How to make a 12' oak slab from 8' boards

[scott vroom]

I want to build a 12' long oak desktop for a home office. The 12' top would span (from the left wall to the right wall) a 42" wide base, a 60" wide open chair well, a 42" wide base. Total 12'.

Several questions:

1) I'm considering qtr sawn white oak for the desktop. My local hardwood supplier (Macbeath San Francisco) carries only 5/4 and 8/4. 2" is overkill so I'm wondering if 5/4 milled to 1-1/16" would be thick enough to span the 60" chair well. If not, I had considered a 1.5" front edge band for support. The rear of the desktop will be supported with a cleat at the facing wall.

2) It's unlikely I'll find 12'+ lengths of 5/4 qtr sawn white oak. On a prior project where the customer wanted a cabinet door made from shorts, I did a "running bond" (staggered) glue up to make a 36" door from 24" boards. The butt ends fit tight and looked OK but not my ideal. Don't know of any other way to stretch boards. Ideas?

3) Since this is for a writing desktop I want the finish to be smooth as glass. Could someone recommend a clear grain filler? I had planned to finish with General Finishes Enduro Clear Poly.

[Chris Padilla]

Scott,

Try Jackels in Watsonville. I've gotten 10' 10/4 maple from them in the past. I would hunt around the Bay to find what you need: I'm sure it is out there.

Oak is a difficult wood to make glass smooth or I should say it would take quite a bit of work and lots of grain filler. See the Finishing Forum here for a recent thread on clear grain fillers.

[Chris Padilla]

http://www.jackelenterprises.com/

Forgot the linky. :)

[scott vroom]

Thanks Chris. I called Jackel - they don't have 12' lengths. Good news is that they're cheaper than Macbeath on their Q-sawn oak, and hard & soft maple. I'm driving down there next week to check em out...thanks for the lead.

Yeah, I was concerned about filling the oak grain, but the qtr sawn shouldn't be as bad as straight sawed, ya think? What other wood would look good for a desktop and that would be in the same price range (and be as hard as) qtr sawn oak? I was thinking that eastern black walnut might look nice, although lots of color variation that comes from mixed heart/sap. By the way, I'm doing an entire office full of cabinets, all painted maple. The only natural finish wood in the room will be the desktop and the white oak floor. This is for a paying customer...their design.

[Prashun Patel]

Consider soft or hard maple. These are (IMHO) better desk materials because they'll require less grain filling and will make better writing surfaces.

If you can swing the price, cherry is perfect. It's easy to machine, and has a lot of natural color and grain interest; if the customer likes the natural darkening color of cherry, then it's probably the easiest thing to finish, so there'd be some savings in terms of time and effort vis-a-vis oak (which'd require grain filling) and maple (which might require some coloring if you don't like it natural).

I also think that doing a running bond may result in a more efficient use of material in the long run.

You can do a lot of interesting things at the joints like dovetails, halflaps and pins, etc which will give the desk a lot of character.

[Glenn Vaughn]

Collector Specialty Woods in Gardner, Colorado has QS White Oak up to 16'.
http://www.cswoods.com/csw_browsebyspecies.php?pageNum_rs_all=0&totalRows_rs_all=36&woodspecies=oak%2C+american+white&Submit=Submit

I have dealt with them and they have been reliable.

[Chris Padilla]

Claro Walnut is more abundant out here and well, it is walnut: it is gorgeous and I think would make a fabulous desktop. They are very often available in very large sizes. There are more places south of SJ (Morgan Hill/Gilroy/Hollister/"out in the country")...Google your way to them and see what they have. Also check Craigslist.

I guess it is all in what your client wants. Maple makes a great desktop and is certainly hard...not sure how its prices compare to QSWO. Even soft maple is great for a desktop...it is by no means soft!

If you need a uniform color, dyes are the way to go. I've successfully dyed lighter & reddish walnut (sapwood or otherwise) to match the darker/chocolately walnut using NGR dyes from Behlens. Swing by and I'll show you some things I've made with our local walnut.

[James Malcolm]

Get some 12/4, cut it in half and bookmatch it down the center.

[Rick Moyer]

I did a bar edge once from maple handrail. Lots of coats of polyurethane wiil make a glasslike finish. I think I put nine coats on the handrail/bar edge. Don't see why you couldn't do that with oak.

[scott vroom]

Get some 12/4, cut it in half and bookmatch it down the center.

May be just the excuse I've been looking for to purchase a good resaw bandsaw :)

[scott vroom]

I also think that doing a running bond may result in a more efficient use of material in the long run.

You can do a lot of interesting things at the joints like dovetails, halflaps and pins, etc which will give the desk a lot of character.


mmmmmm......you've given me some good ideas to consider. halflaps with walnut pins would look awesome, so would dovetails at the butts. thx!

[Van Huskey]

May be just the excuse I've been looking for to purchase a good resaw bandsaw :)

That just makes me smile! :)

Oh and to get the 12' slabs from 8' just plant 'em back in the ground for 2-3 years...

[Chris Padilla]

Oh and to get the 12' slabs from 8' just plant 'em back in the ground for 2-3 years...

I think the bugs would be happier than the woodworker on that one! LOL

Scott, I have a MM20...it resaws very nicely! :)

[Kent A Bathurst]

mmmmmm......you've given me some good ideas to consider. halflaps with walnut pins would look awesome, so would dovetails at the butts. thx!

...or butterfly keys - me likey them. Not really hard to do so much as you need to be meticulous, and patient. First time - 3 or 4 test runs to get past the "pucker factor" before you turn to the real item :p. Take a deep breath..............FWIW - my preferred method is to lay a smooth surface of Famous Blue Tape on the target, use an exacto to trace around the key, then pull the tape off from the key's footprint - seems to work a lot better for me when hogging the field with a detail router/lam trimmer, rather than trying to see the score line itself. I use the score line for the final paring, of course.

