Rebirth of a Denford MIRAC CNC Lathe

[awemawson]

Today I attempted glazing the door and was defeated, deflated and a bit hacked off 

It was going quite well, I cut short samples from the length of window rubber and checked that my superglue satisfactorily bonded it back together - it did and had good tensile strength. (Incidentally the only way I could get a decent straight cut was with a micro-serrated knife stolen from the kitchen - a normal Stanley knife blade was too short to do it in one swipe)

I then tightly stretched the rubber around the glass, marked for cutting off, and deliberately cut it 15 mm too short so it had to be stretched on. Then I glued it using an off-cut of the polycarbonate sheet for alignment.

Then the fun started - now the rubber was glued into a continuous loop it had no desire whatsoever to stay around the window pane, get a bit on and another bit would run for freedom. Multiple hands needed - in fact the wife was called to contribute another pair and even then it was winning all the time. In the interests of marital harmony I resumed on my own and eventually got the rubber on by the expedient of putting clamps on holding the rubber against the window as I worked round the pane (that should really be PAIN !)

Now remember I stretched this rubber tight then deliberately cut it short before gluing and yet it obviously is now too long 

So admitting defeat I've called on the services of Shaun who works for Autoglass and is a friend of a friend - hopefully he'll be round in a few days.

[awemawson]

So to cheer myself up I tackled a dent in the machines plinth. This machine has been roughly handled at some time - the lower edge of the plinth at the headstock end has thumped something and been badly dented. It has a flange bent under it and unfortunately the dent extended across the bend for this flange. Given decent access and an oxy-acetylene torch knocking the flange bend back square would be quite simple, but there is very limited access to the rear of this panel - no room to swing a hammer for instance. And the torch is ruled out as there is wiring and an oil reservoir in the vicinity.


So ingenuity, carver clamps and a bit of brute force were applied to restore some semblance of order. Not perfect but better than it was 

[Pete.]

That's where you need one of those spot-welder studs that screw into a slide hammer.

[awemawson]

Well Pete I do have a proper stud welder:

https://madmodder.net/index.php/topic,10287.msg116100.html#msg116100

I was considering rolling it out for this job, but huge current spikes near electronics that you can't replace took the shine off the idea.

The plate it's bent from is about 3 mm so fairly substantial - I suspect even M8 studs would struggle (that's the biggest it fixes) and the kink in the corner of the flange couldn't be pulled out anyway 

I suspect it'll be filled and rubbed down before painting 

[melgump]

 Hi Awemawson.
I think you are tackling the glazing procedure backwards. You should fit the rubber seal to the hole in the door ( or bodywork if auto) and if necessary hold in place with masking tape. Put the joint at the bottom. It is preferable that the rubber is slightly too long than too short. You then fit the glass from the outside and finally the locking strip. Always works for me.

Cheers,
Melgump.

[kayzed1]

I was thinking some thing along those lines, when i were a lad we used to fit the rubber to the frame then insert the glass, last the locking strip...in Mini's and Ford Escorts and the like..
Lyn.

[awemawson]

I've actually tried it both ways chaps with equal failure  Actually I've come to the conclusion that I've left too much gap between the size of the opening and the size of the polycarbonate so will re-make the window a bit bigger.

Today the PS2 sockets arrived allowing me to do the final drilling of the PC mounting escutcheon and give it a coat of paint. I did pick up some sockets a week or two back, but when they arrived they proved impossible to mount from the rear of the panel - I wanted to be able to remove the cable as an assembly rather than have to make it in situ and the PS2 plug end wouldn't fit through the socket mounting hole, and the thread on the socket wasn't enough to penetrate the escutcheon (2 mm)

The new ones have pigtail flying leads and rear mount onto the panel I'm sure that there used to be a male / female bulkhead PS2 fitting but I couldn't find one.

So today the escutcheon has been finalised and given a couple of coats of paint, and the keyboard and mouse PS2 cable assemblies made up ready for when the paint is hard.

Meanwhile my supposedly creamy white paint for the rest of the cabinet has arrived, but looks far too white to me - sample drying as I type.

