FEATHERBED RAKE ANGLE

3 Things.

Norton frame lugs weren't investment cast - that is a much later development, from the recent bicycle industry ? They weren't steel either. Cast steel was a rare commodity, until quite recently. No other maker used investment cast (lost wax) frame lugs either, where cometh this information ?

The WHOLE FRAME was placed in the oven and heated, not just the individual joints and lugs (of which there were many) so the whole frame got pretty hot.

With all the lugs, and drilling and tube fitting and gas furnaces, this wasn't done to be "cheap", it was because no other method of frame making had yet been made reliable.
With a patternmaker, mould maker, furnace operator, and all the casting cleaning and drilling operations, calling this "unskilled" is just...
WW2 welding developments changed that, of course, (and simplified and cheapened it ?) but not in the Norton world until the welded featherbed came along...

P.S. At 440 lbs dry, the Model 7 wasn't exactly light.
Although not just the ultra heavy frame was responsible, that iron head weighs a ton...

Rohan said:

Reading the very first post may help... ?

Click to expand...

Yep, that clears up things but does not account for the replies, you may as well pick a number out of thin air and go with it :wink:

Jean

True.
But 26 degrees and 24 degrees for a slimline are the numbers quoted in various sources, including in Roy Bacons books and the sketch on the NOC - that have around for some years.
If these are correct, or not in fact the case. then how these came into being is of interest ?
If the frames were not built to the blueprints, that is getting just......?
Kens book is going to be interesting - if it throws any light on this.
All just history of course, and there are now more featherbed copies than ever, built to who knows what spec , to add to the story.

So why not go with 25 degrees :?: right in the middle between 24 and 26 degrees :wink: after all, who will know except you and your last will if you get it notarized :roll: It will most likely handle just fine.

Jean

Says somewhere back a few posts he has decided to go with 26 degrees.
Be interesting to hear how it rides.
Might now have the slowest steering slimline in creation ?!

Or the least unstable daragging a peg though the S'ss at Ton Downt Bipass .

From the following;
http://www.ntnoa.org/General2.htm
The Origin of the Famous Norton Featherbed Frame
The Norton featherbed frame was created around an old fashioned long stroke single cylinder engine with a very top heavy cylinder head. The size of this engine dictated the space between the top and bottom rails of the full duplex cradle. In retrospect the result of this early effort enabled all kinds of engines using all kinds of configurations to be installed ion to this versatile and robust frame. Originally, it came with a bolt on rear sub frame which eventually got welded up particularly when the bolts came loose. Over time there where 3 major versions of the frame. These 3 major groups came in the bolted and welded variety.
a. The Manx racer in Reynolds 531 chrome moly.
b. The single overhead cam International in grade A mild steel.
c. The Dominator twin frames in grade B mild steel.
Then there where 2 subdivisions in category a. 16 gauge tube for the 500cc and the 17 gauge tube for the 350cc. Tube gauge is important so don't go putting a 500 in a 350 frame.
Then in category c.. in about 1959 or 1960, Norton put the old single cylinder Model 50 (350cc) and the ES2 (EaSy2, 500cc) into the featherbed to rationalize frame production. As you can see there where quite a few variations on what looked to be the same frame. Intact they came off the same jig. 1960 was the year the top rails where installed at the rear of the tank. This wasn’t just an Atlas mod, it was across the board. At the same time the tank design and its badges where changed.

the Dominator twins frames were made from 1-1/4" x 2mm CR seamless tube, a strange size which is normally not available off the shelf, I happened to stumble across a bundle of about 60 or 80 lengths cant remember and purchased and proceeded to
build an exact replica of the 60's frames. those frames who ever built them for Norton were stick welded coz some of the frames I used for jig making still had some of the welding flux stuck to the welds in inconspicuous places, I mig welded mine .

madass140 said:

those frames who ever built them for Norton were stick welded coz some of the frames I used for jig making still had some of the welding flux stuck to the welds in inconspicuous places, I mig welded mine .

Click to expand...

Indeed - electric welding with stick on all the road featherbed frames - we've had this discussion here before,
and I showed a pic of the obviously electric welded frame joints, complete with flux/spatter.

Bernhard said:

From the following;
http://www.ntnoa.org/General2.htm
.

Click to expand...

Who is the author of this, when was it written and what were his sources though. ?

It is obvious, with the benefit of 20/20 hindsight, that about all motorcycle histories are folks quoting folks quoting folks.
When new genuine info comes to light, is it just a game of chinese whispers though.... ?

We could also comment that there should be a type d) for the slimline frames.
To lump them in with the roadgoing widelines is just silly,
they are clearly a different frame.

