I am building my new layout using 1/4" Masonite splines cut to 3/4" strips. Once you get 7 splines laminated together the stuff is amazingly sturdy. Question for all you guys who have used spline in the past: in your experience--using the aforementioned specs---what is the safest maximum span, for straight runs and for curves? My curves are in the 27" to 30" radius range. right now 24" on straight is very sturdy, and 45 degrees degrees between risers on curves is surprisingly sturdy. I plan on adding more risers, but it seems most of us tend to over enginger our bench work.
With seven ply, 8' in length, properly glued, clamped, and allowed to cure fully (24 hours-ish), you can use their ends on abutments or risers and leave them unsupported in between safely. However, in practice, you will probably use at least one intermediate riser if for no other reason than to ensure you are meeting grade between the two extremes.
I just finished a 15' section of 8-ply 1/4 x 3/4 with a 180º curve in the middle at about a 28" radius. I used risers every 16" or so and would not be comfortable with less. I find that more risers makes it easier to control the individual splines as I glue them in place. Besides, a riser cost < $.50 and takes less than 5 minutes to install. Why skimp?
I have the right to remain silent. By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.
I've used a lot of hardboard spline roadbed, mostly 3/16" material cut into 1" strips. It can easily span 24" between risers.
Rob Spangler
Cool, thanks for the replies. I don't intend on gong more than 20" for the most part. Was just curious what the safest span was for that (those) tricky area(s) that crop up no matter how much planning I do.
One quick way to tell is to clamp one end into a vise and see how much vertical flexion you get when you try to flex it. My guess is that it will be plenty sturdy enough to go 36-40" between risers. That should give you more than enough support to maintain straight section horizontal integrity, which would be more of my concern.
Marlon
See pictures of the Clinton-Golden Valley RR
I have made my splines from 3/4 inch clear pine ripped to 1/4 inch thickness, so it's a bit different than yours. In any case, my risers are usually 15 to 18 inches apart . . . I would not make it any more. As has been said, risers are cheap and easy to install. Why skimp?