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Discussion in 'BMX & Dirt Jumping' started by Cru Jones, Sep 12, 2008.
A grove, if i'm not mistaken, he made it in a brew bikes frame building class
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I like how you have the middle brake cable runner on the top tube. I hate when a cable smacks against the frame when bouncing around. got a zip tie on mine. I know it's just a mi-nute issue but I like it.
Thanks Y'all. Yeah, the cable slap thing is a pet peeve of mine too. I do not get why so many Co's don't put enough guides on or they just flat out put them in the wrong place. It is a simple detail that keeps your bike from rattling and sounding like **** and pissing off the less tolerant trail inhabitants.
Those guides are actually just small pieces of tubing chopped into 1cm or so sections and I ground through the center of them half way with a really thin grinding stone to make each of them look like two eyelet-type cable guides. I could have just left them as tubing or used ready-made guides but I didn't. It actually took a crapton of time and would be very production unfriendly but I like them.
It ended up weighing about 5.2lbs, which is slightly heavy for a pure race frame, but I wanted it to be more race/trail. It's light enough for me to occasionally race, yet strong enough for trails. I made it for my needs, haha.
nice specs and weight cornfed. it's a beauty.
Nice work cornfed. Those specs sound money. Looks sweet, too. You actually built it? In the brew class?
How tall is the seat tube, center to center?
Hey Cru, those frames turned out fvcking awsome. Great job man!! Are you going to do another run soon because I might be interested in a cruiser frame or even better a custom 26" frame if you decide to do a run of those?
It is 10 1/2" C to top of TT; 12" C T Top of seat clamp. I also went w/ a OS seat tube so I wouldn't have to cold-work the TT where it butts. If the seat tube is smaller diameter than the TT, there will be a gap on the sides and the TT would have to be ovalized where it is welded to the ST. I don't like the way that looks.
The jig I used just holds the head tube, seat tube, BB shell, and dropouts in place. The top, down, and stays are not held in any way so they can be "floated" around to where ever I thought would be best. Because this thing is a one-off (essentially a prototype), all the miters had to be painstakingly hand ground. For production frames, where a Co wants the design to be consistent, all the miters could be cut w/ a hole saw on a Bridgeport or something to crank out 50 TT's, down tubes, etc all in one shot, reducing production time considerably. Proto's/ one-off's will always cost more...more time consuming for this reason.
I wanted a slightly longer seat tube. I think it looks better than the squashed scooter styles.
cornfed- not sure where exactly you made your frame/the place you were taught at... but there is no reason to "painstakingly handgrind" a miter...even on a "prototype." All the frames I've made were all prototypes, but I set up the jig, layed the frame out, and mitered all the tubes on our mill using a hole saw. Proto's cost more because it practically always takes the builder MORE time to fix a jig for the customers desired geometry.
As per the jig you used, that's the jig layout I've built all my frames on too. It allows you to weld more of the frame while in the jig to prevent distortion and also gives you tons of open space to play with tubes and get whatever look you want.
Cad layout of one of the fixtures I used..
You basically restated my point. Prototypes take more time. Exactly.
Not everyone has access to their dad's expensive equipment. There is nothing wrong with hand grinding. It just takes more time.
Sorry if I've interpreted what you've said wrong... but in bold you have stated that if it is a proto/one-off frame, the miters must be hand-ground. I was just stating that as false information. Obviously if you do not have access to the tools, you do what you gotta do. Sorry if it came across as a personal attack as that was not my intent.
Yeah, you're right, it does read that way. What I meant was my tubes had to be hand ground.
You are correct, if you want to set up the hole saw for each cut, it can be done. I just didn't have the resources to go that route. It would probably have a tighter, more precise miter fit too...unless you are one of those that subscribes to the air-gap philosophy and believe there is more tensile strength in the filler rod than welded parent metal and a looser joint can be stronger overall. I am still not sold on that but there are some that believe it.
All is well.. Just misinformed is all.
It's all good. :biggrin:
BTW, Can you ask your dad if he made this part on my old BMX bike? It is the magnesium threaded headset lock at the base of the gooseneck, just below the polished aluminum spacer in this picture. Sorry about the thread hijack:
OOOO is that an Andy Patterson, a DY or a Shadow?
It's a DY.
Yes... I do believe that was a Hutch product. However, he may have designed/produced that before hutch under TiTron as well. That is what went down with the hubs/bear traps/spindles.
So to bring this thread back on point, I dug up an old frame building book I own. I believe it went out of print in the 70's 0r 80's and I think the builder has since died:
You can see in the author's illustration, he did not use a mill, or even a bench grinder for that matter. HAND filed miters:
The author's preferred method is to use a jig crafted from Pinewood, he mentions has even built frames WITHOUT even using a jig and STILL had no need to cold-set afterward. Here he is using the BP drawing to check the geo:
Now THAT is a hand-crafted frame!
