i’m making my first board with 50/50 rails. previously i’ve used the rail band guides from the 1977 primer, but it only seems to have hard rails with tucked under edges. i’ve looked through previous posts and a lot of people recommend the ‘fred’ tool, but i think i would end up with boxy rails. does anyone have advice for making the rail bands for 50/50 rails (perhaps a profile or rail band dimensions)?
When the rails are still square, start with the bottom tuck…
Then when you start honing down the deck, you know by feel and sight where your current state of progress lies.
Check every 7 planer passes, or 10 sureform passes, by holding the board over your head, both hands on the rails evenly, and sliding down the board from outside to center…
Ultimately, your hands feel the rail shape, forget about cheating with rail templates and all the scientific garbage…
Just my POV, you guys can shape by machine, if you want.
Consider that in many fabrication industries a patternmaker comes up with some sort of prototype as the mold or plug. Templates and various measuring devices are usually used in these instances and it is not necessarily considered cheating.
If you check most any board you’ll find that deck and bottom contours are not a symmetrical elliptoid, nor are rails actually 50/50. More often, the rails transition from something like down at the tail to more of a 50/50 contour in the nose.
An outlined blank that has been squared off is a good place to start. Assuming that the bottom will have some kind of curve as it transitions toward the rail along the edge, it might not be a huge transgression to start with some sort of guidelines.
I’ve used sections of an outline template and traced out some light pencil lines (not necessarily where they are shown in this example) to guide where I cut. It all gets blended eventually but it’s a place to start…
I’ve also been known to use a contour gauge to check my rail progress. Most of us use things like thickness calipers, etc. I find that the longer the board is, the harder it is to just use my hands as a gauge. Anyway, there are many ways to skin a cat. Some of us cheat, some of us don’t.
Here is an actual cross section measurement from the midpoint of a Skip Frye longboard. Again, probably not 50/50 but more like 60/40? Note the flat bottom compared to the domed deck. On the bottom ,it’s easier to tell where the bottom ends and the rail begins.
my 3 50/50 soft railed longboards (1 yellow, and 1 red, 1 mini longboard for my boys) that have been posted here many times… all have been true 50/50 rails.
The yellow board has a lot of belly in the board, which basically matches the dome of the deck. This board has a full rail.
The red board was bellied just out near the rail so the top and bottom rail contour match. This board had pinched rails.
My method is after templating to draw a pencil line mid rail (i.e. what will eventually be the rail apex). I then use my rail/cutlap marking tool to mark reference lines on the top and bottom of the board. I use a line 2" and 4" in from the template. This give rail band refenence lines. It can also help to put additional reference lines on the verticle/cutoff rails. Depending on how full/boxy you want your rails deturmines how tall/thick the gap between your origional apex line and the new/additional lines should be. I’d guess between 1/4" to 3/4" a part. If you do a search on “harbour balsa” I’d think you’d come across a picture of Rich Harbour shaping a balsa board that has reference lines drawn all over the rail area.
After that point, cut rail bands. I’m not that skilled with my planner so I just use it to get things close and then rely on my sanding screen. I like to do a little on each and then start back over. (i.e. bottom left, bottom right, deck left, deck right, repeat). by working a little on all 4 rails at a time I find it easier to keep semitry. So far on my 50/50 soft railers I’ve wanted all 4 rail sides to be identical.
Oh don’t remove the apex pencil line until the last few passes of the finial sanding. When working the sanding screen, as you move to finer grits (is that the right term with screen?) then gradually wrap the screen further around the rail.
Like LeeDD said, I rely on the feel of my hands more than my eyes but look and feel frequently. Every couple passes and try to visuallize the final shape and work backwards to an intermidiate stage.
John, my Grandfather was head jig maker at Grumman-Wright facilties at Wright Patterson Air Force base during WW11. He built the Hell Cat F-6, the most feared Naval aircraft by the Japanese during WW11. It wasn’t built by eye or the seat of ones pants, templates and jigs are what got the job done
how’d you make the contour guage??
Howzit going all my 50/50 rails are constant section rails (like the same thickness right around the board) so my method probably won’t help, but they are true 50/50, either an exact semicircle or ‘pinched’ into a perfect 50/50 elliptical section (or as close as my eyes and hand will allow). Here’s a simple drawing of the facets for a 50/50 circular section anyway.
hey Jim my grandfather ran the jig departmen at Lockheed Martin in Burbank Ca… retired in the early 70’s…
it is funny, when i was about twenty i started making wood fins with hopes of turning it into a business… made some many silly jigs and temps it was crazy, one day my buddies scott was like “didn’t your grandfather make jigs?” It was kinda a cool feeling to have a link when there was none before…
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how’d you make the contour guage??
Taking a tip from Peter Rijk (who posted in “diagram” section of resources), I ripped a bunch (44) of 1" X 1" scrap into thin strips on a table saw and ran those through my thickness planer. A hole was drilled in each end before cutting out the strip in the middle. The top and bottom pieces are 1" X 1" rounded at the ends and varnished. Holes were drilled in the top and bottom pieces and the hardware installed. It’s actually kind of floppy but I manage to make it work and it reaches pretty far even on the thickest boards.
http://www.swaylocks.com/resources/detail_page.cgi?ID=216
I also like something to serve as a reference guide. Once the board is mowed to thickness I usually place a pencil dot on each of the squared side where the apex of the rail will be. It’s just a reference point and helps me keep the rails symmetrical. You can use a planer, sureform, or an orbital sander (a lá Phil Becker) to initiate the rail bands and shape the rails down on each side. The trick is keeping those lines straight, even, and consistent. Once your initial bands are created, I’ve found that what really does the trick is a sanding screen over a balsa block. This really shapens up the lines. Doug Schuch made me a couple of great versatile balsa blocks last year that, with the sanding screen wrapped around one, really defines the rail line just before you round it with the loose screen. With the block & screen in hand, sand those lines: define each line that will make up an angle of your rail. Use the reference point as a guide. I usually stop my lines at about 1/8" before the dot on each side. This will leave a 1/4" of unshaped rail which you’ll wrap your loose sanding screen around to fully round. Lighting is key here. Experiement with the light fixture heights to find the right level. Blah blah blah.
I try and make templates and jigs for any job that needs accuracy or will be done again in the future.
I had employees in Fla. told me that a one time employee used to whine that “Jim will spend 4 hours making a tool that will only save him 2 minutes work”. Well I still have most of those “tools” and use tham often, 20 years later
Good representation of how it all comes to be, it is all mechanical, a series of flat panels, each becoming smaller, until unperceivable