Jump to content

General woodworking question


Carman007
 Share

Recommended Posts

When jointing the top plate. How close do the boards need to come together. I have a 22 inch jointer planer. I clamp the boards side by side an go to town. The boards seem flat relative to the jointer but when I put the boards together light shows through the gap. I'd say it's maybe a 1mm gap 2mm at the very most...if I was making a tabletop I'd pull it together and call it a day but is this insufficient for a violin? Any ideas on why I can't get it perfect? Is there such thing as perfect?

Link to comment
Share on other sites

51 minutes ago, Carman007 said:

...a 1mm gap[,] 2mm at the very most...is this insufficient for a violin?...

Yes.

Also, the tool marks left by a jointer are unacceptable.  If you could adjust the infeed and outfeed tables of the jointer to leave no gap, then remove the tool marks with one or two light cuts with a hand plane, you would be good.

Link to comment
Share on other sites

I'm not particularly experienced at making violins, but woodworking I have significantly more experience. A "sprung" joint with a slight gap in it is generally fine on a piece of furniture. On a violin, particularly when the ends of the wood are cut away when cutting the outline, a perfect joint seems a far better approach than a sprung joint IMO. Particularly because that joint is generally going to be under stress. 1-2mm is quite a big gap I would think, and even if you're ok with a sprung joint, that seems like a big gap to me.

If you're using a hand plane (which you should do even if it's just finishing from an electric planer), it's relatively common to have gaps if there's not a proper planing technique. If you're using a 22" hand plane, you could get a great joint, but if you're relatively inexperienced, I personally think a smaller, lighter weight plane would give you more control... unless you are using a wooden hand plane which is going to be lighter. A short #4 hand plane can give you a perfect joint on any length of wood just as well as a longer "jointer" plane can with proper technique. Also taking your time with shallow cuts and checking for square and flatness regularly will help you see how and when you might need to make a correction during the cut. Something small like violin wood definitely shouldn't require a longer plane.

If you're hand planing I would recommend searching YouTube for Paul Sellers videos, he's a very experienced, master hand tool woodworker and has tons of information available about this particular topic, as well as more general information about sharpening, setting up and using hand planes. But generally it's important to make sure you're using the front "Knob" to stabilize and square the plane to the wood, and the rear "Tote" to push forward (not down). Pressure should be gradually shifted from front, to back during the cut, sort of like a slight scooping motion. This is because the plane blade extends beyond the sole no matter how flat the sole is, so it sort of "teeter totters" on the blade. Also a lightly oiled or waxed plane sole (on a metal plane) is super helpful.

If you're using an electric joiner... I'm not sure, but you may need to make sure the jointer is set up properly as stated above. And finish with a hand plane.

Link to comment
Share on other sites

 Do not run two pieces at the same time, use two speed squares to make sure the plate and edges of your joiner are perfect 90. Unless the blade is trashed It will be squared up, if it's not there is a set up problem with the machine, or you are running warped material.

Running two pieces at the same time is a quick way to get off square and could be dangerous 

Link to comment
Share on other sites

22" should be a #7 jointer plane, that's a heavy plane and difficult to use if someone is inexperienced, it's also wide and can easily go out of square throughout the cut on narrow wood. I use a #4 "smoothing" plane for almost everything, it's so nice and light and easy to use. If you have a shorter plane I might try that. Also if it's not sharp enough or the cut is too aggressive and requires excessive force you're going to have a super hard time with any plane. Also you can use the fingers as sort of a "fence" at the front of the plane to help, and the palm on the back of the plane behind the tote on a long #7 plane.

Link to comment
Share on other sites

A 22" is too large to have good control on such a small piece.  My 17" works well.  I bandsaw or table saw to get a straight, right angle cut... Then go to work With the plane.

Adjust to a very fine bite on your cut... you are truing up, not hogging material.

Pay close attention with a straight edge to see if you are overcutting the board ends and adjust you plane strokes accordingly.  When no light comes through the straight edge check, unclamp your boards and check them... They will be perfect.

Link to comment
Share on other sites

I bought a #7 jointer plane several years ago at a swap meet, with the idea of using it for joining plates.  It's so warped and twisted that it could never cut a good joint, and I got other tools instead of trying to flatten the warped one.

The plane needs to be precisely flat, blade straight and freshly sharpened, and take light cuts.  I agree with the others that the joint needs to be precise, with no light showing through.  I don't think any plane could be "too large" as long as it's flat.  My 12" power jointer is pretty big.  At some point, it's better to move the wood rather than the plane.

 

Link to comment
Share on other sites

Yes, should be perfect in most methods. To check it I hook up one side in the bench and put the other half on top of it, move it in different positions, also diagonally and always flip the second half 180 degrees to make the same checks.

During my journeyman’s years I have learned several techniques. 

1. clamping the wood in the bench and pushing the plane over it. (Can be done with pulling a Japanese plane as well) Probably the most common method. Beginners struggle often because they don’t have a good foot position and loose the body balance to use the plane. It can also happen that the surface is not in an right angle to the surface.

There are two possible goals with this method

a. Making a perfect flat fit (good joiner plane needed)

b. Making an even round curve on both sides creating a gap and is done with a Stanley block plane. (A method I learned in Hungary) it is the clamped in a bench with the ‘hammering technique’. (That’s a bit difficult to explain in detail.) 

