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I just got my dad's old Delta 6" variable speed benchtop jointer. I was very excited to use it since I have about 4 sets of tops and backs that I need to glue up. These are for ukuleles so the sets are no longer than 12". I got real excited and after multiple passes over the jointer I can still see light through the joint. And it appears to be the top and bottom. I have tried multiple techniques (force againt fence, force against blade, fast, and slow) nothing seems to work. All I can think is that the table is off, but I dont see any way to adjust it. Or is it just not feasable to expect decent results with a jointer? any help would be appreciated. -shawn

The jointer needs to be set up perfectly that is for sure, if in fact the tables are where they need to be relative to the blade then the process should be short and sweet. Get your tables level/in-line by using a long level/straight edge, then lay the same level from the outfeed table over the blades, turn your blades so the highest point of the blade is up, slowly raise/lower the adjusting screw until the tip of the blade just touches(not lifting the level) the level, at this point you should be ready to make a perfect joint. If all of this is set correctly and you are still having problems then your feed pressure/positioning may be off, try feeding the pieces together keeping your downward pressure even and focused at or behind the the point where the blade/outfeed table meet, if you keep pressure on the front of the piece as you move onto the outfeed table you may create an uneven joint.

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Gwaltney Guitars

Shawn: Guess the question is,are you concerned about your jointer working right or about joining your tops and backs. Don't know your Delta and what it's capabilitys are, but generally jointers can be set up to make a good joint with proper technique. Sharp cuitters, light cut and slow feed. The edge cut by jointer will tend to show a successive series of shallow concaves and lesser so with the best set up and again technique. A few points to remember,some folks like to use a spring joint, touching on the ends and open a few thousands of an inch in the center.A small opening like this can let in a disportionate amount of light and look like you could pass your hand through the opening.Edges cut with duller cutters can tend to also polish the edge ,especially with hard wood.My method involves rough cut on jointer and then finish with hand plane on shooting board. Started out years ago using the sprung joint, but now use the standard straight joint.Both seem to be equally sucessful.Lots of info can be found in previous postings.

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

I'm one of those curmudgeons who feels that there's only one way to get a good back or top joint: with a hand plane. The jointer is useful for getting it _almost_ there, but you need to take a few strokes with a well set up and sharp hand plane to get it right.

It's possible that there is something wrong with the tables on your jointer, and it could be tricky to fix. Not only do that have to be at the proper relative levels, but they have to be aligned properly as well. If, say, the far end of the outfeed table droops a bit you'd end up with the sort of joint you're describing, if I'm visualizing this correctly. Even if you never want to make a center joint with the thing, it's useful to have it cutting properly, so take the time to get it right.

Alan,
You don't need to be a curmudgeon to think that way as you are right.
A word about sprung joints. It is easy to over do. On a guitar top or back you should be able to push the spring out with just your thumb pushing in the middle edge of one of the boards. While in a lot of wood working situations I strive for a very, very, slightly sprung joint, I don't see the value in a guitar, especially the top. One of the main reasons for sprung joints is to keep the ends tight through moisture cycling. The wood will dry out faster on the ends close to the end grain so it is good to be a little tighter there. In a guitar on the top , you cut a sound hole right where your joint would be sprung. The sound hole exposes end grain so you definitely do not want the joint sprung there. The end grain of a guitars top and back is contained by the binding (other than the sound hole) and the wood is pretty thin. I think the change with regards to moisture is even enough that a sprung joint is of very little value in this regard. You don't want the opposite for sure but I would strive for as little spring as possible without going to other way. Not that hard to do given the short length of joint. This is woodworking 101 and well worth the time to get it right.
Link

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

I have never been able to get a satisfactory joint on a joiner, and I have fiddled a lot with the setup. I finally decided that it was easier to use a hand plane than continue adjusting and aligning that jointer. So, like Al, i use the jointer to get it close and then a joining plane to finish the job.

John

I'd disagree that a hand plane is the only way to get a good joint; there are a lot of ways to do it besides plane and jointer.

That said, there's a lot of fiddling involved with getting a jointer perfectly set up. I spent a couple hours when I first got mine, dialed in a perfect setup...and then a friend came to use my jointer and spun the WRONG wheel to adjust the cut depth! If I had a jointer without indexed knives, I'd use a plane for final truing as you only need to get one knife right on a plane.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

I cheat... and use the Charles Fox surface plate sanding method. I still haven't got the hang of planing joints.... so I use the plane to clean up the saw marks and then just sand on the surface plate.

