The next step was working out where to position the reader to get the full length of travel from it. I measured how much space the X axis scale would take up when fitted, added a couple of millimetres for clearance and used that as my forward limit. I then marked the base and drilled and tapped the base.
This is the Y axis scale fitted with it’s swarf cover and working.
There was a convenient ledge on the side of the bed casting which allowed me to add a parallel to get the backing plate up to the right height to mark for drilling the mounting holes. The 123 block is just holding it in position.
I added some engineers blue and marked the holes with a scriber then punched the centre.
Drilled, tapped and cleaned up with IPA
The backing plate in place, so far so good.
A trial fit of the scale to work out where the reader needs to be fastened to.
At this point I realised that I would need some packing pieces behind the mounting plate to make it stand off due to the useful ledge that I referred to earlier and allow the reader a clear track without being forced to run at an angle and to allow the fitting of the chip shield which didn’t quite fit when flush against the table.
I used a slitting saw to cut down some sheet material which some bar stock had been attached to to stop it being bent in the post. It’s quite interesting material in that it is two layers of thin aluminium bonded either side of some plastic material. Being layered it’s remarkably strong and light and I thought it too good to throw away so it went into my useful bits box.
You can just make out in this shot where I slotted the vertical mounting holes in the angle bracket, again to allow the reader to track without adding undue pressure. You can also see the packing strip between the mounting plate and the edge of the table.
The Warco items duly arrived and each scale, came with a main rear mounting bracket and a pair of additional mounting brackets (Shown below) and a selection of M4 and M5 cap screws.
Main mounting bracket.
Warco Glass Scales Mounting Brackets
These are the additional brackets that were spare as I only ended up using one of each along with some sections of aluminium angle which I had rescued from a set of shelves that I had dismantled.
To ensure that the job wasn’t stopped for lack of drill bits if I broke any, I put in and order to Drill Services Horley for a couple of 3.2mm and 4mm drill bits. Of course because I had them to hand I didn’t break a single drill bit.
All the holes drilled in the mill itself were done using a battery hand drill and being cast iron it was quite easy going if a bit messy.
The main mounting bracket holds the glass scale and then the read head is mounted so that when either the read head or the scale moves it reads off the distances. In my installation I have the scales mounted to the moving table axis and the read head’s fixed to the machine bed. On the Z axis this is reversed and the scale is fixed to the column of the machine and the read head moves up and down with the milling head.
I decided to start with the Y axis as being one of the shorter ones so easier to handle and definitely the easiest to access on the left side of the machine. However as soon as I took the 100mm scale out of the packaging I knew that I had made a mistake in getting a second 100mm scale for the Z axis although it would be fine if I was working with the vice or rotary table mounted on the bed it wouldn’t allow the head to come down far enough to mill anything directly mounted to the T slots of the table.
I immediately contacted Warco and explained my error and asked that since I hadn’t opened the second scale, would it be possible to return it, and swap it for a 200mm scale. They were happy to do so and would sort out any additional cost incurred once they had it back with them. I returned it to the address on the signature of the person who had sent the invoice. This proved to be a mistake as it turned out that they had moved from that address so the package was returned to me. I called them and advised that there would be a delay due to my sending it to the wrong address which was on their email.
I looked at the actual invoice and noted their new correct address and re sent it there. As good as their word they very quickly despatched the replacement and didn’t charge me a penny which despite my frustration at them not having the correct address on their correspondence I did appreciate.
For my birthday last October I received a Digital ReadOut (DRO) kit for my Sieg SX1 LP mini mill. I fitted it over a weekend last October and although I took photos as I did each stage, I haven’t yet got around to writing it up. Paul’s posts (@OzzyO) on fitting a DRO to his mill prompted me to get my finger out so that anyone who is interested will get a couple of takes on fitting them to different types of mill.
As I am not anywhere in the same league as Paul when it comes to machining, my first port of call when looking was to YouTube. To see if anyone had done a video on fitting a DRO to a similar mini mill. I was quite surprised that at that time there wasn’t any to be found (there may well be now as I haven’t looked since).
Having realised that I was essentially on my own, my first port of call was to ring Arc Euro Trade whom I bought the mill from. To ask if they did a DRO kit for my mill. I was a little surprised that they didn’t, as they seem to cater well with other accessories and tooling for the range of machines that they sell. Their recommendation was to talk to a company called Touch DRO who apparently do something suitable.
I have seen a few videos which featured Touch DRO units and confess that I was not keen on the idea. This is on the basis that they require the use of scales, which connect via Bluetooth to a tablet for the display. I spent 20 years in IT support and the last thing I want is yet another device.
