Don B's Spine Ramp. RIP
Don B has built a lot of different ramps. He sent us in some pictures of his last ramp, which we've made available. here. (Thanks Don!).
We didn't get the plans for this ramp, but Don tells us he's working on another one, and he'll see what he can send our way.
Don also sent us in a lot of interesting comments about his experience building ramps. So some excerpts from his letters follow below.
Don B, about his Spine Ramp:
The spine ...
3 foot high including flat (2' 8-something?). 5 foot end result radius. That means that whatever you ply with, (and I use two layers of treated 1/2 inch, and in that case one layer of 1/4 inch) so add 1 1/4" to the desired end result to get that exact number. The deck of that ramp was one layer of 3/4 on top of the transition cut at 3', so it's 3' 3/4" to the ground, once again including the flat.
I also use a variation of the string compass. I use a 2x4 with a screw through one end and a 5/16 hole (the desired radius distance away) at the other end. Use a regular pencil, and keep a sharpener close by. I used to draw one, cut it and then trace the rest off of the first, but I stopped doing that a while ago. I set up numbers onto another sheet laying next to the one I want to draw on, and dig the screw end of the compass into the correct spot, and spin each individual radius by just replacing one sheet after another into the same spot. It helps me to be as neat as possible at the beginning to eliminate errors later on. (And I really don't find it to be more time consuming.)
A friend of mine works for a very good ramp building company (in my opinion) and they use piano wire and have cad printouts of where the cross hairs need to be on the adjacent sheet. After they spin those, and I DO NOT RECOMMEND TRYING THIS UNLESS YOU KNOW WHAT YOU ARE DOING, they cut their trannies with a circular saw at a minimal depth. He says that it eliminates the sketchy lines that you get as with a sabre saw, and contrary to my pre-conceived notion, he swears it works. [ We're not sure we believe this either, but it isn't the first time we've heard it. -- R.P.D.O. ]
Next time around I am trying something else. I made a jig for a router that I can bolt to any length arm that I want. I ran a test run on it, and it seems to work well. It's really loud, but I'll get perfect cuts.
Back to the spine, did I mention that it is tight, and a lot of people don't like tight ramps, so if anyone uses this information, you've been warned. I thought it was perfect.
Don B, about tight trannies:
You have a decent looking structure there [in the "R.P.D.O. mini"]. It seems like you have some good ideas. I'll admit that it's not often that I read something on free sites that I haven't already figured out, but I like to check. The thing that I think sticks out the most in my mind about your project is the fact that you found a crude way of having an ellipse effect. I'd have to ride to it to see if I would like it, but you had the balls to try something that I consider unconventional. [ Thanks for the appreciation. -- R.P.D.O. ]
It also seemed to me that your trannies seemed like they might be a bit tight, but it seems that you wanted a small ramp that you could lock smiths and feebles into. (You ride boards, right? If not, sorry...). [ ... ] I wouldn't be surprised to have you say that your ramp is too tight though, and that maybe you should have made it a bit more mellow. I'd like to know what you think. [ We told him it's pretty tight, but we like it. -- R.P.D.O.]
The thing with me is that I do (always have) like tight transitions. Most of what you can build in a yard is small, so you have to have an element that makes it difficult, like you said to make a better skater out of you. When I was a kid I had a really tight 2 foot half, with a four foot tranny. If I learned something on that, I could do it on a 6 footer, and at the time that was a big ramp to me.
Well as time goes on you learn a few things, and what I have learned about tight trannies is simple. With a ramp overall height of 3 foot, including 2x4 flat, just over 5 foot trannies are okay. I'd say 5' 2", and I can honestly say, built it, rode it, loved it. It could stand to be a bit more mellow, but it doesn't need to be. Now I've also built a 4 foot overall with no flat (quarterpipe) with a 6, and if I get hung, I fall straight to the flat, and from 4 foot and up, that [ ... ] hurts! <!-- I had three really hard slams like that, and I am totally bummed out on it. (I built it for a park, and it is still in use, and holding up well, it is mostly used to drop in on to hit the pyramid I made, so it serves a purpose.) You know how people are, some like it some don't, everyone is an expert, right? I know more expert ramp builders from building for a park, experts that can't even use a cordless drill. The stuff I make I use all the recources I have, I build things well, and they look very professional. When I make a ramp, I am using everything I've learned up to that point, and then even that one MAY be a learning experience. To me it's about recource, doing the best you can and PRACTICE. So I've gotten off the subject... --> [ ... ]
My point is that 3 foot high is my personal limit for tight trannies because of the slam to the flat factor. With the 5' cut at 3', if I slammed, it wasn't far. Something about that extra foot just jars my body. This is all not to mention the tight 6 footers that people make. I have a broken knee cap from a six footer that is a mean, tight <!-- bastard. -->[ ramp. ] <!-- The last slam I had, I got hung and the next thing I saw were my hands and arms blocking my face as I hit the masonite. That was the one with the screw head into the knee cap too. -->
Okay, so the whole reason that I have written to you being the know-it-all that I am and not needing anyones help... I want to know how your ellipse theory has worked. Based on my phobias of getting hippers on hangups, I think that an ellipse could be a good idea. Tell me anything that you can, anything that you learned. I know that you didn't make a true ellipse, and if I can think of a way to draw one I'll let you know.
