Glue Joint planing and Scraping questions

Re: Glue Joint planing and Scraping questions

Dean J in MN

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Last night I was trying to joint the edges of 4 boards for glue up. They are about 6" wide, 17" longs, and about 3/8" thick. I thought I would take 2 at a time and put them back to back then put in my vise. Using my sharp (un-crowned) #6 I thought I could get a nice tight joint. When I lay the boards on a flat surface and see how they line up, the middle area of the boards do not come together tight where the ends do. What am I doing wrong?

Doing wrong? You just made a nice sprung joint, you did it right! :)

How big is this gap in the middle? Can you squeeze it out by hand or light clamp pressure? If so, you have no worries.

The only nit I would have with your description is the 'back-to-back' part. I'd say put the boards 'face-to-face.' But, if the backs are flat it really shouldn't matter. I don't plane the backs of the boards flat until after I glue up the panels, so I match plane by placing the boards face to face. Either way works as long as the faces touching are flat and you "unfold" the two boards to make the joint.

Secondly, I was playing around with my Veritas cabinet scraper last night (same project). I noticed that it doesn't create as nice of surface as my regular card scraper. It's not a nice clean cut. Is this normal? I've never sharpened it and have hardly used it since I bought it.

You still need to hone your scraper plane blade. You can start out skipping the hook rolling step, but I would suggest you hone the blade.

-Dean

Re: Glue Joint planing and Scraping questions

Joe in a Cleveland Suburb

>How big is this gap in the middle? Can you squeeze it out by hand or light clamp pressure? If so, you have no worries.

I'm sure could not squeeze it out by hand. With clamps I'm sure I could. My observation is the joint, when the boards are butted together, doesn't disappear like I am used to seeing when I use my powered jointer. But maybe this is normal?

I'll give the scraper a little honing and see how it does.

Thanks,

Joe

You need to sharpen it...

Scott Burr in Ben Lomond CA

>The scraper that is. I They don't come honed.

Dean is correct, you made sprung joint. If they come together at the center with clamp pressure your good to go. When gluing up the panels clamp the middle first and work towards the ends with clamps. The beauty of a sprung joint is it uses less clamps and you get a nice tight joint at the ends of the board where it really matters.

Re: Glue Joint planing and Scraping questions

GolfSteve in Calgary

>My observation is the joint, when the boards are butted together, doesn't disappear like I am used to seeing when I use my powered jointer

It's not normal, but in this case, a sprung joint may be OK. You can get a perfectly straight joint using handplanes. Concentrate on keeping pressure on the toe of the plane at the start of the joint, pressure on the whole plane during the middle of the joint, and pressure on the heel of the plane at the end of the joint.

Then, check your jointed edge with a straight edge, and remove any high spots. Check your jointed edge for square. Once things are almost perfect, take one or two perfect, full with shavings, and you're done.

After a while, the amount of checking you need to do with a straight edge becomes less and less as your technique improves.

Re: Glue Joint planing and Scraping questions

Wiley Horne--Glendora, CA

>Joe,

The amount of spring you want in a sprung joint depends on a number of things, for example, the dryness of the boards, the climate swings in your area, and the length of the boards being joined.

In my climate, and for 17" long boards, I would first get the boards slightly hollow--about where you are right now with them--and then go end to end taking very thin shavings until the blade is just beginning to make contact in the middle of the board, but is not yet picking up a shaving. That amount of gap could be squeezed out by hand. I like it when the boards go together with a distinctive 'clack', the gap squeezes out by hand, and the joint disappears and looks seamless under hand pressure. If you rely on clamps to squeeze out the gap, then the boards will react by twisting against each other, given that they're 3/8" thick.

One other thought. You're jointing 17" boards with an 18" plane. If the plane sole is flat, then the boards should be dead flat unless you've specifically worked to hollow out the center. With this in mind, you may want to check the No. 6 against a reference to test whether the sole is a little convex.

Wiley