AMEN TO THAT. I still, however, would argue against this method... At least he was willing to use SOME sort of a jig. If done right, you can get away with nothing, sure, but jigs and the expensive equipment make sure its done right (with user input, obviously).
Very cool post thought.
Ahhh, see...debating can be fun on the internet.
This is the part where I counter your response,lol.
A mill doesn't guarantee higher QUALITY, just FASTER production time. Hole saws get dull and tear tubes, or distort them if cut too quickly, etc. There are plenty of MFR's, past and present, who build with your preferred method and produce crap (please, in no way is this any reference to you. I have seen your bike and it is sick). From what I understand, the author's frames were highly regarded for quality, and his frames are highly sought after by collectors. Granted, your method could produce a frame in a few hours, where the author's would take a few weeks. Your method has more potential to be more profitable. But then again, the author doesn't have that hefty note hanging over his head for all that expensive machining equipment.
A straight frame is a straight frame, jig or not. I don't think quality discriminates. We aren't debating QUALITY; we are debating PHILOSOPHY.
Would you rather have a high-quality frame built in a few hours by a builder w/ high-tech equipment, or would you prefer the quality built in by a craftsmen who passionately and intimately invested a small chunk of his life to his craft?
In my opinion, there is no right or wrong answer.
Isnt the intraweb great
I agree with everything you have said... Reading and re-reading what you have posted, and what I have posted myself - I would have to say that frame building alone cannot be dictated by strictly your philosophy on welding, jigging, mittering, etc... BUT rather the quality of the tubing, patients of the builder, the builders' personal skill/talents (lets be real... some people ride the bikes, other people build them/fix them. Thats just how the world works), and lastly the PASSION behind the final product. You had said we aren't debating quality, but rather philosophy. I agree, but on the topic of quality tubing, it makes all the difference in the world. If you're using ****ting tubing, its more likely to give you problems when bending stays, etc and even sometimes distortion in the welding process (can argue on that one too...) Sure.. hole-saws die, sometimes distort, and if not careful can easily be damaged. But in my opinion, this still comes down to the builder and the tooling he/she chooses to use. Hell... I know you wouldn't catch me DEAD filling a tube with a dull, worn down file
We could debate this all day.. But in my opinion, both methods aside... It really comes down to who's doing the work and what effort they're willing to put into it.
Give two builders the best tooling, materials, and talent for their particular style and we are back to square-one.
Let's switch gears and take it a step further...
Why stop here?
Let's incorporate 5 axis, hydro-forming,etc--maybe incorporate the robotics used overseas and in the auto industry. Maybe we can build a super high-quality frame w/ the best materials available, and I bet it can be done with very little, if any, human contact or interaction, AND be done at a cost of $40 or even less per frame (I know*run-on*, sorry).
This should be the best, most poular method amongst cyclists, right? I mean, ultimately, quality is all that matters, isn't it?
Nothing wrong with that.
Me neither, and frankly, you wouldn't catch me hand filing every miter or component of a frame in the building process w/o some sort of power tooling/tech. I am just not that patient. But I sure do respect it.
Given the best talent, tooling, materials, and design; a product resulting in a similar, high-quality end-result between different building techniques, the difference still comes down to the philosophy of the builder.
Cool thanks, I missed this comment. It is a Hutch. I have Hutch Beartrap pedals on this bike too, but they are the cast type with the words HUTCH in them. Was this design your dad's too, or just the original, Titron version was your dad's?
Sorry Cru, hijacked again...
Soooo refreshing to see 2 people discussing bikes on the internet and not resorting to name calling, etc, etc.
Also ..... any word on how the frames are coming along?
The world of technology and the taiwanese marketplace is going to bring a whole new realm to the bicycle market, as well as all manufacturing/mass production. It's rapidly reaching the point where all you do is load a piece of material, press a button, and out pops the finished product... obviously lots of programing, etc is involved.
In my opinion, I will always build with a fixture. I will always use a mill (given the resources I am presented with)... And if/when the day comes that I can no longer use either, or one over the other.. We'll see how my philosophy changes. Some people take pride in their work... whether all they did was think the design up and someone else carried out the brains/brawn behind the finished project... or you've done every bit of it yourself. I respect those who use the resources they have (and tons of determination) to hand-miter/build a frame with average tools able to be bought at a hardware store. And at the end of the day, whether their frame is prefect or not, the pride they have in the work they've done is enough to make it all worthwhile.
i'll PM you with info on hutch/titron. Sorry for derailing this thread of sorts, cru, I'd be glad to take my posts and move the to a new thread if you want.