I think if your jointer has a good flat deck -- you could use a piece of roll sandpaper to get your joint good and flat.

Good luck

John

Getting good joints is imperative to luthiery. I am a machinist and no matter how often I set up my joiner , I seldom get a perfect joint every time. I use 2 methods . Like Alan , a good hand plane is the tool. I will run it on the joiner , then plane . I also use the Granite Surface plate technique. Both work well. If the joint isn't perfect ,it isn't a joint, its a crack waiting to happen.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I use a jointer and it works well for me. Proper setup, sharp blades, and a slow feed rate seeems to make the best joint for me. I've tried a plane and shooting board, but the only thing I managed to accomplish was turning a dread-sized set into a parlor set. I just couldn't get the hang of it. I also bought the sanding jig from Luthier Suppliers, but haven't tried it yet.

I may go back and practice with the shooting board and plane at some point so that I can "do it right", but I'm presently still using the jointer.

Alan

I also use a jointer and it works great, they are super finicky to set up though, especially an older machine like yours. It sounds like your problem is just that the knives are not level with the outfeed table, i am not familiar with your exact machine but i would probably get the knives sharpened if they need it and then go through the process of learning to set the knives correctly. Google jointer setup and a bunch of useful info will pop up.

The other issue is that a benchtop 6" is really marginally enough machine for the job, a jointer is a tool where the size and quality of the machine have a huge impact on how easy it is to get results. An 8" is about as small a machine as i would want for guitar work, it is kind of overkill big but all that mass combined with a huge motor is what keeps you from going crazy with funky results.

I also hope that in a few years all jointers and planers will get rid of the sucky 3 knife setup and move towards either a helical cutterhead like these http://www.byrdtool.com/default.htm or a tersa rig. Setting up a jointer with a 3 knife cutterhead can take half the day and make you want to burn your shop down, it's just no fun. I recently switched to a helical cutterhead, which was expensive, but absolutely worth it if you plan on doing a lot of jointing and don't have a shop slave to change the jointer knives for you.

Sooo, i like jointers, and can get nice joints that are indistinguishable from a hand planed joint, but the curmudgeons may be right this time, a hand plane may be faster and less expensive than getting your machine set up to the task.

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Jordan Aceto
Ithaca, NY

I agree that sharp tools are a must . Most people think that the tools they have a sharp . Todd Stock as a great You tube on how to sharpen. If it won't shave it ain't sharp

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

There are two things that helped me get a good glue joint. The first was Todd's sharpening videos and advice. The only thing I do differently is I added a King Ice Bear 4000 stone in the middle. The extra stone isn't necessary, but I started using it because it was a gift. I must admit though that I like using it. I was getting decent results with just the two stones, but now I get a scary sharp blade. Honestly, that could be practice or it could be I needed to add it. Whichever, Todd's video's will get you where you need to be.

The other was to replace the caa-caa blade that came with my plane with a Hock blade. I knew when I bought the plane I would be replacing the blade. I used it until I got around to it, so when I used the Hock blade for the first time it really made an impression on me. Night and day different.

If you don't own a Lie Nielsen or a Lee Valley plane, take the time to make sure yours is tuned up and spend some quality time with Todd. Its well worth the time spent and its a skill set you have to master if you want to keep your frustration levels down.

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Aoibeann

Ah yes the bowed belly joint or dipped ends.... hmmm

Set up and sharp blades are mandatory.

And still it happens. Here is the trick that sometimes works. Use a 5 to 6 ft spruce or pine 2 x 4 and clamp both sides of the top or back to the middle of the side of the 2 x 4 and plane away, as often its the first and last 6-8 inches of the jointed surface that is over removed producing the belly in the jointed edge, while the center is flat Not the proper way...usually works but eventually you gonna come back to ...
the set up and sharp blades being mandatory.

I use the 2 x 4 trick simply because when the jointer starts to produce a belly cut I can't be
bothered to take the sucker apart and reset the tables and blades simply because its aggravation.

Me gots 6 inch jointer...is ok....but still shoot final edge on a #8 hand plane.(24inch bed) And the truth be known, as of late I don't even bother with the jointer much any more and just shoot the edges...much better I find. In fact, other than the rough break out of the wood, I don't bother using any of the machines any more...too much noise in my head already without a dumb machine whining and screaming like a banchie.


blessings
the
Padma

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Audiences and dispensations on Thursdays ~ by appointment only.