[awemawson]

So with the paint reasonably dry (good stuff this paint!) I've populated the PC escutcheon, and re-routed the cables so at long last I don't have monitor, keyboard, and mouse cables erupting from the open enclosure rear door. So now the door can be closed and all those extraneous cables within have been tidied up 

I made another M6 bolt to celebrate 

[awemawson]

After supper I bent up a little bracket to support the Enclosure Isolator Switch Shaft, as it tended to droop a little and didn't always engage correctly.

Went remarkably well considering the two gin and oranges before and the can of Old Speckled Hen during supper 

At least now the two parts come together in correct alignment 

[awemawson]

Time to sort the stand today:

Lift off using Forklift and strops, then invert, remove castors, slap a coat of paint on, put the castors back on, put it back upright and paint the bits that were previously inaccessible.

All fairly straight forwards. I'm using the brushing version of the chassis paint that I sprayed the panels with - went on OK but a bit gloopy

I'll leave it overnight to harden before putting the machine back on.

[AdeV]

A fork-lift is high on my list of Most Desirable Things to Own... Can you post some pictures of yours so I'm sure to get a bigger one?   

[awemawson]

Hyster H2.50 XL Container Spec propane fired Ade - so it lifts 2500 kgs, fits inside a container for stacking and thus has a triple mast to keep the height down.

Only issue I have is the low ground clearance - no good on soft surfaces so don't go off piste 

[awemawson]

The paint on the stand has now hardened off so I was able to restore the machine to it's place on board - just a reverse of the Forklift trick !

Having done that stand I can now attack the rest of the paintwork - but I'm really not at all happy with the results of knocking out the dents from the plinth headstock end - it just looks horrid and will be worse when painted.

So I've bent up an 'overpanel' to cover the mess. It went really nicely. There is a little groove between the plinth and the machine tray, and by adopting a cunning technique I managed to make a very short bend that tucks into this groove and gives the impression it is the original plinth panel 

So how did I make that extremely short bend? Well first I bent an upstand of a couple of inches, then hooked it over the edge of the guillotine with the bit I wanted hanging downward, spaced off the blade by a couple of bits of 1.2 mm sheet. Then pressing the sheet onto the spacers with a long bit of wood to keep fingers clear, I stretched a leg far enough to kick the trip bar and make the cut. It actually worked very well but would have been easier with a second person to avoid the acrobatics 

Not sure how I'l fix that overpanel. Pop rivets would be easiest but look naf. Screws into tapped holes would work but loose the 'original' look that had no fixings. Don't want really to weld for reasons mentioned earlier. I'm considering using a structural adhesive.

(It's balanced with a rare earth magnet in the photo)

. . . suggestions please 

[awemawson]

Well  DEVELOPMENTS 

I've actually managed to fit the window polycarbonate into the sliding door  This was a result of watching yet another Youtube video :

I decided to see just how loose my already cut pane was - I'd allowed 9 mm for the web of the rubber, and according to the web site SealsDirect.Co.UK the choosen seal should have 7 to 7.5 mm, so not massively wrong. The already cut rubber seal was obviously going to be too short - I've bought another length, but I thought I'd have another try, and patch in the shortage just as a practice fitting the glazing.

This having been successful I'll pull it all off again and fit the new rubber.

[tom osselton]

Thats a good video it still doesn't look that bad with the patch piece in your window considering what it does I'd probably glue the ends and hang a don't look sign on it! 
When I stop scratching my head and my lathe comes to life I'll have to give the window enlargement a try thanks for showing!

[awemawson]

Well Tom I already have the replacement rubber, so hope to fit it tomorrow morning (assuming the gathering of the rams goes to plan)

It was a relief to actually get it in - I've done similar sized tractor cab windows before, but with standard factory sized glass and rubber seal.

[awemawson]

I did a pre-emptive strike on the rams and had them gathered before they knew what was happening, so could get on replacing the window rubber.


It went pretty well - no issue taking out the previous bit, and the usual struggle and acrobatics to get the new in but persistence won in the end 

Now at least there is only one joint at the top and it's slightly neater than before (not difficult!)