Frame Building Class
also classes in March, April and May!
are already booking up!
Have a friend who also wants a class. Let me know and I may setup a class.
If you have interest let me know.
We are having a bicycle frame building class that will last for 5 days. Imagine building your own frame and also powdercoating it themselves. We will assist in all areas. This will include a quick TIG welding course also. We will also assist in final welding. Frame design limited to double triangle and dropouts.
We will limit class to 2. Expect at least 50 hours of instruction and hands-on experience.
No experience is necessary at all.
Let me know if any are REALLY interested!!
Imagine riding a bike you built with your own hands!
BMX Frame 20" or 24" $1300
MTB, Road, SS, Cyclocross Frame. $1500
Located 14 miles away from Boone NC. Graet places for nightly food and entertainment.
You will need to bring a long sleeve DARK COTTON shirt.
If you have them bring a pair of safety glasses, leather gloves and a welding helmet.
What is the class about?
This is just some of what you will learn.
2. Metric vs English measurements.
3.Tubing- Butting, single, double, triple and quad.
4. Tubing- how to decipher tubing specs
5. Tubing heat treatments, myths, elongation and hardness
7.Welding methods explained. MIG, TIG and Oxy/Acetylene
8. Welding bicycle tubing methods.
9. Oxy/Acetylene setups for welding or fillet brazing
10. Welder machine selection (transformer or inverter, air or water cooled, foot control, pulse)
12. What is pulse
13. Tungsten types and shaping
14. Weld beads
15. Rod selection
16. Cup selection
17. Nozzle or gas lens?
18. Argon and CFH
19 Torch control
20. Welding 4130 urban legends (MANY)
22. Main tube selection
23. Chainstay design
24. Dropout design
25. Alignments issues.
27. Tube fitment
28. Many hours of weld class and hands on
30. Tubing pretreatments for powdercoating
A nonrefundable deposit of $500 is needed to hold a position.
Thanks again everyone for their support.
Bumpage. Been super busy lately with a new job and moving out to Ventura, but we have two new prototype frames on the way. These will actually be 24" bmx cruiser frames. The basic geo hasn't changed, but I did go with smaller diameter stays and an internally butted seat tube to lighten up the frames compared to the last samples. I also made sure that there won't be an indentation on the outside of the chain stay for chainwheel clearance. Should clear a 30. Here is one of the drawings.
TT - 22.3
BB - 12.7
CS - 14.25
ST - 9
HA - 74
Hopefully we will have them within a few months!
Looking good! I cant wait to see what the protos are going to look like.
pretty killer cru.
nice. some serious stuff.
Can't wait to see these built up. The CAD drawing looks great.
Now those are the specs the Model C should have had.
Thanks, dudes. Glad you guys are stoked on them... I'm pretty excited to try them myself.
Just wanted to clear up a rumor... yes, I am working for Giant now, but Giant is not who I am working with on this project and is not the manufacturer of these frames. I started this project long before this opportunity with Giant came up. I actually started this by working with Ted from Seshin Bikes out of Canada. I was working through him and he was handling all of the Taiwan stuff. Recently, however, Ted has decided to get out of the bmx business for awhile, so he put me in direct contact with his agent in Taiwan. These frames are being made in the same factory that makes a majority of the quality bmx frames (for a bunch of different brands) coming from Taiwan. If you know the biz, you can probably figure it out... I remember they even had a feature on the factory a few years back in Ride.
Thanks again for the stokage and I will be sure to keep you guys up to date on this!!
cool thanks for the insight. very resourceful! my boy sean actually talks about and uses those contacts from the ride article all the time haha. thats pretty much a dream job, best of luck.
can't wait to see the protos.
The actual TT is longer than I anticipated.
Have you worked out how tall of bars to run with this frame? In other words: what would match a 20" with 8" rise bars or a 26" with a 3" travel fork and 2" rise bars?
i'm running 7 5/8" bars on mine...
cru - are you going to help Giant dial in the geo on the Method 24? You don't have to answer that question ha ha.
This frame is 22.3 TT, the other sample will be 21.9. It's hard to compare actual TT lengths across different wheel sized bikes. I would like it to feel like a 21" bmx, but still have tire clearance for x-ups/barspins.
I'm still not sure yet on the bars. When I do the math, it seems like a 5 to 6 inch rise bar should feel the most like a 8" rise on a bmx. But, a lot of people (like WCH) like to run taller bars on bmx cruisers. I have some S&M 5.75 bars that I'm going to try and then go from there.
Haha. The specs on the method 24 actually aren't that bad. Full chromo, 22 tt, 73 ha, 15.3 cs, not sure about bb height. I may pick one up for comparison.