Originally Posted by Blakelidge  Thank you for your replies, so cool that people take time out to help others, maybe the World aint so bad as they make out on the news eh?
Well, I'm working in aluminium so that's pretty soft. Firstly, I trust I am getting my cogs in order?, looking in the gear end of the lathe, I take gears A,B,C,D with "A" being the uppermost and "D" being the lowest ("D" is fitted on the end of the leadscrew)
Assuming I am making the right gear locations, I set them up according to the thread-pitch lable printed on the lathe housing
Chuck my piece and face it to ensure it is true ( a 1" piece of rod about 3" long)
I agree with the 29 Degrees for the compound (not that I know, it's just that's what it said on mini-lathe.com) The compund is normally set transversely I.E its long edge runs parrallel to the bed of the lathe? To set the 29degrees, I loosen the two small hex bolts and rotate it CLOCKWISE until it reads 29 on the scale?
My next puzzle is this: On Mini-lathe.com he shows this photograpgh: [IMG][/IMG] this clearly shows the compound orientated not parrallel to the bed, but turned until its handle is facing towards the operator, albeit offset clockwise to 29 Degrees and with the cutter and toolpost mounted parrallel to the bed of the lathe, is that the correct way to do it? If so, no wonder I'm messing up, so should I set my machine as shown in the image?
Also, thanks very much for pointing out that I should back off the cutter PRIOR to reversing back to the beginning of the thread, I abviously made the wrong assumption that the cutter would have no work to do as it had cut on the forward pass already, but I did notice when reversing that the cutter was making a horrible chattering noise, so I now understand that I must back of the cutter (using the handle of the compound) prior to hitting reverse. I'm off to have another go, fingers crossed.
Thanks again
Dave |
Hi there, good to see that you now pretty much have the hang of it.
The bit I have highlighted in red that you experienced shows just what backlash is and how it can upset your day. As you reversed the machine you would have noticed that the screwcutting tool was no longer lined up with the thread properly but of course as you know it all comes good when going in the normal direction again.
Same thing with the top slide, if you feel you have gone a bit to deep (smaller diameter) on a part you just can't back it off a fraction you have to back a little bit more then go back in to the desired size. That's the backlash in the system again.
Hopefully I am making sense.
I just love it when people just like yourself are learning and stuff things up and then work it out. I feel a great sense of satisfaction for you as I did in my apprenticeship days when I did the same sort of stuff.
Cheers M