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

[awemawson]

Pekka,

There is a  pair of external terminals on the PSU labelled "Power Supply OK" - they are not connected, but of course may also be routed internally to the backboard of the logic crate. They seem to be a N/O relay contact that closes a second or two after the PSU is powered up. Certainly they change state when the 'Reset' button on the PSU is pressed then revert to the closed state after a second.

Of course I have no idea whether relay open or closed is the good state, but as with no mains they are 'open', the likelihood is that 'closed' is 'OK'

[PekkaNF]

Those PSU external contacts are normally routed to big red light on the control cabinet and to maintanance system to tell maintenace dude to change the filters..or check esternal cooling air system. Think that overheating and some other stuff trips them. There were more signals on the bus. But that was in S5 industrial PLC, just earlier noticed that much of hardware and numbers looks pretty much the same I was used to see - long time ago.

[Pete W.]

Andrew,

I've just been catching up on this thread, reading back to page 2 where you write about battery leaks.  I have some battery holders for ½ AA size lithium batteries (as used on old Mac computers).  I also have a few of the batteries as well (unused but they've been on the shelf for a few years).  If they'd be any help to you I happily put some in the Post.

[awemawson]

Pete that is an extremely kind offer, but these are very high capacity units. The cylindrical one is 8 ampere hours with a 10 year life expectancy so I don't think 1/2 AA would cut it in this instance.

I am going eventually to re-mount the batteries in a more accessible place, but will use the same type as original, and probably install capacitors across the leads where the batteries currently are to guard against stray pick up of noise.

[awemawson]

This is the coolant tank that slides under the machine and catches coolant from above. A pipe to a self priming pump sucks it back up and squirts it about at a great rate of knots.

Previous owner had left it outside to rust so it needs grit blasting and then spraying. Suggestions please for a suitable oil proof paint that will stand total immersion  for long periods.

[DICKEYBIRD]

TSuggestions please for a suitable oil proof paint that will stand total immersion  for long periods.

POR15 gas tank sealer maybe?  I used some of their rust paint on a rusty Ford floor pan & it did very well.  Dries glass-hard & seems to be very inert.  I would think their gas tank sealer would be even better.

[WeldingRod]

Truck bed liner.  Make sure they heat it before applying.  My father in law made a mobile steel pool lined with the stuff 10+ years ago.  Still going strong!

Sent from my SAMSUNG-SM-G891A using Tapatalk

[awemawson]

I realised that getting the coolant tank where it needs to be might be a bit of an issue, as the workshop is a bit cramped now (!) so I made up a bit of wood to act as an analogue of the tank  - much easier and lighter to manipulate - and in fact there is no problem.

But crawling on hands and knees to see if there was enough vertical clearance to put the tank on rollers (there may be) I made a DISCOVERY . There is a further big panel that can be removed at the back of the lathe (it's about 1 metre square) that I had previously missed. Taking it off it revealed that the original top of the coolant tank has been stuffed in there along with the coolant pick up and pump - just as well I found it before anything starts moving as the pipes are laying on the Z ballscrew. BTW the Z servo motor is HUGE !

Being able to get my head in the back of the machine here has let me have a better look at a mystery louvred metal box fixed on the rear of the axis drive amplifier cabinet. It's 15" wide x 9" deep  x 20" tall, has a single umbilical cord of Adaptaflex trunking going into it and absolutely no markings what so ever. I suspect that it houses a transformer or maybe from the shape several transformers  Perhaps I'll be able to open it up sometime.

[Pete W.]

Pete that is an extremely kind offer, but these are very high capacity units. The cylindrical one is 8 ampere hours with a 10 year life expectancy so I don't think 1/2 AA would cut it in this instance.

I am going eventually to re-mount the batteries in a more accessible place, but will use the same type as original, and probably install capacitors across the leads where the batteries currently are to guard against stray pick up of noise.

 

Fair enough.  I've just looked up the capacity of the ½ AA size lithium batteries and it seems to be only 1.2 Amp hours. 

[awemawson]

The nice man from UPS (Jock) came in after lunch with a parcel from Germany containing the replacement I/O card, Sheradised mounting plate and Umbilical cord that connects the Sinumerik 820T controller to the remote I/O unit. All second hand but looking in excellent condition

[awemawson]

So with no more ado I marked up the new items with the arbitrary numbers I had put on the old as I removed them, checked the jumper settings on the card and started re-assembling the I/O sub assembly.

It looks slightly better than it did 

[awemawson]

Then when I escaped from some neighbours who had dropped in for tea (excuse - I need to feed the pigs !) I was able to start putting that mad octopus tangle of cables back hopefully where they came from and re-fit the I/O sub-assembly from whence it came.

