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  1. J

    Milling bits for brass?

    Instead of a positive cutting rake on the cutting edge of the say lathe tool you have a zero or maybe a 1 degree negative rake on a drill or a slot drill/ end mill cutter the leading g edge is reduce to a zero rake or a slightly negative rake. This stops the digging in when machining brass. Hope...
  2. J

    Milling bits for brass?

    Hi Use a negative cutting rake for s nice machining experience and a good finish to size Works really well. Johwen
  3. J

    Piston ring rotation

    I Put two rings of half width in the same groove with the gaps at 180 degrees and never have that happen. Have good compression as I make my own rings from the getgo Johwen
  4. J

    Another Knucklehead Build

    Johwen here... One way i would adopt to control oil flow would be to as you have put in an pressure relief valve however I would have made it adjustable by using a screw to increase or decrease the the spring pressure. Alternatively a by pass pipe from the pump outlet to the sump with an...
  5. J

    Kerzel hit&miss by Mike

    (johwen here) Before CNC when reconditioning engines for the auto industry pistons were ground as they were not round but ground with extra clearance across the gudgeon pin axis to prevent seizure. Special grinders were made for the job and a variety of master profiles was supplied to vary...
  6. J

    Info on piston ring pressure requirements?

    Johwen Here again. I use the Trimble formula for making rings and to get great compression from the get go I make the ring groove twice the width and put two rings in the groove with the gaps set at 180 degrees apart. Works fantastic using the trimble formula exactly Ring gap set at .oo1 per...
  7. J

    Problems with face cutting on lathe, wavy pattern

    Johwen from Australia, Many years ago now we had this problem on some Asian lathes and it was caused by the drive belt, they were molded and had hard and soft spots and in some cases had uneven sections causing the belt to ride up in the groove as it drove the pulley. I would suggest checking...
  8. J

    Help Please. Troubleshooting a New Webster

    Hi Johwen here. Check the colour of the spark, Is it a blue spark or yellow? It should be blue. It would appear to me you should be getting pops and bangs if you have ignition even if if won't continue to run because of timing, even gasket leaks and carburation. If you have any evidence of fuel...
  9. J

    4 jaw chuck selection--Self centering or individual jaw adjustment type

    Johwen again. A four jaw self centering chuck will accurately hold a hex bar just jiggle it a little and it will chuck up dead accurate give it a try. I make nuts accurately using this set up. Can guarantee it saves so much time and will chuck all hex sizes within the capacity of the chuck! John
  10. J

    4 jaw chuck selection--Self centering or individual jaw adjustment type

    johwen here. I have been using a 4 jaw self centering chuck for 40 years. They can hold concentrically all sections round, square and hex accurately. Can hold all these section in short lengths for cross drilling holes. Can also hold short length flat section for certain machining operations...
  11. J

    Should I buy this?

    I have a Chinese copy of the Multi Fix Tool post and it is fine save so much time in tool setting Cheers John
  12. J

    4 cylinder ohv engine plans

    The reason is simple, it is to balance the rotating motion two pistons going up balanced by two going down
  13. J

    valve lapping problem

    The cause here is the grit is causing the grooves and to get a good seat you mus oscillate the valve back and forth after refacing the valve Cheers John from johwen.
  14. J

    Design and build side-shaft hit and miss engine from bar stock

    The Problem as I see it is the mass of the rocker arm at the cam end out weigh the opposite end by a large amount. the pivot for the the rocker ar is too far off centre. I would shorten the rocker arm on the cam side and put the roller under the centreline of the cam shaft. The rocker on the...
  15. J

    Design and build side-shaft hit and miss engine from bar stock

    Hello again Brian never give up as you will win. May I suggest as another follower has suggested Place the carb direct on the cylinder head. I believe your problem will end then Your new foot valve has overcome the drain back and smaller venturi overcomes the slow running. Bringing the carb...
  16. J

    Design and build side-shaft hit and miss engine from bar stock

    Brian, I make my own valves and use a smaller ball say 5/32 diam as they are lighter and tap the ball on the seat to get a good seal. I use a brass or alumiium body for the valve. A smaller choke diameter will raise vacuum with the slower engine speed Cheers and good luck with your good looking...
  17. J

    Design and build side-shaft hit and miss engine from bar stock

    Hi Brian, Try a smaller carburetor bore size and i think you will find it will run slower and pick up petrol easier. With piston rings I make my own and put two rings in the groove with the gap set at 180 apart I use 2 narrow rings i a .0625 ring groove seal very well and hold compression...
  18. J

    Heat treat rings

    I have made many rings using the above type fixture it is important to have the gap set correctly otherwise when compressed to fit the bore the ring will distort from a true circle. Wrap some paper around the rings so it burns when the fixture is heated removing any oxygen and the rings sealing...
  19. J

    It will not run.....

    Hello, I would think the timing of the valve eccentrics are out of phase they should be set 180 degrees apart also. Cheers. john
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