Bike 0001

[Luke]

OK 2nd question of the night...
This is a general layout/geometry question.
I will try to explain my process step by step, then ask specifically my query.

I started my layout point at the BB...(This seems the most logical point to begin)
Then, from there I layed out the seat tube angle 73.5...
and followed thru with my top tube. I layed out my head tube at 73 and a length 160mm(that I just effing came up with for no knowledge based reason)
I connected the dots back to the BB to complete the front triangle.
I determined that I wanted about a 72mm BB drop and a CS length of 412mm...which a wheel fit into nicely.
All seemed well.
I took a fork similar to what I'm planning on using, to get the crown height layed out (with the 45mm offset)
After drawing out the fork, and the location for the front dropout...my heights came out different front to back.
After some adjusting (shrinking the HT length to 140) I made up a bit of difference.
Now leveling off of the two drop out points I have a real number of 68mm drop.
This is very close, and a usable number s far as I can see.

I think that I went at this backward...
My question is this:
In contruction the fork should be the 'known' factor, and the head length determined almost by default??
By subtracting the known fork dimension, from the TT position, the length fits itself, yes??
By pulling a number just out of my ass for a headtube without any relationship to the BB drop or the fork crown...
I had some errors to correct.
Black Sharpie is sooooo easy to fix with WD40.

What process, when starting from scratch, do you men use to obtain the HT.

You guys are show horses, I'm just a dumb old donkey....LOL

Luke

[devlin]

Bar drop and reach from the saddle along with axle crown height wouLd determine bulk HT length. As well as headset stack height and the height from the underside of stem clamp to bar ctr. if it has a deep clamp. They all add (subtract?) up for a nett length.

[Andrew R Stewart]

There are differing ways to design/draft a frame. It sound like you're drafting. When I started out we did full size draftings. We started with a horizontal line for the ground, another for the BB height, then the axle height line and finially the top of top tube (when they were always horizontal too). Next came the ST at the angle (or set back) that you want. Then the TT length. The steering axis drops down past the axle height line. From this you start building up from the ft axle. The rake. The axle to brake hole (including tire radius, tire profile, clearance and brake reach), hole to crown race (crown dimension), lower stack height, end of lug (remember them) to center of joint. this gets you the DT/HT center. Whatever the HT results as is what it is (the upper lug also has it's dimensions as part of the HT length).

I was always taught to work with the center points of the tube intersections, this fixation on HT length is only because it's easy to measure. It has less to do with frame design then people place on it. The center points don't change with tube diameters either.

The rear triangle was simply adding a CS length from the ST/DT point to the rear axle height line. The SS then went up to the ST/TT or where ever you wanted to have it attach.

We did direct measurments from this scale drawing. We placed the tacked/pinned joints over it to check the angles and tube lengths.

Having a known fork means that you use it's rake, crown/axle dimensions when working from the steerer axis to the axle point and up. Don't forget that measuring the fork along the front side is different then along the steerer's center line. I measure along the front then then rear and average to get the true centerline dimension to the crown race seat. Andy.

[Luke]

Thanks Andy...seems like you've got it nailed down.
I'll follow along with that as I proceed.

[e-RICHIE]

I'm at Ballers
Off duty for a bit atmo.

Ok...no pics tonight,
Only a few questions:

#1 question for tonight...for the lugframe builders out there.
I would like to know what everyone's process is for preparing lugs.
I understand the clean up, sand and file.
Should I backfile my shorelines?
What grade of paper is best?
What are some options for holding the lugs while working?
Etc.etc.
I know that I don't need to take them smooth like polishing, but is 500 grit going to far?
Just emory cloth OK?

School me, O brothers of Tube!
Thanks in advance....
Luke

[Luke]

Understandable...
Enjoy the event, perhaps next year...we shall see.

I'm at Ballers
Off duty for a bit atmo.

[Luke]

I left the bench a mess tonight...
tired after a long week at the shop.
Here are a few more pieces that I needed for my fixtures.
Hand delivered by a good friend with a CNC at his work.
;)
I'm still improving on my designs as I go.
He still owes me two cones...with a1.370" x 24TPI L and R thread on one end for my BB fixture.
We decided that would be more rigid and straighter than wedging cones from either side, as I had first thought.
(Plus no worries on the threads being tortured in the squeeze)

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Off to bed, we have an 80 miler layed out for tomorrow before work.
;)

[Will Outlaw]

I think this is great to watch. I'm always checking back to see what's new in this thread.