Apart from bally inaccessible screws it went well. I could then start re-wiring the Control Panel ready for re-fitting

[awemawson]

Now the corrosive fluid managed to put a drip or two on the 9 pin 'D-Type' plug and socket for the MPG Encoder - I've opened up the cable mounted socket and there was not much there to clean out - mainly just external - I've not opened the Euchner Encoder - I'll leave well alone unless it proves not to work when finally I get everything back together.

I've put the Control Panel back in place, but only with three screws - pushing my luck I suspect to 'assume' all is well in there


. . .that brings me to the end of the first week of working on the Beaver Lathe, and I think quite a lot has been achieved. But a long way to go yet I suspect before it's back up and running.

[Pete.]

Just goes to show you that something that looks on the outside to be a very nicely kept machine can hide a whole host of problems.

Is all that damage from one little failed battery Andrew or is there another source for the corrosion?

[awemawson]

Just one 8 ampere hour 3.6 volt Lithium Thionyl Chloride  primary battery Pete, but left for best part of ten years to  ooze and rot.

So as I'm going to have to wait a week or so for the Interface card and it's RAM Daughter Board to show up I thought that I might as well set the Coolant Tank up de-rusting with citric acid.

First I gave it a good thumping and scraping to shift as much loose rust as possible. Tipping out the loose made quite a pile. Then I blew it out with an airline, and set it up on 'builders trestles' strategically close to a drain and very carefully levelled it.

Then came bucket after bucket of hot citric acid, filling it until there was a meniscus visible so that hopefully the underside of the top surface will be wetted as well.

At least this has shown that there are no pin holes (YET!)

Covers over it over night to stop any wild life drinking it and dying 

No doubt it's going to take quite some time to have it's beneficial effect, meanwhile I can try and decide on a paint treatment that is affordable (large tank this!) and effective.

POR15 would be nice as would Glyptal but either would bankrupt me. The other suggestion has been marine quality two pack epoxy paint

[chipenter]

Two pack car paint stands up to a lot nowadays and is available everywhere .

[awemawson]

But doesn't it need extensive air fed masks etc?

[AdeV]

But doesn't it need extensive air fed masks etc?

It depends on whether you're sensitive to cyanoacrylates... apparently you can cheerfully paint away with 2-pack until one day your lungs pack in... or you can avoid the danger & use air-fed masks, etc., as you say.

[Will_D]

You've just re-furbed your hydrovane - so no shortage of air!!

Seriously though:

2 pack car paints sprayed in a sealed spray booth need an air fed mask.

Spray outside, be upwind of the painted object?

I used 2 pack brushed yacht paints (International 2 pack) with no problems. Am sure this could be sprayed without too much problem.

A lot depends on the chemistry of the two pack products!  AFAIK Aralidite does NOT contain a breathing vapors health warning

HTH Will

PS: More pig info/pics please

[awemawson]

According to the HSE vehicle paint sprayers have 90 times the chance of asthma than non sprayers:

http://www.hse.gov.uk/mvr/bodyshop/isocyanates.htm

[vintageandclassicrepairs]

Hi Andrew,
Would galvanising the tank be an option?
The last lot of hot dipping I got done was very good value

John

[awemawson]

It would be an excellent solution but probably pretty expensive, I'll ask around

[mc]

I knew POR prices had gone up, but never realised they're now that expensive.

My thoughts would be to speak to an industrial paint supplier, as they should have knowledge on what will withstand oils/coolants.
A quick google for milling machine paint, just threw up http://www.paragonpaints.co.uk/home.php
Certainly better priced than POR stuff, but probably worth a call.



PS you've obviously got too much spare time to do all these projects!

[vtsteam]

Hate to say this amidst the high tech solutions, but here, I'd just brush on some Rust-Oleum. I bulit a 13 foot by 4 foot shared coolant tank for two Fadal CNC mills this winter and added a centrifugal cleaner to remove the glass fines (these mills are used for diamond coring thin film coated glass). The coolant used is full oil, not soluble oil. And yes, I brushed it after fabricating, with less than a quart of Rust-Oleum. About $7, U.S. Been going 6 months so far. Paint is as new.

[awemawson]

That's very interesting Steve. They offer something here called 'combicolour' that sounds good, but whether it is the same formulation that is sold in the US I don't know, I'll give them a call today.

Whatever I use I'm coming to the conclusion I'll have to cut open the top panel of the tank to get proper access. Then a bit of redesign to refit a top.