4472 Flying Scotsman 5"

[Grasshopper John]

Brilliant as always Pete.

[greenglade]

Thanks John.....

 

Hi guys

I decided while I was working on the expansion brackets that it was about time that I made the links themselves, Some may recall that Malcolm (MEL) drew these up for me in CAD some years ago and then got them laser cut, these are now available in his range of laser cut parts for Doncaster, in fact there's an awful lot of parts in the range that were done to my request, drawn by Malcolm and also many others that were drawn up for me by John Baguley, I am most grateful to both. Having now worked on these I can highly commend them to other builders of Gresley's A1/3/4. If building an A4 you will need the later expansion bracket, same goes for the A3's but you'd need to research when the upgrades for your particular loco were done as many started life with the early A1 bracket. FS today has the A4 bracket fitted.

Anyway, to begin I'll post a picture of the link on the full-size loco for comparison, this is the R/H side which also has the spigot for driving the lubricator arm, more on that later.



I'll start with a picture of the laser cut parts laid out for clarity, I have already made a start of filing off the rough laser cut edge on one of the links and give it a quick polish.



This is the order that I've tackled things, first I silver soldered the spacer tabs to the inside face of the trunnions, remembering to make up two pairs. The picture shows how I held the parts, the right-hand base is magnetic and each tab was held with a strong clip. Both faces to be joined were covered in a fine layer of flux, a strip of 0.5 mm SS was laid against the join and the whole lot was heated from below, each heating session only took approx 30 secs.



Here are the 4 trunnions after soldering, note they are paired, as seen here they are actually upside down, the shorter slot goes to the top. It's important to get this right as they won't fit into the bracket upside down.





Next up was the 4 journals to fit into the bracket bearings, 3 are identical, the 4th has a spigot on the end to operate the lubricator arm, this is for the right-hand side where the two lubricators sit on the running boards. Journals are 7/32 long and 7/32 dia, I needed to include 1/16 that's a drift fit into the trunnion.



A picture to show a journal silver soldered in place, as I said these are drift fits, I filed a small chamfer around the bottom and also a few small cross nicks to aid penetration of the silver solder. These were heated from below with a ring of 0.5mm SS placed around the joint.



I then needed to drill the 4 bolt holes, these are easy enough as the trunnion has already been spotted by the laser, all I had to do was line up with the hole and drill through, as can be seen, this was done while held flat in the machine vice.



and so after a good clean up, we have the near-finished article...I have shown the link from the rear to show the lubricator drive spigot and also that the rear trunnion faces are CSK for clearance.



a close up of the link in position, I have to say that I was very pleased with how this fits/looks, no issues in getting the 3 sections together within the bracket. I have no bolts long enough so it's only barely held in place for now. A couple more things to do, I need to drill/tab an 8BA hole to lubricate the eccentric rod bearing and of course turn up the 5/32 bronze bearing to fit.



The final picture for tonight I have taken at a similar angle to the full size shown at the beginning of tonight's update, I think it looks the part, once I have reduced the size of the oil cup lids I think it will be pretty close...



Thanks for looking in guys...

Pete




 

[greenglade]

Hi all

I have done some more work on the expansion links, I think that will be it for now with these. Jobs left to do are the oil pot/caps for the eccentric rod bearing. I have no drawings for these, I'm guessing that they are similar to the oil points on the coupling rods although made out of brass going by the pictures I have. My pictures show no sign of 'cork stoppers' all I can see is a brass coloured flange around the oil hole. So I'm not sure how these work? if anyone knows (Andy) please give me a shout.

The first picture is a closer view of the expansion link on FS that I took at York a couple of years ago. I have tried to follow this with one change, that being the top bolts in the link, looks like they are shallow round heads with I guess the nuts and spacers on the rear instead of the front as with the lower two bolts. It's obvious that this is to give plenty of clearance from the running board flange. This would be a pain trying to fit the nuts from behind, my fingers are far too big so I have followed Don's drawing in this respect. The spacers mentioned I have done as they look pretty prominent in the photo. I would guess that they are approx 3/4"-1" thick, I machined up 8 from some suitable silver steel just over 1mm thick and bored 2.25mm. I currently have no plans to fit split pins into 8BA bolts, well not for now at least. Luckily the nuts are plain for the links, I have plenty of castellation nuts to make already without adding these to the list. This picture also clearly shows the various motion oiling points with their cork stoppers, the one for the eccentric rod can be partly seen but with no cork stopper fitted and brass/bronze in colour. It may be that it's a brass (or such) screwed cap and thus no cork?



