BARF - Bay Area Riders Forum

Go Back   BARF - Bay Area Riders Forum > Club House > Who Let the Smoke Out!?


Notices

Reply
 
Thread Tools Display Modes
Old 02-02-2021, 12:53 PM   #91
Frame Maker
Veteran
 
Frame Maker's Avatar
 
Contributor

Join Date: May 2011
Location: Livermore
Motorcycles: sportbikes, dirtbikes, and some odd bikes that I've built myself.
Name: Julian
Quote:
Originally Posted by GPzPop View Post
is there a weight advantage to cro-mo over mild steel tubing?
Thanks for two more really good questions...

Since mild steel and cromoly are virtually the same density (weight per volume), the general answer is that there is no direct weight advantage. That said, its common knowledge that there are some applications where weight is a primary concern. In those cases you must consider all three properties and what tradeoffs you are okay with.

Bicycles and aircraft are two examples where weight and strength are both very important. For those applications you will almost always see use of cromoly (or similar high grades of steel) used. Because both bicycles and aircraft are optimized for highest strength with the least amount of weight, the tradeoff is in allowing for flex. So weight savings is very much a factor of design priorities. Motorcycles tend to be prioritized for both strength and reducing flex. Commercially available motorcycles are also designed for ease of manufacturing. So with motorcycles, weight savings becomes a lower priority.

With my frame design, I could switch to cromoly steel while reducing the wall thickness and gain some weight savings without sacrificing strength. I would however see a reduction in stiffness and in increase in difficulty to construct. So everything becomes a tradeoff based on design priorities.

Quote:
Originally Posted by GPzPop View Post
...what about your "sourced" cnc parts from overseas ? is there a choice in the alloys used? how is the quality control vs price point ratio?
I'd say that 20 years ago it would be a crap shoot trying to get Chinese made parts reliably made from a specific alloy. These days the reliability has greatly improved. So not only can I specify the alloy, but also the temper. As an example, with my last batch of parts I specified "6061 aluminum". Here in the US it is implied that you want 6061-T6 since T6 temper is the most common way of supplying wrought aluminum. My Chinese vendor assumed I wanted T0 (soft annealed state). Luckily I caught this and was able to clarify 6061-T6 (which is slightly more expensive from this vendor).

As for quality vs price, its like everywhere else. I've seen some extremely nice quality CNC machined parts from Chinese vendors, but its expensive (still cheaper than US). And I've seen low quality CNC machined parts that were dirt cheap. The vendor I've been using is closer to this. I want my parts to look nice, but they aren't being used on SpaceX so I'm okay if the quality and accuracy isn't the absolute best.

Last edited by Frame Maker; 02-02-2021 at 12:57 PM..
Frame Maker is offline   Reply With Quote
Old 02-02-2021, 01:03 PM   #92
auntiebling
megalomaniacal troglodyte
 
auntiebling's Avatar
 
BARF Moderator (ooh, fancy!)
Barfie Winner 2017
Contributor

Join Date: Apr 2004
Location: atop the parapet
Motorcycles: .
Name:
oooh. nerd speak. i can participate!?

Quote:
Originally Posted by GPzPop View Post
is there a weight advantage to cro-mo over mild steel tubing?
they have the same density, so unless you optimize every tube for needed strength vs material dimensions there will not be any weight change.

4130, the usual suspect when people say cro-mo (there are dozens) has significantly higher yield strength than mild steel. It Depends (the favorite phrase of engineers and those that like to be scienc-y) on which specific mild steel, and which heat treat condition the 4130 is in but it's safe to say 4130 is at least 30% higher yield strength. it can easily be nearly double.

it is a pretty complicated subject but if you're really lucky, a 30% weight reduction could be realized if the design were optimized for cromo. it would be a LOT of work just in the Figuring It Out stage, and as julian mentioned the material cost is higher, harder to work with in every way.

a reasonably easy way to observe this difference is with bicycles. a high end steel frame bike frame weighs 5 lbs or less. a department store bike frame of similar proportions will weigh 10, maybe more.

the difference is in the individual tubes. often the wall thickness varies along the length of the tube, thicker on the ends and thinner in the middle and quite thin to begin with. on the department store bike, the tubes have overall thicker walls, do not vary in section along the length.

