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Forum topic by joshw posted 02-08-2010 04:38 AM 1134 views 0 times favorited 18 replies Add to Favorites Watch
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joshw

5 posts in 2157 days


02-08-2010 04:38 AM

Complete woodworking newbie here so this is probably a no brainer for some of you.

One of my projects this spring is some raised beds. My idea is to use 4×4 posts with a dovetail groove running down the middle from top to bottom, then cut the ends of my boards to slide into that groove. I know I can use a router to make the dovetail groove. How would I make the cut on the ends of my boards?


18 replies so far

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a1Jim

112502 posts in 2297 days


#1 posted 02-08-2010 05:00 AM

Just make the groove big enough for the board to fit in. I don’t think you need to dovetail them just a little tite bond III.

-- http://artisticwoodstudio.com Custom furniture

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wseand

2503 posts in 1762 days


#2 posted 02-08-2010 05:04 AM

Not sure what size your cross members are but usually you use the same router bit. With the bows and curves in the posts it might be a bit difficult to slid them in. Is this for a garden.

-- Bill - "Freedom flies in your heart like an Eagle" Audie Murphy

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joshw

5 posts in 2157 days


#3 posted 02-08-2010 05:15 AM

Yes it is for a garden. I like the idea of using a dovetail joint because I don’t want a board separating from a post when it is loaded up with soil on one side. I’m thinking I would use the same router bit on the end of the board but my question is how do you router the end of a board that might be 8 or more feet long? Is there a way to use a router in a horizontal position or would this be done some other way?

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miles125

2179 posts in 2726 days


#4 posted 02-08-2010 05:45 AM

Might try putting dado blades on a tilt and run it in not too big bites to get the angle, then finish out with dadoes straight up (emphasis on small bites). 4×4 ends sound like a good job for the bandsaw.

-- "The way to make a small fortune in woodworking- start with a large one"

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joshw

5 posts in 2157 days


#5 posted 02-08-2010 06:16 AM

Sorry, should have mentioned the boards between the 4×4 post would probably be something like a 2×10. It doesn’t sound like there is any way to run the router along the end grain of a long board like this. I don’t have a table saw yet but could probably pick up a used one. Another thing I thought about was using a radial saw to make cuts of varying depth and then knocking out and cleaning up the rough male end of the sliding dovetail. I’m actually going for a loose fit so it slides well and for a garden bed these joints don’t need to be pretty. I was just hoping there was a faster and easier way to do it with the router.

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Pete_Jud

424 posts in 2473 days


#6 posted 02-08-2010 06:21 AM

With an edge guide on the router and the same dovetail bit, you could cut the male end of the dovetail just make the female cut in the post wide enough to take the oversized male.

-- Life is to short to own an ugly boat.

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GFYS

711 posts in 2191 days


#7 posted 02-08-2010 06:33 AM

the problem (using an edge guide on a router) is going to be using dimensional lumber that varies as much as 1/8 inch in thickness.

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sphere

109 posts in 1751 days


#8 posted 02-08-2010 06:35 AM

How about forget the router and use a saw and a chisel ( slick, a large chisel). It goes faster than you may think. Think timber framing, not furniture.

-- Spheramid Enterprises Architectural Wood Works

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jsheaney

141 posts in 2708 days


#9 posted 02-08-2010 07:03 AM

I never have done this before, but here’s what I would try. Route the posts first. The router bit is going to define everything. Start with oversized posts. Make sure the face with the dovetail groove is the final surface. Removing any more material will change things.

Crosscut a bit off the end to use as a marking template for the dovetails. Mark both edges of the board carefully. Use a marking gauge to mark the baseline of the dovetail on both edges and both faces. You want the baseline consistent all around the end of the board. You might want to go over the baselines on the faces with a marking knife. This will help later.

Use a back saw of some sort to establish the shoulder. Stay off the baseline, you’ll want to clean that up last. Just cut down as close to the layout lines for the dovetail checks as you can. In fact, you can probably speed things up by making a series of cuts parallel to the baseline just to remove some waste.

Square up some 8/4 stock. A clean 2×4 is fine. Then cut a bevel that matches the dovetail on one edge. I would run a jointer plane over the bevel face just to make it nice and true. Clamp it on the knife line to use the bevel as a fence. Run a shoulder plane to plane down to your layout lines.

