Help with 'Speedy' valve gear and other issues...

[mbrown]

The two GWR whistles are nicely pitched to play Ilkley Moor B'aht 'at.... Assuming any Yorkshiremen ever worked on that railway!

Malcolm

[steamer5]

Oct 6, 2018 16:39:20 GMT uuu said:

We were discussing whistle valves at the Pump House earlier this week. John has had success using the innards of Schraeder valves, which might be about the size you are proposing. They do pass sufficient steam.

Wilf

Hi Wilf,
 I did this, gives a good shut off etc, stops hot water / steam  attempting to cook the fingers!

One thing I remember being told many years back was the valve needs to pass to keep the whistle warm, guess it stop condensation (maybe the whistles were installed throat up.....not a good idea). Doubletops experiments on whistles, & comments there in from others should help lots.

Rodger, have you considered just making the whistles etc dummies, but feed with a small steam supply at the same time as the”main” hidden whistle blows? 
Either way this sub project is going to be fun to follow!

Cheers Kerrin 

[Roger]

Hi Wilf,
I think the schraeder valve innards might be a similar size to what I've designed. It's certainly worth a try to see if there's enough volume, but my expectation is that it won't be enough.

Hi Kerrin,
I definitely want to feed dummy whistles with a puff of steam, I think that's a really nice touch. At the moment I'm thinking that the design that Jim Scott has posted looks the most promising.

[jma1009]

Hi Roger,

I think it is quite possible to make the GWR type whistle valves with a few alterations, and pass enough steam to work both whistles and work as described by Gary. I certainly managed to make one in the 1990s using as a basis the drawings for Keith Wilson's 5 inch gauge Dukedog, heavily adapted by me.

I will have to dig out my 'drawings' on a piece of cardboard that evolved as I was making the bits, and a few pics and email them to you, and I can't recall the exact details without refreshing my memory of what I did over 20 years ago.

Cheers,

Julian

[Roger]

Oct 6, 2018 21:13:06 GMT jma1009 said:

Hi Roger,

I think it is quite possible to make the GWR type whistle valves with a few alterations, and pass enough steam to work both whistles and work as described by Gary. I certainly managed to make one in the 1990s using as a basis the drawings for Keith Wilson's 5 inch gauge Dukedog, heavily adapted by me.

I will have to dig out my 'drawings' on a piece of cardboard that evolved as I was making the bits, and a few pics and email them to you, and I can't recall the exact details without refreshing my memory of what I did over 20 years ago.

Cheers,

Julian

Hi Julian,
I'd be very interested to see what proportions you made those. I'll certainly try to make the passages as large as possible.

In the meantime, here's the first half of the 'Y' piece with the location holes and 'U' channel..

20181006_205343 by Roger Froud, on Flickr

... and this is the other side with 1mm diameter pips to locate the two halves.

20181006_211230 by Roger Froud, on Flickr

It's pretty small so I don't want to end up filling the cavity with Silver Solder.

20181006_211923 by Roger Froud, on Flickr

This is how it looks as a dry assembly.

20181006_214110 by Roger Froud, on Flickr

I've added some of the CC4000 gunk I bought at the Midlands show a couple of years ago, carefully scraping it off the surface. It's not in the least bit sticky, so it wasn't easy to get it to stay where it was needed... 

20181006_215227 by Roger Froud, on Flickr

... then fluxed it and squashed it all together using a Bulldog Clip.

20181006_220608 by Roger Froud, on Flickr

I hammered out a flat piece of 24% High Temperature Silver Solder and put a generous piece on top of the joint, covered with flux.
The whole thing was then brought up to a pretty bright Red heat to get it to flow which it seemed to do right through. Once it's cleaned up, I'll be able to assess whether it's joined as needed. The idea is that if it isn't good enough, I can caulk it with 55% Silver Solder without it falling apart.

20181006_220959 by Roger Froud, on Flickr

[ettingtonliam]

Roger
What is the CC400 stuff you refer to? Presumably it prevents solder adherence, but is it any better than Tippex? Is it any good, if so who sells it?

