Search results

Help Support HMEM:

  1. M

    Ouch!

    It is G1, not G0! :) And turn the rapid down for the first part (don't ask how I know). Nick
  2. M

    Valve seat cutters.

    Yes, that has been done to speed up the initial lapping in of valves. Using the valve guide (with a pilot pin on the cutter) is what all commercial tools do. BUT with the small diameters in model engines, that setup gets quite wobbly. It doesn't scale down linear. Half the diameter is 8 times...
  3. M

    5 cylinder radial running

    Sounds good, looks nice. What else would you want? It will take some breaking in to cure the oil spitting. Great job! Nick
  4. M

    CNC machine

    Looks like djjones just registered here to make a little advertising for that contraption. From time to time I read at HSM. And -oh wonder- the same thread (also first post, registered also in May) where "a friend told him" about that POS. Nick
  5. M

    CNC machine

    Hahaha! What a crap! Do you intend to build your locos out of balsa wood? This is the typical crap of someone who has neither the slightest idea of machining nor engineering. Sorry for the rant Nick
  6. M

    Crankshaft model BMW R 75

    Made a crankshaft data sheet. This is the first draft: Nick
  7. M

    Brushless motor shafts

    Tuff task turning a 5 mm shaft to IT6. You'd have to hit within 8 µm. Doable, but not on the first try and not on the second one. Even if the price sticker on the lathe is ten-fold compared to a mini-lathe. Lapping is an option, but you would have to start with something straight. Nick
  8. M

    Crankshaft model BMW R 75

    Thanks for reminding me of this excellent work! There are two points that would stop me building one in that scale: * Idle RPM is too high * I don't like milled billet when there should be a casting Don't get me wrong, this work is extremely good. I personally would like these feature on my...
  9. M

    Brushless motor shafts

    Try to get 42CrMo4+QT (that is 4140H or 4140RH) It is quite reasonably to machine, but still quite tough. That material is already quenched and tempered (thus the QT). I bet, the original shafts are centerless ground. You can't get any good fitting for a ball bearing with a plain vanilla drawn...
  10. M

    Crankshaft model BMW R 75

    He has one already. And I can't afford one, I have to stay with my $5 bicycle. That would be a nice model, admittedly. I had a deeper look into that. The fins of the cylinder barrel and the cylinder head are quite thin, even on the original. So a reasonable scale would be 1:2. But still quite a...
  11. M

    Mill rattling

    That rattling is very common, not just for the Pessimum mills. Usual solution is a friction brake that slightly brakes the spindle and thus keeps the driving flanks in contact. Don't forget to open the brake at high RPM. :) Nick
  12. M

    Crankshaft model BMW R 75

    Only if someone wants them. hahaha I made a few, because it really looks nice if you arrange them in an array. I did not intend to build an engine around it. One is in the bag of my trousers now. But still, I can spare some of them or make a new run. I like crankshafts, they are like the heart...
  13. M

    Crankshaft model BMW R 75

    I don't have them. But a good friend in my little village. Nick
  14. M

    Crankshaft model BMW R 75

    Last but not least: A video Enjoy! Nick
  15. M

    A radial 3 cylinder compressed air engine ...

    Here is a short video of it running: YouTube I have cleaned the lens now! hahaha Nick
  16. M

    A radial 3 cylinder compressed air engine ...

    It is the other way round. The pattern is green and is a positive (embed in sand -> negative, pour with aluminium -> positive) Same with the core. Just an other breed of sand. The core box now? Well, I milled it. What can I say? :) Milled it in three layers (or two?) because it is quite deep...
  17. M

    A radial 3 cylinder compressed air engine ...

    connection rod Spinner Cylinder Cylinder head. If there's something missing, let me hear. Don't take all dimensions too seriously (like the 10.39, 17.49 & 24.48 in the housing's plan). Have fun! Nick
  18. M

    A radial 3 cylinder compressed air engine ...

    And now for the plans … Inlet tube Exhaust tube housing Piston crankshaft web Crankshaft shaft Crankshaft assembly TBC
  19. M

    A radial 3 cylinder compressed air engine ...

    Here are a few more pictures: The fully machined case. and from the back A cylinder barrel. The fins are 0.4 mm wide, the grooves too. Maybe a bit challenging. I'll change that in the drawing to come. The cylinder head. The left port on the left head is just a fake for the...
  20. M

    home made 3 cylinder radial engine

    I like it! Very interesting and distinct construction! Nick
Group Builder
Top