The first job was to drill/tap the oil holes for the eccentric rod bearings, these are 8BA. Due to the position of said holes, I used a pin vice in the mill chuck to be able to reach the part concerned. The bearings themselves were turned up to be a drift fit in the link and drill/reamed 5/32 ready for fitting the eccentric rods later, much later...



I also reworked the link bearing oil cups reducing their height closer to scale, I also adjusted the fit of the lid so that it follows the prototype with a gap between lid and hex base below. The lids could do with a little more work on the grip as they vary in size a little, the thing is this only really shows in the photo's, these things are very small.



I took this picture just to show the new size of the cups when fitted, they look much closer now, whether I add a 'grip' pattern will be decided on later. You can also see the link for the other side which I'll fit tomorrow once I have turned the model around. Please forgive the picture quality, the sun was directly in front of the camera at the time.



In the last picture, I have tried to replicate the full-size picture, not really possible as I can't get the camera in the same place but I think close enough. You can just see the spigot that the lubricator drive arm will fit too when fabricated.



next update will hopefully see me finish off the weighshaft and then see what else I have the materials in stock for to make.

More soon...

Pete


 

[greenglade]

 

Post by greenglade on 6 minutes ago

good afternoon chaps and chapesses 

It's the end of the week again and so here's the last update for this week, nothing much for tonight, I have finished machining the weighshaft and fitted the other expansion link.

Some will recall that I my son CNC'd the basic shape of the weighshaft when I asked if he had any 5/16" silver steel to hand, when he said he only had metric in stock but could grind it down I jumped at the chance of also getting the ends ground square at 7/32 sq as they need to be accurately cut to the same orientation which is a piece of cake with CNC.. I asked for the ends to be left over length, the only critical measurements being the 7/32 sq to the same orientation and the distance between the two square ends at 7 11/16.

here we have the shaft in the chuck with one end already machined down to take a 3/16x40 thread.



And a view of the drawing and part together.. before anyone says 'but it's bigger than the drawing' that's because I just print off each part that I make to a size that I can read easily, I don't worry about getting the drawing to scale. I do this so that the originals stay intake (wish I'd done this from the beginning) and I can make notes on the prints and file away for future reference. I nearly had a 'bad' moment when reading the drawing...I at first saw the ends squares being of different lengths at 27/64 and 11/64... if you look closely I'm sure you guys can work out why... the 0.187 measurement was me taking a guess at the thread length having looked at the nut drawing until I realised my error and cut the thread length to 0.171.. as the saying goes, measure twice/ cut once...



Lastly, the other side of the loco (fireman's side) showing the fitted expansion link and the finished weighshaft back where it belongs.



I'm going to have a good sort out of the workshop over the next few days, it's a mess and the lathe/mill both need a good clean/oiling, i'll be back on the case soon enough though..

cheers

Pete

 

[greenglade]

Evening all

well, I did as planned and gave the workshop a good sorting and cleaned down the lathe and mill. I then needed to see what material I had to hand before deciding what to build next, one item that has been on my mind of late is the main driver springing arrangement. I think I have most of what's required, I bought the spring steel some time ago and since it mainly consists of small components there's a good chance that I have what I need, especially as my youngest son came up trumps yesterday with some silver steel round bar and some flat steel closer to the sizes that I need. Some of this it turns out is gauge plate so I think that I'll keep that for doing the motion later.

So where to start? as this assembly hangs below the axlebox I shall start with the part that connects the two which is the 'spring swivel' a simple part to make but a little time consuming due to it's shape. The swivel is made up of two parts, a cylinder that the axlebox bottom central pin slides into and the tab that's brazed to this cylinder for the spring buckle to fit too with another pin. This part allows the spring assembly to pivot on both axis, this will become clearer as more parts are made. First picture shows the cylinders, 6 off, these are machined from 1/4" BMS, drilled No.22 and cut at 5/8 length.



