Oh Blimey I bought a CNC Lathe !!!!

[awemawson]

In practise, even with my largest tip on the torch it was a struggle to get up to temperature due to the large radiant losses from the disks of steel.

However I got there, and here is the built up blank compared with the sensor actuator that I removed yesterday with the slide hammer

[awemawson]

The silver solder seems to have flowed ok, but it'll be interesting to see just how well when I come to machine it. Next issue to resolve is how to machine the inner and outer faces truly concentric.

Current plan is to machine the inside to finished dimensions gripping it in the 3 jaw with the reversed jaws on the outer (rough flamecut) diameter, then transfer to the four jaw, indicate it in holding on the inner bore, then machine the outer diameter.

I may rough turn the flame cut surface first.

[awemawson]

Well I finished the new style proximity sensor thingy this afternoon. This is how it turned out, not forgetting the dustbin full of swarf !

[awemawson]

The braze line between the two disks in not perfect, but quite acceptable for the service this will see.

So hopefully if I can get a bit of time tomorrow I can re-fit the housing and set the proximity sensor up

[vtsteam]

Looks good from here. 

[awemawson]

Today I managed to set up the proximity sensor actuator etc and after a few tweaks got to what I think is a satisfactory result. It's a question of setting the length of my temporary adjustable adaptor such that the system acknowledges that the chuck is gripping WHEN the chuck is gripping and not loose 

I wrote a little diddy program to repeatedly clamp the chuck, start clockwise at 100 rpm, pause for two seconds then unclamp the chuck. This just repeats so that I could observe the led on the proximity sensor and the jaws of the chuck

[awemawson]

Then a took a couple of short videos of both ends of the action.

In this one you have to look VERY closely to see the chuck jaw mounts actually moving (no jaws fitted yet)

And this one from the outer end of the spindle shows the movement of the co-axial hydraulic cylinder and again by looking closely you will see the led on the proximity sensor going on and off as it crosses the step in the bit I made yesterday

I'll still play about a bit more but at the moment it's looking as if I need 110 mm of that 12 mm studding protruding forwards from my temporary adaptor.

Next step is to remove the chuck and adaptor, and reassemble it on the bench with 110 mm poking forwards, allowing me to measure a definitive length for my adaptor from end to end. All this is to avoid messing up when machining that huge chunck of expensive EN8 

[awemawson]

At last I got back into the workshop (had to clear half an acre of scrub that was over grown with bramble and gorse - by heck that flail came into it's own !)

Enough tests I decided - break it down and measure up what you need to make. So I removed the chuck having first carefully measured the thread protrusion. Then I re-assembled my mock up set to the same measurement, which allowed me to measure the over all length.

[awemawson]

So at long last I could draw up the part I need to make with a reasonable chance that it'll be the right size 

[awemawson]

So that big bar of EN8 was turned into an adapter and a HUGE pile of swarf

[awemawson]

So how did it go . . well ok except that I dropped a b@@@@k 

Cutting the female thread somehow I managed to set the lathe up for 1.75 mm pitch and not the 1.5 mm that it should have been - silly error involving putting a selector lever into position '6' and not '8'.

I remember making a scratch cut to check pitch with a thread gauge, the gate alarm went off announcing a visitor, I went and dealt with them, and came back and cut the thread WITHOUT checking the pitch. I got a funny feeling about it when I'd cut about 1/3rd of the depth, checked, had a hot flush, set the pitch correctly and re-cut the thread. It actually doesn't look too bad, but I'm concerned regarding it's tensile strength - if it strips the chuck will let go of whatever it is gripping and that's not a nice thought.

So I've decided to make another one 

However I continued finishing this one off, made a slight design change reducing the outer diameter from 82 mm to 79 mm which allows it to pass through the chuck converter flange, making assembly easier.

[awemawson]

Having reduced the diameter to 79 mm to allow it to pass through the chuck adapter flange has meant that I can get the replacement out of an 80 mm bar, whereas before I had to start with 100 mm - so the next one should make less swarf.

80 mm bar on order 

It has at least allowed me to operate the chuck - I've increased the operating pressure to 5 bar so about 1/4 full spec, which has let me experiment with some of the bored jaws that came with the chuck.

Next thing is to set up for jaw boring, so I need to investigate clamp rings that allow the boring with the jaws under compression.

[vtsteam]

Sorry about the mistake, Andrew. I know how that feels. 
On a regular basis! 

[awemawson]

Only myself to blame Steve!

