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Forum topic by ryno101 posted 09-10-2009 03:42 PM 968 views 0 times favorited 9 replies Add to Favorites Watch
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ryno101

384 posts in 3128 days


09-10-2009 03:42 PM

Topic tags/keywords: question joining

I’m in the middle of building my workbench, and have come up short on one piece… This is the design for my base assembly, it’s all 4×4 mahogany:

The problem is that I don’t have a single piece for the top section of one of the leg assemblies… I mis-judged my cuts (learning!) and would very much like to avoid going out an purchasing another 10 or 12 foot piece of mahogany!

What I have is three pieces, 11 3/4”, 13 7/8” and 9 1/4” long that I want to join together to make the top piece. My thought was to do something like this:

What do you think? Is the mortise too close to the joint? Is this the strongest way to do this? Keep in mind that the pieces in the above pic are rotated 180 degrees to show the location of the mortises, they’ll actually be on the bottom of the piece, fitting into the tenons on the tops of the legs.

-- Ryno http://shawsheenwoodworks.com


9 replies so far

View PurpLev's profile

PurpLev

8523 posts in 3112 days


#1 posted 09-10-2009 03:50 PM

glad to see you’re busy Ryan, hows the new saw?

my first instinct on this one is – don’t do it. just looks too much of a hassle. I would prob try and find a piece that would work for this as a 1 piece. If you want to stop by and look through my lumber – maybe you’ll find something good enough (I can’t tell what would fit the color/hardness of what you’re using).

another option is to use a different specie (maple? I have a feeling you’ve got some of that…lol) and veneer it with the mahogany to keep the color consistency – although – honestly – this piece is under the top and might not even show.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Kindlingmaker's profile

Kindlingmaker

2656 posts in 2990 days


#2 posted 09-10-2009 03:59 PM

With Purplev’s advise maybe replace both sides so they will match. I you want to continue then possibly a lap joint and doweled from the back side… I think this would give the greatest amount of long grain surface for gluing and there would only be vertical joints. ...finger joints would be even better.

-- Never board, always knotty, lots of growth rings

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ryno101

384 posts in 3128 days


#3 posted 09-10-2009 04:00 PM

Sharon,

New saw is AWESOME! Can’t tell you how much of a difference a proper saw makes! (but you knew that, didn’t you!)

I was wavering between swapping out another piece as well, but without a planer, getting the dimensions right is going to be very difficult. The only thing I have “in stock” that I could dimension with my table saw is 5×5 white cedar left over from our new fence, and it’s at the opposite end of the spectrum from the mahogany in terms of hardness and heft. I’m reluctant to use that if I can avoid it, and everything else I have would need to be done as a glue-up.

I’m not all that concerned about matching, as you noted this is going to be under the top, and will be hidden by the skirt I’m planning on wrapping around the top.

I see the effort involved in cutting these joints as a learning experience anyway. The mortises and tenons I’ve cut for this project are the first I’ve ever done, and I’m happy to have some more practice on a more challenging joint like this one.

-- Ryno http://shawsheenwoodworks.com

View PurpLev's profile

PurpLev

8523 posts in 3112 days


#4 posted 09-10-2009 04:07 PM

I wouldn’t be concerned about the difficulty of making that joint – on the contrary – I would suggest you do it – but on a different project. for reason is because the purpose of this part is to keep the top from cupping, and with 2 extra joints under the top across it’s width you are introducing another 2 weak spots where you have inconsistency with the grains – which might result in inconsistent movements between the sub-pieces which might result in strange forces applied to your top that can take it off flat – as you recall it is only held with nails, and there is a tendency in the material to rock and roll.

you are welcome to use my planer if you need it. however – I think the cedar choice may be too soft and brittle for this application. I have some 4×4 (3.5×3.5) leftover Douglas FIR if you want them – I originally planned to use them for a base similar to yours, but ended up not using them – it’s all yours if you want it.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Moron's profile

Moron

5032 posts in 3357 days


#5 posted 09-10-2009 04:53 PM

Wood is like a mountain os snow…...if you down hill ski, the mountain will humble you and so will wood.

When you pay for your own mistakes your learning curve increases exponentially.

Suck up your pride, cry and get another chunk of wood…..........I’m betting you wont make the same error twice!

-- "Good artists borrow, great artists steal”…..Picasso

View Don Newton's profile

Don Newton

714 posts in 3082 days


#6 posted 09-10-2009 06:34 PM

Definately the “brick wall” approach as suggested by DaveR. It would result in a structurally sound and stable piece.

-- Don, Pittsburgh

View Rick  Dennington's profile

Rick Dennington

5177 posts in 2658 days


#7 posted 09-10-2009 06:35 PM

I have to go along with Kindlingmaker on the leg.
I would cut a half-lap joint, glue it up, and then use dowels to pin it.
It’ll be just as strong as you need and won’t give. I would also “wallow” the dowel holes out just a touch for wood movement, and to get glue in there. Rick D.

-- At my age, an "all--nighter" is not having to get up and pee...!!!

View a1Jim's profile

a1Jim

115202 posts in 3041 days


#8 posted 09-10-2009 06:35 PM

I agree with Sharon I would use anything that is one piece and not the three section glue up as shown in your sketch . laminating length wise is fine .

-- http://artisticwoodstudio.com Custom furniture

View TopamaxSurvivor's profile

TopamaxSurvivor

17671 posts in 3140 days


#9 posted 09-11-2009 07:35 AM

If you insist on using the 3 pieces, I think I would dovetail the white faces in yoiu sketch.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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