2.clamping the joiner plane in the bench and pushing the wood over it. 

3. On a Japanese shooting board the wood is made flat on the side facing ribs and put on the board. A Japanese plane is pulled (not pushed as you might know) over the surface to be joint.
 

4. the same as 3 but with a European plane which is pushed. 

5. Several years ago I made a cello and didn’t have a good joiner plane. So I made it with a Mittenwald type tooth plane and clamped it together with much pressure.  I thought I’d see a black line from top to bottom when finished but it was by far better than I  expected. In some areas there were slim black lines. Supposedly this joint holds better than a flat joint because both surfaces are interlinked. 

Link to comment
Share on other sites

Carman007:  I went through your pain and can offer the following (with apologies from the newbies to Bodacious Cowboy, who I assume has dropped out of this thread).   

1.  Pay close attention to the advice in the other posts and the old threads on this topic, especially the advice to check out Paul Sellers' videos on plane truing, sharpening, and use. 

2.  The light test is probably the best, but beware only one linear portion of your joint needs to be perfect to cut out all the light.  If the rest has gaps, then you will find them when you carve out your plates.  Hence the need to make sure everything is square.  

3.  It took me too long to realize the value of learning to sharpen blades properly.  I can't stress too much the need for a good set-up of the plane before trying to make a nice joint.  Hearing that nice "shhhhhh" of the plane as it cuts a paper thin shaving with minimal effort is worth all the fuss.   I am a bit extreme, but I start at 400 and sharpen up to 3000 grit, then use a leather strop on all the blades I use on a violin.  I only push the plane forward, never drag it backward over the wood as I understand this can dull the blade.   The pic attached is my peg shaving blade, just sharpened yesterday to a mirror finish; took about 20 minutes as I had not used it in a long time.  

4.  You can't clamp your way out of a poor joint.  If you do succeed in clamping enough to bend the wood together, you may have squeezed out the glue so much that the joint will fail at some future inopportune moment.  (And yes, I did that.)  Davide Sora has a nice video on YouTube on using gentle clamping over a rub joint, which is what I do.  Some just do a rub joint with no clamping, allowing the hide glue to do its magic with a very well planed joint.  

5.  The spruce top is easier for me to joint than the back.  I would do that one first.  

6.  Don't plane a nice joint one day and try to glue it on another day.  The humidity and temp changes may render yesterday's great joint a poor one today.  

7.  I thought I needed to create the perfect joint with using single full length passes of the plane. For me, that is not true.  Once I am close to perfection and am cutting very thin shavings, I use the light test to selectively plane the high spots.  

Good luck!  

 

 

Blad.jpg

Link to comment
Share on other sites

2 hours ago, Jluthier said:

 

6.  Don't plane a nice joint one day and try to glue it on another day.  The humidity and temp changes may render yesterday's great joint a poor one today.  

 

 

Fair point. But what do you think happens to the joint when you brush hot, water-based glue all over it?

Link to comment
Share on other sites

3 hours ago, Bodacious Cowboy said:

Fair point. But what do you think happens to the joint when you brush hot, water-based glue all over it?

Good question, and I can only speculate; probably different from spruce vs maple, the former becoming softer and maybe swelling more.  At least one of the internet mentors advises brushing on a thin layer of glue over a planed surface, letting it dry, planing it again lightly, then doing the rub joint, perhaps to counter any of the above effects.   I wonder if any of you do that?  

Link to comment
Share on other sites

30 minutes ago, Jluthier said:

Good question, and I can only speculate; probably different from spruce vs maple, the former becoming softer and maybe swelling more.  At least one of the internet mentors advises brushing on a thin layer of glue over a planed surface, letting it dry, planing it again lightly, then doing the rub joint, perhaps to counter any of the above effects.   I wonder if any of you do that?  

Time might allow changes to the whole piece. Brushing glue on is local and quick, unlikely to have an effect.

Link to comment
Share on other sites

1 hour ago, bkwood said:

Time might allow changes to the whole piece. Brushing glue on is local and quick, unlikely to have an effect.

In general, I've found that it makes the initially flat surfaces become slightly lengthwise convex. Which is why I think it's a good idea to plane the joining surfaces just a little bit concave.

Not 1-2 mm of a gap though, as the OP mentioned. That's not a gap, it's a chasm...:D

Link to comment
Share on other sites

3 hours ago, Jluthier said:

I can only speculate; probably different from spruce vs maple, the former becoming softer and maybe swelling more.   

Spruce is very stiff along the grain, and not porous across the grain.  I haven't noticed warpage with joining spruce.  Maple is different, mostly in how much glue it absorbs, and therefore warps (particularly true for off-quarter figured maple).  I always glue size maple first, and re-flatten the joining surface.

Link to comment
Share on other sites

13 hours ago, Don Noon said:

Spruce is very stiff along the grain, and not porous across the grain.  I haven't noticed warpage with joining spruce.  Maple is different, mostly in how much glue it absorbs, and therefore warps (particularly true for off-quarter figured maple).  I always glue size maple first, and re-flatten the joining surface.

I'm sold, Don.  I will do that on my next back.  Thanks, --J

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.


×
×
  • Create New...