Tumbler Reverse For Warco 918

The proposed modifications will closely follow the design shown by J.F.E.Weight in the Model Engineer 1st Jan 1993.

For those that don't have access to the original article here is a zipped copy tumbler_reverse_article.zip I hope I'm not treading on anyones toes but if requested this link will be removed.

Existing Gear Train

Below the gear train connecting the leadscrew has been disconnected in preparation for the new gear carrier, the noise is also considerably less which means that an additional bonus of fitting the tumbler reverse mod is that you also get a neutral position

In order to complete the design by Mr Weight 2 off 45t and 1 off 28t gears No1 module are required the 45t gears will be in plastic, the 28t in mild steel. Plastic will be used for the 45t gears because I've never cut gears before and this should make them be easier to deal with and they will act as safety gears if anything should jam. They also make for quieter running but as to durability only time will tell. Below is the mandrel being machined that will allow the gear blanks to be mounted on my rotary table the short MT2 end which fits in the rotary table is on the right the parallel end being held in the chuck.

Below is one of the 45t plastic gear blanks complete with bronze bush mounted on the rotary table ready for machining

Here the plastic blank is being cut, the gears behind are for packing/support for the blank

Now that the 45t gears are complete the next task was the 28t unfortunately the dividing plates that are normally supplied with the 6" rotary tables do not cover 28 divisions, luckly for me Captain Bob bought a 6" rotary table at the Harrogate Model Engineering Exhibition and was itching to use it and voila he came up with a new plate with 25 and 28 holes.

Below with Captain Bobs dividing plate I'm cutting the 28t steel gear, these should always be cut full depth in one pass with the appropriate feed

The completed gear carrier is shown below with the 2 plastic 45t gears at the top meshing with steel 28t. The 28t gear required a smaller fixing head due the clearances required when in situ

The new gear carrier has now been installed and below can be seen the staggered arm making an inboard select lever possible, this still has to be cut to length and a ball handle fitted.

Well here it is completed and photographed in the neutral position the chrome conical part is actually from an electric shower pull cord and just finished off with a brass plug

For anyone working on the Warco 918 I would recommend visiting Steve Bedair's 920 lathe site and the Yahoo Groups 9x20Lathe, 9x20Lathe2 and Lathe9X20

Home    Aeromodelling   My Engines    Casting    Live steam    Coolant Tank   

Links Page    1.25cc_Diesel    Captain Bobs Pages    Zebo's Page    Contact/Comments