Author Topic: Assistance with M21 frame  (Read 498 times)

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blackdog

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Assistance with M21 frame
« on: 02 July, 2017, 14:04:01 »
Hello

I am putting an M21 frame together and am baffled by an extended tube on the nearside chainstay location. This extended tube makes the distance between the two sides too long for a standard stud to go through. The bike was in bits when purchased so I have no idea what its for. Before I grind it off does anyone have any idea why it may be there?


JulianS

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Re: Assistance with M21 frame
« Reply #1 on: 02 July, 2017, 14:38:04 »
It should be there dont cut it off before you have done a test assembly of the bike. I think it is for  the brake pedal.

Photos shows M20/21/33  plunger frame.
« Last Edit: 02 July, 2017, 15:02:23 by JulianS »

blackdog

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Re: Assistance with M21 frame
« Reply #2 on: 02 July, 2017, 18:19:45 »
Thanks for the response, The brake pedal that came with the bike will not fit the tube as the hole diameter in the pedal is too small. I have also purchased the chainstay stud and this is too small in length by about the extra tube length mentioned. I am assuming both the stud and the pedal are the correct parts however........  ::)

JulianS

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Re: Assistance with M21 frame
« Reply #3 on: 02 July, 2017, 19:26:19 »
Is the stud you have about 9 3/4 inch x 3/8 inch diameter? Shown as part 66 4198 for plunger?

If that stud was 11 1/8 inch x 3/8 inch diameter would it go all the way through with length enough for nuts and washers?

The reason I ask is that in the early parts books there is a stud for rigid 15 6325 given as 9 3/4 x 3/8 inch.

By the 1952 book 15 6325 is shown as having grown to 11 1/8 x 3/8 and 66 4198 shown as the shorter dimension. I wonder if the lengths were transposed in the later books.

Does the brake pedal have a casting number on it?
« Last Edit: 02 July, 2017, 19:33:10 by JulianS »

blackdog

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Re: Assistance with M21 frame
« Reply #4 on: 02 July, 2017, 20:55:18 »
It is part 66-4198 and having measured it its 9 3/4. which is the distance between the ends of the two tubes. I cannot see a casting number on the brake pedal,do you know if the earlier pedals had a smaller diameter mounting hole?

blackdog

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Re: Assistance with M21 frame
« Reply #5 on: 02 July, 2017, 21:54:03 »
Having looked at the receipt it is shown as 15=6325 tie stud 3/8 cei26 x 10" :-[

JulianS

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Re: Assistance with M21 frame
« Reply #6 on: 03 July, 2017, 09:17:57 »
Looking at the parts book for 1951-52 there are a number of similar brake pedals shown.

In the photo

66 7012 for M series spring frame

65 7060 B series rigid

66 7005 M series rigid.

Could not tell you what the differences are.

Then going to the later book illustrated in earlier post the pedal is listed as 65 7060. I think this must interchange with 66 7012 because the backstay part number remained the same. The rigid M pedal has a different mounting.

So I think you need a different pedal and the longer stud as above post.

Its all part of the fun of a bike in boxes!!

blackdog

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Re: Assistance with M21 frame
« Reply #7 on: 03 July, 2017, 19:43:29 »
Never a dull moment !! Thanks for you help

JulianS

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Re: Assistance with M21 frame
« Reply #8 on: 03 July, 2017, 19:59:10 »
Sorry forgot the photo!