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Thread: To Build A Ski Press...
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02-12-2009, 09:24 PM #26doughboyshredder Guest
Too funny. I was just going to send you a pm. I am gonna post up a real thread about the whole process and the plan shortly, but here's a teaser.
I will be posting a full thread sometime in the next couple months, with more details including the first production run shapes with graphics, company name, etc...
This is probably the funnest project I have ever completed. The stoke of carving turns on something you built is unreal. And I gotta say, my boards kick some serious ass.
Watching ON3P has been motivational to say the least.
If this is something you want to do, fucking do it. Seriously. The resources available thanks to the net are incredible. Will it cost a bunch of money? Yeah, more than you thought. Will it be fun? Yeah, more than you thought.
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02-12-2009, 09:35 PM #27
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02-12-2009, 10:02 PM #28
[dickasshole] bull shit post, that is highlighted below but has no business being here at all. I'm sorry to all the people who read it, and I'm erasing it so it doesn't kill the momentum of the thread. I'm embarrassed and I sincerely apologize for it since it was everything that was not "community".[/dickasshole]
okbye
EDIT: I think this is pretty fucked. Sorry, shitty day and I'm snapping at everyone. This was uncalled for, inappropriate, and not constructive at all.Last edited by RaccoonFace; 02-13-2009 at 04:36 AM.
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02-12-2009, 10:23 PM #29doughboyshredder Guest
Why are you being a fucking douche?
Seriously? If you want to help and be constructive, then you might want to adjust your attitude.
You do consider every bolt in the press for one specific reason. You have equal pressure. You are basically building a pressure vessel. When built correctly with pressure dispersing molds you should have an equal amount of pressure on each mounting point. If your pressure is unequal then you would have some bolts needing to take more force than others, but with the molds that most builders are using this is not the case.
Anyway, fuck it. where's your press dickbag?
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02-12-2009, 10:34 PM #30Registered User
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Man, I just finished my homework on for design of machine elements; the topic was bolt loading and static failures.
The amount of FAIL in this thread is astonishing.
iggy, your on the right track, without running numbers it looks to be way overbuilt. Keep doing what you've been doing.
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02-12-2009, 10:39 PM #31
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02-12-2009, 10:42 PM #32doughboyshredder Guest
I had the same day yesterday. is all good. hope you feel better tomorrow.
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02-12-2009, 10:52 PM #33
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02-12-2009, 10:57 PM #34
Yeah, I'm thinking about building mine from hemp and recycled paper, actually. I think some of your comments about how a structure like this simply should be welded are a bit OTT. More than one way to do things right. Note that I'm not making any value judgments about this particular press, I was told there'd be no math at TGR. Back of envelope calcs are eyebrow raising for sure.
iggy, there are aspects of your design that raise concerns just at first glance. I think RF is wise to suggest you take a second look at this, and I'd go further to suggest you bring it to someone qualified to do the analysis. At the very least those are good suggestions for version 2.0 no matter how it differs. One of the things that concerns me is that a)it can be disassembled and moved ergo b) a well meaning person might crank on the wrench and add a lot of preload to those bolts.Last edited by Garrett; 02-12-2009 at 11:01 PM.
If you're a relatively moral, ethical person, there's no inherent drive to kiss ass and beg for forgiveness and promise to never do it again, which is what mostly goes on in church. -YetiMan
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02-12-2009, 11:14 PM #35
I was present every time it has been disassembled and reassembled, and definitely know not to crank super hard on the bolts. The person who know has it now was told that too, and I don't foresee him selling it anytime soon, but who knows.
As I said, I know it was not the most optimal design. I knew this even while building it. But I also had to build something within my own manufacturing capability and that is how it turned out. For something that was literally made start to finish alone by a kid who had never designed anything like it before, never used a drill press, or never taken a single engineering class, and was balancing school, a thesis, and anything even remotely enjoyable all at the same time, I think I fared pretty well.
And I will definitely have someone who knows more about this double check everything when I finally get around to building version 2.0. Or by then learn how to do it myself. Already learning the business side of everything, might as well pile on a little more.Last edited by iggyskier; 02-13-2009 at 06:08 AM.
Seriously, this can’t turn into yet another ON3P thread....
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02-12-2009, 11:50 PM #36doughboyshredder Guest
fuck doublechecking. close the door and pump the shit up to 150psi. If it doesn't blow, then you're good to go at 75.
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02-12-2009, 11:59 PM #37
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02-13-2009, 12:10 AM #38
iggy,
thanks for all your info. i'm drunk and wasted from riding all day in our lovely tahoe storms, so when i get sober (probably around sunday) i'll re-read everything to get a better understanding of what the hell you were saying. my main take aways:
1) weld the bitch
2) over build
3) put it in a room, close the door, and crank it up to 150 PSI. if it holds, i am good to go at 75 PSI (i keed, i keed!)1 WIDE Ski
'and don't worry its clean, because I never get laid anyways.' - leroy jenkins
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02-13-2009, 09:41 AM #39
DBS,
With all due respect, you took my comments about Happy Monkey's press incorrectly. I stated that it was a design issue. If they rotated the beam 90 degrees into the strong direction (the direction the top and bottom beams are running), they could have used a much lighter beam and saved on construction costs and press weight. That is not to say that they could not have built the press the way that they did with a larger beam, it just lends itself to bending, and they chose the worst possible solution (purely from a design standpoint). Now the construction reality of it was that they got a length of I beam and built the whole damn thing from it, and that was cheaper than sizing and ordering every part.
