Magnetic Drill Screws Through Wood Leaving No Visible Holes
http://www.archdaily.com/874108/this-ma ... ible-holes
Joinery with No Visible Holes
Joinery with No Visible Holes
Paul Harding FAIA Restoration Architect for FLW's 1901 E. Arthur Davenport House, 1941 Lloyd Lewis House, 1952 Glore House | www.harding.com | LinkedIn
I caught that. Pretty nifty. (The Lamello company introduced the widely-used biscuit joiner as far back as the 'seventies. Very expensive machine; I'm quite happy with my DeWalt version.)
There are semi-hidden connector bolts used for handrails, etc.; there's a good-sized hole on the underside of the handrail, though. This Lamello fastener depends on the strength of the threaded insert set into end-grain wood, always a compromise with any threaded fastener compared to the same unit driven into cross-grain wood. Under extreme strain, that's the part of the system where one could expect a failure to occur.
Here's the alternative, demonstrated by a somewhat sloppy carpenter:
https://www.youtube.com/watch?v=NCy_sshWkaU
SDR
There are semi-hidden connector bolts used for handrails, etc.; there's a good-sized hole on the underside of the handrail, though. This Lamello fastener depends on the strength of the threaded insert set into end-grain wood, always a compromise with any threaded fastener compared to the same unit driven into cross-grain wood. Under extreme strain, that's the part of the system where one could expect a failure to occur.
Here's the alternative, demonstrated by a somewhat sloppy carpenter:
https://www.youtube.com/watch?v=NCy_sshWkaU
SDR
Two issues that the user of this system might want to keep in mind: One has no way of knowing how tightly the bolt has been driven. And no one unfamiliar with the system, and not in possession of its tools, would be able to tighten a joint which has come loose -- unlike with the screwdriver-operated cam fasteners found in today's flat-packed DIY furniture.
On the other hand, those cam fasteners have only one pre-determined "tightness," while the Lamello magnetically-driven bolt can be re-tightened if the joint should begin to show signs of opening. The variable in both these systems is the medium itself, wood -- which is capable of compression, one of the causes of joint failure. The inferior materials much IKEA furniture is composed of compound that problem: particle board is much more compressible/friable than hardwood.
This new fastener might lend itself to a situation where oddly-shaped members, difficult to clamp, need to be invisibly fastened, and where other means such as dowels or splines are not practical. A glued joint is highly resistant to the initial loosening which precedes many joint failures. A combination of glue and the Lamello bolt might be just the ticket, in such an instance.
Interestingly, wooden dowels are best suited to end-to-end wood connections, like the stair rail example in the video, because the parallel-grain glue connection is so strong. Conversely, threaded fasteners are best used in through-the-grain applications, where the threads interleave with multiple layers of material -- plywood, or solid wood.
Unfortunately, much wood joinery combines cross grain and end grain, as in the corner and intermediate joints of a chair or table. Thus, there is no perfect method for making such joints, particularly where the members are relatively (or very) slender.
The difficulty with dowels is the need for very precisely placed and angled bores. The beauty of the second bolt system seen here is that the holes bored in the wood members are somewhat oversized. The purpose of the bolt is only to draw the members together; the glue prevents side-slip or rotation. The Lamello bolt system, on the other hand, has very little if any tolerance for mis-alignment of the mating holes. Drilling jigs and fixtures, including the many doweling jigs out there, would be of help in making the joints shown in the illustrations. A drill press is also handy, especially for flat parts, etc.
It could be said that the Lamello hidden-bolt system is ideally suited to production runs of furniture, where fixturing is the norm so that identical parts are easily made.
SDR
On the other hand, those cam fasteners have only one pre-determined "tightness," while the Lamello magnetically-driven bolt can be re-tightened if the joint should begin to show signs of opening. The variable in both these systems is the medium itself, wood -- which is capable of compression, one of the causes of joint failure. The inferior materials much IKEA furniture is composed of compound that problem: particle board is much more compressible/friable than hardwood.
This new fastener might lend itself to a situation where oddly-shaped members, difficult to clamp, need to be invisibly fastened, and where other means such as dowels or splines are not practical. A glued joint is highly resistant to the initial loosening which precedes many joint failures. A combination of glue and the Lamello bolt might be just the ticket, in such an instance.
Interestingly, wooden dowels are best suited to end-to-end wood connections, like the stair rail example in the video, because the parallel-grain glue connection is so strong. Conversely, threaded fasteners are best used in through-the-grain applications, where the threads interleave with multiple layers of material -- plywood, or solid wood.
Unfortunately, much wood joinery combines cross grain and end grain, as in the corner and intermediate joints of a chair or table. Thus, there is no perfect method for making such joints, particularly where the members are relatively (or very) slender.
The difficulty with dowels is the need for very precisely placed and angled bores. The beauty of the second bolt system seen here is that the holes bored in the wood members are somewhat oversized. The purpose of the bolt is only to draw the members together; the glue prevents side-slip or rotation. The Lamello bolt system, on the other hand, has very little if any tolerance for mis-alignment of the mating holes. Drilling jigs and fixtures, including the many doweling jigs out there, would be of help in making the joints shown in the illustrations. A drill press is also handy, especially for flat parts, etc.
It could be said that the Lamello hidden-bolt system is ideally suited to production runs of furniture, where fixturing is the norm so that identical parts are easily made.
SDR