My one thought -- and I mean it from the heart, with the best of intentions and as a guy tip-toeing in the very shallow end of the knowledge pool -- is to say at least consider sticking all that very cool fixture stuff in a drawer someplace and build that first frame with as little tooling as possible.

If we were out having a burger together, I'd probably say something like "dude, fuck worrying about building a jig. Grab a file, a ruler, a protractor and a straight edge and go for it."

There's no right or wrong way to get it done, and I'm pretty dense when it comes to fabrication, but I spent a lot of time and effort on FrankenFrame thinking about jigs, fixtures and tools when what I really should have been concentrating on was making tight miters and just building the damn frame. I didn't have enough available bandwidth to get the miters perfect or braze the joins without making a mess. Dealing with using a jig, much less designing one from scratch, was out of the question.

Honestly, the only jig I felt a need for was to get the rear drop outs/chainstays in the right place and I could have done just fine with an old true rear wheel and some string.

Anyhow, that's my unsolicited $.02 and however it progresses I can't wait to see. I think it's brilliant that you're putting it all out there.

[Luke]

I think this is great to watch. I'm always checking back to see what's new in this thread.

My one thought -- and I mean it from the heart, with the best of intentions and as a guy tip-toeing in the very shallow end of the knowledge pool -- is to say at least consider sticking all that very cool fixture stuff in a drawer someplace and build that first frame with as little tooling as possible.

If we were out having a burger together, I'd probably say something like "dude, fuck worrying about building a jig. Grab a file, a ruler, a protractor and a straight edge and go for it."

Will, it starts back in about 6th grade...lol
I got bored, and started writing my numbers consecutively one day. I was tired of boring school work,and tired of 'them' wasting my time.
I've always been fascinated with numbers...I wrote to 34,000 something.

The precision element has always been there for me. I think I took Dad's micrometer and mic'd my Cray-ons at one point. LOL
I figure that the margin of error, if kept to a minimum will result in a better frame.
I'm going to make mistakes...I'm going to make a mess too!

But,I like designing this little shit too. I get off on smooth metal pieces reflecting in the flourescent bulbs of the garage!
Especially when the numbers jive how I want them too.
A lot of people can just go out and grab a hacksaw and a file and build cool shit.
My OCD doesn't allow that. LOL

I've been building engines since I was a teenager too...after I cooked my first two-stroke Yamaha,
Dad said,"It's time for you to do your own top-end jobs." LOL
So, I'm used to working in thousands of an inch...even when I do dishes,sweep the floor, or cuddle with the 'old lady'. ;)

And as for that Burger,I would reply something like... "Man, you know how numbers fuck with me,dude. It's like Ernesto Colnago dropping acid with Einstien at a Waffle House after watching Joe Dirt."

Thanks Will.....

Luke

[Willie1]

Luke, you and I are a lot alike. I have been messing with shit as long as I can remember. I haven't been as active as you in the past 2 months. I was snowed with a knee surgery and tonsil surgery. I have a partially completed fork jig built so far. I made a stand for my drill press out of leftover teleposts from my house. I learned that the proper shade on the welding helmet makes a big difference LOL. I built a 1/4" steel topped work bench with built in stand for the frame jig. I bought a used bringhelli but toyed with building my own. I realized I didn't know enough about what I wanted to make my own yet. I really want to "just grab a hacksaw and files" but with my ADHD, I have to not put the cart before the horse, as I have done so many times with poor results. Setting up properly always pays out in the end. I would suggest you read Einstein's biography. I think you would relate to his experience with the world. Also, check this out:

Gifted & Creative Services Australia

Read "I think in pictures, you teach in words" This is common in asperger's disorder, adhd, and dyslexia. All three were at one time linked to low intelligence, but the opposite has been shown in many cases.

[Will Outlaw]

I love it. I think I rebuilt my first motor when I was 15.

Can't wait to see how the jig comes out.

Now get out there and crush that 80-miler.