[ We told him that the tight pseudo-ellipse we used is fun to ride. It's been pretty challenging for some complete beginners to learn lip tricks on, and that we've also thought this might be a good way to have a larger ramp with less "fall to flat" issues making all the slams harder. <!-- Also a reader sent in a way for drawing eliptical transitions which is posted in the R.P.D.O. FAQ. --> -- R.P.D.O ]
I've been looking into it on and off for quite some time because of hips on ramps with transitions. On a true radius tranny you need a proportionate elliptical tranny at the center of the hip.
I am in the process of building my next ramp right now. It's been in the making for 9 months or so. I like to have my ramps ready at the beginning of spring. Due to [ bad ] weather, winter is for cad drawings. [ ooh.. he said "CAD Drawings!!" that's actually the thing that's slowing us up in making our own ramp plans. We don't know how to do any cool drafting stuff but we're learning. -- R.P.D.O ]
I just about have it all worked out. I know all the numbers and such, there are just a few things that I'm dealing with. (Railings, a bench, my 6" Skatelite strips behind the coping needs to be raised up 1/8 of an inch...etc.) My numbers are based on getting the biggest ramp that I can get, cutting two templates out of one 4x8 sheet.
I am cutting a 4 with a 6' 8", but the four includes the flat. The deck will add 3/4 plywood, and 3/8" polyboard. (I drove out of state to pick up 12 sheets of poly at a good price.) I got the Skatelite for behind the coping, that's why I need to build it 1/8 of an inch. I am using 8' 8" of flat to stay in multiples of 8". The very bottom of my tranny has an extra 1 1/2" inches added to it to have my bottom stud sitting square. It's 14 feet wide because I am just barely missing being able to make it 16. I like multiples of 4, but 14 is better than 12. One two foot deck, one four foot deck. The two foot deck by the neighbors side as to not have people stand there as often. (And to save 2 feet in the yard.) It's overall 27' long. I am building each wall in two four foot wide sections with a six foot wide section between them.
I use 2" galvanized (electrical conduit, plumbing pipe, same material and size.) with a 2 3/8" outside diameter, the definite standard. I use galvanized so it doesn't rust, and I prefer the way it feels to black pipe, it's just a little softer. I weld and grind my seams where I need to make my pipe long enough to cover the ramp, no open seams. I used to make my coping stick out 1/4 inch on the deck surface and riding surface (bump), but this time I'm shooting for a light 3/8". I think that little bit more will make it come out right to where I want it to.
Well, hey, I wrote enough, [ ... ] When I can I'll send you a pic of my old spine ramp. If you could, I'd really appreciate posting it as sort of a temporary monument, it was a fun ramp. (R.I.P.)
[ No problem Don, Your spine ramp is what this page is all about. Thanks for sharing your experiences with future ramp builders of the world. Hopefully you'll encourage others out there to do the same. -- R.P.D.O ]
A reader question:
Trey asks, "what kind of stuff did don put on the surface of his spine ramp? it looks shiny like there is something put on the plywood. What is it?
[ It's luan coated with Urethane ] Luan breaks easy and the breaks spread like wildfire. Urethane's biggest problem is sun, but it lasts longer than the sheets. Luan is only about ten bucks a sheet, but that's all it's worth. By the time you replace a few sheets, you're better off with poly. You can even re-use poly. Flip the sheet and use the same screw pattern on a different ramp. Not a salesman, it just worked well for me. [ Don B ]