off the guitar, its harder when you have to route the slot while the bridge is on the guitar... it severely limits your options as you don't want something too heavy. The slight curve on the top also makes clamping a nightmare. A plunge base for my laminate trimmer would be very nice but I don't think one exists for a laminate trimmer.

_________________
Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

Neil: If you have a decent drill press you can use that as a router. A fence with a couple of stops is all I ever use for bridge routing. Use the highest speed. Use a fixture to hold the bridge of course.
Tom

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A person who has never made a mistake has never made anything!!!

That's how I used to do it too. Not ideal, but not too bad either.

I just wish I can add an additional pulley for "super high speed" like 6000rpm.

_________________
Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

If I remember correctly, Grumpy does this and his are angled 4-5 degrees.

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I'd like to be able to prove, just for once, that money wouldn't make me happy...

Hi Tai,
You can "plunge" a laminate trimmer by using a firm grip and while resting one edge of the subbase on the work piece tilt the already spinning bit into the work. I use a simple jig for cutting saddle slots in already glued down bridges and use a plunge cut to start the slot.
I have used this technique to plunge through 1/2 inch thick material using a 1/2 straight bit and a 3hp router, but for that it's best to use both hands on the router.