Jointing Tops first build
 

Hello 👋,
So I’ve bought wood a few years ago and currently starting my first build, my plan is to build an OM or Modified dreadnought depending on if the wood lasts after my jointing attempts.
I’m currently trying to joint the back and the top ( bought one spare to practice) and the back (Indian rosewood) came out almost perfect just a hair of a gap at the end but for the tops ( one cedar, one Sitka spruce ) I keep getting a perfectly tight midpoint but two gaps at both ends. So my question is how can I get rid of those rounded off edges. I’m currently aligning the grain and then taping the pieces together, clamp them to the table( which is flat) and afterwards plane them with a blockplane.
Thanks in advance, cheers.

https://i.imgur.com/KW43tKa.jpeg
https://i.imgur.com/obV2I1v.jpeg

Getting a perfect joint with a block plane is possible but challenging, especially for someone just starting out.

Most people use a #5 or longer. Even then, the plane bottom needs to be flat, the blade adjusted for fine cuts and very, very sharp.

I suggest you practice on scrap until you perfect the skill. There are quite a few videos on youtube that teach how to shift your weight to the front and then back of the plane depending on whether you're starting the cut or ending it.

I have several sizes of planes, but use the biggest (IIRC it's a budget brand No. 7) to do jointing. Even then, I just use the plane to get it close then will use a piece of MDF as a back board to sand it to full closure, but by no means am I an expert.

A couple of thoughts have come to my mind though:

1: when jointing the top, is it really necessary to get 100% closure? The way I see it, only the lower bout is really necessary to be closed. Otherwise, you're cutting out the soundhole and a slot for the truss rod - then covering it all up with the fretboard anyway.

2: when you're jointing the back, you're going to cover/route the joint with a center strip on the outside and the reinforcing strip inside so why bother?

FWIW I'm currently joint a set of mahogany and intend to add a single piece of black purfling to act as a simple center strip. I'm struggling with gaps there too but am struggling with the idea that it's going to get pore filled eventually and reinforced with spruce on the inside anyway.

Agreed a longer plane helps.

You can also run them together over a well set up jointer. I fold the bookmatch together, held by not too much double sided carpet tape.

There is also the router method where you lay them flat together attached to a piece of mdf with a straight factory edge on it. You then use a flush or pattern bit guiding the bearing along the mdf edge. I find it easier with a router table.

People also use a shooting board but I've not had great luck.

If your joint gaps are within the soundhole area, no problem. A small gap under the fretboard extension may also be forgivable.

I cut the joint close with a router and edge guide then do the final fit by placing one plate overlapping the other, sanding the edge with a machined aluminum level covered with 220 sandpaper. Do both edges and check the joint for being light tight.

I look for NO gap between the mating edges. The center joint is arguably the most important joint in a build. It's worth taking the time to get it right.

I recently saw a video of a well known factory heir using an electric jointer to create his center joins. I would never do that! No matter how slow you go, the surface is a series of little scallops, and the truly great join we need is impossible to achieve by anyone.

IMO, of course.

I use a long (16”?) wooden joining plane with an exceptionally high quality iron in it. Every now and again (2x or 3x in 50 years) I put a bit of effort into truing its sole. It is as flat as I can make it, and the blade is shaving sharp. I clamp the two halves of the plate in shooting board and plane using an ever finer blade protrusion, which is adjusted with a mallet, and in the end make it slightly hollow by planing out the middle but not the last inch of either end. The blade is cutting the least possible amount at this point. Then I cut the full length with all the control I can muster. After a couple or three strokes there will be a cut that takes an even slice off the whole length. Do not make another cut! Hold the two pieces edge to edge in front of your face with a strong light source on the other side and inspect for gaps, of which there should be none. If there is/are, do it again, you’ll get better with practice.

I bought my joining plane from Bill Lewis Music Supply in Vancouver, BC over 50 years ago. Bill sold out to LMI, and neither are still in business . . . but I believe the German maker of the plane may still be around. It was $15 at the time.

