Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

L-girder or open grid?

17401 views
36 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    February 2005
  • From: Southwest US
  • 12,914 posts
Posted by tomikawaTT on Saturday, August 2, 2008 1:07 PM

The quick and dirty solution to the problem of screwing into end grain is - don't.

Just use L girder construction and end grain problems don't come up.  There is no particular stress on any L girder fastener except in shear - and serious shear stress is only encountered at the tops of legs or at the screws which hold shelf bracket tracks to the walls.

Of course, if you absolutely, positively have to build a grid, you can cross-bore the joist and insert a piece of 3/4" dowel, and then screw into that (nice, long screw, predrilled hole.)

My own construction is steel, and my 'end of joist' joints would be two screws driven vertically if I was building horizontal wall structures instead of using L girder design.  (Hard to rip the end grain out of a steel stud...)

Chuck (modeling Central Japan in September, 1964 - on steel-stud 'C acts like L' girder benchwork)

  • Member since
    December 2001
  • From: Northern CA Bay Area
  • 4,387 posts
Posted by cuyama on Saturday, August 2, 2008 2:55 PM

I find corner blocks work pretty well and eliminate the need to screw into end grain. If there is a requirment to make components removeable, one can glue and screw one surface and use screws with no glue on the other. No special tools or fittings needed.

Hand-wringing over benchwork is one of the biggest time-wasters in the hobby, IMHO. Usually multiple approaches work and there is so little benefit from choosing one over the other that spending many hours thinking about it is wasted. Again, IMHO.

  • Member since
    June 2003
  • From: Culpeper, Va
  • 8,202 posts
Posted by IRONROOSTER on Saturday, August 2, 2008 3:09 PM
 tomikawaTT wrote:
 IRONROOSTER wrote:
 tomikawaTT wrote:

If you are going with hard, straight-line layout edges, are good at carpentry, want a dead-level surface and will never, ever have to move a crossmember that interferes with installing a switch machine or turntable pit, by all means use open grid - inaccessible rear fasteners and all.

...

The nice thing is, there is no single right way.  After looking at the options, pick the one that makes you most comfortable.

Chuck (modeling Central Japan in September, 1964 - on steel stud 'C acts like L' girder benchwork, and shelf brackets)

Personally, I like open grid and haven't had any of these problems.  Admittedly I'm an amateur, but I do enjoy working with wood and building stuff with it.  Open grid also has better portability and has more clearance underneath.

Enjoy

Paul

I rather like the way you edited my original post to reinforce your 'my way is the best way' opinion...Grumpy [|(]

Open grid may have better portability if you are moving modules to train shows and NMRA conventions.  It loses that advantage in a hurry as the sections get larger.  As for clearance underneath, if I had built open-grid to the usual dimensions (4" thick) I would have gained a whole 2.5" of additional clearance.

To re-state what you edited out, L girder fastened from below is very forgiving of imperfect carpentry, lends itself to easy modification and can make use of odd sized and mismatched joists under cookie-cut plywood supported on risers.  I consider it much more user-friendly than open grid (suitable for a backyard deck) construction.

I also mentioned shelf brackets as an option - with or without open-grid or L-girder superstructure.  For a foot wide layout along a structural wall that has to be the easiest way to fly.

In the final analysis, the original poster will have to examine the choices, weigh the options and choose which of several methods will work for him.  One size does NOT fit all.

Chuck (modeling Central Japan in September, 1964)

Sorry, my intent was to try to keep the post short since I was only commenting on the first part of your original comment - the "..." of course alerts the reader that your full comment was not included.  

Nor did I say my way was the best way, only that I like it and don't have the problems that you have with open grid.  Plus there are advantages to it.

Enjoy

Paul

If you're having fun, you're doing it the right way.
  • Member since
    July 2008
  • From: Amherst, N.S.
  • 248 posts
Posted by kcole4001 on Saturday, August 2, 2008 3:36 PM
 cuyama wrote:

I find corner blocks work pretty well and eliminate the need to screw into end grain. If there is a requirment to make components removeable, one can glue and screw one surface and use screws with no glue on the other. No special tools or fittings needed.

Hand-wringing over benchwork is one of the biggest time-wasters in the hobby, IMHO. Usually multiple approaches work and there is so little benefit from choosing one over the other that spending many hours thinking about it is wasted. Again, IMHO.

Corner blocks do work well. Glued and screwed they help support the load and provide more surface area for the joint. Metal brackets would probably work equally well.

Another way to make sections removable is to use carriage bolts, suitably spaced from adjoining sides of benchwork for easy access with sockets or wrenches. I think small diameter bolts such as 1/4" should suffice given the normal load expected, but heavier bolts such as 3/8" or bigger if one desires could just as easily be used.

Personally, I'll use whatever method of benchwork construction that seems appropriate at each particular part of the layout. Each way has it's own pros and cons, as long as it supports the load adequately, I'll only have to worry about it once (I don't plan to move-ever).

"The mess and the magic Triumphant and tragic A mechanized world out of hand" Kevin
  • Member since
    September 2005
  • 52 posts
Posted by Lloyd2 on Saturday, August 2, 2008 11:29 PM
You guys are terrific!  I really appreciate all your ideas.  I think I will try the diagonal tension wires, because the local ICC  has agreed to an around the walls layout (3 walls) in a small room that has a computer desk, bookcase and (worst) a sofa.  It might not be a good idea for future railroading if the brother-in-law sat on the sofa and creased his head on a metal bracket, so the tension wire sounds like my solution.  I never would have thought of it on my own.  Thank you!  Thanks also for the discussion about the problems with butt joints in open grid framework.  You guys helped me twice!! - Lloyd2
  • Member since
    April 2002
  • 921 posts
Posted by dante on Sunday, August 10, 2008 10:26 PM

 Lloyd2 wrote:
You guys are terrific!  I really appreciate all your ideas.  I think I will try the diagonal tension wires, because the local ICC  has agreed to an around the walls layout (3 walls) in a small room that has a computer desk, bookcase and (worst) a sofa.  It might not be a good idea for future railroading if the brother-in-law sat on the sofa and creased his head on a metal bracket, so the tension wire sounds like my solution.  I never would have thought of it on my own.  Thank you!  Thanks also for the discussion about the problems with butt joints in open grid framework.  You guys helped me twice!! - Lloyd2

I have concerns about tension wires secured as described above:  attached to the bottom of the front header.  I believe the header could still be prone to sagging.  Note that when a canopy-for example-is braced or supported in part by cables, the cable is secured to a wall or mast above the canopy and to the top of the front structural member it supports. 

 

  • Member since
    March 2007
  • 247 posts
Posted by BCSJ on Monday, August 11, 2008 6:58 PM

L-girder is much thicker than open grid so if you're concerned about maximum space under the layout that would be pushing you towards open grid.

L-girder is a bit easier to adjust.

Either one can work with land forms below track level (if the tracks are laid on risers coming up from the joists so there's room for the valley/canyon to extend downward.

Regards,

Charlie Comstock 

Superintendent of Nearly Everything The Bear Creek & South Jackson Railway Co. Hillsboro, OR http://www.bcsjrr.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!