Oh Blimey I bought a CNC Lathe !!!!

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awemawson:
Thanks chaps for the support - should be signed off (or is it back on?) in a couple of weeks - hooray I can drive again.

Anyway back on topic. :ddb: I cut my first thread today :ddb:

It may only be simple but it took a long time coming :clap:

This is the first 'real' operation sequence since I got the lathe running. First I cut the profile of the thread, which is 20 mm o/d by 25 mm long with 45 degree lead in and lead out, cut from 25 mm mild steel stock. Then I cut the thread itself, which is 1.75 mm pitch using a 'partial' thread form insert as that was the only one I had on a tool holder! Then profiling was an exercise in "G96" roughing cycle following a defined profile. Then the thread was a "G76 thread chasing cycle"

Made my head spin understanding all the parameters but we seem to have got there!

Only slight down side is that I've had a few 'trip outs' on the axis drives - no real rhyme or reason and so far they've always reset, but there's something lurking there still :(

Anyway on a more positive note have some pictures, and a video will follow as soon as it's uploaded

lordedmond:
that looks a fine thread ( I mean a well curt thread ) was it on spec ?

better get down to chasing those pesky bugs , but I fear that you may well have a few more to sort the more you use the beast

Stuart

mattinker:
Those moments when it all works, those moments are special...................

Regards, Matthew

awemawson:
Here's the video of the screw cutting. The 'roughing' and 'finishing' tools are in fact the same tool as the roughing tool I had mounted fouled on the 45 degree chamfer nearest the headstock.

I'm using 'constant surface speed' machining so if you listen hard you can hear the spindle changing speed with the diameter of the cut.

awemawson:

--- Quote from: lordedmond on October 21, 2013, 11:27:33 AM ---that looks a fine thread ( I mean a well curt thread ) was it on spec ?

better get down to chasing those pesky bugs , but I fear that you may well have a few more to sort the more you use the beast

Stuart

--- End quote ---

Stuart, well it's what I aimed for :clap: I don't think 20 mm x 1.75 can be a standard by any means. The pitch is as right as I can measure it, and the o/d is dead nuts on at 20 mm as I specified, whereas if it was being made for proper the o/d would be slightly under nominal size. Thread form is down to the insert, but looks ok in comparison to a thread gauge. I've bought a new set of metric full form inserts, but didn't want to mount them and wipe them out whilst learning :bugeye:

Andrew

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