Next, the tabs, these are 3/16 wide, 5/32 thick , the closest metal that I had was an offcut of 4mm by approx 20mm wide (i didn't measure this). Don's method is to machine some steel bar to size and cut off the required lengths, drill the No.22 hole one end using a button to file the radius and scallop the other end to fit the cylinder. I prefer to keep things together when machining identical sized parts and so did it this way. The next picture shows the offcut of 4mm steel which has been marked in engineers blue, had a line scribed 3/16 from one edge, 6 center lines drawn and then 6 No.22 holes drilled where these lines intersect. Held in the machine vice I then drilled the 6 holes with the bit's shown, doing it this way keeps all of the holes at the same height from the bottom of the tab. 




This was then cut roughly into individual parts and bolted together through the No. 22 holes, as the tops and bottom edges of the steel are untouched I can use this to help keep things square for the following machining steps. The picture shows the first side being machined, a 5/16 button is used to gauge the size, the bottom edges are sitting on some flat steel and the whole assembly held in the machine vice. This keeps everything solid for machining although as per my normal practice when dealing with parts like this I always rest one finger along the job opposite side to the cutting face to feel for any sign of vibration. 



And the other side..



After a little clean up with a file the assembled parts were turned over and placed back in the vice along the other axis for the lower sides to be machined.



with that done I then removed the access material from the bottom, as can be appreciated I now have all 6 tabs of identical sizes ready for the next stage.



I now needed to machine the scallop along the top edge to fit the cylinder ready for brazing, after a couple of passes and checks I had the correct height to match the drawing which states the distance between centres needs to be 1/2", once I had achieved this I locked the spindle and machined the other 5 tans to match. Each tab was set at the same height in the vice by sitting on a suitable strip of steel and was sitting upright as the top face was still the unmachined face of the original steel bar. Hope I explained that well enough?, of course, a suitable ball nose cutter was used for this exercise.



I then needed to braze the parts together, the picture I think is self-explanatory, the white stuff seen is soap, I use a bar of soap over the jig parts to stop any parts becoming stuck due to unwanted silver solder and the parts are held with a rusty clip. 



Last picture shows the finished parts, well I need to do a little more on the radiused ends but they're nearly there. The radius was done using the same button as used for machining the tabs to width but before doing so I hardened the button, I didn't do this before in case I kissed the button during machining and thus damaging the cutter.



The next part in the assembly is the spring buckle but I think it would be prudent to do the spring leaf's first, I'll have a look at this next week.. cya, then guys...

Pete

 

[greenglade]

Evening guys

Continuing on with the main driver suspension (it's going to take a few sessions before completed) I have now done all of the leaf springs, a mixture of spring steel and Tufnol as per the tender and trailing axle. As with those Don specifies a different thickness to what's scale, I had thought when doing the tender that this was an error on the dimension written, IIRC the drawing stated 0.28 when in fact it's closer to 0.38 for all but the top which is thicker. I didn't realise the error until after making all of the springs and assembling them to discover they didn't fill the spring buckle void, not even close. Ever since I double check Don's sizes for springs and the main drivers are no different, Don states 1/32 which is just under 0.8mm, full size the leaf's are 5/8, when scaled down this equates to 1.4 mm so we are a long way out. Don shows 12 leafs, works details states 11. if you tried to fill the spring buckle with 0.8mm leaf's, even with 12, you'd have 1/3rd of the void empty? 
There's always going to be trial and error with springing but the tender and trailing axle steel/tufnol mix works very well and can't be seen once painted so I'll stick with what works. IIRC, I have used 0'048 steel and 0.047 tufnol which are the closest thicknesses that I could find. I bought the steel some time ago but the tufnol is new and cut for me at M-metal who sell 1.2mm sheets 300x300mm, they kindly cut this into 7/16 strips.

Ok so that's the background, onto the work, I started with the spring steel which is in it's annealed state. The top two leafs are 4.218 long and have a No.21 hole drilled centrally each end 11/64ths in from the edge. I first cut 12 lengths oversize, held/taped together in the machine vice and machined each end square. The first picture for tonight shows this...



Next was the No.21 hole, this was done in 3 steps (after finding the center of the strip), first, center drilled, then 1/8 and lastly the no.21, all taken slowly with plenty of cutting oil to ensure the drill didn't wander. 




Here we have all of the steel springs cut/machined to size ready for forming...



I then scaled up the digital drawing and printed that to scale and cut out the top spring profile from it, which I then used as a template to cut out the shape from a suitable piece of wood as shown in this next picture, I then shaped each spring steel leaf using the heavy round steel bar also seen in the picture, forget the decorating roller shown, this wasn't heavy enough for the job in hand.



