# mixte progress



## blue.RACCOON (Dec 5, 2009)

hey yo, here are some pictures of a garage project townie bike I'm making for a friend. It's constructed with aircraft spruce tubing (with the coating sanded off), it's going to be an 18 speed, and put together with old / old looking parts. Hope you like. BTW, this is my first post. I've been reading up on the forum and absorbing a lot of good info recently, so here's a thank you / contribution.


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## Clockwork Bikes (Jun 17, 2006)

Thanks for posting. Great fab. pics, I'm looking forward to more.

-Joel


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## j-ro (Feb 21, 2009)

Wow, that thing is B I T C H E N ! lucky friend. thank you.
(spaced for auto censor)


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## Schmitty (Sep 7, 2008)

Nice setups. I'm feeling that jig.

-Schmitty-


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## HomeGrownSS (Jan 18, 2006)

i love your simple straight-foward milling setup. thanks for the brain food!


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## dru (Sep 4, 2006)

That's some really nice fabrication. The townie is a cool present for your friend. How'd you get the milling machine into the basement; aren't they a little heavy for the homeowner?

Drew


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## coconinocycles (Sep 23, 2006)

nice 1st post! definately beats the "where do i buy flux?" 1st posts - you figure **** out with what you got & i like that. great fab & what looks like a nice shop. cheers, Steve Garro, Coconino Cycles.


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## OneGearGuy (Jun 15, 2004)

Heck yeah!
Great post. You have a really nice looking setup. I am interested to know more about your jig.

OGG


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## Linnaeus (May 17, 2009)

dru said:


> How'd you get the milling machine into the basement; aren't they a little heavy for the homeowner?


You can just disassemble the machine and carry it down in pieces.


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## blue.RACCOON (Dec 5, 2009)

Thanks. Here's a picture of the jig unloaded. It was made by a friend of mine for his senior project and it's on indefinite loan to me in exchange for some fab work I've done for him (welding of two single pivot mtb's of his design). I've never used another jig, but it seems like the setup is an excellent way to locate the heights of the BB, dropouts, and head tube. The only downsides I've noticed are that it's difficult to access the "backside" of the tubes during tacking, and the arms that locate the head tube and seat tube can pull off the backing plate if you're careless with the tacking order, they're only fixed near the pivots. And the shop's in a garage, not a basement, so I was able to roll the mill in through the truck door.


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## Linnaeus (May 17, 2009)

I'd love a print of the jig if your friend has one. Perhaps you can post one or otherwise make it available?


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## byknuts (Aug 9, 2008)

Clockwork Bikes said:


> Thanks for posting. Great fab. pics, I'm looking forward to more.
> 
> -Joel


hey joel, you're not in England right now are ya?  
if not, you have pm


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## adam728 (Jan 25, 2006)

That jig looks BEEFY. Frame looks like it's going to turn out nice. 


Now the real question - what's the story on the long travel, 3.4 four cam conversion Toyota? I like the XR500 too, that has to be one of the ugliest bikes made!


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## pvd (Jan 4, 2006)

Very nice.


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## blue.RACCOON (Dec 5, 2009)

My fabrication background is mostly automotive. In the picture is also two of my favorite broken down vehicles.


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## biketrials25 (Jan 20, 2008)

Very cool!


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## zank (May 19, 2005)

incredible.


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## A-Town212 (Sep 17, 2009)

*Me too!*



Linnaeus said:


> I'd love a print of the jig if your friend has one. Perhaps you can post one or otherwise make it available?


+1 on some drawings


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## A-Town212 (Sep 17, 2009)

*Me too!*



Linnaeus said:


> I'd love a print of the jig if your friend has one. Perhaps you can post one or otherwise make it available?


+1 for some plans if possible.

Beautiful bike, BTW.


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## blue.RACCOON (Dec 5, 2009)

I don't have any files or prints for the jig, and I don't really want to ask for them to distribute them via the internet, sorry. The concept of course is up for grabs if you wanted to design your own, design time will be a drop in the bucket compared to build time.


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## unterhausen (Sep 28, 2008)

it seems to me that if you need plans, you aren't going to be able to build it anyway. I wonder if there is anyone near me that can blanchard grind a plate like that.

I like the concept of basing the design off of the wheel centers and moving the bb up and down.

I'm sure a lot of people would be interested in seeing more pictures of the frame as you make progress.


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## Linnaeus (May 17, 2009)

unterhausen said:


> it seems to me that if you need plans, you aren't going to be able to build it anyway.


That is complete and utter BS. Why reinvent the wheel if an effective design is already out there? Ever make a tool or die before? I have, it's much quicker and easier to base your design on something else or copy it outright. That said, I have no qualms with blueRaccoon's choice not to share plans.


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## unterhausen (Sep 28, 2008)

might be a little too harsh, but I don't think it's bs. Plus you'd probably want to make wholesale changes.

I'll draw it up if you promise to have a copy built before June, 2010. What format do you want?


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## Schmitty (Sep 7, 2008)

unterhausen said:


> I like the concept of basing the design off of the wheel centers and moving the bb up and down.
> 
> QUOTE]
> 
> ...


