Suggestions to making long cone shaped bedposts?

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10
Location
Wentzville MO
Hello, Newbie here, and thought I'd say hello by asking for suggestions on one of my more recent project plans.

I'm in the design stages of a pencil post (king) bed frame and headboard using Mahogany. The posts in the design are cone shaped, and need to have a 7" wide foot, tapering to a 2" diameter top point.

Here's the kicker. Each post needs to be 7 1/2 feet high. I have priced 8"x8"x8' mahogany cant's FAS... and well... I can't cant! :eek:

I do have about 500bf of 6/4 reclaimed mahogany that I would like to use for this project.

Making the final cone shaped post would be done with a router and an MDF jig, setup much like a Legacy mill...but without the 5 digit price tag. The rough post would be set on an angle in the jig, and I would turn the piece, while a router moves along on a make-shift gantry & way, creating a long, tapered dowel - so to speak.

The problem is figuring out the best way to making the initial post.

My first thought was to rip a birds-mouth joint into strips of 6/4 mahogany to make an 8" wide cylinder. But then it occurred to me that I wouldn’t be able to taper this to a 2" wide point at the top.. as it would be hollow. :doh: And adding a hex-block to the inside would show a distinctive horizontal joint line when I milled out the cone. Since the goal is long straight grain patterns on the length, any horizontal line would stick out like a sore thumb.

Then I thought I could make an 8" x 8" x 8' post buy gluing up sections, and then rip a taper with the TS. But then I would face the same problem... distinctive lines when inside rows are exposed to the outside face. It wouldn’t be as blatant as the above, but I think they would still show, and look bad. It would also be a real waste of material as I milled 1/3 of the lumber to make the cone.

Then, I courageously thought again: If I can figure out to rip a compound miter on a TS that runs the whole 8' length - consistently, creating a set of long isosceles triangles that can be glued up to make a hexagonal cone. Sounds easy enough….scared to death!

Going this route, I wouldn't need to mill much after, just make it round, which I could probably do easier with a spokeshave then making a router mill. It would use the stock very efficiently, and wouldn't have the joint line issues, which is what I'm after.

I’ve thought about this for over a month now. How to cut a compound miter...and How would I glue this up since there wouldn't be any square edges to clamp? Strap clamps would slip too easily I would think, packing tape won’t bind tight enough to avoid having a glue line.

So...My new friends... does anyone have any suggestions? (other then redesigning the bed)

The kind of work I like best is the kind that makes folks wonder "How the heck did he do that?" Too me, that's the ultimate in woodworker satisfaction. Achiving that level of satisfaction is still a work in progress.

Tim
 
hi tim, welcome to family woodworking!
when doing tapers or curves you throw most of your wood on the floor......a large percentage anyway...so as i see it your question is how to create a tapered/round post without visable glue lines....and you would like to cut staves for a glue-up using a conventional table saw and a router?.....
first question i have is since the posts will be round, is there a transition point where they can be broken into two shorter posts? or will the posts be a smooth cone over their length? it`s possible to jig up a router to cut the beveled tapers, or even a skillsaw but you`re still going to show gluelines, if you could break the posts into an upper section and a lower then you could stave the lower and turn the upper out of a cheaper blank of solid stock....that way the section at eye level wouldn`t have any gluelines....
how `bout a sketch?.......tod
 
Does the grain have to run vertically? I'm wondering about a 78" stack of 6/4 x 8" x 8" laminated mahogany. I know you were trying to avoid the vertical joint lines from the staved approaches, but I wouldn't think the horizontal joint lines would be objectionable. I also wondered like Jesse about using veneer but that would probably result in vertical seam lines. Unless you pieced it together you'd end up with grain running straight up only on one line up the taper and getting more and more askew from vertical as you go around the taper.
 
I'm with Tod on this one. I know you said you didn't want to redesign, but if you can put some decorative element on the post about half way up, you can break the post there and build it as Tod suggests, without any lines in the upper part. The decorative element doesn't have to be much, maybe just a couple or three grooves around the cone. Use one of the grooves as the place to join your two parts.

If you decide to do that, just turn a round tenon on the top piece and turn a round mortise on the bottom piece to fit them together. By turning the mortise and tenon, you'll have them centered.

Let us know what you decide. And welcome to Family Woodworking.

Mike
 
Welcome ole buddy but..... your dimensions seem a bit off 7" at the base and 2" at the top... Doesn't sound like pencil post bed to me,... sounds like a Gothic monster to me. Pencil Post bed, be it king, queen or gigantic, it still will have the same relative dimensions (only the rails and width will change)

Revise the dimensions and re consider the relationship to the size materials you will need. Mahogany is a fine material but be realistic in your dimensions.
 
HI Tim, welcome to the family.

Sorry I don't have any brilliant ideas to get you over this hump in your project.

I'd have to agree with Mike and Tod, a minor change in your design would allow you to use stock that would eliminate the glue lines and or minimize them, and to be honest, the minor design change, if done right, would only show to experienced folk where the joint is.

On a turning of such length, you seldom see a solid piece, , it will almost always be made up of two parts, an upper and a lower, and usually a glue up as well, because as we all know, wood can move around a bit, and if you had 4 7" thick, tapering to 2" thick, nearly 8' tall posts, there is a fairly good chance that none of them would ever be standing straight :rolleyes: :D

I know you don't want to redesign, but just a couple of thoughts for you; why not show the glue lines, instead of trying so hard to hide them?

If you do a glue up with mainly mahogany, but with a thin piece of another wood in between the mahogany, and then turn that on a taper, you would have one heck of a neat/pretty effect. You don't have to use a very light wood, just something that contrasts the mahogany. If you used something like Maple, the contrast would be a lot, but maybe some other wood would be more subtle?

Then if you also added that wood into some small design elements on the head and foot board, you could really have a very nice end result.

Sorry, if I'm of little help, but at least I'll welcome you again!

Cheers!
 
Thanks for the thought's folks. Good stuff. Very thought provoking.

I've given more thought to this yesterday and today. The idea of a 2-part post, using veneers, and laminations were all included and it made a light blub go off in my head. (or rather...go ON!)

I realized that my horizontal joint transitions fears are completely unfounded after I recalled some basic geometry. A 'cone' shape couldn't produce a horizontal glueline. It would HAVE to be an arc in the direction of the apex.

Now, this being the case... there may be some real interesting design details specifically added just by thinking about how the assembly will glue up. I think the only other time I've even considered gluelines as part of a design were in box making, where I try to put a bookmatch joint exactly where I want to seperate the top from the bottom.

A series of deliberate gluelines? This may prove interesting. I do plan on building a scaled prototype, so I guess I'll see how things unfold.

Thanks folks!
 
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