Douglas 2 3/4hp and 4hp - Tanktop Exotic Wood Gear Lever Knob and Stainless Steel Centre Bolt


Douglas 2 3/4hp and 4hp - Tanktop Exotic Wood Gear Lever Knob and Stainless Steel Centre Bolt

Product no.: 0698 DG234_008

In stock

from £19.00
Recommended Retail Price, plus delivery


This is a faithful reproduction of the gearlever knob fitted to early 2 - speed Douglas motorcycles - the 2 3/4hp and 4hp models.  It is CNC manufactured from exotic wood - either Wenge (dark) or Yew (light) to a high finish, lacquered and comes complete with CNC manufactured gearlever bolt in Stainless steel.  Price is for the pair

A bit of background to these:  as part of rebuilding my own Douglas 2 3/4hp model - I did have a knob with the correct original profile, but quality was not good, so decided to write a CNC program to replicate the same shape from an exotic hardwood.  The process to do this is quite labour intensive - I purchased seasoned branchs (yes brankchs - complete with bark!!) or unplaned lengths of exotic hardwoods, then turned them down into 'cotton reel' bobbins on my manual lathe.  I then bore and counterbore for the gearknob bolt - that sits almost flush, but bore deeper so I can fit a stainless insert into the wood, so it will reduce wear of the gearknob.  You  can see this process in the accompanying photographs.

I have then made jigs to hold the bobbin's in my CNC lathe so I can machine the original Douglas gearknob profile.  After machining, each gearknob is given a final polish with fine sandpaper, before 2/3 coats of ethanol proof clear acrylic lacquer.  As far as I know the original Douglas two speed gearknob was fitted to both 2 3/4hp and 4hp models up to the mid 1920's - but original knobs I have seen have normally been in a darker wood.   To replicate this dark wood I chose a very dense/heavy hardwood which is suitably dark - Wenge.  However, I also wanted to experiment with a lighter wood so I have also tried a length of Yew wood, which is much lighter but has a lovely veining between the inner and outer diameter.

As well as the wooden gearknob, I have also faithfully CNC replicated the gearknob bolt in stainless steel.  To ensure I got the right thread dimensions, I went to the original gearlever/bolt I had fitted to a second, heavily corroded, 1917 Douglas 2 3/4hp chassis I also have.  You can see in the photographs that the gearlever and bolt were very heavily corroded and most of the bolt had actually rotted away, along with any traces of the wooden knob itself.  But having derusted the lever/bolt, I was able to oxy/acetylened the lever to release the original bolt and - as hoped, this was able to provide me with a very good original thread profile and the small rounded nipple at the bottom of the bolt that fits into the gear plate recess.  From this I was able to ascertain that (not suprisingly), the original thread is a Douglas 'special' thread of 0.255" x 24 TPI, which I have replicated on these bolts.

Sorry these wooden knobs/bolts are not cheap - but are very labour intensive to produce.  That said, I do think that they add a very nice original touch and should look very nice if your current Douglas gearknob is looking a bit worn or dilapidated.

Customers who bought this product also bought

*
Recommended Retail Price, plus delivery

Browse these categories as well: 8. Douglas 2 3/4hp Parts, 1.g Norton SOHC Gaskets,Seals & Fasteners