for grins i looked at mcmaster carr (probably the most expensive place to buy but should illustrate the difference) using some arbitrary dimensions. today a 6 foot piece of mild steel 7/8" OD .0625 wall is ~$12

the identically dimensioned tube in 4130 is $38
__________________
no shirt, no shoes: No dice BARF TOS
every book is a children's book if the kid can read
-mitchbarf memes
my dad is an engineer
17/38 sprockets
CARB bikes list CA DMV fee calculators

Classifieds Forum Rules
Quote:
Originally Posted by Abacinator View Post
Love that subway tile backsplash, auntie
auntiebling is offline   Reply With Quote
Old 02-02-2021, 01:03 PM   #93
bergmen
Veteran
 
bergmen's Avatar
 

Join Date: Feb 2006
Location: Ukiah, California
Motorcycles: 2014 Yamaha FJR1300A
Name: Dan
As a Mechanical Engineer for the past 30+ years I enjoy attending the Frame Maker technical seminars here. I always learn something and thank you for taking the time to carefully explain everything!

In my experience, I had difficulty in accepting material certifications from Chinese fabricators. The ones I did receive appeared to be fabricated. I simply did not trust them (and I had corroboration from some domestic Chinese sources). As a result, I went with domestic fabricators with real, honest material certs. More expensive but quality guaranteed. Customer appreciated it as well.

Dan
bergmen is offline   Reply With Quote
Old 02-02-2021, 01:07 PM   #94
Frame Maker
Veteran
 
Frame Maker's Avatar
 
Contributor

Join Date: May 2011
Location: Livermore
Motorcycles: sportbikes, dirtbikes, and some odd bikes that I've built myself.
Name: Julian
Here's a mini project update.

Remember the frame revisions I was doing in CAD a few weeks ago. I had created an aluminum mid-frame and modified front engine mounting plates...

rz350 frame image 20210112.5 by andbike, on Flickr

Yesterday I received the 3D prints that I will use to verify these design changes before investing in CNC machined aluminum parts. The 3D prints are good insurance for catching potentially expensive mistakes before they happen.

20210202_115939 by andbike, on Flickr



Back of the side plates.

20210202_120159 by andbike, on Flickr



In the next few days I'll be doing some test fitting with the 3D prints and making any necessary adjustments to the CAD model.

Frame Maker is offline   Reply With Quote
Old 02-02-2021, 01:48 PM   #95
Frame Maker
Veteran
 
Frame Maker's Avatar
 
Contributor

Join Date: May 2011
Location: Livermore
Motorcycles: sportbikes, dirtbikes, and some odd bikes that I've built myself.
Name: Julian
Quote:
Originally Posted by bergmen View Post
As a Mechanical Engineer for the past 30+ years I enjoy attending the Frame Maker technical seminars here. I always learn something and thank you for taking the time to carefully explain everything!
Hah! Thank you



Quote:
Originally Posted by bergmen View Post
In my experience, I had difficulty in accepting material certifications from Chinese fabricators. The ones I did receive appeared to be fabricated. I simply did not trust them (and I had corroboration from some domestic Chinese sources). As a result, I went with domestic fabricators with real, honest material certs. More expensive but quality guaranteed. Customer appreciated it as well.

Dan
I can't say that I disagree, except to say that quality (and honesty) of Chinese manufacturing has improved in recent years. I'm still not 100% sure that I'm getting exactly the alloy that I specify. If I ever have doubts about a part with a very low safety margin my plan is to design a test slug into the geometry of the part. The slug will be connected by a very small web to the main part. That way I can break off the slug and test it compared to a known material of the same dimension. However, for the majority of my moto projects I feel comfortable with the quality.

Here's an interesting story that I'll add... A few years ago I was working on a small medical instrument that would be housed within an aluminum extruded housing. I was working with a local engineering team, but the end customer was a Japanese company. Since historically the Japanese don't like the Chinese, we were told to have the device manufactured anywhere in the world except China. This was great news at first. We were proud that we could have it MADE IN USA!.

Thats when the problems started. We sent out RFQs to several domestic aluminum extrusion vendors and made a selection. We kicked off the tooling and waited for samples to arrive. Well, we waited and waited and waited then finally samples arrived... and they were bad! This was the beginning of much more waiting, lots of poor communication, and more samples that weren't correct. Out of frustration we contacted an independent industry consultant and explained the problems we were having. His solution was simple... go to China and problems will go away.

