Steam bending Large timber

[MikeG.]

.......(google curved glulam beams images.........

:lol: :lol: :lol:

I'm an architect. Here's a house I designed a while back, still going through planning. It's all glulam beams. It will be the first example of glulams curving in 3 dimensions in domestic architecture in Britain if it gets built:

https://imgur.com/SooygYB

 

[MikeG.]

The point I am making is that .......you can select a laminate thickness to suit your specific job but I would say you should have at least 8 laminates......

Right, I understand now.

Eight laminates would put them all at just under 10mm thick, which I reckon is a bit of a stretch for the curve we're talking about (see my drawing, above). I'd be looking at 12 to 15 laminates of 5 to 6.5 mm, I reckon. It's a reasonably tight bend.

 

[JDGreen]

Is there a problem if there is a 1.5mm springback on the project?.

Probably not as there will be a shelving unit to house the speaker at the top of the structure where the spring back is likely to happen so that should keep it braced against the direction of spring back from all four corners, which would all be curving outward so am I correct in thunking the direction of spring back would be inwards? . As you well know by know I don't really know the correct things to say what I've got in my head. I shall add a rough design on here so you can see my intention. I've yet to come across a design like this for speaker stands but I haven't searched through all the worlds catalogue of images so it may not be plausible but I'll never know if I don't try!

 

[JDGreen]

Rough idea of what I have in mind. Pleas don't be too critical of my design skills. Just trying to give you an idea of what I'm thinking.

Again not to final dimensions but is probably more based on the extreme of the curve needed.

 

[worn thumbs]

Easy job.You will need to add a wedge at the top by the look of it unless you plan to mitre the vertical piece on.Springback doesn't look hugely significant just lay the cleaned up laminate on top of your rod (full size drawing if you aren't familiar with the term) and carefully mark the parallel lines for the top and base.You can use these lines as the baselines for whatever type of joint you choose to use.If there is any splay front to back the true lengths may need to be expanded from the vertical height.

 

[JDGreen]

Thanks worn. Yes the vertical pieces would be attached separately to the bend in some way. Purely the curve that I'm interested in at this point.

 

[custard]

Rough idea of what I have in mind. Pleas don't be too critical of my design skills. Just trying to give you an idea of what I'm thinking.

What a waste of time all this laminating discussion has been! Cut it from the solid, rough cut on the bandsaw followed by copy routing with a template to ensure four identical components. Massively quicker than laminating and plenty strong enough.

Look at the feet on this Shaker "Harvard" Table, they're cut from the solid. Over the past five years or so I've made about twenty of these. I was nervous about selling them as the feet looked so vulnerable, I told clients they weren't suitable for homes with "small boys or large dogs"! But I shouldn't have been concerned, I haven't had any complaints.

If this works then your design will certainly be okay, yes there'll likely be some grain run out (but if you selected your timber with care even that could be avoided) however, remember that boat builders scarf long lengths together using a 1:8 to 1:10 angle, any run out on your legs would almost certainly be within those limits.

 

[Beau]

Have to agree with above having seen the picture. One other thing though is it does look the most stable design for a speaker stand unless what we are looking at is upside down :?

 

[MikeG.]

.....What a waste of time all this laminating discussion has been! Cut it from the solid.......

It would need a board 425mm wide to achieve the curve that the OP wants. Thus 5.4m x 425 x 75 (see below) for all 4 legs. I don't know about you, but that's too much wasted wood (and money) for me. We're back to laminating, in my workshop at least.

 

[JDGreen]

Have to agree with above having seen the picture. One other thing though is it does look the most stable design for a speaker stand unless what we are looking at is upside down :?

Like I stated not the final design and the base is likely to match the dimensions at the top for stability.

 

[JDGreen]

.....What a waste of time all this laminating discussion has been! Cut it from the solid.......

It would need a board 425mm wide to achieve the curve that the OP wants. Thus 5.4m x 425 x 75 (I'll show you the drawing if you like) for all 4 legs. I don't know about you, but that's too much wasted wood (and money) for me. We're back to laminating, in my workshop at least.

Those are my concerns as well. Granted the waste could be used on smaller projects but that's stagnant money until / if I can make the money back on the waste, which isn't likely in a hurry!

 

[JDGreen]

What a waste of time all this laminating discussion has been!

Hopefully I've not wasted anyone's time! Certainly as novice you've all helped me and passed on knowledge and surely imparting wisdom is never a waste of time!

 

[custard]

It would need a board 425mm wide to achieve the curve that the OP wants.

I'd edge joint up a board from straight grained stock so the joint would be invisible, and I'd nest the four components. The cost of scrap wood is trivial compared to the time saved by not having to make formers, machine up lamina, etc.

Besides, in my workshop there's no such thing as "scrap", it all gets used one way or another!