At this point, you have established most of the dovetail cheeks and have a good start on the shoulder. There’ll be a bit of waste to remove between the two. Pare that away with a sharp chisel. You can lay the back of the chisel on the cheeks you’ve established.

Now, the shoulders. Lay your widest chisel into the knife edge and chop straight down. If you want to speed up the process (if it’s a wide board), replace the bevel fence with a nice square one. If you started with square stock for your fence, you can just turn it around and then hold your chisel up against it.

You’ll have to clean out the corners where the cheeks and shoulders meet. Just keep in mind that no one will see this part. The only parts anyone can see are the shoulder lines on the face of the board and the dovetails at the very edges. If you care about how it looks (and I can’t imagine why you would in this application), those are the only areas you need to concern yourself with.

Use the template to check the bevel angle and to check the dovetail while you work. I’m pretty certain this is taking longer to explain than to do. I hope it helps. I almost want to go do it myself to see if it works. :)

-- Disappointment is an empty box full of expectation.

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jsheaney

141 posts in 2708 days


#10 posted 02-08-2010 07:49 AM

You’ve written some more while I was writing my response. Since you say you’re a newbie, I just want to add some pointers about making the dovetail groove in the posts. You aren’t going to be just running a dovetail bit down the center of a 4×4 post. I don’t know what you have for a dovetail bit, but my dovetail bit won’t give me a depth much more than 3/8”. Maybe you have a beefy dovetail bit. At any rate, you are probably making a dovetail much wider than your bit. You really need to hog out most of the waste with either a straight bit or with a dado set on the table saw. I would go with the table saw at the dimensions you’re talking about.

Once you have a groove, you need to route the edges of that groove with the dovetail bit, which will establish the cheeks and the depth. The groove, at this point will be wider than the bit. Assuming you are centering the groove, you will route the post once, flip the board and route it again; once for each cheek. Make sure that the side of the groove that you are routing is the side AWAY from the fence. You don’t want to pinch the board between the bit and the fence. You will crap your pants at the result. This is true regardless of whether you are using a router table (recommended) or taking the router to the workpiece.

Note that this is different than when you are routing both sides of the groove simultaneously (i.e. the initial groove is narrower than the bit).

-- Disappointment is an empty box full of expectation.

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Kindlingmaker

2654 posts in 2246 days


#11 posted 02-08-2010 02:44 PM

How about an unglued, pinned, through mortise and tennon…

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

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sphere

109 posts in 1751 days


#12 posted 02-08-2010 03:06 PM

“How about an unglued, pinned, through mortise and tennon…”

Much better engineering wise IMO. All the DT’s do is add weak pull out resistance due to the short grain of the tails and the thin edges of the groove.

Just racking the tail on assembly and it will fracture out somewhere.

Sounds like a time bomb looking for a place to happen.

-- Spheramid Enterprises Architectural Wood Works

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bladeburner

88 posts in 1807 days


#13 posted 02-08-2010 03:41 PM

A router made DT will be too delicate for large timbers and exposure to the elements. And a beefy timber frame DT will require some experience with large framing chisels as well. Personally, I think you’d be much happier with through M&T joints and locking wedges. Good luck with whatever you do.
Joe

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Vicki

942 posts in 2064 days


#14 posted 02-08-2010 08:41 PM

Here’s my 2 cents, from having made lots of things for the yard/garden. The sun and weather are trecherous on these projects and make the wood move in ways you can’t imagine. Add wet dirt to that and you can see where this will lead. If it were me I would use deck brackets, the kind that have a 90 deg. angle. You can use deck screws to attach your 2X10 to your post. That will be on the inside and hidden by dirt and not seen. Line your bed with landscape fabric before filling with dirt.
Vicki

-- Vicki on the Eastern Shore of MD

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joshw

5 posts in 2157 days


#15 posted 02-09-2010 01:48 AM

Excellent input from everyone. I thought about trying the through mortise & tenon. I’ve seen some done this way. I liked the idea of the sliding dovetail because it would allow me to make a long run with short boards. I suppose I could do the same with M&T by offsetting the joints on each side of the post so that the tenons come through side by side? I guess there is a good reason I haven’t seen any beds made using the sliding dovetail…

Might just do the deck brackets too. Would probably be easiest. Aesthetics are important to me even in the garden but could probably make it look nice.

Thanks for all the tips and information!

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