Again on the basis of seeing a few videos on badged variants of the units supplied by Warco I opted to buy from them. I got a display reader, two x 100mm glass scales and one x 250mm.
The idea was that I would use one of the 100mm scales on the Y axis (front to back movement of the table for those unfamiliar with the axis terms) and the other for the Z axis which is the up and down movement of the mill head. This latter proved to be a mistake which I will elaborate upon later. The 250mm scale was to be used on the longer X axis table (which is what the LP designation of the model number refers to).
Following on from my An Evening With session last night (which I thoroughly enjoyed and I hope all those that joined me, did too) I can now share with you how I managed to hold the chimney centrally in place when soldering it.
Whilst machining the base of the chimney I had deliberated from the outset how I might best hold the chimney in place after machining and I had considered boring the base out and adding a short length of tube to locate it when it occurred to me that solder doesn’t stick to aluminum so why not use the arbour to centre the chimney. I parted the end off the arbour and machined the sides so that the chimney sat down properly the other way up.
Centring Support for chimney for soldering in placeCentring Support for chimney for soldering in placeCentring Support for chimney for soldering in placeCentring Support for chimney for soldering in place
Then using a makeshift arrangement of blocks and strips of wood I fed the modified abour up through the chimney hole in the smokebox.
There was enough solder remaining on the smokebox from where the chimney hadn’t sat down flush initially, so some flux and a waft with my microflame had in place in no time with no cleaning up.
One of the things that I have never been entirely happy with on previous locos is the fitting of additional lead weight to the boiler. Tank engines are a bit simpler because the lead sheet can be fixed in the tanks and enclosed. It’s not so much the fitting of the lead, so much as how to retain it and stop it from shifting over time.
Previously where needed I have used epoxy or 100 degree solder to fix it in place (I have built a number of DJH kits and on those the weight of the cast boiler was more than enough without adding additional weight). This time I thought I would try a different method first I rolled up some sheet lead and then some adjustment to make it fit. I used a hollow punch to cut out a section to fit around the base of the top feed which helped to hold the lump of lead in place next I drilled the bottom of the boiler being careful to site the hole behind the middle splasher so it wouldn’t be seen from the side. Then I tapped the hole as deep as I could 10ba and then screwed in a 1 inch 10 ba screw being soft lead once the screw got beyond the tapped section it continued to cut it’s own thread and now the ballast is held firmly in place.
DA Princess Screw to hold lead ballast.1 Inch 10ba ScrewDA Princess Lead Ballast
I would be interested in the methods used by other builders to retain lead ballast in boilers.
The last week or so has been spent on lots of little jobs that don’t seem to change much visibly on the model. The visible bits are the trimming of the cylinder drain pipes and having to rethink how I planned to mount and retain the motor from moving.
I also milled a hex on the ends of the front crank pins to replicate the fitting on the prototype.
DA Princess Front Crankpin
I had initially envisaged that the mtor would sit flat and I did add a nut on to a frame spacer to retain it via a strap around the motor but it wouldn’t fit through the hole in the firebox with it in this position. My final solution was to replace the rear frame spacer with one that is removable. This was needed because the large final drive gear on the ABC gearbox wouldn’t pass between the gap under the existing frame spacer and the top of the rear frame section. A different motor gearbox combination might not have needed this solution.
Now that it’s removable, the motor/gearbox can be lifted out for maintenance etc. and the position of the spacer once fitted, also acts as a stay preventing the gearbox from rotating about the axle. Win, win.
The last parts to be made and fitted are the cinder guards that fit on the cab side. Even though they are nickel on this kit, they are very vulnerable and a friend mentioned that he always models them folded back which seems like a good idea. but I was concerned about painting around them. I also had the idea that I would like them to fold in like the real thing and so I decided to experiment with the extra etched frame that David supplies.
I cut off the two pegs that fit into holes etched in the cab side and soldered a length of 0.5mm piano wire on the back of the frame. Then I drilled a length of 2mm x 2mm brass angle at the ends and soldered in some filed down brass dressmakers pins which I cut down to fit through the holes in the cab. I then drilled the other leg of the angle to accept the pain wire and once soldered to the cab it folds back just like the real thing.
Having got the first one fitted I made up the second. Which I took a photo of. Keen eyed readers will note, that there is only one bracket. Sadly, the second made a bit for freedom as I was shortening the peg after a test fit. So unless a miracle happens I will be making up another.
Today saw the last of the tiny components that make up the cylinder drain pipes made and assembled. I also ended up with a nice little bag of extra nuts. I made six for the operating bar and then decided they were a little big (lengthwise) so I made some smaller ones.
