The Obsession
- Thread starter c.o.d51
- Start date
Awesome. Looking forward to seeing the finished product.
When are you gonna start taking orders?
done any FEA on that beauty?
Yeah, he did. The thing is WAY overbuilt for the first one.
Orders, probably not for a while because he's really going to want to test it first.
Here's some pics of some of the materials and his work. I was over at his place last week and how he didn't get a headache from sitting an inch or two away from that lathe for 9 hours is beyond me...
OBSESSION BIKES said:The program is SolidWorks student edition.
I have the first set of build pictures and there is much more to come. Last week a spent about 40 hours at the lathe machining parts for the bike as well as doing some welding.
Raw Materials
Main tubes .049 wall thickness (first one is going to be overbuilt)
machining tools
machining tolerance check
Raw stock left- finished product right
upper mounting eyelet mock up
TIG Welding in the bat cave
[img]http://www.freeridesouth.com/pics/pictures/10527.jpg
Side one of eyelet welded
More to come soon.......
Welds look great! I love the amount of detail youre putting into this, it should turn out awesome.
Me likey, nice and clean. Good job!
This thread should be a mandatory read for all the bike industry goons-shows ideas at work and a love for making cool stuff. Good luck-sweet looking project.
solidworks did you say he was using?? wow mush have been hard to make it on that, i find it hard to use, but im only learning it now..
Tig welding barehanded? You're a brave man. If you find that tig gloves don't give you the tactile feedback that you need, some guys cut off the index finger and thumb.
Your project looks awesome so far.
Can I make a couple of suggestions? Make that top gusset tube straight. You will have to use a really heavy wall tube in order to bend it. You can save a lot of weight with a straight one or 2 plates.
Also, look at using a higher end butted tube for the TT. You can save about 1/4# easy. True temper makes some nice BMX tubes that look like they would work. They are easier to work with too since they don't have all the mill scale. Cheap too!
If you get stuck, check out the frame forum
It's like ridemonkey but only for people who build bikes.
Your project looks awesome so far.
Can I make a couple of suggestions? Make that top gusset tube straight. You will have to use a really heavy wall tube in order to bend it. You can save a lot of weight with a straight one or 2 plates.
Also, look at using a higher end butted tube for the TT. You can save about 1/4# easy. True temper makes some nice BMX tubes that look like they would work. They are easier to work with too since they don't have all the mill scale. Cheap too!
If you get stuck, check out the frame forum
It's like ridemonkey but only for people who build bikes.
sorry to burst your bubble, but you might want to read some books and take some classes before you bother believing any FEA data you have. if you make one tiny mistake your numbers mean nothing. looking at the loading/boundary conditions on that link it looks like you're missing some things. also, it would be best to correlate your data to real world testing. otherwise all you have is a bunch of random numbers and colors and a big waste of time.FEA pic
Thanks for the positive feedback, my buddy is so stoked on this project.
the bike looks sick, i wouldn't even bother with FE models
The FEA that runs in Solidworks IS a big waste of time.
It's good for making pretty colors though.
It's good for making pretty colors though.
Are you guys at a University? If so, try to get your hands on (or go to a computer lab) visualNastran for your FEA.
Curtis is totally 100% right on this. Inaccurately constrained FEA can be worse than no FEA at all.
Why yes it is. He just liked it so much:biggrin: He needed a hanger quickly, so he popped it off his Sunday.
As for the FEA, this is what he said:
Forgive my long response, but I will attempt to answer all the questions and comments, that have been posed since my last post, to the best of my knowledge.
I couldnt agree with you more about the FEA. There is absolutely no substitute for real world testing. I have a watered down version of the COSMOS FEA program and consequently that is the reason why I have only bothered to analyze one link out of the entire bike. I have a strong physics background and have read up extensively on FEA analysis, but that is not to say I know how to precisely analyze a part using it.
I realize that the numbers that FEA generates are totally worthless if calculations or restraints/ loads are off by even a fraction. I also realize that I did not include all restraints/ loads in the picture I posted. I know the actual numbers that the program generates are probably not accurate, but the program does show high stress areas and I use that information to try and make educated decisions on link design and geometry.
As for the concerns about the links being flexy and the eyelet under the seat tube being a weak point, they are the least of my concerns. Consider that the links are 25mm thick at the widest point and are made out of 7075 aluminum which has a shear strength of about 48,000 psi. I feel confident that the links will hold up fine and if they don't, than I will redesign them based on the previous failure.
The eyelet is .120 wall 4130 seamless which is ridiculously thick for a bike and also takes advantage of the great compression strength that tubes offer. The eyelet itself has many advantages over the bent top tube. I will go into that further if anyone is interested.
The seat tube gusset is also being revised. After much consideration I decided a bent tube is not the ideal profile to have there and not the most cost/ fabrication efficient. I will post updates of design when I post next set of build pictures sometime next week.
That is a Sunday hanger. Because of my extremely limited budget for this bike I decided to use a preexisting derailleur on the first one in order to cut the cost of having a custom one machined. I chose the Sunday hanger because it is so well designed and allows me greater flexibility in dropout design. If and when I build a second revision to this frame I will design my own hanger and have it machined.
hehehehe, its a joke about the links.... you need to paint them rootbeer color.
nice work on the bike!!! keep us updated!
i designed almost that same exact bike just over a year ago. My inspiration came from the old cortina/avalanche bike and the sunday. My problem was that i couldnt get the leverage ratio where i wanted but your buddy got it spot on. i wanted the BB a hair lower then your buddy has it.
