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Offline babyfood1217

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one-off frames?
« on: August 12, 2006, 12:08:06 PM »
So, say a person with way too much time on their hands and access to the right equipment for building/aligning a frame, where would this person acquire materials?  Tubing to be specific.  I'm getting antsy to try building a trellis-type frame, but I haven't a clue where I can get the right size tubing.  Any thoughts?

-Chris
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I need help moving my project bike from Wisconsin to Seattle, WA.  Willing to pay well.  Contact if interested.

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Project: 1976 CB750K
GSXR forks, Monoshock Rear end, 836 in progress, RC51 pipes, custom frame and everything else.

Offline angeldeville

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Re: one-off frames?
« Reply #1 on: August 12, 2006, 12:23:24 PM »
there is a certain steel alloy that is best for frames but I can't recall the ###. Just be sure you are working with an experienced frame builder. A frame isn't something you want coming apart at 90mph.

And post pics!
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76' cb750f custom
69' cb750 sandcast
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Amen Saviour 750 Chopper frame
and enough parts to build about 6-7 more bikes

Offline hondachopproject

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Re: one-off frames?
« Reply #2 on: August 12, 2006, 03:42:13 PM »
I got tubing (not pipe) from a Welding Fabricator.
I found I had to go to "fabricators" not justs "Joe's Welding" shops to get the correct tubing.
They fabricators should be able to help on this.
Lee
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Offline Tommy Neimeyer

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Re: one-off frames?
« Reply #3 on: August 12, 2006, 05:36:25 PM »
Custom frames are usually made of 4130 chrome moly but it can be difficult to work with and needs to be post weld heat treated to relax the grain structure and keep from cracking.  Although a lot weaker, mild steel tubing can be used.  I have bought some tubing from this place...

http://www.aircraftspruce.com/menus/me/steel.html

Some of the problems in making a frame are keeping it square, getting the steering head straight and at the correct angle.  Additionally, placement of the swing arm pivot is critical to proper handling.  The tubing will need to be notched which is very time consuming and then welded.  Most custom frames are either gas welded or TIG welded (Heliarc).  Welding the acute angles of the frame joints is a challenge.

There are several good books that are about Race Cars that have info that applies to mototcycles.  One is Race Car Chassis Design and Construction by Forbes Aird and the other is Engineering to Win by Carroll Smith.

Another great book by Carrol Smith is Nuts, Bolts and Fasteners.  Info about millions of fastener.

I will attach a neat tube framed Aremachi I saw at Willow Springs a few months back.

Good luck and keep us posted.
Cheers, Tom
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Offline Tommy Neimeyer

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Re: one-off frames?
« Reply #4 on: August 12, 2006, 05:48:07 PM »
Some of you will notice the CB550 in the background.  It belongs to Dr. Tom Marquardt.  He races it in the AHMRA Series.  I helped him race at Willow Springs and Mid Ohio this year.  We got a total of 2-1st and 1-3rd place in 4 races.  We ran out of gas while leading the 4th race (yes a stupid mistake).

The bike is a "period racer" from 1978-1980.  It has Morris Magnesium wheels, magnesium fork lowers, braced swingarm and a 692cc SOHC/4 (550 stroke/750 cylinders and some magic machine work).  It has a set of 31mm CRs to ensure it gets all the gas it needs.  It is a very nice bike that scoots very well.

The tall guy in the previous picture is Dave Roper, a well known (and successful) racer and member of Team Obsolete.

Cheers, Tom
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Offline Lumbee

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Re: one-off frames?
« Reply #5 on: August 12, 2006, 06:30:44 PM »
DOM tubing is usually the choice of chopper builders.  My impression was that it is stronger than chromoly, though I can't speak to it...
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Boomologist

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Re: one-off frames?
« Reply #6 on: August 12, 2006, 06:35:34 PM »
Years back a friend built a frame using square box tube. Looked a little strange but worked quite well.
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Offline Tommy Neimeyer

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Re: one-off frames?
« Reply #7 on: August 12, 2006, 07:18:54 PM »
I may be wrong, but I think DOM stands for "Drawn over Mandrel" a manufacturing process.  DOM mild steel tubing like 1010 have about 30,000 psi bursting strength with 1028 having closer to a 70,000 psi bursting strength.  DOM 4130 tubing starts out at 60,000 psi bursting strength and can be increases to 90,000 psi with heat treating.

There a lot of frames made from mild steel and there is nothing wrong with it.  It is easier to bend and weld.  4130 is used a great deal in aircraft manufacturing where strength and weight are prime considerations.