As far as igs black press, the connections to the legs are absolutely relevant BECAUSE THEY ARE DOUBLE BOLTED. This gives resistance to the moment imparted on the upper and lower beams as pressure is applied. The shear loading in these bolts is the first point of failure in the frame. It would actually be safer if one set of those bolts was removed so the top and bottom beams could rotate on the frame and put the bending stress where igs calculated it for, on the three stacked tubes on the end.
Raccoon--Chill winston. 1. I didn't realize you were a civil engineer. I keep track of my cohorts on the board. 2. Unless the compressor is running and tubes are inflating, if a press were to fail, the yielding of the steel would cause the press to open REDUCING the pressure applied to the mold, leaving a bent press or deformed bolts. No explosions, fireballs or shrapnel. Death is not happening here. 3. The eight 1/2" bolts holding the stacks of tubes together at end of the beam are good for 56,500 lbs. He's good.
krp8128--Here's a homework problem for you: Two 1/2" bolts (36ksi) are spaced 3" apart. What is the maximum moment that can be applied to the connection?I've concluded that DJSapp was never DJSapp, and Not DJSapp is also not DJSapp, so that means he's telling the truth now and he was lying before.
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02-13-2009, 09:48 AM #40doughboyshredder Guest
Honestly I didn't even look close at how the legs are attached, because in my experience it doesn't matter. If the pressure vessel (press frame) does not deflect there should be no added stress on those bolts. On my press the legs are pinned on with a bolt with no nut. Inflated I have zero deflection and could easily remove any one of the four legs bolts.
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02-13-2009, 10:06 AM #41
DBS, just because you can't see the deflection doesn't mean that it is not happening. From your description, the reason it doesn't matter is that your legs and pressure vessel are allowed to freely rotate between each other and your pins are only holding the weight of the press. If you double bolt it, the legs are now resisting the rotation of the loaded pressure vessel by shearing the bolt connection (assuming the legs are secured to the ground).
I've concluded that DJSapp was never DJSapp, and Not DJSapp is also not DJSapp, so that means he's telling the truth now and he was lying before.
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02-13-2009, 10:49 AM #42
That came out retarded, my apologies. A well meaning person might yield those bolts. You've got your shit together though, and I can't wait to see version 2.
iggy, I can relate quite a bit to your post about doing this with a bunch of other time commitments and without much experience with tools. Tools aren't usually rocket surgery, but it sure is nice to have someone around who can show you how to do things in the most efficient way. Been learning lessons the hard way with tools since I was 16, and I'm always looking for opportunities to learn them the easier ways...
Originally Posted by DJSappIf you're a relatively moral, ethical person, there's no inherent drive to kiss ass and beg for forgiveness and promise to never do it again, which is what mostly goes on in church. -YetiMan
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02-13-2009, 01:18 PM #43Seriously, this can’t turn into yet another ON3P thread....
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02-13-2009, 01:27 PM #44
Hey man, I am an ASME QC manager, calculator, welder and engineer. Figuring out this type of thing is what I do for a living. Dood, he's using 70psi. That's like blowing a fart at it. It is overbuilt, but that's how it should be. U should see the bed I built for myself... Nice job Iggy.
Holy shit man- you need a TIG welder! I know, I know- I read the part about the $$ and the experience, but DAMN THATS ALOTTA BOLTS!
Let me know if you want somebody who does this shit professionally to look at your drawings. The key here is DRAWINGS. If you can put it on paper, I can make it. I've been at this for ten years and work at a family shop where I have the keys and would do it off the books. Your press is sicktah, but I'm sure you've found things you'd like to have done differently.
Werd. Again, nice work Iggy. Let me know if you want it welded next time. You'll probably spend the same money you spent on nuts & bolts on shipping, but it'll be done to the nines with a TIG welder...
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02-13-2009, 01:56 PM #45
Saving this thread for down the line. Iggy Thanks for the details mang! Love the pic with the backyard full of skis.
Ελευθερία ή θάνατος
"Great moments are born from great opportunity."
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02-13-2009, 03:08 PM #46
I'm nervously laughing because, a few years back I had a not very fun accident with a compressor based potato gun. I didn't let the PVC glue cure on a 4" pipe cap, and it blew off at 120psi - missing my head by a few feet, and making a hole in the door next to me!
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02-13-2009, 05:04 PM #47
PM Mongo for some insight on this topic. He should be doing test runs on his second press by now.
(Mongo, are you reading this?! )
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02-13-2009, 07:51 PM #48doughboyshredder Guest
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02-14-2009, 07:53 AM #49
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02-14-2009, 09:28 AM #50
im not sure thats hydraulic
looks like a ball screw actuator to me, but ive been wrong in the pastLive
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