Smoked out...

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Working through a 3 day stretch here at the FD, back in the shop Tuesday.

rody

Purge/Heat Sink fitting for Paragon dropouts

Tacking up Chad's rear end, I decided that I needed to spend some time to create a purge/heat sink fitting for the rear hooded dropouts that did a little better job at protecting the underside of the hoods than the foil dams used in the past.  I wanted a piece that would purge the underside, provide a heat sink for both sides, and be interchangable between the chainstay fixture and the frame fixture.  All in the anticipation of creating a tool that will increase the efficiency of building the rear Ti ends and provide a cleaner end product.

Starting off with some 1.75" 6061 stock, I cut some rough pieces to begine turning...

The first part I began working with would be the inside heat sink, an interference fit piece on the dummy axel that would slide tight against the inner plate of the dropout.  Here we are turning it down to the 1.5" od to match the dropout.

 A visual for ya, showing the size...

Next, I layed out the center of the axel line as it sits offset in the dropout, so that when the final hole is finished, my outer diameters will line up perfectly.  Starting with a center drill so that the position does not travel under initial tool pressure, I'll use increasingly larger drill bits and then finish with an endmill to insure the correct size for the friction fit on the axel.

Checking the rough fit on the axel and against the dropout, looks like we did ok...

Working on the inside piece, I'll turn it down to fit the inside diameter of the dropout so that it nestles up under the hood with a small gap for argon flow. 

After I parted off the .75" inside piece, I set up for the axel bolt centerline, then drilled it through. 

The next two processes are for the argon purging...a center bore hole that cuts laterally through the piece, and then multiple air holes that intersect that center bore for the gas to disperse through under the hood of the dropout.  I could not find my tap for the argon fitting, so left the hole undersized to fit the tubing until I can locate that little bugger and thread a larger hole for the quick connect...adapt and overcome I guess :)

Three purge exits that area spaced evenly under the hood's footprint area.

The tool all assembled...ready to begin tacking the rear end together...

Took a bit of time, but a dedicated tool like this is what's necessary to insure a quality finished product.

rody

What day is it?

Seems like the weeks are just moving by me faster than can be imagined.  Other than a brief stint in the shop on Friday to machine and set up a cutom 1x9 chain guide for Chris before he flew back to Arizona, I've been immersed in work at the Fire Department with a little construction thrown in after dusk.  To date, I've logged more extra hours at the FD than all of last year, and there are still 4 months to go, ughh.  As for construction of the new shop, all the roof I beams are up and sheeted in, coming along...

I missed Em's birthday due to work constraints, so I took a few hours off Sunday afternoon to take her out rock climbing.  It was real nice to actual spend some time with one of my kids that did not involve having them polish headbadges or cutting tubing :)

Chad's rear end should be finished today and ready to add guides and fiddlybits.

Email and voicemail that Christi cannot answer has been put on the back burner of late, will try to catch up late tonight/early tomorrow.

rody

Laying out the rear end...

Laying out Chad's rear triangle consumed the early morning hours at the layout table.  I wanted to insure that Chad's Ti frame was stiff enough to be able to handle those County Line sprints and playful accelerations that are common when a bunch of overgrown boys get out on the road together.  To do so, I'm using .875" diameter tubing for the chainstays.  Let's draw it out and see how it fits...

I planned the rear spacing out to accommodate for up to a 35mm tire and larger non-compact rings...both items that will not be used at this time on Chad's build, but looking forward to the future, it's nice to have the capability built into the frame if it becomes desired or necessary.  As you can see from the layout, utilizing round stays there is some interaction between the front chainring position and the drive side stay.  To grab the clearance we need, I'm going to shape the ti stays into a nice oval to round profile.  It sounds easy, but there is a high probability of cracking the tubing with the process, as the finished width needs to be .45", six inches back from the bottom bracket centerline.  To accomplish this, there is a significant amount of pressure on the tubing at the terminal end to create the gradual taper towards the dropout.  In the end, I had two beautiful stays, and two that went into the bin.

Now you can see how ovalizing the stay gained the necessary room...

The pressure to repair Jeff's bike before the weekend turned up just like the 95 degree heat in the shop. When Jeff crashed, he literally tore out the down tube water bottle bosses from the tubing, taking almost .500" out of each area.  Folks talk about how silver is weaker than brass, but this was a good example of it's strength...the .5mm tubing failed before the silver did.  So we stripped the frame, filled the dent with silver and replaced the torn downtube bottle bosses with custom machined .5" diameter plugs that filled out the cleaned and drilled out holes.  It was a shame to see the snazzy paint dissolve away to be replaced with a simple powder coat due to time constraints, but it's more important to have a bike under Jeff than something purty...he'll just have to be the eye candy, eh ladies?