Whatever....any of these options would be neat......the general point is that sometimes, rather than trying to make a joint "disappear", you can go the opposite direction with nice results - emphasize the joint. While not necessarliy an example of your specific case, think of what Greene & Greene did - the joints are one of the focal points of the pieces. Or, the Stickley gang[s], with keyed through-tenons.

[Prashun Patel]

I recently did pinned half laps - about the easiest of the options on a counter. I have less experience than you guys, probably, but manipulating long stock on the tablesaw or router table was tough - even to cut the basic half-lap joints; and my stock was only 5' long at the max. Keys would allow you to take the router to the work instead of the other way round. All the joint strength comes from the edge gluing anyway, so any treatment north of a butt joint on the ends is purely aesthetic.

[Brian Tymchak]

I want to build a 12' long oak desktop for a home office. The 12' top would span (from the left wall to the right wall) a 42" wide base, a 60" wide open chair well, a 42" wide base. Total 12'.

Several questions:

1) I'm considering qtr sawn white oak for the desktop. My local hardwood supplier (Macbeath San Francisco) carries only 5/4 and 8/4. 2" is overkill so I'm wondering if 5/4 milled to 1-1/16" would be thick enough to span the 60" chair well. If not, I had considered a 1.5" front edge band for support. The rear of the desktop will be supported with a cleat at the facing wall.



Making the following assumptions:

desk top width = 30"
a load of 100 lbs at the center (like someone leaning heavily on the edge)
no front edge strip
Sagulator (http://www.woodbin.com/calcs/sagulator.htm)shows a .019" deflection per foot. Over 60" span, that's .10" total deflection. (I actually expected more.) That would be up to you to decide if that's too much deflection. Adding the front edge strip, assuming the 1.5" wide edge strip is same as table thickness (1 1/16"), sagulator actually gives a negative reading which I will assume is a software issue and should be either 0" or the absolute value of -.004" per ft, which is pretty good.

[Kent A Bathurst]

...... Over 60" span, that's .10" total deflection.........

If you screw a cleat to the wall and rest the top on that [or screw the top to the cleat] that will reduce deflection. Done that before.

[Quinn McCarthy]

The best way I have found is with a finger joint cutter for the shaper. I made a toggle clamp jig that I use to hold the board down.

I made some 16' stringers that way.

Hope that helps.

Quinn

[Peter Quinn]

I know you can source QSWO from here in the east in 12' lengths if needed and the budget allows. Otherwise a long tapered scarf joint would be my next best option, so that both pieces are basically a long grain to long grain glue up and not a butt joint of some kind. A long half lap would be my next choice, followed by some finger joint or decorative keys being my last option personally. I like dovetail keys to fix a defect in a large natural slab top, but that can get a bit distracting visually and approach kitchy IMO if used all over in a long top.

[Brian Tymchak]

If you screw a cleat to the wall and rest the top on that [or screw the top to the cleat] that will reduce deflection. Done that before.

The OP mentioned using a cleat and I accounted for it by using the "fixed" option of shelf attachment. Didn't note that in my response though. I agree a cleat in back does help a lot. Use that method myself quite a bit. How much benefit is somewhat dependent on the width of the top.

[scott vroom]

I know you can source QSWO from here in the east in 12' lengths if needed and the budget allows. Otherwise a long tapered scarf joint would be my next best option, so that both pieces are basically a long grain to long grain glue up and not a butt joint of some kind. A long half lap would be my next choice, followed by some finger joint or decorative keys being my last option personally. I like dovetail keys to fix a defect in a large natural slab top, but that can get a bit distracting visually and approach kitchy IMO if used all over in a long top.

I'm not an expert, but I'm thinking the strength in a running bond glue up comes from the edge joints. I agree a scarf or half lap joint would add some strength, but the real value in those 2 methods might be to minimize joint shrinkage you might otherwise get in a simple butt joint. My only previous experience with this was where the customer wanted us to use 24" mahogany boards (sentimental value wood) to make a 36" bathroom cabinet. I used a running bond glue up with simple butt joints. After nearly a year in a moist environment, the joinery looks tight including the butt joints.

I've pretty much givn up on finding a local supplier of 12'+ QSWO and am not interested in paying shipping for out of state sight-unseen wood. Looks like I'll be gluing up a running bond with 8 or 10 footers, possibly using half lap joints instead of butts.

Now my next challenge will be how (more like where) to do a 12' long glueup. My work table is only 80" so I was thinking of setting up 3 or 4 sawhorses and use cauls every 2 feet in addition to the edge clamps. I'll be starting with milled flat lumber so the slab should come out fairly flat. I figure I can do some on-site flattening by screwing to the base cabinets that support either end.

[David Cefai]

Regarding surface smoothness: Would one actually put a paper on the desktop and write? I would have thought there would usually be a desktop blotter on the desk.

[michael osadchuk]

On the pore filler question, try Timbermate, a water-based filler available in 21 wood species colours. It's imported from Australia and is used by a lot of professional floor finishers.

I used it on plainsawn red oak - which is horrible to fill - and managed to get a piano top smooth finish in two applications of the stuff thinned to the consistency of cream.

You can request a sample from their website.... www.timbermate.com

good luck

michael

[Jamie Buxton]

If you're willing to use other woods, and you want a hard small-pore wood, look into Jatoba. It is very hard. On the Janka scale, which is a measure of how difficult it is to dent the wood, it is about twice as hard as hard maple (http://tinytimbers.com/janka.htm). It has very nice color -- somewhat in the area of cherry. It has small pores, so it won't need filling, like oak will. Macbeath sells it for $5-$6 per bdft. I've bought 12 footers from either them or PALS.