Hi and Andrew Barclay model engine

[timb]

Hi Kevan,

There are 101 ways of doing these and most of them will require a file and emery to get the perfect finish.

If you want to use the lathe only then I would mark out the blank on suitable steel using blue and a scriber, including the outline.

Drill both holes accurately and square to the blank and each other.

Mount in the lathe using the larger hole on a mandrel and reduce the thickness.

You will then need a jig of sorts to allow the part to be mounted on the cross slide/vertical slide to traverse the part against a milling cutter held in the chuck to get the taper on the sides.

To get the tapers equal, set up one side with a pin in the other hole to act as a locator, then turn the part around without moving anything to machine the second side.

The rounded ends can be filed against buttons held in the holes or if you want to machine them them you need another jig for the cross slide/vertical slide that allows you to rotate the part about each hole bringing the faces to be machined against the cutter. Not easy with a small part!

The other way to do it is invest in a CNC and let it do it all in half an hour!

No doubt there will be others with better ways, as I say there are 101!!

Hope this helps

Tim

PS, See DonF's Austin 7 series, he gets a great finish and we are all hoping he is going to tell us how!

[ettingtonliam]

Drill the holes, locset to a 5/32" shaft, turn the boss, trim the rest to size with a file. Warm it up so it comes off the shaft, job done.

[stevep]

I recently did a number of brake arms for my Pansys that were very similar to this. LBSC's method, which I used, is to make the 'arm' first, out of a piece of strip, making the hole in the bigger end larger than the shaft that it is to fit on. Then turn the boss out of round stock, drilling a small hole through the middle, and turning a shoulder that will fit in the hole in the arm. Then silver solder together.

After cleaning up, hold the assembly in the lathe chuck by the boss, and drill out and ream the hole to the required size.

Use filing buttons to round off the ends of the arm.

[Kevan]

Thanks for the ideas, it seems a mandrel approach is best, for filing buttons can I get away with mild steel for these as long as they are free to rotate? I don’t have any silver steel to hand that I can harden?

[timb]

IMHO all filing buttons should rotate - stops soft mild steel ones getting filed and stops hardened silversteel ones buggering up your file!

Tim

[mbrown]

True, but I have found it difficult to keep rotating filing buttons from wobbling sideways and messing up the bit being filed, especially if the pivot pin is quite small. It's hard to leave enough clearance for them to rotate and keeping it small enough to keep them in line.

It would be interesting to know if others have managed to get around this.

Malcolm

[stevep]

Sept 28, 2020 17:43:33 GMT timb said:

IMHO all filing buttons should rotate - stops soft mild steel ones getting filed and stops hardened silversteel ones buggering up your file!

Tim

Totally agree with Tim. (Is this getting to be a habit?)

If they are free to rotate, then mild steel should suffice, but in my opinion, hardened silver steel is much better. I have a tobacco tin full of all the different (and sometimes odd) sized ones I have made over the years.

[stevep]

Sept 28, 2020 17:55:16 GMT mbrown said:

True, but I have found it difficult to keep rotating filing buttons from wobbling sideways and messing up the bit being filed, especially if the pivot pin is quite small. It's hard to leave enough clearance for them to rotate and keeping it small enough to keep them in line.

It would be interesting to know if others have managed to get around this.

Malcolm

I use a piece of silver steel through the work, with the buttons on that, and a toolmakers clamp across the end, to stop them moving away or falling off.

[simplyloco]

Sept 28, 2020 17:55:16 GMT mbrown said:

True, but I have found it difficult to keep rotating filing buttons from wobbling sideways and messing up the bit being filed, especially if the pivot pin is quite small. It's hard to leave enough clearance for them to rotate and keeping it small enough to keep them in line.

It would be interesting to know if others have managed to get around this.

Malcolm

I glass harden mine, and fix them in place with a nut and bolt. The file just skids off when the button is encountered and no harm is done to the file.
Not yet anyway...

