Douglas - For Sale Items

Douglas 1913 Model P motorcycle

Douglas - Wanted Items

Douglas 1915 3 Spd-Gearbox and Clutch

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Dave

2024-06-11, 20:02:05
Have you tried the new Drafts feature yet? I just lost a long message today and learned my lesson. It is a good idea to save a draft of any long post you are writing. You can then just keep writing and keep saving a draft, knowing you have a backup if there is a glitch. The draft is automatically deleted when you post the message.

Dave

2024-06-08, 18:30:04
For Sale
xman has two very nice 1950's machines available - a green 1950 mk4 and black 1951 mk5 - both in good condition and running well.

Dave

2024-06-07, 02:13:36

Dave

2024-06-03, 08:23:05
For Sale
Duncan has just listed his green and cream 1957 Dragonfly for sale with spares and documents.

Dave

2024-06-02, 08:34:05
Parts avalable
alistair still has parts available - barrels, carburettor, castings - see all listings.


Dave

2024-06-01, 18:33:27

Dave

2024-05-28, 00:09:46
Welcome to the new site!
Recommended viewing for a fast start...
 - Quick Tour of the Front Page
 - Quick Tour of the new Attachments
Learn all about attaching photos in the User Guide. Any problems with anything please Contact us     Faulty links fixed - 01June2024

Recent posts

#31
Quote from: Andy Smith on 09 Jun 2024 at 06:01 Is it not viable to sleeve the barrels back to standard and then use the original pistons? Andy
Hi Andy
It's not a sleeve type engine. That option would have been nice, but the cylinders are iron-nickel alloy all the way through. The very rather beautiful +0.020" re-bore has already been done, as has the head job with the phosphor-bronze valve guide inserts. We only got here because the pistons supplied were the wrong ones. :frown:

Hence, I am doodling about exploring "fix the pistons" options. I do have some scuffed up +0.030" pistons, on which we are trying out TIG welding up the ring slots with 4032 aluminium filler, so to try machining back. It might not work!
#32
Quote from: cardan on 09 Jun 2024 at 04:47 I'm reluctant to buy into this conversation, as I'd just pay for new pistons either made specially for the engine, or I'd modify something else to suit.

However there are now two mentions of using emery on aluminium pistons as part of the fitting process. I was taught never to do this because of the risk of leaving particles of grit embedded in the alloy, and instead to use a new file (new because a used file may have slivers of steel that could be transferred into the alloy while filing).

Anyway, call me old fashioned but it's a clean file for me.

Leon
Hi Leon.
Don't be reluctant, because what you have to say is very much applicable. I had not come to consider it until Kev suggested it, because up to then, it was all about machining.

Using a fine flat file in that precision manner peculiar motion "start at the back in one fluid movement" is a skill I was shown at school, but I never trusted myself to replicate that muscle memory motion to get a decent outcome. It occurs to me that a good rub up to shiny with Scotchbrite could remove any embedded abrasive.

"Just pay for a new pair" is not really an option. I don't even own the engine. The work I do on it I am happy to provide the Heritage Centre for free, but the quote from JW Pistons (in Oz land) was AUD$600 each. Add that up, add 20% UK VAT, and convert to UK pounds£, makes it £746 before any shipping charges. The whole thread about the little aeroplane with the Douglas engine is ..

here --> https://www.douglasmotorcycles.net/index.php/topic,9736.0.html
#33
Quote from: kev on 08 Jun 2024 at 11:15 ovalling a piston..from an EW ..or any 20,s motor..just roll them on a wide belt sander

Hi Kev
Thus far, learning from you that some careful use of a belt sander to thin the two sides of the skirt to achieve a workable oval is by is the best thing so far - thank you much! :)

[Edit: BUT - from some other posts, one has to not have embedded abrasive. Have to use a file, or work the surface afterwards with Scotchbrite to remove it. Maybe just a nice file will be OK.]
#34
General Douglas Discussion / Re: Casting Pistons with help ...
Last post by kev - 09 Jun 2024 at 10:50
Quote from: eddie on 09 Jun 2024 at 07:46 Barrels for the generator engine and the T35 Mk1 were very thin just above the base flange and liable to fracture even if bored out to anything above +.040", so sleeving may not be a good option. With the amount of generator engines that are about, wouldn't it be better to look for another pair of barrels with good standard bores - the standard pistons are a lot easier to source.