I few years ago I was in China for a work related project and took a tour of a top tier aluminum extrusion facility. I have also toured domestic extrusion factories. The Chinese facility was amazing in the breadth of what they could do and the post opp services they offered were surprisingly sophisticated. The part I was working on was a very large and complex profile with multiple open and closed cavities. This was no problem to extrude except that we need an extreme bend formed on one end. They were ably to construct the most complex mandrel bending dies I have ever seen and successfully bent our parts to a very high degree of precision. It was very impressive to see and a pleasure working with them.

I am very proud to say that my experiences working in China have been amazing and I have made some very close personal friends there.

mmexport1553485015339 by andbike, on Flickr

Last edited by Frame Maker; 02-02-2021 at 02:01 PM..
Frame Maker is offline   Reply With Quote
Old 02-02-2021, 02:24 PM   #96
chrisweir.com
Home Loans for Riders!
 
chrisweir.com's Avatar
 
Contributor + + 2%

Join Date: Jun 2004
Location: Sacramento, CA
Motorcycles: *bikeless*
Name: Chris Weir
Thank you for this amazing content! I want to ride it!
__________________
Be kind, you never know what someone is going through
chrisweir.com is offline   Reply With Quote
Old 02-02-2021, 02:29 PM   #97
bergmen
Veteran
 
bergmen's Avatar
 

Join Date: Feb 2006
Location: Ukiah, California
Motorcycles: 2014 Yamaha FJR1300A
Name: Dan
I need to clarify - my personal experiences (with my own project, not the company's) was about 15 years ago. Forgot that it has been that long. Things have evolved dramatically since then and many sources are leading-edge hi-tech for sure.

Very interesting story on the extrusion company in China. I'm not sure where we source our extrusions (our vacuum manifolds on our gas phase mass specs are extruded) but they are of excellent quality.

Dan
bergmen is offline   Reply With Quote
Old 02-03-2021, 02:17 PM   #98
DannoXYZ
Veteran
 
DannoXYZ's Avatar
 
Barf Roadside Angel

Join Date: Apr 2006
Location: East Bay
Motorcycles: CB125T EX250E Ninja250R racer CBR250R-MC19 CBR250RR-MC22 NSR350R-MC21 VF500F CBR600RR VFR750
Name: Danno
As with any project, it's best to stay on top of specs. Problems I've had with any manufacturer was lack of detailed specs and making sure samples meet those specs.

About 20-yrs ago, I had some automotive EFI systems designed in NZ and manufactured in China. Along with friend who made high-end home-theatre equipment. Didn't stay on top of specs and first samples where horrible! I tightened up and made my requirements more stringent and results were much better. Similar to your 6061-T6 vs. T0 example.

A lot of urban-legend and stereotypes of bad Chinese products was due to greedy U.S. importers. Things like home/auto electronics, aftermarket auto/moto-parts, etc. So you've got Napa Auto Parts or AutoZone going to Chinese suppliers and asking for lowest-specs possible for cheapest costs. Then marked up as much as market will support for biggest profits. High failure-rates ensues and everyone (including politicians) points their finger at "Made in China" label.

The manufacturing-location is really irrelevant, it's specs the importer wants that determines how product will perform. Heck, you can get crap products made anywhere, Thailand, Germany, Poland, even in U.S.A!!! When I made headlight/wiring-harness upgrades for Porsches with 50-year warranty, I knew exactly which components and manufacturing processes were needed. It certainly wasn't made from stuff found on shelves at FLAPS.

Last edited by DannoXYZ; 02-03-2021 at 03:38 PM..
DannoXYZ is offline   Reply With Quote
Old 02-03-2021, 04:50 PM   #99
Joshman
-
 
Joshman's Avatar
 

Join Date: Apr 2009
Location: Oakland
Motorcycles: sv650
Name: Josh
I don't know how I missed this thread, but I'm glad I found it.

I'm excited to see the progress Julian!
__________________
______________________________________________
AFM #438
TWF Racing
Joshman is offline   Reply With Quote
Old 02-03-2021, 05:09 PM   #100
Frame Maker
Veteran
 
Frame Maker's Avatar
 
Contributor

Join Date: May 2011
Location: Livermore
Motorcycles: sportbikes, dirtbikes, and some odd bikes that I've built myself.
Name: Julian
Quote:
Originally Posted by DannoXYZ View Post
As with any project, it's best to stay on top of specs. Problems I've had with any manufacturer was lack of detailed specs and making sure samples meet those specs.

