Filing/sanding down ebony - tools?

[RJVB]

Hi,

I've begun slimming down the base of the ebony adjustable saddle that's supposed to replace the leaning stock saddle on my Loar. Initially I was looking at belt sanders for that, but the luthier who'll (hopefully) do the ultimate install said he'd do such things with files. A few weeks ago he asked me to retrieve the parts as he'd had to put his work on halt for medical reasons. He promised to send me some photos of the tools he'd use but I guess he didn't get around to that.

So, I've started having at it. Shortening the wings was easy (with my nice little japanese saw). Slimming the wings down wasn't too hard either with my flat/half-round metal file plus a few bits of sandpaper.

But now there's the entire part between the 2 posts, about 15mm wide by maybe 4.5cm long,where I want to take of 2-3mm. Given the lean in the posts of my stock saddle I don't want to remove any wood around the posts themselves, so they remain anchored as designed.

Any suggestions how I'd tackle that?

Afterwards I'll need to take off approx. 1.5-2mm from the underside of the saddle but I hope I'll get the brunt of that with the aforementioned saw, with the saddle held in a soft-jawed vise.

SUIZAN japanese flush cut saw 5 inch for hardwood and softwood
– SUIZAN JAPAN

[Dennis D]

Sorry for not having a solution. Good luck w/ the repair.

Is there an explanation for why the saddles are left with a tilt / lean, and not corrected at the factory or by the dealer ? My Gibson '34 L-5 R/I had that and I have another 16 in. also w/ a pinned bridge, which also has that ' condition '.

Thx and again good luck.

[RJVB]

Is there an explanation for why the saddles are left with a tilt / lean, and not corrected at the factory or by the dealer ?

In my case see 2:
- it developed during the 1st or 2nd ownership of the guitar (I'm not aware of more owners)
- it was OK'ed by famous Loar overseas QC...

[Dennis D]

In my case see 2:
- it developed during the 1st or 2nd ownership of the guitar (I'm not aware of more owners)
- it was OK'ed by famous Loar overseas QC...

Is that bridge pinned ?

How does that develop ?

[sgosnell]

I'm not sure exactly what you're needing to do. Are you removing material from the bottom of the base, the saddle, or something else? For the bottom of the saddle, a small plane can do the job, but ebony is hard and brittle. What I generally use to remove relatively small amounts of wood is sandpaper. You can attach it to a straightedge to work as a plane, or tape it to a flat surface and move the work over it. That's the default method for shaping the bottom of the base, on the guitar top. IME sandpaper is quicker than files. I may use files to do the final finishing, but starting with something like 120 or 180 grit sandpaper then using finer grits for the finishing is my usual method. A belt sander makes the work much easier, but they aren't cheap.

[docsteve]

I did that last year using 80 grain sandpaper. Took me a couple of hours (and wasn’t worth it in the end, but that’s another story). If it’s the base of the bridge saddle you won’t be seeing it anyway, so don’t bother with finer sandpaper.


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[RJVB]

Is that bridge pinned ?
How does that develop ?

Floating, and from what I can tell perfectly stable. It does bother me a little bit for doing percussive things (but I suppose the impacts we create with that are in reality tiny compared to the string pressure).
I probably would leave things as they are if the string slots were not as badly done as they are (there's some saddle slot buzz I cannot seem to get rid of). Also, the lean is worse on the treble side and I do feel like the instrument doesn't ring as nicely high up the treble strings as I've heard from its siblings.

I'm not sure exactly what you're needing to do. Are you removing material from the bottom of the base, the saddle, or something else?

From the top of the base (which is way thicker than the stock base, and thus heavier). That's weight reduction, and as I said I don't want to remove material around the posts so just sanding the entire top down length-wise isn't an option sadly. I also have to take wood off the bottom of the saddle, in order to get the action low enough. These Loars don't have very high saddles, which suits me fine - less difference for my right arm with playing a flattop.
Re: weight: I play acoustically, fingerstyle, so I want everything as light as possible to get a maximum sound.