And here we have all of the steel leafs formed to shape ready for heating to harden and temper. The filed semi circle recess seen at each end of what's the 3rd leaf in the sequence is there to locate the leaf into the spring hanger bolts which I'll machine from 1/4 hex later after the spring buckles are done.



I forgot to take a picture of the heating/tempering process but it's basically the same as with the tender except for this time I used the house oven to temper. Not obvious is the amount of time taken to polish these parts before each heating process, my fingers are very sore....'again'.... I have one final heating session to do on the top springs which is to add the 1/16 grip around the no.21 hole, I'll cover that in the next update. So next up was the turnol leafs, I first tied together two sets of 6 leafs with fuse wire and forced them into a small saucepan and boiled in water for about 20 minutes leaving them to cool in the saucepan. The result being rounded leafs as shown here...



Thus we have a set of leafs ready to assemble into springs, once I have made the spring buckles that is...for those eagle-eyed among you may notice my error...I got carried away and copied the drawing forgetting that there should be one spring less..oh well.. I'll just leave the small tufnol leaf off...:0



Before I finish for the night I will cover the start of the spring buckles, it will mean less to write next time, this will bring tonights tally of photo's up to 9 which I think is enough, I don't want to bore you guys too much.. One good thing about these buckles is there's no central spigot as on the tender so I don't have to fath around with the 4 jaw.. Material size is 9/16 x 3/8 with an overall length of (IIRC) 1.087 inch. I had no suitably sized flat BMS in stock but a quick call to my youngest son produced some 150mmx10mm flat bar cut up into 14mm strips which I then machined to size..0.561 x 0.375. A picture to show the cut strips and two strips that I have machined to size..



Lastly, I then cut up the strips into 6 pieces using a very blunt chop saw as can be seen by the edges on one side. The other ends are all machined square. Machining the other end to 1.087 will be the next job...



Thanks for looking in guys...

Pete


 

[greenglade]

Good day all

Moving on with the spring assemblies, I have now made all of the main parts, bar 'spring hangers, washers, nuts and assembled one spring to date. I'll go through the details now but first correct a measurement given in the last update, I stated that the spring buckle length was 1.087, in fact it's 1.187, I had made them to the correct size but written it down wrong... must be getting old..

First picture shows one of the buckle blocks having the next stage done which was to cross drill a no.23 hole 3/16" down for the top edge of the 3/8th wide side. Each block was marked and held in the machine vice for drilling, as with previous drilling sessions the hole was first center drilled, followed by a 1/8" pilot and then opened out with a no.23.



I then started on the 3/8 wide/deep tongue, to make life easier I set up a stop which was then used for most of the following milling sessions. The picture shows the second side having just been machined 0.093 in, 3/8 deep to match the first, both sides done using the stop, just a simple case of turning the part around with X and Z axis locked off.



Next was the fork, this is 4mm wide, simple enough but I had to be extra careful here as the only cutter that I had was a cheap, plain shank cutter and with no 4mm collet for my ER25 I was forced to use the drill chuck. This took some time needing to machine 0.375 deep at a max of 0.025 depth of cuts (first starting with just 0.005 until cutter felt good), this took more than a day but I got there in the end and most importantly with no mishaps. Picture shows the last fork after machining, again the same stop was used with x axis locked.



With each block then stood upside down i drilled the no.44 hole ready to be tapped 6BA for the leaf retaining grub screw.



It was then time for one of my pet hates, forming squares in round holes or in this case rectangles. The opening is 0.593 high and 0.437 wide leaving just 0.062 sides, distance down from the fork is 0.93. This time I placed the block on it's side (still using the same stop) resting on two oak strips so that I could drill straight through. I chose a suitable bullet drill that with two holes along the X axis just fitted between marked lines, first block so drilled.



Using the stop again and this time a 6mm cuter now held with a collet I machined out the bulk of the material needed to form the slot, I then checked each one with one of the steel springs to ensure that there was enough clearance for the spring to work.



And then my favourite part (not) filing the rectangles by hand, yes I have sore hands again...this completed the roughing out stages for the buckles.



I then returned to the top leaf springs and silver soldered on the half round grips, as with when doing the tender leafs a trusty 'spud' was used to protect the hardened middle section while brazing on the grip, the picture shows the second grip of the first leaf ready to be silver soldered.



