[CR][bi-lam] My version 3 of 4

(Example: Framebuilders)

Date: Sat, 31 Jul 2004 07:55:05 -0700 (PDT)
From: "Norman Kilgariff" <nkilgariff@yahoo.com>
To: classicrendezvous@bikelist.org
In-Reply-To: <CATFOODikJcnlMOxpyH000046b6@catfood.nt.phred.org>
Subject: [CR][bi-lam] My version 3 of 4

Bi-lamconfusion, the plot thickens:

Mick's Posting 23 May 2004 ********** ...Tom Board served his frame building apprenticeship with Harry Rensch at Paris Cycles also Ken Janes worked for this company. Rensch were the pioneers with Bi-Laminate frames (CB spelling). So I should think they would know what the true definition of a bilam is. ------------ my response ----------- That doesn't really follow. They pioneered a new type of construction, but it was Claud who adopted the name bi-laminated. If Claud and Harry were competing they may not even have discussed it. If Harry and Claud pioneered the method, they have every right to choose their own names for it, however they do not become chief definers for the whole trade. Neither Claud nor Harry had any say within Holdsworthy or Hetchins regarding the naming of their lug embellishment methods, Hetchins call their lug extensions 'Tangs'. --------------- Mick continues----------------- ...If that's not good enough for our Kiwi cousins who are supposed to speak the same language perhaps the Oxford dictionary will help clear this one up. Laminate 1. Beat or roll (metal) into thin plates. 2.Overlay with metal plates. 3. Manufacture by placing layer on layer. 4. Split into layers or leaves. 5. A laminated structure or materials, esp. layers fixed together to form rigid or flexible material. ----------------- my response --------------- The word laminate has different meanings, depending on how it is used, they are all given above, but it may be best explained. A lamina is something that has a significant area but is thin. The plural is laminae (laminas USA?). A chess board, a chapati or a thin pizza base, are all laminae.

If you take a piece of metal, which is too thick to be considered a lamina, and you beat or roll it, or do anything else to it such that you make it thin and wide enough to be considered a lamina, then you have laminated it. Here to laminate something is to turn it into a lamina. That is definition 1 above. In this context the term Bi-Laminate would not make sense, so we try another.

If you take a solid cube it is clearly not a lamina. If you slice it into 100 parallel slices, you have made 100 laminae. This is definition 4 above "To split into layers or leaves". In this context Bi-Laminate would mean to split something into two laminae, which again does not apply in our context. In both the above, something that is not a lamina, gets turned into a lamina or laminae.

Definition 2 is appropriate. Laminate= "Overlay with metal plates" but we must take care, this does NOT mean that the metal plates are the laminates. Making this error, Mick wrongly deduces that to bi-laminate must be to overlay with two or more metal plates. But 'bi' means 2, not two or more but 2 exactly. A bi-lam frame can have 5 or more sleeves added. The bi here, applied to dictionary def 2, refers to the number of layers in the final structure, definitions 3 and 5 explain it. But let me return to this, because if you think Mick has erred just wait until you see Claud.

If you take a slice of thin bread (a lamina) apply jam (glue) then another slice of bread you have a structure known as a laminate. As the structure consists of 2 bonded laminae, it is bi-laminated (2 layered, or a bi-laminate (2 layered structure). Stick on another slice and it is a tri-laminate. This conforms to definitions 3 and 5 above "layers fixed together to form rigid or flexible material". They have to be one on top of the other, in a stack, to increase the order of the laminate.

If you lift the upper slice of a sandwich, half it and replace the halves side by side on top of the full slice, it is still a bi-lam as there are still two layers to the structure (the glue being ignored). There are now 3 laminae involved, a slice and 2 half slices, but the structure is only 2 laminae thick, so it is still a bi-lam. It is just a case of counting the layers. This model explains bi-laminated frames as follows:

The metal that is cut forms a lamina. It will be curved round and bonded to a tube, which is itself a curved lamina. The structure is therefore a bi-laminate and the process is bi-lamination. You can apply as many sleeves as you like to the tube at different points, as long as no sleeve overlays any other sleeve it would remain a bi-laminate, alternatively called a bi-laminated construction.

A simple definition for any laminate is 'layered', a bi-laminate is two layered, albeit the layers must be laminae and not just any glued on little chunk of material. It is a term used in very many fields.

The sleeve is a lamina as is the tube, the act of bonding them together is lamination which creates a laminate (or laminated) structure. No prefix is necessary, but one can be used to emphasise the numbers of layers in the laminate. Claud prefixed everything with 'bi'. A bi-laminated structure, achieved by the process of bi-lamination.

With the dictionary it seems easy, but if Claud used the dictionary at all, he misunderstood it. I wonder if somebody else gave him the name. Instead of referring to a 'bi-laminate' he uses the terminology 'bi-laminated construction' and leads himself astray. ...If the frame is now bi-laminated what has bi-laminated it? The application of a sleeve did, so the sleeve must be the bi-lamination. Glue even one bi-lamination to a tube and you have bi-laminated it!

In Claud's 1951 cat, he talks of bi-laminated construction, and that's fine because when you bond a sleeve to a tube it IS bi-laminated (2 layered), and the process IS bi-lamination. Unfortunately Claud appears to confuse the process name with the sleeve name. The sleeves are laminae, the process is bi-lamination, but unless I am missing something he seems to think a single sleeve is a bi-lamination. He shows a headtube shot, with only two sleeves showing, he refers to the 'bi-laminations' (plural). This simple misnomer or misconception leads to crazy scenarios.

How can one sleeve be a bi-lamination when bi means two and lamination means creating a layered structure, when there is only one and it is not layered? It's bonkers. He cannot mean one sleeve is a lamination so a pair makes a bi-lam, because there can be any number of these, even an odd number, on a frame. Also, the Southerners talk of cutting a bi-lam (singular) and Claud uses the plural when showing two.

If bi-lamination is Claud's revolutionary new construction method, how come it's just a small metal sleeve? If a sleeve is a bi-lamination, and if that means a lug extension is a bi-lam too, how does a lug extension enhance the frame strength 25%? When Ephgrave brazes-up a lugged frame, is it classed as lugged (brazed) construction until the lollipop goes on, at which point it transforms into a revolutionary bi-laminate? How much extra strength does this lolly give? Should we send one to the Nat. Phys. Lab for testing? What flavour should we send? It's a real hoot.

We cannot blame the Southerners for Claud's use of this word. I prefer to call them sleeves. Bond any number of sleeves directly to the frame as you like, that's bi-lamination, you have made a bi-laminated frame. However, only by fitting them to the tube ends of a lugless frame will you significantly increase frame strength, a central claim Claud makes for bi-lamination construction.

I think cycledom has embraced the bi-lam concept and relaxed about the wording. The Southerners have held on to Claud's wording, lost the concept and completely lost the plot (re lug extensions). In my last post I will demonstrate this and suggest a model to proceed with.

Norman Kilgariff (Glasgow, Scotland)

__________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com