Official Luthiers Forum!

Hello all,

I recently inlayed carbon fiber beams into a jatoba/purple heart neck. I cut the channels a little deeper intending to level with a hand plane when after installation.

First problem arose with planing. I'm using a stanley smoothing plane, and have just gone through the sole flattening operation (plate of glass and emery paper) have sharpened the blade as best as possible, up to a 4000 water stone. yet on the jatoba/purple heart wood I find the knife just slides over the wood without taking a chip. Advancing the blade slowly I'll suddenly reach a point where the knife does finally engage the wood but now is protruding too far, and takes a massive, tear out inducing chunk.

Mostly I'm interested in why this was happening and how to make the hand plane do its job on the very hard wood.

Last night I was getting frustrated with this and just wanted to level out the mess I had made with the smoothing plane to ready the neck for the fingerboard. I thought, never mind with the carbon fiber not being flush with the surface, it's glued in well with epoxy and won't mind not making contact with the fingerboard. So I took it over to the 8" jointer, setting this up for the lightest possible cut so as not to hit the carbon fiber.

Woops, the jointer knives hit the carbon fiber. This created a little divot in the blades of the jointer but more relevant is that there are now parts of the neck where the carbon fiber is sitting proud of the wood, and the wood surface is still not flat enough for the finger board. I think this project is a write off now, unless there is some way to level the surface which is a mixture of carbon fiber and wood. I suppose sanding it flat on the same piece of glass I used to joint the planes is an option but then at best I'll have a sanded joint, not a knife cut surface and the fingerboard joint will be compromised.

Any thoughts much appreciated,

Stefan

Blade not sharp enough and/or too coarse a cut
Try planing in the other direction, and at an angle
Jatoba and purpleheart are tough woods to plane, often with a fair amount of runout, which you seemed to have experienced.

_________________
Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

Planing will not work if the epoxy graphite is proud.

Sanding sounds like your best option. The thing about a sanded surface not making a strong glue joint is fairly moot here because you are dealing with a very large joint that is not highly stressed.

Check the bevel angle on your plane. And if it isn't easily shaving the back of your hand, it isn't sharp.

But now that you have the carbon fiber/epoxy exposed, sanding is the way to go. I would use my belt sander.

_________________
Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Stefan,

I had an extremely similar time just yesterday planing an ebony fingerboard - I thought I had my planes sharp (I go up to 8000 on a Norton waterstone) but they just wouldn't cut and then I'd get my blade so far out that when it did catch - huge gouge. I tried my Stanley #6, #5, #4 w/ Hock blade and finally my infill plane that I built this year. I was quite surprised that even the infill at 55 deg bed angle did not do well. But then!!! I tried something new - I re-ground the bevel on my blade so I had more exit/relief angle on the blade. I had it at about a 45deg bevel with a 5deg micro bev on the 55 deg bed - so I only had about 5deg of relief behind the blade = NOT ENOUGH!!! When I reground the blade to a 38deg primary and 3 deg micro bevels, it cut beautifully. (if this description is to confusing, let me know and I'll reword it)

This may not be your problem, but it sure sounds similar to mine. Also, if you are only going to 4000 on a water stone, you may want to strop the blade on your palm or a hardwood "strop" with polishing compound. Like they said - you should be able to shave with it and have a scratch-free mirror polish on both back and bevel.

As for the carbon fiber - I would be looking for someone with a thickness sander.

I know Stefan mentioned that he was worried about the joint not being a planed surface, as most people mention that a planed joint is the strongest joint. I would think that with the large glueing surface of a fretboard to neck joint, that a sanded surface would work perfectly well.

Your plane problem sounds like the blade was not sharp. It is pretty much impossible to make very thin cuts with a blade that is not properly sharpened. Did you sharpen until you felt a burr along the back of the entire blade edge? Sounds like a stupid question, but I have had the same problems with planes and I know how frustrating it is. But getting the blade properly sharpened makes the experience of using them very enjoyable, especially with a #3 or #4 smoothing plane, they are my favorites.

Another thing worth mentioning, I don't know what others feel, but I prefer to sharpen to an 8000 grit water stone, though 4000 gets you pretty sharp, you can definitely get sharper.

CF is hell on edge tools.... Want to ruin a blade... just go cutting CF... It is amazingly abrasive on tool edges...

My best advice is to either sand or maybe buy a carbide router bit... and the bit may end up kinda dull when you are done.

A dremel cut off wheel also works.... but will smoke and throw CF bits everywhere....

Thanks

John

Get a roll of 120 grit psa sandpaper (80 grit if you really need to take off a lot of material) and stick a long piece on your jointer table. That should be flat enough to sand the neck. Sand across the grain to start with and it will go faster, even though you can only take short strokes with 4" wide paper. Make sure you only put downward pressure on the high points.

As for planing tough woods, in addition to the other suggestions, try skewing the angle of the plane a bit while still pushing parallel to the grain.

_________________
http://www.chassonguitars.com

If your blade is truly sharp and we can eliminate that as the problem what you are describing is exactly what happens when the sole is slightly humped in the area right behind the blade. This can happen when you lock the blade down. When you flattened the sole of your plane did you do it with the blade in the plane and under tension. (retracted of course ) You should have. What I do is to tape off the sole and by hand sand a little relief in this area. At the very least flatten the sole under tension. You can see the area to be flattened in this picture of a wooden plane. Same on any plane.
Link

_________________
Cut to size.....Beat to fit.....Paint to match.

CF eh?