I finished up the late afternoon in the shop by working on Chris's single speed.  Chris, who recently relocated from Texas to Arizona, has found the single speed a bit more challenging than desired in his new mountainous area, so he flew into town to have us change it over to a 1 x 9.  We also trimmed the steerer tube on his Fox fork, and made a custom spacer to clean up the look a bit as the bike has changed/ been repurposed through the years.  We'll hit the trail Wednesday night to check it out.

As personal time outside the shop has been suffering a bit, I found myself getting home at dark and getting on the mower, as our yard is beginning to look like the hay fields to either side.  As the sun rose this morning, I gotta admit, mowing in the dark is not a good idea...looks like a kid with ADHD was behind the controls :)

rody

Chad's frame melted together...

After a couple of long shifts over the weekend at the fire department, I groggily stumbled into the shop on Sunday morning to take care of a few items, namely finishing the plumbing on the fixture so I'd be ready to weld Chad's frame this week.  I've been putting this off for months, but finally buckled down and got it done. 

A view of the backside...routed so that I have full adjustment capability, swivels 360 degrees in two axis without binding, and with the flip of a quarter turn valve on the front, gas where it needs to flow :)

Picking back up where we left off, all of Chad's tubes were mitered and beginning to look like a front triangle.  The last task before being able to put the big clean on the tubes and weld them up is to get the seatpost binder welded on and slotted.  We had previously tacked the binder in place to allow for indicating off of for proper orientation of the tubing for mitering the bottom bracket.  Now, we're going to fully weld it and cut it up :)

I've had some folks express an interest in Ti fabrication, so I've been sharing a bit more on the process to fullfill their curiosity.  We'll look a bit more in depth at this process too.  The welding of Ti must take place in an oxygen free environment, most often resolved by replacing the atmospheric gases inside the tube and in the weld zone outside with an inert gas, Argon.  This is accomplished by sealing up the majority of the tube, leaving a relief hole at the superior portion for the lighter atmospheric gases to escape through.  How long do you have to purge before starting your weld?  I typically allow enough time for the interior gas space to be replaced 3 times.  Although I use a screened cup on the Tig torch that sheilds much of the weld puddle, it is subject to contamination and embrittlement until it cools below 800 degrees, so ya gotta keep it bathed in argon.  Below, I've built a make shift dam out of foil to help hold the spill over argon and prevent any stray air currents from blowing my shielding gas away from my happy little area...

I pre-flow the gas for about 12 - 15 seconds to allow it to pool a bit in the foil dam and then begin to weld...

Your weld should be shiny and bright with no discoloration if you have good gas coverage and heat control.

Here you can see the completed weld...wait, what's that?  He left part of it un-finished, eeegads!  Not to worry, I leave a small section on the center top and bottom of the binder unwelded to allow for easier slotting.  Trying to cut through your weld will dull your tooling in short order.

Off to the mill...

Once my binder is on, it's time to drill the terminal slot hole and slot the sucka!  There are lots of ways to insure that the tube is level and in phase when drilling the hole...here I'm using two squares off of the table surface to get it right.  Once correct, I center the tooling on the tube using the DRO and measure down 1.5" from the peak of the angled cut.  Then I drill away.

Once the relief hole is placed, the tube gets turned 90 degrees, squared up again, and the cutter centered on the tube again.  A nice even speed and plenty of fluid, cut in progress...

The finished product, pre-clean up...

With all the tubes finally finished, everthing gets scrubbed with warm water and mild detergent to get rid of all the oils.  Then it's off to the Scotchbright pads to scrub away the oxidation on the surface, and a final rinse in Acetone to insure that all surfaces are squeeky clean.  From this point forward, I no longer touch the tubes with bare hands, electing to use latex gloves with my golden needle gloves over top for welding.  I placed the bottom bracket and seat tube in the fixture, plugged the holes leaving a small outlet open at the top of the tube, and ran a root pass on the section that will be covered up by the down tube intersection...

I then placed the balance of the tubes and purged the whole shebang, tilting the fixture so that my escape hole was at the highest point to allow the oxygen out...

Once purged, I fusion welded the joints together, using only the base material for the first pass.  Here's what you are looking for...even material use from both tube surface areas, bright shiny finish, and even heat control...

With the whole frame fusion welded, it's off to the granite slab to check for distortion, looks good :)

It was late evening when I finally got home, but I was able to help get some walls up on the shop.  So much to do and seems like there's never enough time...

cheers,

rody

PS...I'm gonna have Christi read over the contest entries and choose a winner tonight, thanks to all who entered.

Monday morning news, ummm, dilemma

What do you do when both your rider and his bike are broken; Again!




That's how my Monday morning went.

