Martin's Ti belt drive 650b

Martin is looking on from afar, so I thought I'd shoot some step by step pics of day one of his fabrication.

This will be a Ti 650b belt drive single speed with custom EBB, post mount disc brakes, internal cable routing for geared use, and use a curved seat tube and top tube for funk.

The first hurdle of this build is insuring that with a curved seat tube, that the end saddle position remains the same as it would with a straight post.  It takes a bit of math and some datum point fixturing to insure that the intended overall cockpit length stays the same with the curved seat tube, as the design angles the post further back. 

The math done, I need to move the post forward .66 inches or about a total of 1.25 degrees to retain my saddle position.  To double check my math, I set up the fixture with the desired measurements using a standard post, attach a quick extension bar, and mark the saddle center point on it. Then the fixture is reset to the adjusted angle and checked to insure the intersect point at the correct saddle height stays the same.  (sorry for the rotated pic, can't figure out how to turn this one and make it stay).  Here's a quick pic holding the straight post up to show the forward offset to compensate...

With the fixture position set, I began making the seat tube by turning down the top mast insert, creating a shoulder to press in and then boring out the ID to allow for welding shrinkage...

The top insert done, it's time to cut the seat tube to accommodate, face the top edge, then press the insert into place and weld it in.

 

The weld is sanded smooth so that no indication exists of the coupling, then I begin setting up the binder.  The tube is fixtured and the top cut at a 12 degree angle, then the center is found and marked for the binder placement...

 

 

The binder is machined to fit the seat tube OD...

 

 

And then everything is cleaned and the binder welded in place, carefully leaving the soon to be slot open so as not to dull my tools by cutting through the weld...

 

Once she's all welded up, the binder slot is drilled and slotted with a slitting saw...

 

With the seat tube mostly done, I prepped the custom EBB, the stock is cut on the cold saw...

 

Then turned and faced to get our desired width dimension...

 

The ID is then bored to fit our custom insert...

The insert is a custom aluminum piece that allows for over 1/2" of throw and can easily be adjusted on the trail using your crank arm and an allen wrench, simply loosen the pinch bolts, put the allen wrench in the recessed hole on the EBB face, then use your crank arm to push against the wrench and rotate the insert to loosen and tighten...

 I then turn down the OD to take some weight off then clean it up, fixture the pinch binders in place, and weld it up...

The EBB shell is then cut on the cold saw and the edges filed smooth...

Once the EBB is on the frame fixture, I can then miter the bb end of my seat tube...

With the seat tube all nicely fitted up, it's on to the down tube.  I cut in the bb end first, then fit the head tube end...

The next cut is the st/dt junction...one of the most difficult on this build as the curved seat tube enters at an acute angle and falls away, so the cut must be precise the first time, as there is no filing this one in if you miss.  I begin by setting the down tube adjacent to the seat tube and using a square, transfer across the front edge of the seat tube...

I then mark around the seat tube, remove it, and place the down tube.  I use calipers and basically connect the dots to see where my miter margins should be.

The head is tilted and the miter fixture is tilted to match the entry angle for the curve...

One shot to get it right, so I double check everything and then make a cut.  You just see the remnants of my lines...

Spot on, whew!  I'll have to be very careful with my heat control coming through the crotch as the angle provides a tapering wall, getting thinner as it approaches the seat tube.  Will probably use a bit larger diameter filler there to fight the edge's desire to pull away.

The front triangle coming together...

 

cheers,

 

rody

Reggies LD stem

A blow by blow visual depiction of the process...


I started off by machining the back plate to accept a 1.25" x .058" aircraft chromoly tube...

The stem has bee designed to match his current set up and marked appropriately for the center line and heights...now just to start cutting and facing...

The stem is rough cut to the required dimensions and then faced on the mill to insure it is straight and perpendicular to the center axis.

A quick peek to insure that the back plate machining and counter sunk relief match the tubing profile and wall thickness.

The binder is then cut on the mill to the OD of the stem tubing...

With everything machined and set, I insure the stem is upright and square to the table, then tack the faceplate on.  With a 6' tube installed, I then use the height gauge to gently align the orientation to insure the bar will be perfectly positioned in the stem.

 Once the position is set, everything is welded up and secured...

Next up, I drill and cut the slot for the binder relief, allowing the stem to tighten on the steerer tube.

Checking the new stem to see how it matches up with the original...although a different shape, all the important datum points match up.

 A little time in the paint booth and bake box and we have a graphite black ceramic coated beauty...

cheers,

rody

Creating the spine of the frame...

I'm running a bit behind on documenting some of the work coming out of the shop, for that I apologize.

Below we have the beginning of a steel race frame.  Perhaps one of the most important pieces of the whole is the seat tube, as it is truly the spine that everything else is built off of.  I thought I'd walk you through my process of creating the seat tube...

