Claud Butler Frame Numbers

[VeloFellow54]

Judging by the number of queries relating to dating 'real' Claud Butler frames that keep appearing both here and elsewhere, I am posting this in the hope of generating some interest in this topic. OK - so we are talking frame numbers for the period up to the Holdsworth takeover - i e genuine CB's. The period after 1951/2 seems quite straight forward. 2 rows of numbers under the BB and on the steerer tube. One the frame number - the other the date code. I have a 'Massed Start' model with codes 518 over 4183. The 518 denotes a manufacturing date of August 1951. Simple !!
However, what of frames from the late 40's (or earlier) ? I have a lugless frame (ca.194 with simply 8104253 - and I have seen other similar period CB frames with frame numbers like : 91651 or 111742 or 883499. There appears to be no logic here at all.
So - maybe it is time that we made an attempt to sort out this numbering problem once and for all. I invite all CB owners of frames pre say 1950 to post their frame numbers with a picture and brief description. Let's see what results from this. Maybe we can sort this mess out !

 

[SullyW5]

Re:

Great idea!

Here is what I suspect to be a 40's CB frame:

http://s666.photobucket.com/user/Sulleb ... 0CONFUSION

Frame Number: 2101147

Would love to get confirmation and heaven forbid, a build year!

Sully

 

[VeloFellow54]

I have made some progress with this in as much that it seems that the first 2 or 3 numbers of a CB frame should give the date - Examples 91651 - would be January 1949, 883499 - would be August 1948 - 111742 - January 1951 - or is it November 1951 (These are all from actual frame) However, I find it odd that if the date numbers are deducted the numbers remaining make no sense at all. Still more work to do.
I have studied the photos of your frame and have to confess I cannot identify. There are certain similarities to a lugless CB 1940's (or even pre war) frames, but there are some areas that I have never seen on a CB - the collar at the top of the seat tube by way of example. I have never seen anything quite like this ever before. CB were not the only builder to fillet braze frames. There was a shortage of frame lugs after WW2 and the options were make your own or find another way. The fork crown on this frame would seem to indicate early post war.m I am no expert though - so you should treat what I write with caution.
I would post pictures on here and and ask for help - someone out there will know what you have.
Steve

 

[OldTel]

Re:

Hi, I believe as a generalisation, during the thirties and forties the first digit is the year and then the month, and then the number. I've not seen this pass 1950, where I believe it switched to a two digit year. The troublesome ID's are late 30's, late 40's ones, as not a lot changed between, and the same materials were used. Terry