Next was a simple turning job in machining the 6 retaining pins required to secure each buckle to it's respective swivel joint, these are tight fitting pins. According to Don, full size has small metal boxes that sit over the joint to stop the pins sliding out, he states that these are not needed for the model? They certainly won't fall out as they are tight fits but if anyone has details on these shields I'd be interested in seeing them as I think they may be visible and thus I may include them on the model.



Last picture for today shows the first spring assembled, as i said all of the parts are now made but need some hand filing and pokishing to get to this state, should get the others finished tomorrow.



I have a few things still to do before the springs can be fitted and finally give me a fully sprung chassis. Next week i'll machine the spring hangers, washers and nuts and then make a start on another pet hate of mine, 'shocker absorbers', 12 of the little ######...grr...


I forgot to add that the fork tongues were rounded off with the usual hardened button (3/8)and hand file.

more soon guys..

Pete


 

[greenglade]

One last picture for the week's end... here I now have all 6 main driver springs assembled, resulting in some very sore fingers..there are a few machine marks left but I think I'll let my poor fingers heal a little before filing/polishing the final finish....



next week I hope to get on with the rest of the components required to enable the springs to be fitted, how far I get depends on if I buy the new DRO that I've been promising myself or not. If I do, then the mill and lathe will be fully stripped down which may take me some time. 
We shall see what actually happens next week...

Thanks for looking in guys...

Pete

 

[dajt]

Beautiful work, as always.

 

I put a DRO on my mill table a few years ago and it made an amazing difference to the ease of use of the machine. I have a scale for the Z axis and it would be awesome but I can't figure out how to mount it. No simple clear space on the head casting to use it with the quill, and putting it on the column would be a waste of time as the adjustment is too coarse without some counterweights or something to smooth it out.

 

I keep thinking about putting one on the lathe but never get around to it.

[greenglade]

Thank you sir..likewise on your project....I do have a DRO on my mill that my youngest son rescued from his work, a very old unit that had been sitting in storage for many years after the company upgraded their machines, it was supposed to have been thrown out but one thoughtful sole stored it away and offered it to my son. It was a lifesaver for me as the dials on my Warco aren't very accurate, no real problem for general milling as it's all checked with the mic but when it comes to accurate between center measurements such as coupling rods it's IMHO essential. It's been a little temperamental of late with 'X' glass scale sticking one end (have stripped and cleaned a number of times without success) and 'Y' scale which has stopped altogether due to the head falling apart. 'Z' still works ok. I have seen the unit that I want and hope to order it next week, this will be for the mill and then I'm going to try fitting the old unit to the lathe, as stated 'Z' is fine so can use that for the cross-slide and the mill 'X' scale which sticks is much longer than the lathe longitudinal travel so I'm hoping to fit it as it's never going to reach the bad section. I could cut it but that may lead to other issues?...

 

We shall see...if all goes well I'll have a decent DRO for the mill and a workable DRO for the first time on the lathe...this will save me a lot of time, again the dials aren't accurate, in fact, worse than the mill. The machines themselves are good enough, they are rigid...you just can't rely on the dial movement to measure anything except for roughing out.

 

Pete

[Mike Boucher]

Good day all

 

8>< snip ><8

 

I then returned to the top leaf springs and silver soldered on the half round grips, as with when doing the tender leafs a trusty 'spud' was used to protect the hardened middle section while brazing on the grip, the picture shows the second grip of the first leaf ready to be silver soldered.

 

 

Pete

 

Neat trick. I've never seen that before.  I'll put that in my memory bank for (hopefully) future use.

 

BTW - a while back I mentioned a friend built a 4.75" gauge, which is now in a museum.  Recently paid a visit, here she is, in all her "behind glass and badly lit" glory..

 

[greenglade]

That looks very nice Mike, I'd love to see more pictures of her....

 

Pete

Hi guys

This will probably be the only update for this week as I have other commitments for the next two days and Friday I should have my nice new DRO arrive for me to set up. As mentioned I'll take the opportunity to strip down the mill and lathe for a general overhaul/clean/oiling and move the old DRO over to the lathe.