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## Live Wire (Aug 27, 2007)

Schmitty said:


> unterhausen said:
> 
> 
> > I like the concept of basing the design off of the wheel centers and moving the bb up and down.
> ...


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## wyatt79m (Mar 3, 2007)

wow. just wow, that's gonna be a nice bike.


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## blue.RACCOON (Dec 5, 2009)

Here's an update. First time fillet brazing. Still need to do the braze-ons, paint it and assemble the complete bike.


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## unterhausen (Sep 28, 2008)

very nice.


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## j-ro (Feb 21, 2009)

dude, I gotta say, you are like some sort of framebuilding savant or something.
you have an incredible skill set.


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## Teague (Jul 2, 2005)

Wow, thats beautiful! 

How do you do your bending?


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## Schmitty (Sep 7, 2008)

Did you use a rotary table to cut the radius of the drops from the plate?

Looks great.

-Schmitty-


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## blue.RACCOON (Dec 5, 2009)

thanks for the comment j-ro, I have _a lot_ of fabricating experience from the automotive world and the skills translate.

I use a JD2 model 3 bender for the tight radius bends and a Harbor Freight tubing roller for the large radius stuff. The roller works great for the small OD stays, but starts having trouble at 1" OD, it crushes the tube instead of bending it, at least with thin wall stuff. I originally tried a 1.125" .049 top tube and crushed it, then a 1" .049 and crushed it, then finally 1" .058 worked, granted that's an aggressive bend for a roller.

And the radii on the dropouts were cut with an angle grinder. A couple incisions with a cut off wheel, then touched up with a hard wheel, then some hand filing.


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## Teague (Jul 2, 2005)

Hey, i'm using aircraft spruce tubing for my project as well. Could you elaborate on your technique for sanding off the coating/mill scale?
Thanks, Teague

sorry if this a stupid question


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## blue.RACCOON (Dec 5, 2009)

after cutting the tubing to length for a specific part of the bike I debur it and then put it in the lathe and hold a peice of sand paper on the tube with a full grip like holding onto a handlebar and run the sand paper up and down the tube. Sometime have to take the tail stock off for longer peices. If you don't have a lathe regular old sanding works too.


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## Teague (Jul 2, 2005)

Thats brilliant! What grit would you suggest? Do you use multiple grits?


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## blue.RACCOON (Dec 5, 2009)

I used 120 grit, which leaves the tube a little rough. Not a problem in my opinion, but my bender didn't like the roughness of the tube, so in the future I'll probably finish with a finer grit.


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## Smokebikes (Feb 2, 2008)

Very nice work. I like the way the product came out like the drawing........many times when I start out on a project "things"seem to change the initial plan. Please post up a pic when it's built up.


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## zipzit (Aug 3, 2005)

Nice work!



blue.RACCOON said:


> The roller works great for the small OD stays, but starts having trouble at 1" OD, it crushes the tube instead of bending it, at least with thin wall stuff. I originally tried a 1.125" .049 top tube and crushed it, then a 1" .049 and crushed it, then finally 1" .058 worked, granted that's an aggressive bend for a roller.
> .


Questions: did you fill the tube with either sand (and end caps) or braze rod prior to bending? Are those techniques worth doing?

thanx, zip.


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## blue.RACCOON (Dec 5, 2009)

I've never stuffed anything inside of a tube during bending so I don't know if that would help, probably would though


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## rocwandrer (Oct 19, 2008)

blue.RACCOON said:


> thanks for the comment j-ro, I have _a lot_ of fabricating experience from the automotive world and the skills translate.
> 
> I use a JD2 model 3 bender for the tight radius bends and a Harbor Freight tubing roller for the large radius stuff. The roller works great for the small OD stays, but starts having trouble at 1" OD, it crushes the tube instead of bending it, at least with thin wall stuff. I originally tried a 1.125" .049 top tube and crushed it, then a 1" .049 and crushed it, then finally 1" .058 worked, granted that's an aggressive bend for a roller.
> 
> And the radii on the dropouts were cut with an angle grinder. A couple incisions with a cut off wheel, then touched up with a hard wheel, then some hand filing.


Mixte:

That is turning into an awesome first frame in both design and execution!

Cleaning up tubes:

When I clean up dirty mill scale covered straight gage aircraft tubing, I use 320 grit 1" "shop cloth" tape. This is the kind that is like strips of belt sander belt, with fiber reinforcement. It works very quickly with the tube clamped in a block and a shoe shine motion (maybe 2 minutes to do a downtube).

I have learned to always clean up a section of tube before any cutting, drilling, or joining operation. If i cut the miter first, the tube adjacent the edge of the miter is much harder to clean up without undercutting the end of the tube. Drilled holes like bottle boss holes sometimes do the same thing slightly. In practice this is probably no big deal, but it isn't any harder to do it the theoretically better way of cleaning before cutting.

Tube rolling:

I just borrowed one of those tube rollers for a project using similar tubing. This is a good data point for me, with a little more info if you don't mind my asking.

