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  1. M

    Look what followed me home

    That looks like the one with total indicated runout of less than 1.27 microns. Should be good enough I reckon!
  2. M

    What have you been doing today?

    I had a package from AliExpress that was delivered somewhere (not to me) and I told AlieExpress that I didn't receive it and they said it's not their problem, it has been marked as delivered by the carrier. They did not chase it up. They flatly refused. I haven't ordered from them again.
  3. M

    microcontrollers for the model engineer

    The MOST fun I ever had (with microcontrollers) was in the mid 1990's on a PIC16C84 writing a protocol converter. It had to convert commands over RS232 to a proprietary protocol for a mining machine (and back). Programming the PIC in assembly was really fun. The 12C508 (now I think it's 12F508)...
  4. M

    Measuring length on a lathe

    What spec are you trying to hit on length? I know you say you want to get them as accurate as you can, but you should really get an idea of what you will be happy with. I'm NOT trying to be funny here, you should really decide what you will accept for this job. When you say your lengths are all...
  5. M

    LONGBOY'S MODEL ENGINE COMPILATION 2017-2021!

    Nice work! I look forward to seeing your next creation.
  6. M

    Making a one piece crankshaft from 1144 stress proof steel

    Yes that makes sense now I think about it. The main errors to control would be 1/ the relative error between hole separation distance on each end and 2/ from the centrepoint of the holes on the ends not being coplanar. Using the mill means the error in distance between the holes on one end would...
  7. M

    Making a one piece crankshaft from 1144 stress proof steel

    Any tips for getting the centre drill holes in the correct spots? Obviously, the first set it easy as long as there is enough material left to machine the crank when it is mounted in the lathe with them. But how do you get the second set to be as parallel as possible with the first?
  8. M

    How do I model a supercharger rotor?

    Would a thorough running in on the bench (just the blower) help in this regard? Even going as far as heating the assembly up to engine running temperature. What's the clearance on a full size blower meant to be? Say a 6-71?
  9. M

    Bolton No.2 Mill Engine

    I hadn't seen this thread before, but I went back and read the lot. Nice work on a great engine! It's looking fantastic. It's amazing how many good workholding (and other) tips you can pick up on this forum.
  10. M

    How do I model a supercharger rotor?

    This site reckons the angle for a 6-71 is 30 degrees. I guess the 8-71 would be similar. http://victorylibrary.com/mopar/blower/blower-GMC2.htm I guess the limiting factor on the upper helix angle would be that that the back edge of the rotor has sealed against the housing before the front...
  11. M

    Glow Plugs Voltage

    Haha, and I'm the sensitive one. Output impedance of the source matters and it was unclear from the original post as to what it would end up being. True, that's not what OP asked, but are we allowed to probe a little to find out what he's actually trying to achieve, or should we all just stick...
  12. M

    Glow Plugs Voltage

    Motorman1946, the answer is stick the voltage at 1.5V and the current will fall where it may. It's been answered. Round about 3 amps or so I believe the answer was. It's in the third post because you missed it. People digressed after that answer because tornitore45 didn't specify in the original...
  13. M

    Glow Plugs Voltage

    If you rectify the 24V, you'll need a switch mode power supply to drop to 1.5V. Using a linear for the big drop will mean 2-3 amps at 24V which won't last long.
  14. M

    Glow Plugs Voltage

    The biggest problem I had when I was a kid trying to start engines with glow plugs was the carbon zinc cells with their high internal resistance. Nicads and NiMh are so much lower internal resistance so the plug still glows in the presence of a cooling incoming air/fuel charge. If I was to...
  15. M

    Help cutting thin cooling fins

    Looks great! I'll remember your trick on my next project's cooling fins Matt
  16. M

    Hi Everyone!

    Hi Everyone, I have been a long time reader of posts (almost 10 years - yikes) and member of this forum. I live in Brisbane, Australia. I joined back in 2010 after I bought a Sieg SX2 mini mill to complement the Taig lathe my brother gave me. I had bought a Bolton No.2...
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