Made a start on the axle boxes.  They were made from steel with Gunmetal liners to reduce the amount of gun metal requires.  The ME drawing of the keeps are not quite correct and need to have a small section machined from the outside edges to make sure they fit into the frames correctly.  I also had a go at making the springs.  The spring pins were made from 1/8 steel as per drawing but I noticed in the description Martin suggests some users may use 3/16.  So I hope the 1/8 pins should be sufficient.

Made the buffers this week.  Although as I found out talking to the guys at the club they are only decorative as a solid beam is required for connecting carriages.  They said buffers can be quite dangerous on small gauge locomotives as the carriages can push the locomotive off the rails if they make contact with the buffers.  The front profile on the buffers were machined on the lathe using the radius function on the DRO and finished with a file and emery. I need to get some 15g and 16g spring wire to finish the springs not sure where?  

Machined up one of the castings for the axle pump.  This is Martin Evan’s improved design for the Simplex published in ME March 1980.  I think I will end up using this for the hand pump. I drilled the four No 46 holes for the pump suction first before drilling and tapping the 3/8 x 40 hole.  The valve lifts were all checked by measuring from the top of each of the suction and outlet bosses to the top the ball.  And the measuring the lengths of each of the fittings.

Phil,

Martin published a new design for the Super Simplex and I will make that one for the main pump just to follow his design. I did not want to waste this pump and looking at the hand pump published for the Super Simplex ME 7 July 1989 page 36. It looks very much the same

Regards

Peter

I had a go at casting the horn blocks.  My son has a 3D printer and printed out the pattern for me.  Due to the size of my furnace and crucible I can only cast one at a time and I had some mixed results and a few short pours.  I eventually got three sets but found that I had not left enough machining allowance:( I installed one set in the frames and as I was machining the last 10 thou the cutter caught and ripped the casting out of the frame as the side wall was too thin.  So it was back to the drawing board.  I got my son to print another pattern with better matching allowances.  I also had to weld all the holes I had put in the frames as the new horn block holes did not line up.  I reused all the old castings but that did not go well as when I started machining there were porous holes everywhere.  I spoke to a local guy who supplies casting material and he provided me with a billet of casting bronze. This worked much better. Up until now I was just using bar stock and after a few re-melts it is no longer bronze and looks not reddish in colour. Finally finished with a good set of castings

Here is my final castings. A big learning experience.

The second attempt at machining the horn blocks worked a lot better with the new castings as there was about a 1/16” more material all round. The front and rear part of the horn blocks were all machined in pairs to dimension and then riveted to the frames before machining the centres using a long mill cutter.  The travel on my mill was not big enough to machine the horn blocks in a single set up.  So I used one of the centre frame cut outs as a reference between setups. There is a number of ways to machine the horn blocks to ensure correct alignment and spacing but this is the method I chose.  Six lengths of scrap bar stock were first bolted to the mill table and 3mm slots about 1/8” deep were cut out at the required frame spacing.  Three of these bars were removed and the frames were fitted into these slots and bolted down between the bars.  The setup was rigid enough as long as small cuts were used. One horn block was left out of centre cutout and the DRO was zeroed at its centre. The rear two and the one centre horn blocks were machined to dimension first.  The frames were then removed leaving the bottom fixed bars in place.  The last centre horn block was riveted in place and the frames were repositioned on the mill table to allow the remaining blocks to be machined.  The DRO was re-zeroed to the previously machine centre horn block and the remaining horn blocks were machines to dimension.  The slot widths were checked using gauge blocks and test fits of the associated axle block. The slot depths were checked using a depth micrometer.  Here are some photos of the setup.