I assume you used the 1" dies for the 1" tube, and the 1.5 dies for the 1.125" tube? Did the 1" x0.049" tube take some set from rolling nicely but crush before you got the curve you wanted, or just roll without taking a set, and then at increased pressure crush without rolling? By crush do you mean wrinkle up on the inside face, or just buckling the tube like bending a paper towel tube?

Thanks,
Richard


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## Live Wire (Aug 27, 2007)

Have you mocked up a drivetrain on it yet? I'm asking because it seems the middle stay will be awfully close to interfering with the chainline. I hope that's not the case as your frame is the only mixte I've ever seen that can be called "cool".


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## blue.RACCOON (Dec 5, 2009)

did a trial assembly of the parts this morning, cheers.


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## zipzit (Aug 3, 2005)

Live Wire said:


> Have you mocked up a drivetrain on it yet? I'm asking because it seems the middle stay will be awfully close to interfering with the chainline. I hope that's not the case as your frame is the only mixte I've ever seen that can be called "cool".


 Ouch, Ouch. I wonder how many of us looked at this frame, thought it was way cool and never noticed this one little detail. I'm guessing it was well over a thousand or two views since thread inception. doh!


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## j-ro (Feb 21, 2009)

I would of left it and made her push it everywhere, ;-)
i'm positive you will come up with a seamless fix


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## blue.RACCOON (Dec 5, 2009)

oops ...build and learn. Here she is back on her wheels. Was at least able to salvage the stays and reposition them.

And to reply to some of the other questions and coments; rocwandrer, this isn't my first frame, sixth frame. And you guessed correctly about the dies that I used for the various bends but I didn't pay close enough attention to the 1" 049 to answer you're question, but it seemed like it was mostly just crushing the tube.

And zipit, I wouldn't be suprised if there were a couple other pros out there that spotted or at least suspected the mistake but didn't mention anything.


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## problematiks (Oct 18, 2005)

Cool solution :thumbsup: (I actually wanted to suggest the same thing)
And it even looks nicer (more flowy) now.

Marko


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## benwitt11 (May 1, 2005)

Totally sexy city bike.


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## bent steel (Oct 24, 2005)

Wow! I didn't think it could get any better, and I didn't think I'd ever like a mixte, but you've pulled both off beautifully, well done.


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## ~martini~ (Dec 20, 2003)

indeed, this thing is fantastic. Love the style, and the construction has been fantastic.


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## Smokebikes (Feb 2, 2008)

Grinding those nubs off from the original position must have been "_*fun*_"! Did you use an angle grinder and how did you get into that tight space? The finished product is just plain art! Please keep posting........ :thumbsup:


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## Blaster1200 (Feb 20, 2004)

Question...if you're TIG tacking in the jig, how do you thoroughly soak the inside of the joint with flux to ensure the brass is flowing to the inside of the joint?


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## blue.RACCOON (Dec 5, 2009)

hmm, I wasn't aware that you're supposed to flux the inside of the tube. I have been smashing flux into the seem between tubes with the application brush as good as I can, and the tubes that I cut apart had a crusty film of brass inside of them, and the part of the dropout that was hidden by the tube was also largely covered with brass. I guess I'll re-think the tacking procedure in the future.

And Smokebikes, yes that took a long time to clear the stubs out. I got a lot out with an angle grinder but couldn't get in with about a quarter inch left to go and switched to hand files. Mostly a coarse round file and then finished it off with a trianglular file which could get all the way into the corners.


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## themanmonkey (Nov 1, 2005)

Blaster1200 said:


> Question...if you're TIG tacking in the jig, how do you thoroughly soak the inside of the joint with flux to ensure the brass is flowing to the inside of the joint?


Brass doesn't actually take a lot of flux. Silver takes a lot of flux if you're thinking about piles of flux.


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## CheeseSoda (Jan 8, 2007)

Off topic: If this is a "garage project" then I want to live in your garage.


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## rocwandrer (Oct 19, 2008)

themanmonkey said:


> Brass doesn't actually take a lot of flux. Silver takes a lot of flux if you're thinking about piles of flux.


Also, though not ideal, both can be encouraged to flow ahead of the joining metal puddle into regions not precoated (how flux coated rods can even work at all, though they certainly don't work as well.)


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## rocwandrer (Oct 19, 2008)

another sort of off topic post:

I finally got a chance to try out that HF tube roller. I did a successful curve in 1.5x0.049, which implies 1.0 x 0.049 should work awesome. I've noticed a couple things:

dies must be perfectly clean, and the tube must be fairly clean (any significant crud will dent the tube as it passes over the roller).

a tiny bit of grease on the support dies seems like it helps.

sucks for aluminum, cuts two grooves in both sides of the tube.

for this to work, you can only tighten the drive roller a tiny bit at a time.

to avoid dents when you tighten, stop ever so slightly short of the end of the last pass before tightening each time (more waste, but less chance of creating junk).

it does oval the tube enough to be visible turning a raw tube over in my hands. Hopefully not enough to be noticeable as part of a frame. I wonder if the thicker walled, smaller diameter stuff stays closer to round?


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