[awemawson]

As I can't get on stripping the cream coloured cover off  and sand blasting it due to the weather (a bit of snow this morning) I decided to attack the keyboard.

The user facing surface is legend printed on the underside, but it's not a membrane keyboard as such. There are individual switches below on a PCB. Now this upper surface has suffered a bit over the years. The lower right hand corner has had impact damage, and the plastic is peeling away all round the edge. The correct repair is to install a replacement plastic membrane, or even a keyboard, but as neither are available a work around was needed.

I decided to make a bezel that being held down by the same screws that retain the keyboard, would trap the plastic preventing further peeling, and cover the  major damage areas.

So I created a simple drawing in Autocad, exported a .DXF to Sheetcam to produce a  .TAP file of G code which I imported to MACH3 driving my CNC Plasma Table.

(Did I ever tell you I LOVE my CNC Plasma Table  )

It makes what would be a time consuming job simple, accurate and fast - how did I ever manage without one - how do you 

Being a low mass item, once cleaned up and suitably drilled I was able to get a couple of coats of black satin on it before lunch by the simple expedient of accelerated drying using a hot air gun.

Popped it on, tested all still works - job done and I think the keyboard will last OK now for a few more years

[nrml]

Why don't you get a replacement panel made? There seem to be a few companies doing this sort of thing.
https://www.fasciagraphics.co.uk/our-products/graphic-overlays
https://www.bex.co.uk/what-we-do

[awemawson]

Money perhaps 

Bezel = Zero cost - all bits to hand, all equipment needed to hand 

[nrml]

Can't argue with that .

[awemawson]

Apart from touching up, I think I've finished the black paint 

Quite a bit of rubbing down, masking and spraying going on yesterday and today - not perfect but perfectly acceptable.

. . . just the cream to do now 

[awemawson]

I've decided to experiment with the 'too white' machinery paint that I had mixed to RAL 9010

Having delved inside to a bit of the cream paint that hasn't been exposed to the sun, in fact it is far whiter than the rest of the machine. So I have diluted a bit by 10% and sprayed the headstock end removable  panel to see how it comes out.

All the black panels have been rattle cans (aerosols), the base frame was brush painted, but for the cream I'm using a small 'touch up' gun in the hope that it's a bit more controllable than my normal sized paint sprayer.

However this panel needs to harden off and convince me it's going to be OK before I commit to doing the rest.

[awemawson]

To facilitate the clean up of the remainder of the cream paintwork, which has rust spots in places and is generally a bit knocked about, I decided to revive a bit of kit I've had for decades, and frankly I'd forgotten I still had 

It's a 'Drester  1650-844' Spot Blaster. I think it was intended for the motor trade for detail blasting stone chips and little dents and is of a cunning design. The sphere is half full of abrasive medium, and just above the half way level is an extract port connected to a workshop vacuum cleaner. Fitted to the top is a co-axial hose leading to a hand held pistol. Down the  inner hose travels abrasive medium carried by compressed air and picked up by a 'straw' being sucked by a venturi. The media impacts the work, does it's stuff, and is sucked back up the outer hose and back into the sphere, any dust going into the vacuum cleaner.

This results in a blasting operation WITHOUT abrasive going everywhere (so long as the rubber nozzle is held firmly in contact with the work)

I picked this up from an advert in the local paper at least 20 years ago, and at the time I wasn't very impressed with it. I now realise that was because my compressor at the time was inadequate, and I was using actual sand.

Digging it out today I replaced the rotten rubber air hose, chucked out the sand and replaced it with fine crushed glass, and find that actually it's quite good for it's intended purpose of small detail work, and it will be very useful preparing the rest of the MIRAC for painting 

[tom osselton]

I have one that is about the size of a paintgun that was bought years ago from Princess Auto but it is only good for a 3/4 - 1" spot if I remember right.
Your doing a great job on the machines as usual!
I pulled some cards out of mine and put them back in hoping the problem was a bad connection but not so lucky I"ll go back out today and scratch my head some more looking at the scematics.