Author Topic: 1912 2 3/4 forklincs  (Read 4415 times)

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Offline joeis6

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1912 2 3/4 forklincs
« on: 29 Nov 2011 at 07:47 »
hello i am new to douglas   having bought my veteran project a few weeks ago.  they are an interesting motorcycle, the major one at the moment is threads used . the rear dropouts seem to have bsf thatsgood for me. the fork spindle use a 25 tpi  that is larger than 1/4 bsf, i can make that. but my question is the links they seem to be 3/16 thick for the top pair and 7/32 for the bottom pair, have a mix of veteran andvintage parts or is this how a 1912 should be?
neale

Offline Chris

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Re: 1912 2 3/4 forklincs
« Reply #1 on: 29 Nov 2011 at 09:50 »
Hi Joe
There are several variations of fork link. Some were almost straight and later ones curved. The straight ones sometimes tended to clash with the spring nuts which is why I believe the curved ones were introduced. I doubt after nearly 100 years that it is possible to be definitive about what was originally fitted as they are known to wear and break and most will have been replaced at some time in their life. I have seen machines with mixed designs. Providing they fit OK I would not worry about the differences in thickness and clearly the 7/32" will be stronger. You can always grind the lower ones down to 3/16" if they worry you.
In respect of threads, the slightly larger than 1/4" that you have detected is only one of the special threads that Douglas used to ensure that any spare part down to a nut or bolt that an owner required had to be purchased from Douglas. The LDMCC has the special taps and dies for this size which is 17/64" x 25 tpi in its pre-war spares inventory available to members of the Club. If you do a Search on "Threads" within this Forum you will find a posting I made a few years ago giving comprehensive details of threads used on the 2.2/4hp models. Chris.

Offline Dirt Track

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Re: 1912 2 3/4 forklincs
« Reply #2 on: 29 Nov 2011 at 23:54 »
G'day all
Some time ago I bought a set of "Terry's Patent Spring Links" which are NOS for a 2 3/4HP Douglas.
I have never seen a photo of an early Douglas with these fitted!
I have owned a few Rover's over the years and they seem to have fitted them to every bike.
Howard.







« Last Edit: 30 Nov 2011 at 20:34 by Dave »

Offline joeis6

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Re: 1912 2 3/4 forklincs
« Reply #3 on: 30 Nov 2011 at 09:26 »
thankyou forrrr the help
neale

Offline Chris

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Re: 1912 2 3/4 forklincs
« Reply #4 on: 30 Nov 2011 at 10:20 »
Hi Joe and all
    I have seen 2.3/4hp models fitted with supplementary springs pointing back towards the rider at the top of the forks but I have never seen springs like these which according to the illustration on the box are intended to actually replace the upper fork links. I can only assume that like Zoom Zoom exhausts, leather knee pads and even high compression pistons that these are non Douglas factory items provided by the after sales accessory manufacturers to enhance your Douglas. Chris

Offline Reg

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Re: 1912 2 3/4 forklincs
« Reply #5 on: 30 Nov 2011 at 13:52 »
In response to Howard and Chris, I've just had a look at my copy of a catalogue from around 1924/25 issued by W.G.Coram well known Douglas specialist and agent of Victoria Street, Bristol. Inside we have a picture exactly the same as on the box that Howard has with the following description;
'Terry's Spring Links for old pattern 2 3/4hp Douglas Forks, pre 1919. Replaces the top fork links. A wonderful shock absorbing device    ...   per pair 15/6'

W.G.Coram was responsible for the manufacture of many accessories for the Douglas such as the 'zoom zoom' exhaust for the 2 3/4 models and the 'zoom the second', a similar device made for  the 4 hp models. Other items available were patent alloy air cooled valve caps, barrel type valve springs, Coram alloy pistons, patented twin rings for pistons, high duty valves, hot air intake pipe and even Silver Scot machine mascots. Even 'shop soiled' Douglas silencers taken from new machines when owners purchased a 'zoom zoom' silencer. Sold for half price at 15/-

According to the catalogue Mr. Coram was with Messrs. Douglas in charge of the Repair Department from 1910-1920. If I can get my head around the methods of sending photos/emails then I will copy some of the pages. They do make interesting reading.

Reg. 

Offline MRD

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Re: 1912 2 3/4 forklincs
« Reply #6 on: 30 Nov 2011 at 16:06 »
Hi All
I know we're all going off track with the original subject.
But I've  just taken a couple of photos of the 1913 which has a set of these links fitted.
I can't really say they make a lot if difference in smoothing out the bumps in the road compared to my 1924 TS.
Regards     Martin





« Last Edit: 30 Nov 2011 at 20:43 by Dave »

Offline MRD

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Re: 1912 2 3/4 forklincs
« Reply #7 on: 30 Nov 2011 at 16:40 »
Hi all again,
Although the links look good, and is a bit of a conversation piece, they are a pain to keep clean!
Regards      Martin

 

 

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