About 20-yrs ago, I had some automotive EFI systems designed in NZ and manufactured in China. Along with friend who made high-end home-theatre equipment. Didn't stay on top of specs and first samples where horrible! I tightened up and made my requirements more stringent and results were much better. Similar to your 6061-T6 vs. T0 example.

A lot of urban-legend and stereotypes of bad Chinese products was due to greedy U.S. importers. Things like home/auto electronics, aftermarket auto/moto-parts, etc. So you've got Napa Auto Parts or AutoZone going to Chinese suppliers and asking for lowest-specs possible for cheapest costs. Then marked up as much as market will support for biggest profits. High failure-rates ensues and everyone (including politicians) points their finger at "Made in China" label.

The manufacturing-location is really irrelevant, it's specs the importer wants that determines how product will perform. Heck, you can get crap products made anywhere, Thailand, Germany, Poland, even in U.S.A!!! When I made headlight/wiring-harness upgrades for Porsches with 50-year warranty, I knew exactly which components and manufacturing processes were needed. It certainly wasn't made from stuff found on shelves at FLAPS.
Yes, yes, and yes. My experiences have been very similar.

Even with good specs, its still funny what can happen. I'll never forget sending out drawings for RFQ to a domestic shop. The drawings had big bold text that clearly stated "FOR QUOTE ONLY". We didn't hear anything for a few weeks, then they finally called and said our parts were ready... that was super weird.
Frame Maker is offline   Reply With Quote
Old 02-03-2021, 05:13 PM   #101
Frame Maker
Veteran
 
Frame Maker's Avatar
 
Contributor

Join Date: May 2011
Location: Livermore
Motorcycles: sportbikes, dirtbikes, and some odd bikes that I've built myself.
Name: Julian
Quote:
Originally Posted by Joshman View Post
I don't know how I missed this thread, but I'm glad I found it.

I'm excited to see the progress Julian!
What the hell Josh? Well, I'm glad you found this thread... and your name should be at the top of the list for potential track test riders

PS- what's your preferred seat height on those yellow bikes you ride?
Frame Maker is offline   Reply With Quote
Old 02-09-2021, 09:48 PM   #102
Frame Maker
Veteran
 
Frame Maker's Avatar
 
Contributor

Join Date: May 2011
Location: Livermore
Motorcycles: sportbikes, dirtbikes, and some odd bikes that I've built myself.
Name: Julian
This past week's progress:

With the 3D prints now in hand, it's time to build a mock-up of the mid-frame and see how it fits to an RZ350 engine. In the shop I turn the cross tubes for the mid-frame. Some scraping with a utility knife is needed to smooth and remove a small amount of material from the 3D prints to get the aluminum cross tubes to a nice press fit. The 1/4" plate engine mounts and lower suspension mounts have already been laser cut a few weeks ago.

20210206_161119 by andbike, on Flickr


My aluminum welding skills are virtually non-existent, but I manage to tack weld the plates to the tubes and assemble the mock-up.

20210207_113335 by andbike, on Flickr

20210207_113403 by andbike, on Flickr


With the mid-frame mock-up completed, time to see how it fits... Oh Shit! It kinda doesn't fit. Well, this is exactly why I made the 3D prints before spending real money on CNC machined aluminum parts. So I'm glad to catch this interference early.

There is an area where the 3D printed side plate is interfering with the clutch cover. Using my Dremel with a small saw, I trim away some material and now the mid-frame will fit, although I don't like how the clutch cover is now captured under the plate and can't be removed with the engine in place.

20210207_142245 by andbike, on Flickr

20210207_150045 by andbike, on Flickr

I'll readdress this issue later and possibly make some design changes to the side plate. On the left side there is an interference with the left side engine cover. If I use the original RZ350 side cover the interference is significant, although the left side covers are plastic and can be trimmed. The interference is only in the area that covers the c/s sprocket so nothing structural or containing fluids would be compromised. If I swap to a Banshee left side cover the interference is very minimal. The RZ side covers are getting scarce while the Banshee covers are still available from Yamaha. So that will be the solution.

