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-   -   Kirk Frameworks (https://forums.thepaceline.net/showthread.php?t=115818)

David Kirk 01-07-2022 01:29 PM

Quote:

Originally Posted by roguedog (Post 3033039)
Oooh... That frosty crown is cool. I haven't seen you do that before. Though, now that I look it looks like you might have it on your new bike.

How do you get it frosty?

I use two different blasting media....glass bead and sand.

I use glass bead when I want it to be super subtle and sand when I'd like more contrast. In this case it's sand.

dave

David Kirk 01-10-2022 09:43 AM

4 Attachment(s)
For some reason I ended up building a good number of stainless/fillet Onesto framesets in a row and it looks like I'll get a bit of a break with a few lugged bikes coming up in the queue....my hands will appreciate that.

This one is headed to California today and with any luck will be on the roads there soon.

dave

merckx 01-10-2022 07:58 PM

That is fabulous work, Dave. Super!

soulspinner 01-12-2022 09:41 AM

Did not realize Fizik sold headsets.

David Kirk 01-12-2022 10:28 AM

Quote:

Originally Posted by soulspinner (Post 3036438)
Did not realize Fizik sold headsets.

The rubber ones are super light and never need maintenance.

dave

soulspinner 01-13-2022 05:57 AM

Quote:

Originally Posted by David Kirk (Post 3036472)
The rubber ones are super light and never need maintenance.

dave

So where can one obtain one of these? Google cant help. Sure looks like the bottom is one of their seat collars.

David Kirk 01-13-2022 08:43 AM

Quote:

Originally Posted by soulspinner (Post 3036873)
So where can one obtain one of these? Google cant help. Sure looks like the bottom is one of their seat collars.

That is all they are. I had a bunch of the Fizik rubber seals sitting around and found that they make for a good way to hold the fork in the frame for taking photos without things banging around.

dave

homagesilkhope 01-13-2022 04:24 PM

Beautiful fillets and all the rest too, Dave. Compliments!

donevwil 01-14-2022 03:13 PM

Hi Dave,

I'm curious about your recent fillet brazed MRB BB-CS junction, the MRB stays meet the shell much further inboard than those on the recent road frame. Is this due to the bend required for the big clearance MRB, maybe these are pre-bent stays and this is what was required? How would you, or could you, pull off this big clearance MRB with a lugged shell?

https://forums.thepaceline.net/attac...1&d=1640366362

versus

https://forums.thepaceline.net/attac...1&d=1641829376

David Kirk 01-14-2022 06:03 PM

Hey - thanks for the question.

Yes....the stays on the bike in the upper photo are ovalized and bent to snake the tube between the 38 mm tire and the chain ring.

The stays used on the bike in the lower photo are round and straight and are the same tubes I'd use if making a lugged bike.

When building with lugged construction the builder is somewhat constrained by the angles of the sockets of the BB shell....and the socket angles of nearly all BB shells are set up for a straight chainstays. This means that making a lugged frame with bent c-stays is usually not going to happen.

There is a bit of a compromise that can be made however....the BB can be fillet brazed and the rest of the frame can be lugged. This will get you the lugs where they are most visible (seat and head lugs) while at the same time having room for a big tire between the bent stays.

Does that make sense?

dave



Quote:

Originally Posted by donevwil (Post 3037773)
Hi Dave,

I'm curious about your recent fillet brazed MRB BB-CS junction, the MRB stays meet the shell much further inboard than those on the recent road frame. Is this due to the bend required for the big clearance MRB, maybe these are pre-bent stays and this is what was required? How would you, or could you, pull off this big clearance MRB with a lugged shell?

https://forums.thepaceline.net/attac...1&d=1640366362

versus

https://forums.thepaceline.net/attac...1&d=1641829376


donevwil 01-14-2022 06:58 PM

Quote:

Originally Posted by David Kirk (Post 3037877)
Hey - thanks for the question.

Yes....the stays on the bike in the upper photo are ovalized and bent to snake the tube between the 38 mm tire and the chain ring.

The stays used on the bike in the lower photo are round and straight and are the same tubes I'd use if making a lugged bike.

When building with lugged construction the builder is somewhat constrained by the angles of the sockets of the BB shell....and the socket angles of nearly all BB shells are set up for a straight chainstays. This means that making a lugged frame with bent c-stays is usually not going to happen.

There is a bit of a compromise that can be made however....the BB can be fillet brazed and the rest of the frame can be lugged. This will get you the lugs where they are most visible (seat and head lugs) while at the same time having room for a big tire between the bent stays.

Does that make sense?

dave

Thanks for the reply and yes your explanation makes sense. I guess my curiosity lies primarily in the chainstay region between the tire clearance area and BB shell. It appears the ovalized chainstays continue to curve in this area as opposed to straightening out and heading more directly to the shell. Any particular reason? Are more complex, or compound bends difficult to execute? Maybe these stays are pre-formed by the manufacturer? Does it even matter where they meet the shell if fillet brazing is already the plan, all else being equal?

Evan

David Kirk 01-15-2022 09:17 AM

Quote:

Originally Posted by donevwil (Post 3037911)
Thanks for the reply and yes your explanation makes sense. I guess my curiosity lies primarily in the chainstay region between the tire clearance area and BB shell. It appears the ovalized chainstays continue to curve in this area as opposed to straightening out and heading more directly to the shell. Any particular reason? Are more complex, or compound bends difficult to execute? Maybe these stays are pre-formed by the manufacturer? Does it even matter where they meet the shell if fillet brazing is already the plan, all else being equal?

Evan

Good morning.

It sounds like you are wondering why the c-stays have a single long radius single bend instead of two short radius bends. If so....it boils down to the tube wall thickness (thin) and the fact that the tube is oval in cross section. If the tube maker tried to stuff in two short radius bends where there is currently just one the walls would ripple or kink.

In this case the tubes are bent by the maker and then they are heat treated after the ovalizing and bending process is completed. The tubes are annealed (soft) when bent/ovalized which makes it possible and then they are heat treated to bring the strength up where we want it.

In the end it matters very little where the c-stays meet the BB shell. One could argue that it would be stiffer if the c-stays met the BB shell as far apart as possible....that said the difference would be so very small as to be irrelevant. In the end the single bend allows the stays to be shorter (the big contributor to stiffness) while still allowing a wide tire and room for most 1x or 2x chainrings.

I hope that answers your questions - let me know.

dave

donevwil 01-15-2022 12:43 PM

Quote:

Originally Posted by David Kirk (Post 3038072)
...I hope that answers your questions - let me know.

dave

Exactly what I was curious about, thank you Dave.

tv_vt 01-16-2022 05:19 PM

Quote:

Originally Posted by soulspinner (Post 3036873)
So where can one obtain one of these? Google cant help. Sure looks like the bottom is one of their seat collars.

Is it already April 1st? ;)

soulspinner 01-16-2022 06:10 PM

Quote:

Originally Posted by tv_vt (Post 3038672)
Is it already April 1st? ;)

I thought he was spoofin me. :rolleyes:


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