Yamaha AC1M Bone Saddle Upgrade

Worked on this Yamaha A series guitar this past week.


The A series was launched a few years back as a dedicated stage guitar. It’s got the SRT pickup system with onboard preamp and a host of other features like a slim neck and cutaway.

The AC1M is the entry model of the A series featuring a solid spruce top and laminated mahogany body. This is probably the tried and tested combination of tonewoods for an acoustic. In fact, this combination hardly ever fails.


Do not be fooled. This guitar is very well made, with nice wood binding on body and fretboard. The finishing on the back of the neck is also great, giving that bit of sheen but without the stickiness you’ll find on lesser guitars.


Here’s a look at the SRT 66 analog pickup system. It has a very clever battery system that uses two AA size batteries and not the block of 9V thing. Just look at the beautiful binding here.


On to the project. The guitar came to me strung in HD Light Elixirs (13-53 gauge) which I felt was unsuitable for both the guitar and owner. We had a good chat and owner (super nice guy) seems to place much priority in playing comfort.

The neck also seem to have more relief than needed. I suspect the heavier strings may have caused the up-bow.

My recommendation in this instance is to go for 80/20 light gauge (12-53) for comfort and playability. It may not be a lot of difference for some players, but it is true that 80/20 strings create less tension than phosphor bronze types, thereby requiring less power to fret the strings.

Let’s start with Bearclaw Special. Tender loving care for all them guitars!

We started with about two days of dehumidifying with the aim of bringing down the top a little. The HD Lights do not do any favours to lightly built guitars.

Time for some fingerboard moisturising. 0000 steel wool and lemon oil are the stuffs needed. Bob sits by to wait for the lemon oil to dry.


I gave the truss rod a half turn to straighten it out a bit. The supplied tool by Yamaha is great! Remember, righty-tighty, lefty-loosy.


Nut slots were lubed with pencil. Good ol’ pencil lead. 🙂

Bone saddle over plastic


These drop-in bone saddles are great to enhance the tone of Yamaha guitars. These guys need a 75mm saddle that’s not too easy to find.


We got a nice serpentine compensation here. Some attention was required for the B string. Saddle height is also important. If you go too low, prepare to hear buzzing and loss of tone.


Alrighty, it’s almost done. Just a wee bit more rounding off to match the fret radius and sanding to get the correct height. We’re having 3/32 inch at 12th fret capo on 1st. Plenty of meat here on the saddle. You get great tone this way. 🙂


Body clean and shine, put in some fresh Elixir 80/20 lights. Nice, bright sounds from the guitar. Very comfy to play now. Roger is smiling away here.




5 thoughts on “Yamaha AC1M Bone Saddle Upgrade

  1. Hi, thanks for the article. I just bought an old AC1M to learn on. I learned that poorly built guitars made it a lot harder on newbies and caused many to give up. As the AC1M is a pro model, I thought that could only help. Someone beat the hell out of it and I got it for $200. It cleaned up better than I thought it would, aside from the chunk out of the top of the pegboard. I took the saddle down a lot and the action’s easier. I put on Elixir Extra Light strings to try to take a little tension off the belly which was rounding a bit and they’re a little easier on my fingers, I suppose, to press down. The nut is busted, so I want to replace the nut and saddle with Tusq. I found a British site with a really handy luthier’s tool to slip under the strings to judge how much more to lower the saddle. But I need to know the right fret radius to order the right tool. Do you know what that radius is? In any case, thanks for your time.


  2. Hi Marcus, thanks for dropping by.

    The Yamaha would need a 16inch/400mm radius saddle. It’ll probably need some fine adjustments to suit the player. I haven’t come across a drop-in saddle that doesn’t require fine adjustments.

    One main thing for the Yamahas would be the saddle length. Make sure you get a 75mm saddle. Anything too small would mean the saddle moves in the saddle slot.

    Hope this helps. Enjoy your AC1M!


  3. Yes, great information, thanks for helping me out, PJ, and for getting back to me so quickly. I’m hoping to become old friends with my AC1M. And thanks for making your knowledge available to everyone through your site,


  4. PJ, you might want to check out this tool from GMC. Here is Gary’s answer to me about if they have a 16″ radius tool.

    GMC Luthier Tools replied to your message:
    Hi Marcus, thank you for your message. The 15″ is designed for 14″-17″ guitars. There is a diagram at the bottom of the description page (link attached) which will hopefully explain this. Because the difference in geometry is so slight and with manufacturing tolerances also – it would be virtually impossible to distinguish between a 15″ gauge and a 16″ gauge.
    Hope this helps.
    Kind regards,
    Gary Carter


    also, here is the tool on eBay


    Thanks again for your help.


  5. Hi Marcus

    Thanks for sharing too.

    I’d normally use a stock part and then adjust to taste. So sometimes it involves using good old stuffs like sandpaper and a simple small file.

    Let’s hope you dial in a great setup on your Yamaha. They are really good stuff for the money.


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