Ok, so what do I have to show..not much but it involved repetitive work and you know how much I love that.. Spring Hangers, or in fact machined bolts, simple enough but there's twelve of them. Specs are 1/4 Hex head, a plain shank of 5/32 x 1" long and a thread of 5/32 x 40 at 11/32 length. First, the shank including threaded section was turned down to size, 1" marked off and the thread cut with a die in the tailstock up to that mark, then parted. The first picture shows the first hanger after turning/thread cut, I reground the tool after seeing this close up as it was clearly blunt.



The 12 bolts were then held the other way round in the chuck to finish the hex head to the correct height of 3/32. I also added a small chamfer to the top of the hex to finish off. Picture shows all twelve spring hangers completed, two of which I have fitted to one of the springs to check it's fit.



So this leaves the nuts, washers and shock absorbers to complete the suspension for the main drivers. It will probably be late next week before I can make a start, I will probably do the nuts first and for them I'll do some spare, the bolts aren't likely to get lost in service but the nuts are a different scenario and not being a thread that's commercially available it's probably prudent to do a few extra.

More soon guys..

Pete

 

[dajt]

Looking good. I don't mind a bit of machining repetition as once in the groove I feel I'm making good progress without much chance of a stuff-up. But twelve is about enough.

 

If you remember to take a few photos during the machinery overhaul I'd be interested to see them.

[greenglade]

As it happens I will be taking some photo's...I managed to get a discount if I take photo's and give a brief description of the install as the company concerned hasn't done a guide for my particular mill yet.....

 

Pete

[tigerburnie]

Is the plan to use a method of locking these difficult to access nuts, or did the prototype not do this? I might be tempted to add a bit of "thread lock" if spring washers or cotter pins are not permitted. 

[greenglade]

Yes...they will need locking...either double nuts, splitpin or threadlock....I need to fit them first to see whats what...I'll leave actual locking until final assembly..

 

Cheers

 

Pete

[greenglade]

 

Post by greenglade on 3 minutes ago

Hi guys


As stated last week I'm on DRO's this week beginning with moving the old mill DRO across to the lathe, I have also made the 5/32 x 40 nuts for 4472's suspension. Lathe first, I have stripped it down and given it a good clean/oiling. The 'X' and 'Y' scales have been fitted using the mills old 'X' and 'Z' scales, 'Y' was dead. As I hoped the sticking section experienced with the mill on 'X' scale isn't a problem now as the lathe doesn't have the same longitudinal movement as the mill. I have it up and running but not finished yet, need to add shields to protect from swage/fluid and re-route the cables but other than that it's all working fine. I've had this lathe 20 years and this is the first time that it's had a proper DRO fitted and at a good resolution too of 2 microns. 
A picture to show the old girl after fitting the DRO etc...




The flash new Easson ES12B DRO for the mill has arrived and will be fitted soon, I'll cover that in a little more detail later. As far as work on the loco is concerned, just the one picture to show the 5/32 x 40 nuts for the spring hangers. I have only made one spare, that was enough 'nut' machining for one day...




I'm also busy working on the house so progress may be a little slow over the next few weeks, I'll do what I can though...

Cheers

Pete
 

 

[dajt]

Hi Pete,

 

What's the reasoning behind putting the cross-slide scale at the front of the saddle?

 

It's the logical place for mine to go because (a) the saddle can't get anywhere near the headstock because the bed gap piece is missing the rack and (b) the locking set screw is at the back, but I'd think the scale would be safer behind the saddle.

 

Regards, David.

Edited September 17, 2018 by dajt

[greenglade]

Hi David

 

 

Two main reasons, the tailstock only has 50mm movement and tbe stock reach is relatively short which I have struggled with numerous times in the past. Fitting the scale in the more tradition position would make the reach far too small. The cross slide being reasonably wide for milling adds to the issue. Also the gib adjusting/locking screws would be covered by the scale. I have plenty of room at the front although will of course need to be more careful re swage/fluid. I'll make up suitable shields in due course..

 

Regards

 

Pete

[tigerburnie]

50mm of movement? is that not 50 cm's?

[dajt]

I hadn't thought about the tailstock yet. As you say the scale behind will push it even further back. My locking screw is at the back too so that needs considering.

[greenglade]

50mm of movement? is that not 50 cm's?