We could further comment that there are quite a number of variants in each of the a b c and d type frames, for the about 2 yearly update cycle,
so all up there are more than 20 variants of factory featherbed frames - that customers could buy.

Rohan said:

Bernhard said:

From the following;
http://www.ntnoa.org/General2.htm.

Click to expand...

Who is the author of this, when was it written and what were his sources though. ?
It is obvious, with the benefit of 20/20 hindsight, that about all motorcycle histories are folks quoting folks quoting folks.
When new genuine info comes to light, is it just a game of chinese whispers though.... ?
We could also comment that there should be a type d) for the slimline frames.
To lump them in with the roadgoing widelines is just silly,
they are clearly a different frame.

We could further comment that there are quite a number of variants in each of the a b c and d type frames, for the about 2 yearly update cycle,
so all up there are more than 20 variants of factory featherbed frames - that customers could buy.

Click to expand...

http://www.ntnoa.org/index.htm
is in Texas –I have absolutory no idea whom the author is, this is only a general guide that I found on the internet -it is hardly going to be the A-Z of all the frames made by Reynolds for Norton as there are a lot of omissions that the author did or did not know about, like the 500 lowboy Domiracers with smaller diameter tubes in 531, or the special one off Norton frames built for (amongst others) Geoff Duke and the like.
Reynolds build one off frames frames for NSU, Velocette e.t.c
They even build frames for scooters like the Dayton Albatross;
http://www.britishscooters.com/gallery/ ... albatross/
read all about it in Ken Sprayson book “ the Frame Man” •ISBN 978 0 9564975 6 7.

http://www.realclassic.co.uk/books/ken_ ... e_man.html

re; “It is obvious, with the benefit of 20/20 hindsight, that about all motorcycle histories are folks quoting folks quoting folks .When new genuine info comes to light, is it just a game of chinese whispers though.... ?” & “so all up there are more than 20 variants of factory featherbed frames - that customers could buy.” Quote.
Unless you refer to each frame (this is referring to the road going versions only-NOT racing) chassis number by chassis number and the model it was made for i.e 350 single or 500 single e.t.c (Pushrod engine) you could talk all day till the cows come home on the different types of frames that where produced and whether or not a 650 engine will fit into a 750 frame or even a 350 frame made from lighter tubing that was not designed to take a 650 engine –I could go on………..but I won’t life’s to short.

So the nett result is we are none the wiser. ?
And there are still more than 20 different versions of featherbeds that Nortons (Reynolds) made for different models of out-of-the showroom Norton bikes for customers...

I've recently had reason to revisit this topic. I note the mention of two rake angles 64.5 degree and 64 degree used with featherbed frames. That would be the difference I would expect from changing a manx from 19 inch to 18 inch wheels, if you did not want the steering to become more heavy (stable). As I understand it the manx with 19 inch wheels has 64.5 degree rake.

Sorry , I have a habit of always subtracting the rake from 90 degrees - in the terms you were using . The common rake used on Japanese two stroke is 26 degrees with 18 inch wheels and it is usually neutral handling . A manx uses 24.5 with 19 inch wheels with 18 inch wheels it would probably need 25 degrees using the same offset fork yokes as a manx, if you wanted the same handling. Going from 19 inch to 18 inch wheels make the handling heavier and more stable which is what you would expect with some road bikes. Half a degree more rake would move the handling slightly more towards self-steering - less stable.
I think the Domiracer probably had 18 inch wheels and the shallower (25 degree) head angle.
Modern manufactured Australian manx frames often use 26 degree head angles with 18 inch wheels and normal manx offset yokes - they handle like Suzuki two strokes.

The tension on the head steady is an important item on a featherbed frame.