Long story...Jeff ran over to Pa for what would be hopefully his last race to qualify for his Pro credentials to be able to race on the national level next season. Racing in the Cat 1 category, he was leading the race with a comfortable margin when a moment of inattention caused him to crash hard in a rock garden, his bike hitting him in the head and knocking him senseless for a brief period. Getting up, his left knee was gashed open and swelling, his right forearm had a large laceration, and he could not use his right hand. He finished the race with one hand on the bar, solidifying his win and his qualifications for next years season. The guys at the finish line badaged him up and told him to go to the hospital. Typical of a mountain bike, there's little health insurance and less common sense, so he and Chip drove the 9 hours home and went to bed.

When he showed up at the shop, I asked if he wanted me to fix his bike or him first ;)

The layout table is good for more than forks and stems...

With a little Betadine to cleanse the area...

After a little numbing and a LOT of scrubbing with a stiff bristle brush to get the dirt out...

I trimmed up the margin where some of the subcutaneos fat was displaced and that's when I noticed that Jeff was looking a bit "off"... so we got him off the stool and into a little better position to avoid having to close a gash in his head from fainting...

With a much better systemic homeostasis, I began to close him up, one more stich to go...

and finally, the icky knee... it's on deck for the next round :)

Now, how bad is the bike?  That will be for another day.

rody

PS...no medical expertise demonstrated or implied...just cheap fixin :)

Chad's Ti frame...front triangle

When we last left off, we had just got the seat tube to the point of being ready to weld the insert in place.  I layed down a fusion pass that draws a bit of material from both pieces to join them together, then a second filler pass that was a bit heavier in the center rather than feathering in the edge.  I set it up like this so that I can then skim pass the positive overage leaving a seamless, visually pleasing seat tube.  Here we are with two seat tubes all ready for the next step; the binder bolt.

I've got a pretty good stash of 6/4 Ti rod that I use for fabricating binders.  Yeah, I know, Paragon sells them cheap enough, but heck, I enjoy the task of making them on the lathe.  That's why I do this, right?

After some enjoyable lathe time...

The binder is important for my build process as I use it to orient my seat tube and keep all the processes in phase...keeping the bottom bracket miter square, aligning for the water bottle boss holes, etc...  Tacked on and ready for the next step.

...cutting in the bottom bracket miter.  Here you can see that I use the seat tube binder to square up to the face of the miter system to insure that the bottom bracket miter is 90 degrees to my binder and angled top cut.

and checking it in the fixture for position, final length, and oveall good vibes :)

As involved as the seat tube is, the next step takes a lot of time for a couple of reasons we'll discuss.  The down tube is normally pretty straightforward, but I wanted to utilize a larger downtube and manipulate it to create a stronger, more energy efficient frame for Chad's physical size and power.  I started with a 1.75 x .032 straight gauge round tube, cut it to a rough length, and then swaged it at the head tube vertically and at the bottom tube horizontally.  The trick here is to...

1.)  keep the ovalized sections in phase, 90 degrees to each other
2.)  swage the ti material to the approriate final size (remember the dreaded springback) without creating a peak or a subsequent crack.
3.) get through the now almost 2.5" inch long sections of thin tubing without destroying the tube...yikes!

The downtube took almost 4.5 hours, without taking time for pics. Why so long?  Well, the swaging is not difficult, but does take time to do it right the first time.  To achieve the final width I needed over the 12" tube length, the end of the tube almost closed off under the squeeze pressure. With the tube bi-axially ovalized, I then had to address how to miter it. Unlike Aluminum or steel, Ti will tend to pull and tear rather than cut smoothly, often dragging the side wall of the tube in with the direction of the cutter.  To prevent this, I broke out the jigsaw and the sander and created internal wood plugs that matched the internal shape of the tube.  This wooden plug allows me to miter the tube end in a supported fashion.  It takes more time, but it saves some serious cursing and frustration if the tube gets destroyed by a wandering hole saw tooth.

A nice looong oval to round profile...

The basic bottom bracket miter...still have to cut in the seat tube intersection miter.

Setting up for the long head tube miter...

checking the fit at the headtube...

With the downtube in place, let's move on to the top tube.  We'll start by parting it off to it's rough length...

And cut in both ends to match the angles of the head tube and seat tube.  Because this is just a happy nice round tube, no special accommodations are necessary to cut it, just slow and even pressure.

Looking like a triangle...

Next up, I looked up the specs for the Dura Ace crank, front derailleur, and then used the data to lay out the water bottles to insure I had enough space for all the equipment and that it matched my original numbers.  Once satisfied, I drilled all the water bottle holes to spec, 2.5" apart...

With the bottle boss insert in place...fits well :)

Final step for the main triangle is to drill all the purge holes, placing the holes as close to the superior margin of the internal tube diameter as possible to allow the argon, which is heavier than the ambient air, to push as much oxygen out as possible during purging.  The exception is the seat tube top and top of the head tube, as those areas will be occluded partly by heat sinks.

In the morning, I'll clean everything up nice and tighty then focus on welding it up.

cheers,

rody