Two blocks of potential swarf and the initial scriblings
Setting the cavity centre true with a 'wobble' bar and DTI
Rough boring the crankcase cavity
Centre drilling the position of the cylinder liner bore
Drilling through with 20mm drill. Drilled with 4mm pilot first
Rough milling the lower case and mounting lugs. 10mm (Rippa cutter used, 'climb' milling, coolant brushed on)
Early stages of rough milling
Rough milling exhaust stacks (Rippa cutter)
Next stages, first exhaust slot roughed out
Exhaust slots finished
Steel mandrel for mounting crankcase turned to - 0.02mm fit on crankcase bore. M6 tapped hole
Crankcase held by 6mm studdding and supported on tailstock for rough turning front of crankcase
As previous image
Portion of turning mandrel parted off and bolted to angle plate set square to mill axis. Rough milling contour of crankcase in small steps (6mm FC3 cutter). Case rotated in small steps and locked before cutting.
Initial light 'finishing' cuts. Part carefully rotated by hand against cutting forces.
First stage in finishing cuts
Second stage 0.05mm cuts and very small radial steps. Note all longitudinal cuts taken between fixed stops on table
First fettling using swiss files
Finish boring the cylinder liner bore. Block set square to faceplate using parallels behind mounting lugs
This shot is for posterity! After twenty five years unused the sine bar made at work in 1985 finally gets its day! Setting the angles between crankcase boss positions to enable the stops to be set on the rotary table
Milling between stops
Using 4mm slot drill for finishing. Corners of cutter radiused on offhand grinder
First stages of crankcase contouring
As previous
Rotary burr (carbide) used for roughing shape
Smotthing using swiss files, red marker pen to show low spots
The Basic set up. Note stops set to limit travel
Finish boring the crankcase cavity, the inner bearing housing and the crankshaft bore. The outer face skimmed 0.05 to clean up and ensure face square to bore
Rough turned basic expanding mandrel and 2 BA caphead expander screw. (Rough turned .2 on dia., slots put in using hacksaw, reset in lathe with screw just engaging and finish turned - in this case to fit crankcase bore and locking area on crankshaft bore)
Crankcase mounted on expanding mandrel and finish turning outer bearing housing true to inner.
Drilling for backplate mounting screws
Tapping holes 5BA using chuck as a tap guide. Tap has small flat ground on by hand for tap wrench. Tap held very lightly by chuck. Tapping carried out using wrench.
Set up on rotary table to mill transfer slots using 4mm long series endmill
Final op was to finish turn front of crankcase using expanding mandrel.
Finished crankcase
The finished pair.
Rough milling the waste away around the crankpin
Initial stages in roughing out the crankpin
Rough turning the major diameters using soft jaws
Finish turning the crank pin and rotor drive
The simple catch plate for finish turning between centres. The soft centre is replaceable - locked by grub screw and is turned in situ
Finish turning shaft. The inner shaft is Loctited in the main shaft using 638 high strength retainer. Outer shaft (Web major and intermediate diameters) is EN24T - inner shaft is turned from 8mm caphead bolt. Orange part is ali protection around crank pin
Finished Crankshafts.
Starting the back plates
Centre drilling the centre rotor pin and the intake hole positions
Turning the register on the backplate and drilling and reaming for the rotor pin
Offset and drilling and boring divergent taper. Small boring tool ground from 1/4 slot drill - makes excellent small hole boring tools
First stage of turning
Milling inlet port using rotary table
As previous. Tool makers clamp is acting as dead stop for second b'plate
Previously used turning 'fixture' modified for use on back plates
Boring the taper in the inlet
Using same the fixture rough milling intake tube on rotary able.
First stages
Ditto
Milling backplate cavity. Corners of cutter have been radiused on off hand grinder to leave radius in corners at bottom of cavity
Still in fixture - back on lathe to taper turn intake
Finished back plates
Boring lightening relief inside the spinner. Tool ground from discarded FC3 cutter shank
First stages on an expanding mandrel for turning cylinder fins
Drilled and tapped 2BA. Deep centre is for 60 degree tapered cap head expanding screw.
Slots cut with hacksaw off the lathe, replaced and screw lightly nipped up and OD finish turned for cylinders.
Cylinder blank held tightly for gashing fins. Tool ground from discarded FC3 cutter
Drilling for cylinder bolts in situ using cross slide mounted drilling attachment
Cross slide drilling attachment set up
Method of detent on 60T bull wheel. This can be removed and bracket fitted with detent for holes in chuck - 48 and 50 divs.
Using cross slide drilling attachment spindle for handtapping
Simple chucking fixture for cylinder heads
Profile shaped with series of flats applied by turning then smoothed by hand using scraper.
The finish off the scraper. Note 'button' is just thick washer from a previous job
Turning stage finished. Head on left has been 'initial' finished - turning marks are accentuated by photo - actually very fine but they will have to come out!
Finishing medium excellent for the job. Grit in the packet is 60 - 'coarse'- the small cut off piece is 240 - 'extra fine'
Drilling for the head bolts using the cross slide drilling attachment
Using 5.5mm FC3 cutter to counterbore for boltheads. FC3 cutter holder in drilling attachment
Ready for the finning operation
Establishing the 'Y' axis stopping point using a 2mm pin. Reccessed button fits over centre boss - pin brought to button and DRO reading noted. Note previous witness marks on button.