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One thing that hasn't been mentioned in depth is sanding the joint.
I've advocated that a planed joint is better because.... well just because it is.
And that a sanded joint is bad because the sand paper damages the wood on the joint face in ways that a plane does not.

However, I'm starting to change my tune. Using 100 grit sandpaper on the joint faces does dull that fine shiny surface left by a plane, BUT it does create more (albeit a tiny bit) surface area for the glue to bond together.

My usual set up is a shooting board and a big, sharp plane. Then if things are starting to taper at the ends and I just can't get it right, I'll swipe it a few times on a piece of granite counter top scrap that a friend gave me from their kitchen project.
The granite is about 3' long X 1.5" wide X 4" tall. I glue 100 grit paper to the 1.5" surface, and run it through the shooting board just like I would do with the plane. Two or three swipes will usually clean up the miniscule light line that's was formerlly visible.


Hope this is helpful. I sensed from the original post that you were questioning whether or not a jointer was the right tool for the job. It very well could be, with proper set up and practice. The responses have shown that there are lots of ways to get the job done that might be easier than getting the jointer going.

Good luck with your project,

Dave

One thing that hasn't been mentioned in depth is sanding the joint.
I've advocated that a planed joint is better because.... well just because it is.
And that a sanded joint is bad because the sand paper damages the wood on the joint face in ways that a plane does not.

However, I'm starting to change my tune. Using 100 grit sandpaper on the joint faces does dull that fine shiny surface left by a plane, BUT it does create more (albeit a tiny bit) surface area for the glue to bond together.

My usual set up is a shooting board and a big, sharp plane. Then if things are starting to taper at the ends and I just can't get it right, I'll swipe it a few times on a piece of granite counter top scrap that a friend gave me from their kitchen project.
The granite is about 3' long X 1.5" wide X 4" tall. I glue 100 grit paper to the 1.5" surface, and run it through the shooting board just like I would do with the plane. Two or three swipes will usually clean up the miniscule light line that's was formerlly visible.


Hope this is helpful. I sensed from the original post that you were questioning whether or not a jointer was the right tool for the job. It very well could be, with proper set up and practice. The responses have shown that there are lots of ways to get the job done that might be easier than getting the jointer going.

Good luck with your project,

Dave

We had a nice discussion in the Saturday class about planes. One of my students is a cabinet maker, and he spent all of about ten minutes (including setup) getting his scarf joint right with a hand plane, starting from bandsawed surfaces.

There is a certain amount of skill involved in using a hand plane; no doubt about it. A big part of it is in what I call the 'koan of lutherie':"The slower you work, the faster you get done". If you're taking light cuts you can't mess things up too much with any one pass. If you're watching what you're doing, and can control the cut, you can very quickly correct things in most cases.

Most important, though, is getting the tool working right. For the most part, you have to assume that what you've got from the tool store is a 'plane kit'. With some time and effort you can get it to work well, even if it's not a high-end unit to begin with. I've done all of my joining for the past thirty-five years with a Record #4-1/2; not a Lie-Nielsen or Vertias by a long shot. There are plane setup tutorials on line, I'm sure, and you really should go through the process with any plane you get. The better ones won't need much, if any, work to true up, but they will all need sharpening. One of the hallmarks of a sharp and well-set-up tool is that it _can_ take a consistently fine shaving, even from difficult wood. If your plane won't do that, it's probably not set up correctly. If it can't do that, you have little hope of getting a good top joint in any reasonable amount of time.

I'm not a big fan of sanded surfaces in glue joints. For one thing, a good glue joint is not a matter of the surface area involved, but rather how much glue there is in the joint at the end. There is a 'proper' glueline thickness, of about .001"-.004" iirc, that gives the highest strength, and all the business of surface prep and clamping is aimed at ending up with that thickness of glue line. A rough surface simply ends up with more glue in some places and less in others, so that it may _look_ like the right thickness, but it's not optimal anywhere.

My violin making teacher used to cite a study done by the Forest Products Lab back in WW II. At that time they were using a lot of laminated wooden propellors on airplanes. Sometimes the glue joints would fail in service, which is a drag when you're flying the plane! They looked into the manufacturing process, and found that companies that were sanding laminations to thickness had a much higher failure rate than those that planed them. Therafter all the manufacturers had to plane the laminations down.