Well then...joint the neck on ether side of the CF leaving it standing proud and route a channel in the Finger board for to fit the CF. This would be easier to me brain than trying to deal with leveling CF.

Then of course there is the belt sander.


Padma

_________________
.

Audiences and dispensations on Thursdays ~ by appointment only.


.

If you sand that CF, wear a MASK and vacuum up all the dust generated before removing the mask. You don't want any of that residual dust floating around waiting for you to inhale it!

_________________
Hank Mauel

Word!

_________________
Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

I used carbon fiber and all other types of fibers for 16 years as the owner/designer of a factory building composite aircraft propellers.

Pretty much the only thing to use to cut or mill a cured carbon/epoxy matrix and get clean cuts is sharp carbide tooling or diamond tooling. When cutting this material one should not expect their tooling to remain sharp very long either. Basically, diamond is carbon molecules that are highly organized. Carbon fiber is carbon molecules less organized than diamond...but still pretty hard and dense. In fiber form, and contained within a matrix (epoxy, polyester, nylon,...ect.), carbon is decidely less dense than pure carbon but each fiber still retains the basic, hard properties of carbon. In a battle with steel, carbon always wins.....so if your tooling isn't made of a carbide (metal and carbon) compound, it's going to begin to dull almost immediately when attempting to cut carbon fiber.

I would not hope to hand plane this material. Even with carbide tooling under controlled circumstances, fiber orientation, feed rate, and tool dimensional integrity play an important role in getting a clean cut. Use aluminum oxide sandpaper instead and wet sand where possible with a soapy water. Otherwise sand dry and unclog every few swipes. And be cognizant of the fact that everything around the carbon is MUCH softer than the carbon and will be MUCH easier to sand....and therefore, damage.

btw...carbon fiber dust is not carcinogenic....not that you want to breate it nor that it won't create temporary respitory issues. It's just not as dangerous as a lot of people might think.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

It consists of microscopic little sharp ended pieces that will cause scarring in the lungs. More than temporary. Like silicosis.

_________________
Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

And, CF dust can cause problems with electrical equipment if enough gets in the wrong place.

Some jobs are definitely in the 'outdoors in a good breeze' category for me, and making CF dust is one of those.

Check out this MSDS for carbon fiber....Toray is a major carbon fiber manufacturer.

http://carbonsales.com/docs/MSDS/toray_msds.pdf

Looking down a ways you'll see it doesn't cause silicosis in lab rats. You'll also find fairly casual precaution requirements when dealing with it. Material Safety Data Sheets are required by law so there is no chance of mistating or misinforming with these information sheets. Carbon is only carcinogenic when it gets small enough to be absorbed into cells, as is the case with some carbon nanotubes but in the dust particle range it's just an irritant. All the same, I don't WANT to breathe it. I'm just saying that there are things in your shop that are FAR more caustic and dangerous than carbon fiber dust.

And John is right.....don't get that dust around electronics. That's some BAD juju.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

I think the point here is not that carbon dust is a carcinogen, but that it is basically like inhaling tiny shards of glass that cut the lungs - much like fiber glass particles. I completely agree - WEAR A MASK AND EYE PROTECTION when grinding/sanding this stuff. I have worked with it a lot and it is not fun. And no matter what Toray may publish, it is not good to breath that dust.

The reason you don't want it around electronics is because carbon is one of the best conductors of electricity you will find out there. SO, when you have carbon dust flying around, you will destroy any electrical motor in short order. We always used air-powered tools for ALL carbon cutting work. You may want to trash this neck.... It is definitely not worth ruining a drum sander over it.

[quote="Stefan"]Hello all,

First problem arose with planing. I'm using a stanley smoothing plane, and have just gone through the sole flattening operation (plate of glass and emery paper) have sharpened the blade as best as possible, up to a 4000 water stone. yet on the jatoba/purple heart wood I find the knife just slides over the wood without taking a chip. Advancing the blade slowly I'll suddenly reach a point where the knife does finally engage the wood but now is protruding too far, and takes a massive, tear out inducing chunk.

Mostly I'm interested in why this was happening and how to make the hand plane do its job on the very hard wood.

What year was the plane made? Better ones were made from years 1890 -
1925. Look at the series of patent dates stamped behind the frog; Stanley
reapplied for patents every 5 years, so a Bailey #5 with 1902 as its patent
date was made until 1907. These are still very common, and sell for less
than $30 at flea markets. New ones are invariably junk -- pop out the
iron, and you'll see why -- and worthless even as paperweights.

How heavy is the iron? Thick replacement irons flex less. Sounds
like yours is biting in and snapping. What honing angle did you use?

Thanks for the awesome advice everyone!

So I took the neck to the belt sander (heeding advice of dangerous dust, mask + vacuum + air filter going) and have achieved a flat gluing surface for the fingerboard.

As for my plane, The iron is not so thick, I believe it is the standard 1/8".

My plan is to get a thicker iron, or else invest in a new plane (I'm considering the Veritas #4 smoother) , and also invest in a better sharpening set up. I plan to get an 8000 grit water stone and maybe use the Brian Burns system.

Next time I use carbon fiber I will bury the beam deeper in the neck and use a wood filler strip ontop of it, so that I can have an all wood surface to work with.

Thanks again for the all the insight, I've learned so much from this forum

Stefan