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The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)

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awemawson:
It always amuses me when making PG threads, which I've had to do a few times for Commando Plugs & Sockets, that all the dimensions are metric, until you come to the thread pitch, which is 'turns per inch' - 16 in  this case  :ddb:

So a plate got cut out from 9 mm steel, painted and bolted up with the 63A socket on it. The SY cable was pulled through the internal ducts and threaded up the 'riser' protected by an anti chaffing shield, then fixed to the main electrical box roof, made off to the Main Machine Isolator and plugged in.

. . . the moment of truth . . no putting it off . . . time to throw the switch Igor  :bugeye:

Now I had been concerned if any damage had been done, as just after the initial tripping and my attempt at a re-start, the main transformer had been making alarming humming noises, presumably running on only two phases. Hence my concern  :scratch:

So, switch on, power up the controller, home the axis's - all well so far - try and home the Tool Turret - cycle starts but never ends  :bang: The dreaded Tool Turret  :bang:

Actually it was simply an internal breaker that had tripped, presumably when 'two phasing' - reset it and all was well.

As a matter of interest I put my Fluke clamp ammeter on 'peak amps' - 90.5 for a very brief time, but usually about 20 per phase

awemawson:
For peace of mind I ran the threading program several times over and over, then measured the temperature rise of the 6 mm 5 core SY cable, and the 4 core SWA cable. Both had gone up by only 7 degrees, so unless I go into mass production of widgets 24/7 I reckon I'm in the safe zone. Both cables are rated up to 70 degrees C and they only got to 30.

While I was in the measuring mood, I put the clamp meter on the DC armature drive cable from the KTK Mentor to the 27 kW Mawdsley spindle drive motor. 109 amps peak  :bugeye: But well within spec

Then I measured the average on phase one of the 415 volt three phase input - only 18.8 amp - but peak 90 plus as above

awemawson:
Indulge me, and bear with me as I try to sort a few things out in my head regarding tooling  :scratch:

I'm getting tied in knots trying to set up tooling in Featurecam to match what I have and also to produce workable code, but there are just too many variable :bang:

Firstly, this is a single turret slant bed lathe, with the turret BEHIND the spindle - Featurecam details an Upper and a Lower turret, so I assume that the upper one is relevant.

Then (Obviously) the spindle can be programmed to turn Clockwise or Anticlockwise

Then tools can be Left Handed (LH) or Right Handed (RH).

Now the turret Tool Holders come in two flavours so that when using a LH or RH tool, the reference surface passes though the centreline of the turret to allow the correct tool height to be set, and for left handed tooling the spindle needs to rotate CLOCKWISE, and for (inverted)right handed tooling the spindle must rotate ANTICLOCKWISE.

Only the left hand version keeps the force downwards into the bed as in a manual lathe, but the turret and slide arrangement are so massive I don't think that this is an issue unless VERY heavy cuts are taken.

OK fairly simple so far, BUT, each tool in the Tool Crib is defined for CW or CCW rotation, and the M codes for these are embedded into the Post Processor, CW being M03 and CCW being M04

All well and good, but setting all these sensible values FeatureCAM has the spindle rotate in the wrong direction  :bang: Easily changed in the Post Processor coding by swapping M03 & M04 but it's very odd to need to do it.

Having sorted all that, programming a normal right handed thread produces a left handed thread  :bang:

Now I have a feeling all these oddities revolve around the choice of turret (Upper or Lower) - but as soon as I select the other turret the program refuses to allow me to pick the correct tool as it swears blind that the tool is intended for the opposite rotation - argh, my head hurts  :scratch:

Have some tooling pictures

seadog:
Maybe their interpretation of what is left or right handed is not the same as yours or mine?

DICKEYBIRD:
It should be that M3 causes the spindle to rotate clockwise as viewed from the rear of the spindle or chuck & M4 the opposite direction.

I know you British folks drive on the left side of the road but do your clocks run backwards :bugeye: as well?

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