Personally I asked Mr Sprayson when I wanted to know what It was on the Domirace frames Reynold Tubes / he manufactured for the Norton race shop....26 degrees as per Manx etc. It is also shown as 26 degrees on the Manx frame drawing I was supplied with by Mr Sprayson. I could I suppose ask Mr Sprayson if it was any different on the slimline frames but I choose not to disturb him or his wife and phoned a younger Gent instead and his comment was ' Well its 26 degrees on all the slimlines I have ever manufactured and repaired' . He finished the latest new slimline the other week. And no neither of us can understand why anyone would want one when they could of had a Manx frame made out of 17 g T45 or 16g T45 or even 14 g CDS / gas pipe tube for a much safer road going look alike suitable for use with a girlfriend on the rear! (OOPS, in these modern times where total incompetence runs Britain I should of included boyfriend).
For those following the latest news on the gigantic UK Ministry of Defence / so called UK government cock up regarding the 'old' new type 45 destroyers I notice there is more news in the latest edition of Private Eye. Funny how such news does NOT make it into the national press and TV....... I wonder who recommended the equipement that is causing the problems? Was it BAE or was it perchance an Mod / British misgovernment purchasing decision? My money is on the Mod and UK government in an effort to get so many to leave the Navy that they can use the excuse of having no one to mann ships they can scrap the lot Of course when we make the decision to tell the EU to take a running jump..for better or worse...how the hell are we going to protect our fising grounds from the Spanish or even our oil fields ..those that have not run out that is..... Anyone remember that Labour TOSSER who on the BBC news held up in a plastic beaker some of the first North Sea oil to come ashore stating that North Sea oil was going to give the UK economy the money it required to give the country an infrustructure worthy of the 21st century?? Funny how people forget details like that.........Some of us may not be able to find our way home and get lost easily but we remember such bullshit Remember that other one about the pound in your pocket?? Mind you whats the Pound against the Dollar these days?/ 1.42......wasant it 1.62 not long ago?? Clearly the government are devalueing the pound yet again.... I had better order some kevlar clutch plates from the USA tonight!!!

Thanks for the update on the state of the world JM, you are sounding more like Mr Trump every day. !

But we do agree on something - 26 degrees.
That has been belted around here for a number of years now.
Alan just hasn't caught up yet...

Just to put off going into the workshop to produce a T140 diaphragm spring clutch belt system that a friend thinks is going to be ready for him to pick up on Sunday I did a bit of swearing till I found a folder marked REYNOLD. A special BSA A65 frame drawing shows the head stock at 26 degreees but it is 27 degrees on the special frames made for Percy Taits 500/650 Triumph bikes.

This thread seems to go on forever, so I might as well add the little info I have. Not repeating what someone else has said, but real measurements on real frames. I own two featherbed frames, one wideline (1959) and one slimline. Haven't checked the serial on the slimline yet, so no year or model. No signs of crash damage or repair to either one, so the head angles should be original. The head angle on the wideline is 26 degrees, and on the slimline 24 degrees, accurate within 0.1 degrees, just as Roy Bacon claims.

For clarity, all head angle measurements are relative to the line of the lower frame tubes, just like in the factory drawings. I see references here to head angle being affected by tire size, but I don't think that's really correct usage. Head angle is a fixed property of the frame, referenced to the geometry of the frame, e.g. the line of the lower frame tubes in the case of featherbeds. Rake, or castor angle, is the angle referenced to the ground the fully assembled bike is sitting on, and is affected by tire size, shock length, fork tube location, etc.

I don't claim anything about these values except that they are correct for the two frames I have. I'm sure there is at least some variation over the years of featherbed production.

Ken

I have just come off of the phone to Mr Sprayson and asked about head angles on all Reynold produced Wideline, Manx and Slimline frames.
ALL were manufaxctured with the same head angle of 26 degrees.
Mr Sprayson told me that a great many years ago when this discussion raised its head for the first time he checked with the Reynold production people who confirmed to him that all were produced to 26 degrees.
Mr Sprayson also stated that any frame with a 24 degree head angle is bent and that it was so easy to do, requiring little effort to do and was so common that Renold offered a cheapo quick straighening service for customers.
It should be remembered that the frame was originally designed as a race frame and NOT a road frame and that Reynold simply produced them to Norton supplied drawings and that they Reynold had a policy of 'the customer is always right so thats what we will produce' along wwith a policy of not offering advice to customers unless it was specifically requested by the customer when it would be given based upon their decades of experience......
Take a look at that Jubilee frame post and note the tube triangulating the headstock rather than a crappy bit of steel plate attached to the frame in two places by non fitting fixing employed by Norton. I cannot help but wonder what the featherbed frames would of been like had Reynold been asked to apply their vast experience of tubular frame design and construction to the frame.
You only have to remember the total design cock up of the original Commando frames and how easily the main spine and down tubes failed to realise Norton knew VERY LITTLE about the subject..especially when mismanagement employed a Gentleman with NO experience of motor cycle frame design to do it!! Designing bits for the nuke industry does NOt make one an expert in motor cycle frame design. Even Mr Hopwood knew he was not a frame expert and would on occcasion invite a Renold Gentleman over to visit him in his office and on the drawing board in full view would be a proposed frame design for the Reynold Gentleman to fail to resist casting his eyes over to spot and point out the 'deliberate' errors......
If a frame gives anything but a 26 degree head angle run a straight edge up the back of the down tube and find out where the bend is...... thats why Norton added that gusset plate to road frames.