Finning op using 2mm FC3 cutter. The corners of the cutter were radiused on the off hand grinder.
The one at the rear is a 'scrapper' Note the two front slots. A 2.5 mm cutter picked up off the bench in mistake for the 2mm previously radiused!!
Finished item, deburred and 'polished' smooth with a '240 grit Garry flex' block
Spinner nuts, prop drivers and split collets
Finished cylinder barrels
Con Rod blanks machined to plus .5mm on sides and faces. Drilled and reamed 4mm for gudgeon pin and 7mm for big end bush
Initial milling of little end.
Milling boss to depth
Setting blank square to the rotary table 'zero' to mill boss on reverse face
Little ends formed ready for second op on big ends
Simple fixture for holding rods for milling sides and faces
Setting first side parallel with mill axis using 2mm pins
Milling side of rod
Milling top face. Rod then turned over and second side and face milled to ame settings.
Finish milled and fluted rods ready for clean up and surface finishing
Finished rods and phos bronze bushes
All parts finished so far
First 'mock up'
Total parts so far (13-04-10)
Crankcase parts after bead blasting
Blanks for port cutters
Milling teeth in cutter blanks
'Hi-Tech' tempering - getting sand hot before tempering
'Colour' comes up much more slowly and evenly in sand.
First two cutters hardened and tempered ready for grinding cutting edges on off hand grinder
Ground and ready to cut. Backing off - done by taper 'dishing' blanks - proves insufficient
Boring cast liner (made from an off cut - flat insignificant)
Liner mounter to expanding mandrel for reverse turning
First two worn cutters and the third, un-tempered and backed off more on off hand grinder
Cutting ports with third cutter far more successful!
Liners finished ready for lapping. No wear evident on third cutter!
Liners as bored and de-burred
Copper expanding lap
Copper band is silver soldered along leading edge only to 'fixed' part of steel mandrel. The loose, 'floating' part is held captive (and the lap expanded) by a 4BA grub screw.
Lapping in progress. The fibre washer limits the lapping distance into the bore
Withdrawing limit is a 'by eye' task
First lappings - 320 grit on left 600 on right. Lap and bores thoroughly cleaned between grits.
Intermediate and final stage
Finished ready to fit pistons
Holding the contra piston in home made soft jaw extensions for counter boring
A previously used expanding mandrel turned to a push fit in contra piston counter bore
'Spring' of mandrel holds contra piston sufficiently tight for 'lapping'
Using a flat fine stone to obtain 'fit' of contra piston to bore. NB Both hands used to guide and keep stone flat and moving. (Left hand is taking the pic!)
Initial stages in piston manufacture. Top end inner relief about to be bored.
Cross drilling for gudgeon pin
Spindle turned by hand as cross slide wound on for reaming. (Spindle to fast for reaming CI)
Setting piston square to mill axis using 4mm silver steel rod.
Plunge milling main relief in 1 mm (sideways) increments
Plunge milling side relief
Finished internals
Piston finishing fixture
Piston in situ ready for lapping
First piston was reduced by 'lapping' with a fine flat stone. Un-noticed the piston had distorted fractionally after milling the internals and after final lapping to the liner two untouched areas are evident running the length of the piston on each side of the gudgeon pin hole.
Boring out a previously used piston lap to suit.
Ready to see if lap will true second piston
Second piston - round and no sunken areas
Ready for final lapping of piston to bore using 1000 grit
Cutting gudgeon pins from 4mm hard dowel pins.
Initial thoughts on seting up the anodising tank
All the initial bits ready to have a go!
The rather Heath Robinson set up.
First test piece suffered from possible inadequate pre degreasing. Second test piece has a good anodised coating but would not absorb (Dylon) dye. Third, done using 12volt battery at much higher amps is very poor.
Shows reverse side of third piece and pitting caused by excess amperage
Facing con rod ends using expanding mandrel
Finished ends and double ended mandrel
Machining the 'Oilon' oil filled nylon rotor
Parting off
Ditto the 'Tufnol' version
Holding the rotor in a ring collet and reverse facing
Finished 'Tufnol' rotors
Finished rotors, dark face is unmachined outer skin of 'Tufnol'
Milling the tops of the transfer ports in the 'sealing plate'
Finished plate ready to fit with silacon sealant
As fitted - case now ready for final assembly
Conventional spray bars, two waisted to differing dias. - 4ba thread 18swg needles
The finished parts. The long rod is for the comp screws - one each end - to be parted off once thread length is confirmed.
First full assembly
The new 'improved' ano set up. 30volt 3amp supply unit. Inner ano tank is raised off bottom of outer tank. Outer tank filled with water and heated with aquarium heater.
First piece out of new tank actually absorbs some dye (Correct anodising dye) Decision made to increase electrolyte strength to 4:1
Next results much more positve. Centre piece is with same ano dye as left hand previous piece. Right hand piece is using 'Parker' green writing ink. Absorbtion of colour with dye appx 15mins with the ink virtually instantaneous
First parts. Racer cylinder head on left done using 'green' ink. DC Rapier head on right with ano dye
Finally finished
13 x 5 wood prop and nice and oily!
Upon further running one engine siezed. Caused by 'pick up' between shaft and crankcase just in front of main bearing
Second line in bore shows the pick up 'score'
Slightly loose contra piston
Heat treated at this 'colour' for 3 mins and left to cool
Contra piston grew by .01. No diametral distortion and a better fit! Thats it folks!
