The Craftmans Shop > New from Old
The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
awemawson:
Been trying to resolve the 'Turret Unclamped' switch issue where it seems very slow to operate when cold taking up to 10 seconds for the contact to close when the Turret it pushed forwards for a tool change by the hydraulics.
It is a Euchner EGT1/4A5000 'precision mechanical switch' rather than a micro switch or proximity switch as one might have expected. It's end is a ball that bears on the turret shaft that has a suitable ramp shape so the the switch is made in the unclamped forwards position, and open in the clamped reverse position. I had already removed it, lightly lubricated it's shaft and replaced it, but the symptoms persisted. Putting my meter across it and hand operating to be frank there wasn't any stickiness apparent, so maybe it was just mal-adjusted.
The construction is awkward in that the adjustment collar and locking nut are not 'get at able' when the flange mounting is installed, so any adjustment has to be a long drawn out iterative affair, making a little tweak, re-installing, trying and then removing again for another tweak. The movement from open to closed is microscopic, so that the adjustment took many iterations :bang:
I have tracked down a very expensive replacement but hopefully today's tweaking session will have resolved the issue. Interestingly it's locking ring was by no means tight when I first removed it.
awemawson:
I set off this morning with the intention of doing a bit of tool setting, then writing a diddy program to incorporate the Spindle Positioning and milling using the powered tooling.
First set back was no spanner to lock the ER32 spindle for tightening - well I had one but too thick to fit, so the usual 'go plasma cut one' - it may look spindly but that 6 mm steel is not mild steel, something much stronger .
Then I'd just got the 10 mm end mill snugged up when visitors descended, and absolutely no chance of tool setting with questions being fired over my shoulder - you need to concentrate to avoid breaking the Renishaw Tool Arm - I gave up on that !
So I just did a bit of manual milling putting notches at 45 degree intervals round the periphery of a 1" bar - majorly unimpressive but proves the ABS drive dog will transmit a bit of torque and that the M19 spindle positioning locks on adequately.
.. so proof of concept rather than a major step, and when the dust settles, probably in the dead of night, I'll get back to what I started out to do :med:
awemawson:
A few developments today:
Firstly the Ebay seller having failed to sell the Euchner EGT 1/4A5000 precision switch has accepted a more reasonable offer, so that is on the way from the states to hopefully just be a shelf spare and ward off any more 'turret unclamped undetected' issues.
Secondly I've had a very reasonable quote for casting a couple of drive dogs in bronze, so a pair of PLA models went in last night's post to Sheffield.
Thirdly, having a bit of piece and quiet this morning I've completed my cycle of tool setting without breaking the HPA probe - phew.
So on a roll, I decided to see why the remaining powered tool doesn't locate properly in the turret - I knew that something interfered, but couldn't remember what ! It turns out the the Beaver turret has a face mounted swarf guard in the middle that occupies part of the seating plane that the 90 degree tool wants to sit on - as it has an internal gear box it's more bulky than the others.
So there are three possibilities that I can see:
A/ Cut a bit out of the swarf guard - don't like this as it means when the tool isn't mounted swarf can get in
B/ Cut a bit off the 90 degree tool - a possibility as the interfering bit houses a micro positioning feature not used on the Bever turret.
C/ Sit the 90 degree tool on a 3 mm spacer - probably the easiest solution but I'll have to extend it's drive dog to suit.
awemawson:
I decided that it was time to pull the new cables through for the Renishaw OMM probe that PK is kindly working on for me.
This needs doing as the existing cables (as previously mentioned) are just draped roughly in place and not in trunking despite there being a suitable run. Another motivator is that I need to re-fit more of the cabinet metalwork that guides swarf and coolant back to where it belongs, and when fitted, the trunking is no longer accessible.
First job - test fit the socket box that I made weeks ago - a bit of adjustment and it's fine :thumbup:
Then start exposing the trunking and removing as little as possible just to allow me to get a 'pull through' in place to draw in the new cables. I wanted to draw from the rear chuck end cabinet, through the cabinet behind the tailstock, and thence into the duct emerging below the Siemens controller. This allowed me to leave the reel of signal cable uncut and in the rear chuck end cabinet, to await a new piece of flexible conduit that I will install taking it to the place the OMM receiver lives on the left face of the enclosure above and behind the chuck. Currently this cable just hangs in the air unprotected :bugeye:
Now I have two types of pull through. Very flexible nylon cord intended for pulling 'singles' through round conduit, and pretty rigid fibreglass rods that screw end to end in the fashion of drain rods (but much thinner) - intended for poking wires across ceiling voids. I had to use both, using the rigid ones to get the flexible one into place, which then could draw in the cables. Didn't go too badly considering, but cable drawing is always easier if there are two of you (which there weren't !)
awemawson:
...cont:
Now I just need to remember how all this tin work goes together :scratch:
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