  Regards,
              Eddie.

P.S. I concur with Leon's comments regarding using emery cloth to finish size alloy pistons - any inclusion of the grit in the alloy effectively turns it into a lap.
i sleeved my EW and with the thin barrel  issue you mention  my pistons are about .080 smaller
using emery on a piston or any thing...is exactly how you make a lapping tool...hard compound embeds in softer material for lapping tool..and cuts a hardened bearing race ...no trouble at all...and does a fine job at that
#35
General Douglas Discussion / Re: Casting Pistons with help ...
Last post by kev - 09 Jun 2024 at 10:45
Quote from: Andy Smith on 09 Jun 2024 at 06:01 Is it not viable to sleeve the barrels back to standard and then use the original pistons? Andy
i sleeved my EW   made upp a fixing jig...and bored, ought new sleeves ...from a diesel place   and turned th od and bore ID to my new pistons

the engineering places i went to..weren't very enthusiastic as the head is fixed

my cylinders had about .050 taper to top

have to bore very minimum...as EW cylinders walls so thin can almost see thru
#36
Graeme,

Thanks for your post. I had read the previous thread on Grady sometime ago but did look at it again the other day to refresh my memory. I too have some heathy scepticism of certain aspects of accounts of Grady's ride around Australia and have been attempting to put together some sort of chronology of his location during late 1924 as reported in the media, too see if his journey was at least feasible.

It is possible, as Leon states, that the reporting could have been orchestrated or fabricated, but I don't think all of it could have been. Here are some of the reports I have found so far from Trove ( as I suspected, Grady is reputed to have been held up by rain - hardly surprising given it would possibly be the build up to the wet season at that time.)

The first trip around Australia by a car appears to be in 1925 by Westwood and Davis in a Citroen 5CV (possible made a little easier by the new road between Port Hedland and Broome??) so it appears that Grady's ride was at least moderately possible around this time.

https://www.nma.gov.au/explore/collection/highlights/citroen-tourer#:~:text=Today%2C%20a%20trip%20around%20Australia,old%20Seventh%20Day%20Adventist%20missionary.

-Hutch
#37
Barrels for the generator engine and the T35 Mk1 were very thin just above the base flange and liable to fracture even if bored out to anything above +.040", so sleeving may not be a good option. With the amount of generator engines that are about, wouldn't it be better to look for another pair of barrels with good standard bores - the standard pistons are a lot easier to source.

  Regards, 
               Eddie.

P.S. I concur with Leon's comments regarding using emery cloth to finish size alloy pistons - any inclusion of the grit in the alloy effectively turns it into a lap.
#38
Is it not viable to sleeve the barrels back to standard and then use the original pistons? Andy
#39
General Douglas Discussion / Re: Woodruff keys
Last post by cardan - 09 Jun 2024 at 04:50
Best just to measure your keyways, and file a key to suit. Make sure that width matches the keyway, and (particularly) that the key does not sit too proud of the shaft to upset the fit on the gear onto the shaft.

Leon
#40
I'm reluctant to buy into this conversation, as I'd just pay for new pistons either made specially for the engine, or I'd modify something else to suit.

However there are now two mentions of using emery on aluminium pistons as part of the fitting process. I was taught never to do this because of the risk of leaving particles of grit embedded in the alloy, and instead to use a new file (new because a used file may have slivers of steel that could be transferred into the alloy while filing).

Anyway, call me old fashioned but it's a clean file for me.

Leon