First, let me thank everybody for the input on the wood type I seem to using for this project. Probably southern yellow pine.
I have the 3 boards (~12x84x1.5)ready for glue up. I am not using breadboard ends. My plan is to either use biscuits or some kind of spline for greater strength and alignment. I'm not quite sure here so any input would be appreciated.
I also plan to put boards across the bottom of the top, about every 2 feet or so. Probably overkill, but I do want this to last a long time.
If the board edges are true you need nothing other than glue for strength. Biscuits or splines could help with alignment; your skill in gluing together and flatness of boards determine the need for them. If they are not already flat, neither will help as it is unikely you are going to be able to bend the boards to align biscuits/splines.
Myself, I would leave them over-thick, glue up and flatten them later.
If you do that, be sure to slot the screw holes in the outside boards to accomodate movement. At the most. you would need three boards, two would be plenty.
You need nothing for greater strength but a spline or biscuits will aid with keeping everything in place when clamping.
This may do harm if not properly done, you have to consider the width of the top expanding and contracting with humidity changes. I think the apron will be plenty and you should use elongated holes for attaching.
On Wednesday, September 9, 2015 at 9:04:33 AM UTC-5, snipped-for-privacy@jimryan.com wro te:
ngth and alignment. I'm not quite sure here so any input would be appreciat ed.
I vote you use loose tenons, i.e., practice your loose tenon technique. I did this on my trestle table:
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t or so. Probably overkill, but I do want this to last a long time.
Yeah, I think that's overkill, also. On my table, I place a board near eac h leg unit, only, not every two feet. My leg units are 83" apart. Rather than every 2' apart, I vote you practice installing a few dutchmans, even if only on scrap boards.
Not sure yet, I'm thinking of either pocket hole or possibly angle iron. I just think it's too big and heavy for those table top things that go in the slots. What are your thoughts?
Leon wrote in news: snipped-for-privacy@giganews.com:
What Leon said. But, you are going to need to clamp this to get a good glue joint, and with boards that long and thick, you'll need several stout clamps - I'd think 5 would be the minimum, and a couple more wouldn't hurt.
ing for this project. Probably southern yellow pine.
oard ends. My plan is to either use biscuits or some kind of spline for gre ater strength and alignment. I'm not quite sure here so any input would be appreciated.
t or so. Probably overkill, but I do want this to last a long time.
Yeah, the edges are pretty good. Doing this on my jointer was a challange to say the least. What I ended up doing was, once I got close with the joi nter, to but them together with light clamping then find the high spots an d hand planing those down. So now I have them all layed out and I put just 2 clamps on them, at the ends, with light pressiure and put a light below. At this point I see nothing coming through so I think they will be nice a nd tight with 7 clamps, about one each foot. First I'll do two,then add th e third.
The loose tenon idea is interesting. I have a beadlock tool that I've been very happy with. I toyed with using it for this application and maybe I'l l give it a go. I know the glued joint should hold fine, but I've never wo rked with anything this big and heavy and it kind of worries me to not have a little something extra to hold it together. The alignment isn't that cr itical as once I have it all glued up I'm bringing it down to a guy in town that has a giant drum sander and run it through that to get it nice and fl at and smooth. For $25, it's worth it.
As for attaching the top I've used these before:
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But do you think they will hold up to something this heavy if somebody pick s up the table from the top edges? I would use GRK screws to put them on.
using for this project. Probably southern yellow pine.
dboard ends. My plan is to either use biscuits or some kind of spline for g reater strength and alignment. I'm not quite sure here so any input would b e appreciated.
eet or so. Probably overkill, but I do want this to last a long time.
e to say the least. What I ended up doing was, once I got close with the j ointer, to but them together with light clamping then find the high spots and hand planing those down. So now I have them all layed out and I put ju st 2 clamps on them, at the ends, with light pressiure and put a light belo w. At this point I see nothing coming through so I think they will be nice and tight with 7 clamps, about one each foot. First I'll do two,then add the third.
en very happy with. I toyed with using it for this application and maybe I 'll give it a go. I know the glued joint should hold fine, but I've never worked with anything this big and heavy and it kind of worries me to not ha ve a little something extra to hold it together. The alignment isn't that critical as once I have it all glued up I'm bringing it down to a guy in to wn that has a giant drum sander and run it through that to get it nice and flat and smooth. For $25, it's worth it.
cks up the table from the top edges? I would use GRK screws to put them on .
