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| sbwhart:
Some more done this morning. To cut the steam ports the piston needs to be positioned correctly under the mill. First in the lathe and using an independat four jaw chuck set the bore running true. Then mount the chuck on the RT with the RT set on zero clock one of the faces square by turning the base of the RT when level clamp it down. Next you have to centre the RT under the spindle to do this I used one of those indicator things located in the bore. With it lined up zero the DRO Then using the a combination of the PCD feature on the DRO and the RT to generate the 31deg curve machine the ports by first drilling the ends 4mm and joining them up with a 4mm slot drill. To drill into the ports mount the piston on the mandrell in the spin indexer making sure you get it square and with the mill zeroed on the centre line. It is now an easy job to get the correct position to drill through into the port, just indexing round to get the position on each face, repeat for the location of the M3 holes. To complete Tap M3 using the tapping table. Thats the first part done. Stew |
| saw:
Stew, you are doing a greate jobb, but the most intressting thing with you is how you manage to find all of those remarkable constructions :thumbup: :thumbup: :thumbup: I have to edmitt I like to read youre blogg but I am not always understanding the mechanism. :zap: |
| sbwhart:
Cheers :beer: Saw Time for a progress update. Made the side slipper bars for the piston I had some suitable brass bar in my stash. Square it up and bring it to size. Drill and mill the slots And then it was :doh: time I must have got one of the co-ordinates wrong for drilling as a result it was off set 1mm. Rather than waist it decided it would come to no harm if I mounted the assembly in the four jaw and skim things level. I think that came out better than the origonal, it 0.5mm thinner than I intended but that won't do any harm Next part the outer piston/cylinder this part has a duel function it forms the cylinder for the inner piston, and also does duty as the outer piston. I'm making this out of 5/16"*1" mild steel bar, first cut the bits off to length, then for the two side peices that the inner piston will work over, with them clamped together fly cut a light skim off, this takes care of the slight bend that was in the bar. Keeping the parts in the vice so that the step at both ends is exactly the same as this helps to get a square assy, the vice was swiveled round 90 deg and the bar clocked level, doing it this way I could take advantage of the power feed. Then mill the step to the same depth and to the correct width. With this done the parts can be removed from the vice Swivel the vice back and clock it square, and drill the holes and slot set the vice stop Flip it over with the same edge against the stop and counter sink the holes. Thats another bit done. Stew |
| sbwhart:
Thanks for you're interest chaps Finished off the outer piston today. Squared off the ends, and brought both sides to exactly the same length, had to take it steady as there was quite a bit sticking out. Then drilled and tapped M3 Screwed it all together with stud lock. Then over on the lathe in the four jaw skimmed both sides level and to size, had to make sure I was level in the jaws by taking a cut and checking that it was the same size all round, and adjust with a light tap. I made the width just 0.05mm smaller than the inner piston. Mounted the inner piston on the mandrell in the spinidexer and skimmed down each side to give a nice slide fit in the outer, doing it this way ensured it was cimetrical. The outer piston slides in the outer casing, the sliding face needs to be square to the inner sliding face. So clocked the inner sliding face level on a angle plate. Flip the plate 90 deg and skim up the outer sliding face. Its an easy job to get the other face square and parallel by just sitting the good face on a 1*2*3 block and giving it a skim. Quite pleased how that turned out. The outer piston still needs the reces machining for the flange but I will do that when its assembled into the outer frame. Stew |
| Stilldrillin:
Stew........... Will you be making anything I can recognise? :scratch: I can see one of Rob's moulding boxes. Then you went an put a clock face in it....... :Doh: I'm sure you know what you're about! :thumbup: Looking good, though! :clap: :clap: David D |
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