Each one is made from 16 individual parts and the valves are a bit of a work of fiction because I couldn’t find any clear photos of what is actually under there but they pass muster when compared to the castings that I have in various kits and at least they fit this particular loco.
The clips that hold the pipes together are still loose and able to slide along the pipes at the minute until I get them fitted and can determine their final position.
I asked a fellow modeller if he had fitted the cab roof yet, because it too has been yet another challenge to overcome.
The reason for the challenge is that the profile of the roof rib visible in the shot of the roof below is a different profile to that of the rear frame of the cab which supports the cab roof at the back.
David Andrews Princess – Sliding roof Shutters
When I first fitted it the front of the roof didn’t go anywhere near the front of the cab (it did fit when I first “rolled” it some time ago. To get around the issue I cut a front rib to fit just inside the cab front which brought the front of the roof into the right shape again
DA Princess Cab Fitting
This left a gap in the middle of the roof at the rear which I filled with solder (just visible in the photo below as is the additional rib at the front of the cab). Not very elegant but it works.
The last items to make for the Princess, are the cylinder drain cocks/pipes. The castings were missing from the kit and I looked at those offered by Laurie Griffin and Ragstone but I wasn’t convinced that they were suitable for use on the Princess and decided to make my own.
They are not yet complete but this is the first step. The making and alignment of the pipes themselves. I made a jig from a strip of nickel sheet which I milled a series of grooves in. The grooves were milled to suit the etched holes in the bottom of the cylinders with spacing of 10mm and 9mm
I milled them using the point of a countersink bit and supported the material with a shop made machinist jack.
DA Princess Making the Pipe alignment jig
I did the same on each end of the strip of material to give me a top and a bottom for the jig.
DA Princess Making the Pipe alignment jig
The two half of the jig were loosely placed together and the legs of the pipes fed into them and the engineers clamp tightened to hold the horizontal parts together. A small G Clamp and a hair grip made sure that the pipes were vertical to each other and couldn’t slip while I soldered them.
DA Princess Cylinder Drain Pipes – Wrong Way Around
I wasn’t really concentrating when I cut and bent up the pipes and I ended up with enough for two pairs. To compound that minor error I had placed them in the jig the wong way around and I had the 10mm and 9mm gaps the wrong way around. I could have unsoldered them but felt it was easier to cut some more and add these to the spares box.
DA Princess Cylinder Drain Pipes – Right Way Around
I cut these a little different and left the outflow end of the pipes a bit long to cut down when fitted. Oddly when I put these in the jig the other way around I didn’t need the G Clamp, the engineers clamp was sufficient to hold them in place.
Although I had fitted the handrail knobs to the boiler and smokebox earlier last week, I hadn’t added those on the resin firebox. This was for no other reason than the superglue was upstairs in the fridge and I thought it easier to crack on with something else and bring the superglue down later.
When I did subsequently fit the remaining knobs in place, those on one side were fine but for some reason both on the other side didn’t seat properly and the glue set as I was trying to push them home. I tried pushing them in with pliers and gently tapping them but I was very concerned that the resin firebox might crack if I was too vigorous. They didn’t stick out by much but I wasn’t happy having put so much effort in with re-seating the chimney etc. It was during commode time (a term picked up from an american machinist who I watch on Youtube) that an idea came to me.
This morning in between making the end caps for the handrails I plucked up the courage to give it a go. I got a short offcut of the 0.8mm piano wire that I have made the handrails from and put a small bend on one end gripping the wire in a pin vice just in front of the bend.
Tool for extracting handrail knobs from resin casting
I popped the bent end through the hole in the first offending handrail knob. I chose the one that was furthest in, to try the proposed solution on. Then I connected the negative terminal of my RSU to the piano wire which protruded from the handle end of the pin vice. A quick touch with the probe and a slight twist and the knob thankfully popped free without issue. Buoyed by this success, I repeated the same on the second offending knob and I had barely touched it before it popped out.
As a precaution because I was heating superglue/resin I had the extractor fan running at the side of my bench just in case any fumes were created. I was probably being over cautious as the glue just seemed to slightly soften rather than melt.
Then it was a simple job to re-drill the holes making sure that the knobs were a loose sliding fit before attempting to apply more glue. It was at this point that I found out why one of them wouldn’t seat properly. There was a slight rim around the shank on one which prevented it from seating flush. It wasn’t really visible but when I ran my nail across it I could feel the ridge. To save time I swapped it for another one from the stores and both were fitted properly.