I also meant to ask, these type of table top fastners don't offer and later al binding on the aprons at the ends. I have used pocket screws before and not had seasonal issues. The table will be in Maine. I also considered u sing lengths of angle iron around the edges. What, given the size and age of this wood, would these methods present as issues?
In case you don't know this already (and if you are using pipe clamps) it will be much easier to keep the glue up flat if you alternate the clamps, top & bottom. It is easy to set pipe clams so that the pressure is not dead center on the board edges; if it isn't, the glue up will bow. With clamps both top and bottom, you can check for flat and tweak to flat as needed.
Start your clamps in the middle and work towards the ends.
You really don't need the extra strength, the glue joint properly prepared, will be stronger than the wood itself. BUT better alignment to begin with is a lesson in building better quality. While you are going to have some one use a drum sander to flatten the top that may not be necessary if you build better to begin with. Build better/smarter and work less. ;~)
That would depend on whether you use 4 or 40. Keep in mind that you are going to have your groves cut to receive them anyway, adding more fasteners will be simple if necessary. And you absolutely should test lifting by the top to verify.
A suggestion, your greatest movement is going to be along the width so if and when the top expands or shrinks any of the fasteners along the length might become too tight or unattached. It would be better if you added a couple of supports evenly spaced between the ends of the table, similar to the end aprons. Attach those supports to your side aprons and cut groves on those also. Use your fasteners on the apron ends and mid supports rather along the length of the table. Clear as mud? ;~)
Do a dry fit and clamp, lightly, with all your clamps. Stagger your clamp s, one above, one below, above, below, etc.... making sure your boards rema in coplanor, during the clamping process. Clamp on a level surface... you don't want your table top to be twisted, from end to end or side to side.
I'm a sucker for that style of table. Really do like it, thus saved the photo. Might have to build it myself one of these days, but lord only knows for who ...
Leon wrote in news: snipped-for-privacy@giganews.com:
On a 7 foot board, the odds of having an edge straight enough to not need clamping are pretty small. On a 1.5" thick board, if you're going to bend it at all by clamping, you'll need a stout clamping setup.
FWIW, here's a similar table top glue-up I did 11 years ago, which may give you some additional ideas:
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For a better explanation of how this was planned, go here and scroll down to the "Trestle Table" section:
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I noticed that you have a jointer:
with that in mind, might also want to pay attention to the following for increasing your chances of getting a flat glue-up that will save you tons of cleanup and flattening:
~ Do a layout for your glue-up with all the boards face up, and in the correct/final order.
Starting from the top, and alternating with chalk/pencil, a "U" (up) on one side, and a "D" (down) on the opposite side, of _each_ glue joint in the layout.
Then do a final pass over the jointer, with the above marked edge against the fence, AND in the appropriate up or down orientation.
The resulting adjacent edges of each joint will now equal 90 degrees, even if your jointer fence is not precisely set to 90 degrees.
The method takes out any error of the fence being square to the table (and technique for the most part), takes elegant advantage of the principle of "complementary angles" to obtain 90 degree joints for _adjacent boards_ in a glue-up.
Have used this "jointer" method for panel glue-ups, without fail, for years ... your mileage shouldn't vary.
~ Joint the edges of a couple of tubafours to put your panel on while gluing so you can keep thing flat (see photo above). This will also let you easily get clamping pressure from both sides.
~ Have some extra small clamps and assists handy to span the joins on the ends, as needed, which will also help to keep things flat. These are worth making out of scraps for just such an operation as you are doing:
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As you can see from the above, if your joinery is properly prepared, you plan the operation well, and rehearse before you start, you really don't need all that many clamps to get a good flat table top glue-up ... and one that is easy to do the final prep on before finishing.
BTW, biscuits were used for alignment of the various glue-ups that it took to get the desired table width. The table top weighed in at 106 lbs and is attached with figure 8 fasteners to the trestle support.
Then years later you can have some Bud's from the wRec over to properly christen it on a yearly basis:
I have 25 pieces of maple that are about 10' long and I could glue most any of them together with out much issue.
If you use straight lumber, as is stated above clamping pressure, is drastically reduced. Not what you changed it to, "to not need clamping".
No doubt that if you are not working with suitable stock to begin with stout clamps will help. But again, good edges, straight ones do not require as much clamping pressure to close the joint. Straight edges should not be an issue to obtain.
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