Well guys - I survived installing the new lathe and am now making all the mistakes I made 60 years ago when I used a lathe in school !!
Have bought a H and F Optimum 2506V which seems to be a mixed bag.. just have to keep reminding myself that it is basic but so is the price !

  • My first surprise was when setting up to change gears, wondered what the mysterious grit was all over the ones installed and those in the bag. Turned out to be sand - so a few hours of cleaning ensued !
  • Second having got basic turning working, decided to do a taper using the compound slide - started the setup by checking the accuracy of the dial on the slide and found out it was out. With the slide set on zero, got a taper of around 1mm in a 40 mm section. Spoke to H and F who said just to remark the line for zero on the slide - not terribly impressed !!
  • I then started on screw-cutting - have memories of crashing the tool into the chuck at school when I didn't get to disengage the half nut in time and the slowest speed is 150 rpm - so went on You Tube and found a couple of brilliant videos showing manufacture and use of a hand crank to do short threads


  • The result of the above was that I made a rough version of the hand crank then cut a half decent thread in a section of brass bar.



Now the problem

  • I have had two or three goes at cutting a thread under power, (using a long test piece to keep me away from the chuck ! ).
  • I have made a thread cutting tool from HHS and also tried a carbide tool that came with the lathe
  • I have checked the thread indicator gear and that is correctly engaged
  • The tool is locked in tight and the 60 degree is at right angles to the work and at centre height
  • I have the speed set at around 400 rpm
  • I am using a 20mm brass bar that I have turned down to 18mm to cut a M18 with 2.5mm pitch - all the gearing is correct as per the charts on the lathe to give 2.5mm
  • I start up, engage the half nut and when I do a scratch cut the thread pitch is correct ( I have my dads old thread gauges).
  • When I go back to do a shallow second cut ( engaging the half nut at the same number), the tool does not engage in the same place and makes a second track ( also at 2.5mm)
  • What are the likely issues I should be looking for ???



Thanks
Rumble


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