Additionally, there is "Seamed" (ERW) and "Cold Drawn Seamless" and "Hot Drawn Seamless" types of tubing.  Cold Drawn Seamless is very expensive and the best quality (though not needed for a bike frame).

I'm pretty sure that the NHRA requires the use of 4130 in Dragster and Funny Car Chassis construction while also specifing a minimum OD and wall thickness. 

Cheers, Tom
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Offline MRieck

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Re: one-off frames?
« Reply #8 on: August 12, 2006, 07:22:24 PM »
Quote from: TomN on August 12, 2006, 07:18:54 PM
I may be wrong, but I think DOM stands for "Drawn over Mandrel" a manufacturing process.  DOM mild steel tubing like 1010 have about 30,000 psi bursting strength with 1028 having closer to a 70,000 psi bursting strength.  DOM 4130 tubing starts out at 60,000 psi bursting strength and can be increases to 90,000 psi with heat treating.

There a lot of frames made from mild steel and there is nothing wrong with it.  It is easier to bend and weld.  4130 is used a great deal in aircraft manufacturing where strength and weight are prime considerations.

Additionally, there is "Seamed" (ERW) and "Cold Drawn Seamless" and "Hot Drawn Seamless" types of tubing.  Cold Drawn Seamless is very expensive and the best quality (though not needed for a bike frame).

I'm pretty sure that the NHRA requires the use of 4130 in Dragster and Funny Car Chassis construction while also specifing a minimum OD and wall thickness. 

Cheers, Tom
Mild steel is plenty for this old stuff.
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rick1956

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Re: one-off frames?
« Reply #9 on: August 13, 2006, 06:59:40 AM »
Chris, Not sure if your in the US or Europe? I'm an old machinist in California. You can find steel tubing from the same suppliers that machine shops buy raw materials from. Check in the phone book under steel suppliers or fabrication. Be sure you are buying the correct type of steel, mild steel is called 1020 which is too soft for a bike frame. Tell the supply shop you want it for a motorcycle frame and they will recommend the right thickness and Rockwell hardness. Crome molly tubing may be good, but with newer alloys and carbonfiber materials the only limit is your wallet. Good luck

Rick
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rt

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Re: one-off frames?
« Reply #10 on: August 13, 2006, 09:57:41 AM »
Hiya babyfood1217,

maybe there's your answer..  :)    http://www.millerwelds.com/education/articles/articles70.html

success...
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Offline babyfood1217

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Re: one-off frames?
« Reply #11 on: August 13, 2006, 12:29:13 PM »
I guess this is what I was thinking, and remember, this is all in dream phase (college kid budget):  Using the jig I would fabricate, I would tack weld the frame together, and have it finished up by one of the decent bike shops near me.  I trust my welding, but my life isn't something I joke around about.  I would figure out the headtube angle and swingarm placement based on the fork I plan on using and the wheelbase/rear shock (monoshock?)  I was hoping to use a basket-frame to cradle the tank above and the engine below.  I have access to a kiln large enough to do the heat treating, and actually have something as an instructor who knows about heat-destressing.  I figure alot of the frame materials I could slowly purchase, and random bits would accumulate off of eBay.  I would hope to keep most parts Honda based, but who knows.  I have a feeling the engine would be a mod'ed 750, but I don't know of the best options for that (I smell some archive research beginning.)  I think it could be a fun project, and who knows, maybe it will even happen.  I'll start taking random parts donations. ;) 

First up:  engine - 750 - condition: siezed to all hell, but together enough to provide mounting references.

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I need help moving my project bike from Wisconsin to Seattle, WA.  Willing to pay well.  Contact if interested.

SOHC member: #438

Project: 1976 CB750K
GSXR forks, Monoshock Rear end, 836 in progress, RC51 pipes, custom frame and everything else.

Offline Lumbee

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Re: one-off frames?
« Reply #12 on: August 13, 2006, 01:58:12 PM »
...if anyone is interested in free plans for a jig go to http://www.crimescenechoppers.com/jigplans.html ...
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Offline Tim2005

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Re: one-off frames?
« Reply #13 on: August 13, 2006, 02:36:44 PM »
There's always Reynolds tubing, their 531 was used for Rickman and Seeley frame, among others, and I see they now do a number of stronger lighter types too, site here    http://www.reynoldsusa.com/     

A titanium lattice frame would be pretty neat, somewhat beyond my welding skills though. 
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