 

Sorry, I should have explained myself better...50mm is the max that the tailstock quill moves, yes I can slide the tailstock along the bed. Problem is, when the tailstock is locked for drilling/machining etc I only have the 50mm movement..compounded is the fact that the tailstock face is vertical, ie it can't overhang the saddle, this limits how close I can get to the chuck. Such jobs as machining between centers would be severely handicapped, I  already have had to back out the top slide and crank it over at an extreme angle to clear the tailstock for some jobs, reducing the saddle movement towards the tailstock by at least 25mm if fitting the scale on the back face would make some jobs impossible.  Hope I've explained that a little better guys..

 

Pete

[greenglade]

good evening all... this isn't an update as such, it's some details of the new DRO that I'm fitting, I have had a couple of requests to show the DRO being fitted, always happy to help...


There's going to be more pictures than usual, even so, I have forgotten to take many but hopefully I'll be able to fill in the gaps.

First, up the DRO chosen, this is an Easson unit supplied by Allendale using their magnetic scales, the resolution is 5 microns. I'll show the DRO itself later but to get things started here's the large box with all of it's parts.



Allendale do a number of kits which are specific to particular machines, alas not for my Warco VM16, however, they do a kit for the Chester 20V champion which is basically the same machine and this is the kit that I have. Picture of the mill after a clean down and oiling ready for the new toy, if I'd had some paint of the right colour I'd have used that too. You may note the odd holes here and there, these were where the old DRO was fitted which now resides on the lathe.



I started with the 'X' axis, the picture shows two clamps, one either end, holding some steel strips against the underside. Sitting on top of these strips is some 1.5mm shim as per the instructions in the kit.



I should have had the scale profile sitting on the shims in the last photo but had taken it off to take little from it's length, others may not need to do this on their own VM16. The problem that I had was one of the bed ends (yellow part) sticks a little proud of the front face and would produce an error with the scale if it was placed over it, no big deal, I just removed the offending section as shown.

 

The shortened scale was then rested back on top of the shims and a depth gauge was used along it's length to check that it was running true. I then clamped the scale to the bed and began drilling/tapping the 4mm holes. I did the center first, then 1 hole in from either end and then the rest, double checking the height as I went. The scale profile comes with a row of holes pre-drilled every 100 mm. I had to ditch the 4mm pan head screws which came in the kit and use longer ones from stock. It seems that the 'T' slot on the front of the Warco is deeper than on the 'Chester'. Each hole was marked with a transfer punch.



with the scale profile in situ the next job was to fit the 10mm wide magnetic strip, this was cut to match the track with tin snips.



Next was the stainless protection strip which slides into the track profile, it's held in with two lengths of rubber cord, one top, one bottom, I used a shaped piece of hardwood to push the rubber in tight which should stop and debris or oil getting in.



It was then time to fit the reader to the base of the mill and here I failed miserably in taking photos. Probably as I was just assembling the various parts that come in the kit, they are simple enough and hopefully, you can make out their components. The reader needs to be within a limited distance from the magnetic tape, the instructions say between 0.25-0.50mm and not more than 1mm. I cut up some strips of paper which gave me 0.3mm, I later changed this to 0.45mm when I found a suitable piece of card which was easier to use.



The final job for this scale was fitting the protective shield, the track has a 'T' slot along it's top that small nuts slide into. The shield was cut to match the shortened length and 3 x 3mm holes were drilled for small bolts to hold the shield in place. It looks as if this scale is well protected.



It was then on to the 'Y' axis and again I forgot to take some pictures, to be honest, the kit is well illustrated and it's a fairly easy if somewhat involved design. The picture shows the table put over as far as it will go for better access, I have made a start with the first parts of the head reader assembly, this is just the start. these parts are fitted first to mark out the movement and position for the magnetic scale.



The track is cut to length and then held between these two brackets, the drilled/tapped holes are for grub screws to enable fine-tuning of the track's position. The 'X' axis head has the same, it's a well thought out kit.



With the movement worked out the first hole to drill/tap is the one at the rear.



With the scale held by the first bolt it was leveled up using a combination square. Note the brackets have a horizontal slot on the rear mount and a vertical slot at the front to allow final positioning.



The head was then aligned up with the track, as can be seen it's a pretty involved unit with movement on two axis plus a pivot point to allow the head to match the angle of the machine's base.



The scale was then fine-tuned with a DTI, first the top edge



And then the face, fine-tuning being done here by adjusting the grub screws...