John 

[ettingtonliam]

Yes, you can get away with mild steel if you've only a few to do and are a careful filer. It isn't ideal though. Case hardening?

[stevep]

Sept 28, 2020 18:51:17 GMT simplyloco said:

Sept 28, 2020 17:55:16 GMT mbrown said:

True, but I have found it difficult to keep rotating filing buttons from wobbling sideways and messing up the bit being filed, especially if the pivot pin is quite small. It's hard to leave enough clearance for them to rotate and keeping it small enough to keep them in line.

It would be interesting to know if others have managed to get around this.

Malcolm

I glass harden mine, and fix them in place with a nut and bolt. The file just skids off when the button is encountered and no harm is done to the file.
Not yet anyway...

John 

I glass harden my filing buttons too, but the centre hole would have been reamed dead size. Holding the buttons with a bolt - unless it was a fitted bolt - would mean they wobble, and you won't get a true shape. Mounting them on a piece of silver steel ensures they don't wobble.

IMHO the file is definitely going to be damaged rubbing against glass hard buttons unless they can rotate freely.

[steamer5]

Sept 28, 2020 17:55:16 GMT mbrown said:

True, but I have found it difficult to keep rotating filing buttons from wobbling sideways and messing up the bit being filed, especially if the pivot pin is quite small. It's hard to leave enough clearance for them to rotate and keeping it small enough to keep them in line.

It would be interesting to know if others have managed to get around this.

Malcolm

Hi Malcolm,

Solved this issue some time back! The part had a 3 mm hole thru it, so the items you need are.... what ever size axel /rod you need, 2 lock nuts, & a spring that fits over the axel but is smaller in dia that the buttons (in my case a spring from a ball point). Thread the rod both ends, locknut on one end, filing button, part, 2nd button, spring & the 2 nd lock nut. Tighten nuts to keep buttons pressed up against the part. Start filing.

You MUST use lock nuts unless you enjoy hunting around the shop for nuts, you don't need to ask how I found this out!  The gent who got me into this game said you don't need hardened buttons if they rotate,

Hope this helps you out, I used the 3 mm axel to shape some 20 mm dia parts as I was to lazy to make bigger ones! Oh if you sort things so you can hold the axel in the vise then you can use the button as a gauge when rounding items on the mill, the button starts to spin as you kiss it with the cutter

Cheers Kerrin 

[simplyloco]

Sept 29, 2020 8:50:46 GMT stevep said:

Sept 28, 2020 18:51:17 GMT simplyloco said:

IMHO the file is definitely going to be damaged rubbing against glass hard buttons unless they can rotate freely.

A lot depends on how hard you rub...and it is usually a tight fitting bolt.

[Kevan]

Well I tried🤔


I ended again free hand filing most of this after roughing out on the lathe and vertical slide. First attempt I tried to rough out two Blanks together first side went well second slide the mill dug in ruining one of the parts and slinging them across the workshop! I filed ant turned the other one then started another on a new bit of metal.

The turning was done on a mandrel the first one was ok on an interference fit the second needed loctited on presumably as it lost some surface being drifted out of the first one.

These parts are well hidden under the cylinders so I think will do with a coat of black paint! The next challenge is the 3 slotted arms though one of these I think needs making differently to keep the operating rod out of the way of the valve gear reversing rod. I am planning to put the cock operating lever on the same pivot as the reversing lever but inside the frame with the operating rod directly over the frame to miss the firebox, do let me know if this is a daft idea!

Cheers Kevan

[Kevan]

So the cab controls are now complete

I moved the reverser to the right side following Barclay practice. At the moment the latch is in front of the handle. I would need to remake the handle as the pin that operates the reversing rod is well fixed into it.

Next job is sorting out the cylinders, covers and cross heads.

[Kevan]

It has been a while with not much interesting to talk about, mostly just putting bits back together and making gaskets. Today I was trying to set the valves. I have a problem that I cannot resolve. I have the gear set correctly for forward however the valve movement in reverse is wrong. The valve travels the same distance however the centre of the throw is about 3/16ths further back in the valve chest so the front port is open longer than the stroke of the piston and the back Port is barely opened at all. As far as I can see the eccentric straps are the same sizes and the die block is more or less in the same relationship with the link at both end settings. Any idea where I should be looking for problems?