I begin with a True Temper OX Platinum single tapered tube.  The tube is mic'd and marked showing the end of the thick walled section and the end of the taper to the thin wall section of the tube.

The thicker, shorter section of the tube is located at the bottom bracket.  The thin section for the top of the tube does not have enough mass to support the heat from welding the top and the seat stay tubes, let alone the dynamic leverage from the rider's weight passing through the seat post.  To create a more stable structure, I take a section of 4130 heavy walled 1.25" OD tubing and bore it out to fit my anticipated 27.2 mm seat post.

I then flip the tubing around and turn down a shoulder in the piece that will then be pressed into the seat tube and circumferential welded.  This thicker walled piece will resist deforming during welding and offer the physical support necessary for the rider's weight.

The sleeve is cleaned and pressed into the seat tube with a little mechanical force.  It is then welding in place using my tubing roller and a steady hand.

Once welded, off to the cold saw we go to cut a 12 degree miter into the top of the post.

A nice clean cut, the piece then goes back to the lathe and is polished up inside and out, double checking the ID to insure there has been no shrinkage during welding.

 This seat tube is then aligned parallel to the table and rotated against a 90 degree machine plate to determine the apex of the cut.  This apex will be marked and becomes the center line for our binder.

The binder is held in place using my high quality, precision .99 cent spring clamp.  Fantastic!

Using his incredible chin controlled welding powers, the binder is tacked in place on both sides.  Frankie places a tack on opposite sides of the slot to equalize any rotation/pulling from the application of heat.  Notice he's so good, he can do it in his sleep!

Once the binder is tacked in place, the seat post heads over to the mill to have the bottom bracket miter cut .  I use the binder as our datum point to properly orient the tube so our miter is 90 degrees around and spot on.

The seat tube is then re-fixtured and the water bottle mount holes placed.  Here's a shot of me double checking the proper rotation/positioning of the tube using the bb miter and a spare shell, insuring it's square to the table's surface.

The holes are drilled, cleaned up, and ready for flux and heat to set our bosses in place with some silver and a little patience.

I braze the binder in place at the same time, flowing in a little 45% silver and then ready the binder and tube for slotting.  A center drill is used to create our terminal relief hole, then a slitting saw makes a pass, creating our binder slot.

A little filing and clean up later, our seat post is ready to be the spine of the frame.

Cheers,

rody

New England Builders Family Tree...

For those of you who appreciate geneology, a UK mountain bike enthusiast, Dave McDougall, has spent the last year working on a New England builders Family tree. Beginning in the early 70's and working forward, he has traced the intimate beginnings of our sport and taken them forward to where we are today. We are rich in heritage and the tradition of craftsmen passing on knowledge to younger generations. Thanks Dave for such an awesome piece of research...

http://www.anglesandpoise.com/2012/new-england-bicycle-bloodline/

cheers,

Rody

Carmella's Road build...

Boxes are piled high in my storage area...I don't know why, but i HATE to throw away any usable parts.  I've got box after box of random components, partially completed prototypes, and random memories from years of playing with these two wheeled treasures. 

Sometimes, it pays.

In this case, Carmella, flush with excitement from her local ride, quickly loaded her bike onto her trunk mounted car rack and backed out of her parking space.  Her excitement rapidly turned to dismay when she heard the crunch of her bicycle meeting a steel parking barrier, just out of sight behind her.

Her faithful ride had taken a new shape...the chainstay now bent through her wheel to touch the stay on the opposite side, broken free from it's bondage at the bottom bracket and it's dropout end twisted into a funky, Joker like smile.

She brought the bike to me in hopes I could save it's 6000 series aluminum frame, alas, the cost to repair the frame far exceeded it's value.  A frown of disappointment upon her visage, I began to scan the boxes and frames sitting around the storage areas in the shop... "I think we've got some hope" 

So...meet her new ride.

This was the first road frame I built just over 18 years ago for a friend's wife.  Although it has well over 20K miles on it, she could not stand to see it sit in a corner, now replaced with a new model.  I rehab'd it about 5 years ago for Kalten to ride as he grew...that lasted about 9 months before he was rapidly outgrowing it.  Onto the shelf it went.

With a mix of new and old parts, Carmella now has a new bike to flash about our country roads on.  I know she'll take good care of it and perhaps it will be passed on again some day.

cheers,

rody

Ready for the trail...

From a tragedy to new life, I finally got the Frankenstein bike sewed back together and built up. A mix mash of new and battered parts, he'll hit the trail for the maiden journey tomorrow. This one was a roller coaster ride from elation, to bitter disappointment, to redemption. Take a look below for all the detailed build pics...cheers, Rody