[Andrew R Stewart]

Luke- I wanted to share my thoughts about your tooling. The tube clamp blocks on their threaded stand offs are interesting but I think could be more wisely done. The issue I wonder abot is their clamping atube that won't be straight and the need to have a different block foe each tubing diameter. I have seen many jigging designs that used clamp blocks like yours (not on adjustable stand offs though) and the ones that have stayed in production moved from the clamps to other clamping designs. A simple Vee block positioned parallel to the surface it stands off of (so the tube contacts it along the tube's side) will fit many tube diameters and also not change the tube's center height off the surface. Pretty much all the tubes I've rolled out on my surafce plate are not straight. Some are pretty close but others have a couple of mm's of bowing. Some even are snake like with a couple of curves. The jigs that hold the tubes at their ends are less sensitive to this bowing (and said bowing is rotated to be in plane with the frame's plane). With your clamp blocks at least they can "float" on the surface a bit. Some jigs hold them solidly, these i see as problematic. What you don't want is the jig to induce stresses to the tubes. The bigger/longer the clamp the greater the possibility to flex/stress the tube. I do like your approach of adjustability in general. I'm sure any frame you build from these will ride well. Andy.

[Luke]

I love it. I think I rebuilt my first motor when I was 15.

Can't wait to see how the jig comes out.

Now get out there and crush that 80-miler.

WOW...94 degress by noon. Managed to get in 68 miles. Got a bit of a later start than I intended (one compadre's mechanical issue)
and had to cut the ride short a bit. Which was really the right thing to do.
I'm cooked out.
;)

[Luke]

Luke- I wanted to share my thoughts about your tooling. The tube clamp blocks on their threaded stand offs are interesting but I think could be more wisely done. The issue I wonder abot is their clamping atube that won't be straight and the need to have a different block foe each tubing diameter. I have seen many jigging designs that used clamp blocks like yours (not on adjustable stand offs though) and the ones that have stayed in production moved from the clamps to other clamping designs. A simple Vee block positioned parallel to the surface it stands off of (so the tube contacts it along the tube's side) will fit many tube diameters and also not change the tube's center height off the surface. Pretty much all the tubes I've rolled out on my surafce plate are not straight. Some are pretty close but others have a couple of mm's of bowing. Some even are snake like with a couple of curves. The jigs that hold the tubes at their ends are less sensitive to this bowing (and said bowing is rotated to be in plane with the frame's plane). With your clamp blocks at least they can "float" on the surface a bit. Some jigs hold them solidly, these i see as problematic. What you don't want is the jig to induce stresses to the tubes. The bigger/longer the clamp the greater the possibility to flex/stress the tube. I do like your approach of adjustability in general. I'm sure any frame you build from these will ride well. Andy.

Andy,
I worry too about the clamps being too tight and causing a dimple, or a stress mark. I am going to make these a final number just a bit loose over the tube.
I want it to 'hold' it, more than 'clamp' it. They are more about alignment than anything. Once a tube is in place and pinned...really where is it going?
It is a drag that I need one for each tubing diameter, but I don't really have any cost in them. A vee-block is a better concept and I've seen some quick release type that
work on various sizes of material. With my clamps and their 4" stems, hopefully some movement during heating and cooling will be allowed.
I won't torque the hell out of them, and maybe just one per tube would be best. (and keep them out of the way of brazing.)
Thanks for sharing your thoughts.
-Luke

[Luke]

05-27-12_0756.jpg
Final geometry is complete..I think.

I wanted to get up early and get to the hardware store...and the auto parts store...
Time for another bolt binge!
Grrrrrrrrrrr. Nobody opens 'til 9am. WTF?
9am, really?
Sigh.
<Drinks a Full Throttle and eats beef jerky, listening to Brian Protheroes' Pinball>

[Luke]

OK...a bit of an 'Ah-ha' moment on a fixture to hold lugs while I sand/file...
I'm sure someone has done this in the past, or in the future perhaps.
But I've done it now:
A simple rubber freeze plug (expansion plug) for $4.20 at the hardware store...
(one that fits 1-1/8" to 1-5/8" works great)
Clamp it in a vice, tighten it down, and VIOLA!
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[Luke]

More fixture components coming together today...
worked on the headtube fixture.
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[Luke]

More pics of the frame jig as more of it is attached...
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05-27-12_1919.jpg

[pruckelshaus]

Another good lug vise is an old quill MTB stem. 1.125 with shims works well:


Ghettoriffic lug vise by pruckelshaus, on Flickr

[Luke]

I put in some time on the top HT lug this morning (rode tonight instead of working in the garage)
I have most of the cast marks removed, not sure how much more I need to do.
They clean up so nice. ;)

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