Also this past week more laser cut brackets arrived so I can finalize the seat mounts. I love how they blister pack everything so nothing falls out of the packaging. I've used laser cutting vendors in the past who possibly never had customers from remote locations and their packaging was horrible. Anyway, the flat brackets are easily formed to final shape.

20210207_134904 by andbike, on Flickr


One bracket is for the center tongue on the seat. The other brackets are for the rear screw mounts. The rear brackets are intentionally long and require some sanding to remove material for final fit.

20210208_121011 by andbike, on Flickr

20210208_132508 by andbike, on Flickr



Then a few tack welds to confirm fit, followed by final welding and the seat is ready to be mounted.

20210208_141213 by andbike, on Flickr

20210208_143347 by andbike, on Flickr


When I first started building frames I would use rivet-nuts any place where I couldn't access the back side to place a normal nut. Now I like to use these clip-nuts. They work very well and if they ever get stripped or damaged just throw away and use another one. Super handy.

20210208_160246 by andbike, on Flickr


I have a fiberglass tail for a KTM cup bike that I like the shape, however it doesn't fit to the R6 seat very well. For now I'll use a Yamaha replica tail just to see how the bike will look with a race tail. At first I try one based on 99-02 R6 to see how it looks.

It looks much better than the utility rack I had used for the Dirtbag ride, but it still looks kinda clunky.

20210209_114305 by andbike, on Flickr

20210209_114644 by andbike, on Flickr

Next I try a replica tail for a 03-05 R6. Its a little lower and seams to follow the styling of the tank much better. This is an improvement and I'm finally starting to get aroused by how the bike is looking

20210209_145410 by andbike, on Flickr

The long term goal is to sculpt a tail that fits properly to the R6 seat, but has the rear portion based on the KTM cup bike tail. But that effort will wait. For now the priority is getting the frame re-design finalized.


More to come...
Frame Maker is offline   Reply With Quote
Old 02-10-2021, 06:27 AM   #103
kpke
Veteran
 
kpke's Avatar
 
Contributor +

Join Date: Apr 2011
Location: Livermore
Motorcycles: many 2 strokes 06 R1 LE 158
Name: Ken
This is looking excellent. Really quite unbelievable to start with metal tubes (and other things), get bits and pieces ordered and fabricated from all over the world, and end up looking like this. Thanks for the update.

If I may ask, why a wizard fabricator welder dude like you has difficulty with welding aluminum?
kpke is offline   Reply With Quote
Old 02-10-2021, 07:36 AM   #104
auntiebling
megalomaniacal troglodyte
 
auntiebling's Avatar
 
BARF Moderator (ooh, fancy!)
Barfie Winner 2017
Contributor

Join Date: Apr 2004
Location: atop the parapet
Motorcycles: .
Name:
That laser vendor has been pooping up on my facebook feed... I just dont need to laser cut stuff I want to try!
__________________
no shirt, no shoes: No dice BARF TOS
every book is a children's book if the kid can read
-mitchbarf memes
my dad is an engineer
17/38 sprockets
CARB bikes list CA DMV fee calculators

Classifieds Forum Rules
Quote:
Originally Posted by Abacinator View Post
Love that subway tile backsplash, auntie
auntiebling is offline   Reply With Quote
Old 02-10-2021, 08:08 AM   #105
bikewanker
Veteran
 
bikewanker's Avatar
 
AMA #: 178394
Contributor ++++++++++++1%

Join Date: Mar 2006
Location: Eastern Sierras
Motorcycles: TR-650x2, , Rapid Taxi RR, Tiger 1050, ZX-6r, '81 1002 F
Name: chris
Even with more coffee it’s mostly beyond my comprehension how you’re fabricating a frame Julian! Have enjoyed following this process. For me it’s kinda like a Playboy magazine, I gots to have pictures to understand.
Thank you.
__________________
Originally Posted by nebulous
“Being offended by the past using today's sensibilities, or un-sensibilities as it were, is disgusting”

"tis better to wank here than in the hereafter" M.S. Murphy.
"Rivers and roads lead people on" Georgia O'Keeffe

Be Well Ride Well
bikewanker is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -8. The time now is 12:46 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2021, vBulletin Solutions, Inc.