The only reason I didn't order a stock replacement is that I only found them as a custom order with Elderly's so I've been able to buy this ebony Foley replacement plus the version with bone insert that will go onto the same base. IOW, once everything is finished I can swap between an all-ebony saddle or a (rosewood) saddle with bone insert.

[RJVB]

Here’s what I have atm:



you can see where I started to attack the middle section ... and realised it'd be a lot of effort with the files I have.

[RJVB]

Would this be safe on hard, brittle wood like ebony?



BTW, filing down one of the wings I uncovered a "hole", and what looks like 2 hairline cracks. My stock base has a similar crack-like thing in one of its wings, I take it thus that these are some not uncommon kind of growth defects?
I've filled the hole with ebony dust and CA (worked out pretty nicely), I'll try hiding the cracks like that too.

[Dennis D]

Do you have a ' before ' showing the ' list ' ? Maybe the cracks are the reason it developed .

Thx

[RJVB]

Do you have a ' before ' showing the ' list ' ? Maybe the cracks are the reason it developed .

No, the cracks clearly are no real cracks, more like grooves, and they're not close enough to the posts.

Here's a picture I took not long after receiving the guitar:

[RJVB]

I keep forgetting to ask: would using a router/sander (high speed on a dremel, or lower speed on a wireless drill) be a really bad idea to obtain a nice, uniform result?

[daverepair]

No, the cracks clearly are no real cracks, more like grooves, and they're not close enough to the posts.

Here's a picture I took not long after receiving the guitar:

In my experience repairing and setting up archtop guitars, when the saddle is leaning, as in your photo, it's because of possibly three factors:

-the posts(or threaded studs) are not sufficiently supported in the base(that is, they don't extend down far enough, or they are loose in the holes).
-the base is too thin, meaning, even if the studs extend to the bottom of the base, they lean anyway, because the base material can't support them against leaning.
-the studs, or posts, do not extend far enough into the saddle(they're too short), to prevent the saddle from leaning.

I've either had to:
-make a thicker base, to give more support to the studs
-plug, redrill, and tap new threaded holes(for the studs) in the base
-make new taller posts, or studs
-or make a new, taller saddle, that will be adequately supported by proper height studs.

I have sometimes found that bridges on imported carved top mandos and guitars poorly made(showing the above issues), and I'll replace them with a higher quality aftermarket bridge(which needs to be fitted to the top of the instrument).

I hope all that helps. Perhaps it's not relevant, but your photo prompted me to reply.

[sgosnell]

The easiest, and probably best, solution would have been a new base. A Dremel or other power tool would make things easier, but does involve some risk. I think I might make up some sort of adjustable jig to hold the base and allow upward movement to take off a little at a time, keeping the tool on a level surface to prevent jumping around. Doing it entirely freehand may be possible, but allows for the tool to jump around and take off material unevenly and in places you don't want it. You've given yourself a somewhat difficult task, and I don't know of a cheap and easy way to do it.

Bridge bases can develop cracks if the posts are screwed down too tightly, or if the holes are too small. I can't tell what the issues are with your base because I can't see it. Another possible cause of the tilt of the posts not already mentioned is that the holes were originally just drilled crooked for some reason. I can't tell that either. If it were mine, I would just get another quality base, but it's not. Good luck with your repairs.

[RJVB]

more or less done - dremel + 80 - 180 - 800 - 2000 sandpaper followed by the polishing felt on the dremel

[RJVB]

In case it wasn't clear: that *is* a replacement base; the "Foley" adjustable bridge/saddle from AllParts.



I used a small vise to hold it and give me a stopping criteria. There are some tooling marks that are still visible around the post "terps" but for a first time working ebony I think I can be not too unhappy with the result.

The original stock part is still on the guitar, and I suspect the posts were installed in a lousy fashion as I don't see any widening of the screw hole around their base, nor do I see anything at the level of the threading that suggests they might have bent.

[RJVB]

Just about done. Annoyingly I went a bit too far with one of the saddle “feet” and had to restore it to a flat surface with hopefully a homogenous enoug contat area with the thumbwheel.

But overall I think it looks nicer than the stock version