Once happy with the track it was then time to adjust the reader, this time I used the thicker card. One thing to note, you can either refit the 'X' axis handle and loose a little on it's movement or as i leave it off. the machine has one either end and i never use the one this end so that's why i'm leaving it off.



The final picture of the DRO for tonight shows the unit itself, it's a nice piece of kit giving a graphical display of the info plotted, should make life much easier doing arcs, circles etc etc. As can be seen the 'X' and 'Y' are working, I'll cover 'Z' tomorrow, I've made a start but doing it completely different to the kit which I'll explain why in the next installment.



I should point out that the standard 'Chester 20V' kit doesn't have this DRO nor is it 3 axis, making use of the built in digital 'Z' scale, I removed mine some time ago when fitting the old DRO.

I do have one picture relating to the model tonight, I received these this morning, this will be for the Bowden cable to operate the drain cocks. I bought two sizes of steel rope, 0.5mm and 0.8mm, 5 meters of each, I'll decide which to use once I have received the other part needed, that being fine copper tube for it to run in, that's coming from Hong Kong so may take a while, I've ordered both 1.4 and 1.6mm OD tube, we shall see which one works out best...



hope to cover the 'Z' axis tomorrow... cheers

Pete















 

[greenglade]

Morning guys

Well, it didn't take me long to finish the 'Z' axis, as mentioned in the yesterday's post I had already made a start on this but to be fair most of the work I did when fitting the old DRO package. This basically involved two 'L' brackets that fit to the quill, hopefully, the photos will make this clear. The set of parts that came with the kit are designed to read the head movement on the pillar, not the quill, I fail to see why you would do this as there's no fine feed of this only having the large handwheel to crank? I have never needed to move the head once set for machining and thus have fitted the scale to the quill.

The VW18 has a guard that's bolted to the left side of the head, something that I discarded many years ago, I use protective glasses before anyone condemns me... I have used the lower bolt hole for the guard to fix the bottom hole for the scale track, lined it up and then drilled/tapped the top hole, it only needs the two. Picture shows this, the track was later cut to length once happy with the movement of the head.



I've included this picture to give some idea of the 'L' bracket arrangement, the larger bracket that bolts to the bottom of the quill, is made up from two 1/2" thick flat steel lengths which are bolted and loctited together, this is very stable. The thinner alloy 'L' bracket has worked well but I may beef this up with a diagonal cross brace at a later date. It's worked well in service but you need to make sure that you don't knock it during accurate depth machining. you can also see one of the kit's 'right-angled' bracket held loosely in place.



A view from the other side, I found it necessary 9 not shown here)to fit a spacer between the 'L' and the cast right-angle brackets to ensure clearance between track and bracket.



I have used the kit's head support but have drilled through it's width to give the head the reach that it needs to reach the track, hope that makes sense? The grub screws have been added for any fine tuning of the head to bracket required.



all I had to do then was fit the head to the bracket and set the bracket correctly, this was the same as the other two axis using the card shim. So I now have both lathe and mill with a working DRO, this should mean much faster work not needing the constant checks with a mic...happy days..



Last picture to show the DRO with it's graphical display, I have some reading of the manual to do before I can have a play but it looks very impressive and easy for me to understand....er.. I hope...



More soon

Pete


Read more: http://modeleng.proboards.com/thread/5733/building-don-youngs-doncaster?page=130#ixzz5SD8kjk2i

[dajt]

Nice job! I found the mounting of the Y axis on the sloped part of the bed and the tricky head bracket interesting.

 

I have not fitted the Z axis of the DRO to my mill yet, even though I've had it for years. As you say fitting it to the column/head seems pointless as cranking it up and down is hard work so you don't want to use that as your Z adjustment all the time. It is the most rigid way of working and perhaps counterweights or gas struts to make the head easier to move would make it workable.

 

Without them the quill is the common Z axis adjustment. And I can't find a way to mount the scale on the head - it is covered in stuff on both sides where you'd want to mount it - the fine feed worm and wheel on the right, and the return spring, quill lock, and the screw that stops the quill rotating on the left. A long arm to transfer the quill movement towards the back of the head would probably have too much flex.

 

I did have a little battery operated scale similar to a digital caliper on the front but it ate batteries at a rate that meant it was flat every time you needed it. I made a dummy battery meant to be wired to something with more staying power and a proper switch but it didn't work out.

 

So I'm living with the fine feed dial!

 

I like the graphical display you have too.