But thanks for the sympathy

[awemawson]

Yesterday afternoon the new EN8 bar arrived, so today I re-made the adaptor sans cock-up, and it's installed in the lathe and works ok.

No pictures as it looks just the same as the previous one 

Now perhaps I can return the operating pressure to it's set point and start seeing if it grips ok 

[Meldonmech]

    We all make little mistakes from time to time, but it makes us more careful, glad you got the replacement made up, and all is well. 
                            Cheers David

[awemawson]

Well it all went well until lunchtime. In the morning I bored it out to size and cut the pesky female thread that I screwed up last time .

Then I stopped for lunch, and we'd just finished at 13:15 and there was an enormous 'crump' like a muffled explosion. Penny and I looked at each other and both shot outside down the drive to the road - the farm is on the A21 trunk road, but is only single carriageway down here. Sure enough a 'curtain sider' HGV and a 'panel van' were entangled in each other, both drivers being trapped in their cabs.

I stopped to call 999 and Penny went on to tend the injured. Turns out that the panel van driver was a goner with major head injuries, and the HGV driver had a punctured lung. He should be ok having been carried off in the air ambulance to Kings College Hospital in London.

The road was still closed both ways at 19:00 when we went out for a meal with whacking great cranes trying to shift the HGV, but has now re-opened (23:00). Certainly spoilt the day for several families I'll be bound.

After that it was a bit hard to concentrate on cutting the male thread - but it's now done !

It brings it home to you what is really important in life

[chipenter]

That road is always having accitents I have had some close calles , they overtake in the stupitest places I worked on the Blue Boys Inn oast for a few days two accidents on the roundabout , the owner said the fights are the most entertaining .

[awemawson]

Today I started a job I've been putting off for far too long: The main tool turret alignment was not quite 'spot on'

The turret slides in the 'X' direction which being a slant bed lathe is steeply inclined to the horizontal. The testing consists of putting a special cylindrical tool in the turret, and going round it with a DTI mounted in the chuck, turning the chuck by hand, moving X in and out until readings are the same in the direction of the X slide to front and back. Then measuring at 90 degrees 'above' and 'below' to see that (if the cylinder lies on the axis of the main spindle) will show no deflection.

In fact it is quite a bit out as see in these pictures

[awemawson]

So as you can see there is quite a 'height' error. Correction is by rotating the tool mounting block relative to it's 'stopping point'  to get the height reading correct, then putting in the 'X' position into parameter store to say where zero is.

Simples  If only one knows how it's all fixed together. I have a right up describing the turret, but it doesn't include the large chunk onto which all the tools mount. Now the rotating tools and the turret are made by Sauter, so I emailed them asking for a drawing so that I knew what I was getting myself into.

Oh no say they - the tool mounting block is made by Traub (the maker of the lathe) Very strange - you'd think it was all from the same people  However traub managed to email me this drawing:

[awemawson]

So it turns out that there is a circular 'Tee Slot' in the rotating bit of the turret body, and bolts go into Tee Nuts holding it in place. Just get on with it, pull it apart, slacken those bolts, tap it into place, tighten up and bob's your uncle 

So first we need to open up the cover plate to expose the cap head bolts - only all that turret is packed with unbelievably expensive special 'liquid grease' that took me months to be able to source. Luckily I had to buy a sizable drum so I have enough to re-pack it. Expecting it all to come pouring out (after all it's 'liquid grease') you'll spot a baking tray balanced below as I take off the cover (don't tell the wife)

[awemawson]

Someone has obviously been in here before me, as the sealing 'O' ring is incomplete - not just broken, it's not all there! Also there is evidence of trauma to the plate - something has whacked it pretty hard, quite likely this is what put the alignment out.

To expose the heads of all eleven (strange number!) of the retaining bolts it was necessary to remove the driven tools holders as they cross across the bolts in some places.

So at last the bolts are in view. Just need to do a comprehensive clean up, make the adjustment and put it all back together. Shouldn't be too bad from here on but family duties call and I probably can't get back to it until Sunday 

[vtsteam]

I hope this Traub appreciates its owner's commitment! 

I'm glad the saga of rehabilitation isn't over Andrew,, and somehow I suspect you are, too......   

 

[Pete W.]

Hi there, Andrew,

I agree with Steve, full marks to you for stamina and tenacity.          

And I do admire your ability to charm these big firms to provide you with all the technical support. 

[awemawson]

Thanks chaps 

After all, from the start the project was always intended to be an interesting and challenging journey rather than necessarily getting to a particular destination.

Now I'm actually using it I'm fine tweaking things and making the tooling and holders to make life easier.