Tell your buddy sweet job!
Tell your buddy sweet job!
More pics to come soon...A.R.K. said:Ok so here it is. The latest build pictures. I still have lots to do, and I will continue to post pictures and progress until I have a fully built up and tested bike. I still have to weld the upper and lower pivot on the front triangle, but this is what I have so far.
I revised the seat tube gusset because having a thin wall tube bent was not practice and cutting fish mounts in the bent tube also posed problems. I decided upon a saddle gusset because it was lighter, cheaper, and easier to make.
"Thank you Solidworks. I was able to use the sheet metal feature in Solidworks in order to find the unbent profile of the saddle gusset. (it would be very hard to do by eye)
Raw material for saddle gusset.
(No fancy laser cutters for me)
After bending
just how its suppose to fit
headtube before lathe chuck snaped
Headtube after the lathe chuck snapped. (what are you going to do..its a 30 year old lathe that I got for free)
jig
tube mitering
fit up
in jig
just a little size comparison for those who question strength of the frame
Headtube looks like it could safely be a bit shorter to lower the bars, but other than that, I'm just going to repeat my previous sentiments...
Sweet! That head tube junction is unique...it reminds me of this...
That'd be a trick paint scheme. Nice work, must be nice to be able to do something like that, huh?
That'd be a trick paint scheme. Nice work, must be nice to be able to do something like that, huh?
It probably could be shorter, but for a first one, he's really happy with how it came out.Headtube looks like it could safely be a bit shorter to lower the bars, but other than that, I'm just going to repeat my previous sentiments...
This first one is just overbuilt.
Awesome job so far! Can't wait to see it finished.
im with aboveHeadtube looks like it could safely be a bit shorter to lower the bars, but other than that, I'm just going to repeat my previous sentiments...
The welds actually look pretty good...usually the garage framebuilders turn out some pretty ugly welds....not that I could do better or anything.....looks nice! 
It's a bit of a heavyweight right now, I think it's around 6-7lbs. Complete frame, for this first one is going to end up being a little under 13lbs. The next ones are going to shave a few pounds quite easily. I can't wait for his links and the chainstay yoke to come from the machinist. Then he'll be able to get the rear triangle built. This thing is going to be super low too. I can't wait :biggrin:
great stuff!!! someones gonna ask it sooner or later and i know its overbuilt but how much does the front triangle weigh?
looking so sweet wish i had the resources to do that...
i dont know if u said it further back i did not see, but how low is the BB going to be, and how long is the wheel base???
is it going to be lower than the sunday? oh u going to bother with iscg mounts lol...?
i dont know if u said it further back i did not see, but how low is the BB going to be, and how long is the wheel base???
is it going to be lower than the sunday? oh u going to bother with iscg mounts lol...?
Nice fence! what's that ... pine?
just kidding, looks great so far.
I love this thread.
just kidding, looks great so far.
I love this thread.
thats an awesome garage build. I dont know what your financial situation or if you would be intrested, but I think you could start a grass roots company with a bike like that.
Looks awesome.Good work
It's bb height is 14", but I don't remember the wheelbase he went with off hand. It's earlier in the thread. I actually have no clue what he's doing with ISCG mounts. They're in his design, so I'm going to assume that he's using them. Standover height though, this is THE lowest 8"+ travel bike that I've ever seen. It's standover height is lower than my Race Link, and it's a good deal lower than the Sunday. It's going to be long, low, and fast.
As for starting a company, what's holding him back right now is the cost of having parts machined. If he had his own mill, you could probably expect to see a larger production run. He has put in around 65 hours of manual machining so far, and it's just too much for him to do. He is also paying other people to have the links and bb yoke machine, and it's fairly expensive. If a mill ends up coming though...
Budget started at around 3000. He put about 2000 into his new welder, and the rest has/is going into the materials and costs of machining/powder coating.
alan "aka jefferson"- its jordan from trumbull whats GOOD!
all i can say right now is
what you are doing is prob one of my dreams
i am going to SUNY DELHI to get a AOS Degree in Welding Technology.
its a 2 year coarse, and man, if u are getting big with buisness, im hear for ya buddy. welding which is my passion and bikes which is my passion..what could be better
anyways your bike looks amazing, sleek and clean and low.
what about chain growth length?? looks like itll grrroowwww
cant wait to ride with you and rob again, i am now riding an 06 7point5 ( ditched the shatty S.G.S and finally riding something respectable (hehe) )
love to hear from u guys
laaaaater
all i can say right now is
what you are doing is prob one of my dreams
i am going to SUNY DELHI to get a AOS Degree in Welding Technology.
its a 2 year coarse, and man, if u are getting big with buisness, im hear for ya buddy. welding which is my passion and bikes which is my passion..what could be better
anyways your bike looks amazing, sleek and clean and low.
what about chain growth length?? looks like itll grrroowwww
cant wait to ride with you and rob again, i am now riding an 06 7point5 ( ditched the shatty S.G.S and finally riding something respectable (hehe) )
love to hear from u guys
laaaaater
^ I think you'll find if you read the thread there's an idler going in to eliminate chain growth issues.