I use a router as a planer, I clamp down the two pieces with the router bit cutting both (there is a gap between them almost the width of the bit). The router rides against a straight edge, I move it fairly slow, maybe half a minute to do the cut.

https://i.imgur.com/9DqIfqh.jpg?1

No hand plane with a flat sole has the ideal cutting geometry. That can only be achieved when the plane is configured like a jointer, where the outfeed portion of the sole (the back part) is flush with the knife, and adjusts by moving the infeed portion.

Thanks
 

Thanks for all the replies
I am left with very thin shavings along the entire edge which is what we want I guess IÂ’m shifting my weight somehow while doing the cut, IÂ’ll practice more and check after every cut with a straight edge, I only checked every few cuts which was wrong I assume, I got a new no.4 Stanley plane and I also have a new Makita router if I canÂ’t get it to work with a shooting board and the plane I need to use the router or the sandpaper version, but sandpaper will be my last option since itÂ’s slightly less secure than a planed face from what I could gather.
Again, thanks IÂ’ll update as I go along 🙂
https://i.imgur.com/oy8bLSD.jpeg

Plane and sanding bar…
 

The shavings you are getting look to be rather thick.

With practice you can get a good joint with a longer bench plane; I use my Veritas jack plane with a freshly sharpened blade. A block plane just isn’t long enough.

When using your shooting board - I hope you are using one - apply very light pressure to the plane. You can create a very slight hollow by planing the middle section of the joint until no material is being removed. The hollow can then be removed with one or two full length passes. To do this successfully you need a very sharp blade and the lightest of cuts.

This process is something I still struggle with from time to time. A perfect joint can be achieved very quickly by using a levelling beam - ideally longer than the joint - with an abrasive attached. Once you’ve got close with the plane, a few passes with 220 and 400 grit will give a perfect joint. This takes me literally a couple of minutes at most, including the initial planing.

It’s said that a planed joint is better than a sanded one. My last few instruments have had sanded joints and they are both invisible and stable.

My technique is just as Bruce described. You have already found your systematic error, you go heavy at the ends creating a hump in the middle so do the opposite of that. Target the middle till you have a nice crescent of thin light that is deepest dead center and tapers off to each end. Then put back on your shooting board and do a couple full length strokes and test in the light again.

The OP says he uses a block plane. In my experience what you're suggesting (and it's a good suggestion - the same technique I use) will not work with a block plane which is just too short and will follow, to an extent, the concavity.

I missed that part. Yeah there is no hope in doing this with a block plane. The OP might be better off double stick taping sand paper to a level and using that if he/she doesn't have a jointer plane.

Some tips:
1. Sharpen that plane and take finer shavings. Your shavings are still very thick for good jointing. For jointing, you want nearly transparent shavings.
2. Close down the mouth to reduce tearout.

Technique:
General comments, not in order.

Planes cut heavier where you're clamping/supporting the wood and lighter where you're not. Yes, even on a 9" deep section. I generally start with support around 1/4 of the way in from each end and see how that goes. YES it makes a difference. From your hollows, I would guess your clamps are toward the ends. Move them in toward the center some and take a few passes. You absolutely can compensate the plane cut by shifting your support location. In fact, that's how I do it.

Work to get rid of your humps with short, carefully aimed strokes directly on the high spots. The plane must also be set extremely fine. THEN, when the only defect all the way down is the little lump from the start of a shaving, take 1-good full length shaving. Continuing to take full length shavings when the geometry is out of whack only disrupts your geometry more.

Don't tape both halves together when jointing. Do them one at a time and candle against a quality straight edge. Doing them taped together only ends up producing wonky geometry on both plates at the same time. Once both pieces candle to a quality straight edge, candle them against each other and adjust ONE half to match the other. Don't chase the joint on both halves at the same time.

Need practice wood? Paint stirrers are free or extremely cheap. Jointing them is fantastic practice, and it won't wreck EXPENSIVE tonewood.

Early on, I did two "Tops" out of 1" wide, 1/8" thick spruce slats. I think one "top" came out 16 pieces and the other 15. After that, I had my technique down, and jointing actual top and back sets was a snap.

Keep at it. You'll get it.

The block plane might be the problem.