I will close by saying that joining the top is probably one of the hardest pieces of wodworking on the guitar. The differences in hardness between the latewood and earlywood ensure that. It's too bad that this operation comes at the beginning, before you've had any chance to practice with the plane. Even so, a well set up and sharp plane, with a simple shooting board, should bring this into the range of possibility for anybody.

A power jointer will work fine but like others have said it has to be set up correctly. The blades have to be SHARP. They also have to be level with the outfeed table, as well as level with each other. The infeed and outfeed tables have to be on the same plane too. If you raise the infeed table until it's level with the outfeed table you should be able to lay a straightedge across both tables with no gap at either end. I suspect the problems in the original post are caused by either the blades being too high, or the infeed and outfeed tables aren't on the same plane. Alot of times a well used jointers infeed table will....... droop a little, causing the leading edge of the table to be low. This will cause a gap in the center of anything you joint. I got a jointer for almost nothing that had this problem. I built up the leading ends of the slides with brass and it works great.

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I didn't mean to say it, but I meant what I said.
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Tooth in a joint is a long lived myth that needs to die. The way to not starve a joint is to not over clamp it not leave crumbs or irregularities in the joint by sanding it. One can tell by the amount of glue applied and the squeeze out if you have starved a joint. Wetting out both surfaces helps also but I know this is a bit harder to do with hide glue.
Link

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

I'm not an expert in this... but from what I've read you need to factor in the glue type before discussing the surface preperation. It was explained to me that White glue/PVA's need a glass like surface and therefore planing is the optimal strategy. Think of it like wetting two pieces of glass and laying them face down on top of each other. The glue only needs to penetrate a small amount... and of course dry... to create an inseperable bond. The greater the surface tension the stronger the joint. You should not use PVA's to fill anything. If you have any sort of a "rough" surface, the surface tension is greatly reduced and weakens the overall joint. Sanding a joint and using PVA's/white glues will weaken the overall joint. However, if you plan to use epoxy or polyurethane glues, a toothed or sanded surface is appropriate. These glues actually "grab" the surface... so the more surface the better, ala sanding.

Long and short is that planing is best for PVA's with a glass like surface and a good tight fit is required to create a strong joint.

Yes epoxy likes a larger glue line but with poly a large glue line will make for a weak joint. Wood crumbs and torn fibers are not strong. Besides large glue lines are not what most folks want in a guitar top or back from not only a structural point but a aesthetic one as well.
Here is a hand planed, LMI glue, glued joint under magnification on a Adi top. The joint is just under the D on the penny. You can see that you can't see it (the joint) better with a bigger file size but I couldn't do it on the forum.
L.

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

I think starved joints from excess clamping pressure are another myth that needs to die. It's the standard strawman for faulty technique and bad joints. There might be situations where such a thing could occur, but none of them happen while building a guitar. IE: a perfectly fitted joint, with enough glue applied to wet both surfaces and squeeze out, which is clamped evenly and in one direction...which then fails

I have used a hydraulic press from time to time to clamp things up, at psi much higher than anyone's getting with manual clamps...no failures. I thought of doing a 'positive' experiment...but that just proves that I haven't successfully starved a joint. I think the real 'proof' experiment will have to be something involving a cash wager where I make the joints and the glue, then set up the clamps, and my rival needs to apply enough pressure to make my joint fail/weaken without actually splitting the material.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Bob,
I am not following you totally here, are we agreeing or disagreeing ?
Are you saying that by a "straw man" you mean people will blame over clamping for a poor joint when really it is poor technique. I can see that especially sense in a poor joint there is likely to be a too much glue left in there.
The poorly fitted joint will need more clamping pressure to bring things in proximity but this is not a good situation, obviously.
The better the joint the less clamping pressure you need to bring things together. Of course this varies with different woods densities etc.
The important thing for begging and intermediate woodworkers is not to crush the wood with the clamps but instead make proper fitting joinery.
Heavy clamping pressure beyond what is needed can be troublesome with regards to distortion of clamps, the wood, the work and so on.
If your main point is that it is hard to starve a joint by too much clamping pressure I think it depends on the type of joint and the wood. A thin edge joint in a dense wood is much different than a large surface area joint in a softer wood. Cauls play a big part as well in distributing pressure and not causing what Hoadly calls the sponge effect. Which is push in the middle of a sponge and edges will lift.
So if you are saying that generally it is pretty hard to clamp the glue out of a joint, I would for the most part agree, especially with a less than perfect joint.
L.

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