Thanks

[Kevan]

So I eventually figured out the valve timing problem which was largely down to the weigh-shaft fixings so made another and events now seem reasonable. Anyway I bolted everything back together, built a compressor from a fridge compressor and old helium balloon tank and found 100% blow by!

The pistons have graphited packing. As the stuff I had was too small to fit the pistons I had put the old stuff back and despite oiling it up it is no good. I have ordered some more but was thinking PTFE might be better. On a 15/16ths dia. cylinder what size of PTFE ring should I be thinking about as I will likely need to make new Pistons to do this.

TIA Caber😃

[ettingtonliam]

100% blow by seems a bit unlikely unless your pistons are really slack in the bores. Possibly the valves are not seating on the port face, that can give rise to massive blow by. Graphited packing too small to fit the pistons? Just wind it round and round and squash it in, it will work.

[paullovestechy]

Jun 6, 2020 19:40:20 GMT Kevan said:

So today I dismantled the Rob Roy. The stiffness was not the bent frame as I thought it was very nasty gunk in the cylinders resembling dries up graphite grease! The pistons are packed with graphited yarn and I guess the gunk is the result of whatever oil was put In and the graphited yarn. WD40 cleaned it up nicely and the pistons seem a good fit. What should I do to reinvigorate the graphited yarn? The slot in the piston is 1/8” x 1/8” so I am guessing I wouldn’t be able to get a Viton o ring that size.

All the jointing surfaces has been made with red hematite rather than gaskets. I am wondering what sort of gasket I could use that would not upset the alignment of the valve gear too much?

I also found packers between the cylinder block and frames. I guess these were to resolve con rod alignment issues I will measure to see what if anything is not to book dimensions to see if there is another solution. Also the cylinders were bolted to the Frame with 3BA brass screws that look like they are almost sheared I have no idea what kind of force could do that.

The good news is the frames are much less bent than I thought. The only real issue is the deflection behind the rear stretcher that. Is about 3/32” at the buffer beam. The apparent bend at the  guide bar bracket isn’t apparent with everything stripped off.


As for what it is going to end up like, my preferred prototype AB 885, seems to have a significantly longer wheelbase and overall length. Typically 6 coupled Barclays are longer in wheel base than the Caly pug Rob Roy was modelled after, however when you start to look at the prototype Martin Evans made a lot of changes anyway. I am continuing research on possible Barclays to model but if I go this route it will not end up an accurate model of any particular engine.

There are a couple of distinctive features common to Barclays that would be good to do if possible. One is safety valves on the dome. Is there any reason why this can’t or shouldn’t be done ? 

The saddle tank will have limited water content. Is there a minimum I should consider? Also the saddle tank water will likely get warm. I presume attempting an injector rather than the cross head pump would not be a good idea?

I will also need  to relocate The hand pump. One option would be a small tank in the bunker another a well tank under the back of the cab floor any pros or cons to either of these ideas? 

sorry no pictures today the board full message comes up when I try and attach them and linking is producing image not found icons. I really can’t get the hang of reliably posting pictures here!

cheers Kevan


hey Kevin, I think this is WILDLY inappropriate to be posting
however I respect you bravery I think you need a ruler 
yours truly 
paul
paul techy
paul loves techy 

[Kevan]

This thread has been quiet for a while as I was distracted by building a driving wagon for the Kingscale Austerity I bought. It is not forgotten. I visited. The Ribble steam museum as I discovered that they had a Niddrie Barclay and was keen to get dimensions for the tank.

I was surprised to find that it is in exactly the same state as mine! So I don’t feel so bad about neglecting it for the past few months! No one around today knew where the tank was so no dimensions this trip. It is a good museum to visit if you are into industrial locos !