Richard

[Roger]

Oct 7, 2018 6:40:29 GMT ettingtonliam said:

Roger
What is the CC400 stuff you refer to? Presumably it prevents solder adherence, but is it any better than Tippex? Is it any good, if so who sells it?

Richard

Hi Richard,
The CC400 is bit like soft Play-Doh, I'm guessing it's Silicone based. I'm not that impressed with it really, it doesn't stick and it does char. However, it does retain some of its bulk which I thought would be better in the channel than Tippex. On reflection, I reckon it would be better to paint the channel with Tippex first and then fill it with CC400 as a backstop.

I don't know who sells it, I think it was on the same stall as those people who sell the Aluminium 'welding' sticks for low temperature soldering of Aluminium. I can't say that I recommend it though.

[Roger]

Ok, this didn't go well, the Silver Solder didn't flow nicely so I made another one and the same thing happened. Grrrr...

In the end, I abandoned using the high temperature Silver Solder that was causing the problem and decided to use 55% which went just fine, using my usual technique of adding the thin Silver Solder wire to the joint.

Here I've coated the inside of the channel with Tippex, I also put some of the gunk in there too.

20181007_113147 by Roger Froud, on Flickr

I'm using Florist's wire to make sure it all stays together instead of the Bulldog clip. I've left the pips from the parting off in place so I can use them to hold the part in the vice without cooling it too much

20181007_161319 by Roger Froud, on Flickr

This time it worked out fine, you can see the joints are covered in Silver Solder

20181007_161600 by Roger Froud, on Flickr

20181007_162526 by Roger Froud, on Flickr

20181007_162548 by Roger Froud, on Flickr

These are the pockets for the union pieces...

20181007_174043 by Roger Froud, on Flickr

... and this it the hole for lining up the Steel support for machining

20181007_175255 by Roger Froud, on Flickr


The 6mm Steel bar had a 1.6mm reduced section, 6mm long which locates the branch piece. Here I've just pushed it on with the tailstock

20181007_180336 by Roger Froud, on Flickr

Again, it's being held together with Florist's wire and that's also holding Silver Solder wire in place.

20181007_180916 by Roger Froud, on Flickr

It's been heated from the Steel end so the joint to that melts first

20181007_181244 by Roger Froud, on Flickr

That's now firmly attached.

20181007_182913 by Roger Froud, on Flickr

Here the rotary table is being adjusted to the HSS piece resting on the flat is horizontal...

20181007_200635 by Roger Froud, on Flickr


... and finally we can start machining it! It's hard to judge how much stock needs to be left on the initial machining operation. I've set the quill to zero and then gone slowly over the first pass, pausing the machine and checking the tool position by bringing the quill down to its zero position. That way I was able to see that 1.5mm stock was a good starting point. I then copied the operation enough times to reduce the stock left by 0.2mm on each pass. The overlap is 2mm and the cutter is 2mm too. It's all pretty close to the chuck, I had to slide the tool further out of the collet so the ER32 nut missed the jaw.

I fully expect this to end in tears, I'm pushing my luck in several departments. Still, it's fun to try and you don't know whether it's possible until you try. Provided I can machine the outside ok, the big challenge is to Silver Solder on the Unions without getting Silver Solder on the nuts.


20181007_214604 by Roger Froud, on Flickr

Sadly I've run out of time to finish machining this tonight.

[JonL]

I do love a good experiment!

[Roger]

I'm really struggling with problems on the mill at the moment. This is the first really challenging 3D job I've done since the up/downgrade to Mach4 and it's highlighted some serious issues with the backlash compensation. This is resulting in lost counts and the Z-axis not maintaining position. I may have to revert back to Mach3 if they can't sort it out.

Anyway, here are the roughing cuts with a 2mm 2-flute...

20181008_105415 by Roger Froud, on Flickr

.. followed by what ought to be finishing passes with a 1mm 2-flute...

20181008_130652 by Roger Froud, on Flickr

... except it's a dog's dinner...

20181008_170318 by Roger Froud, on Flickr

... on both sides.

I can't risk another pass with the machine as it is, so I think it's time to call it a day and see if it can be rescued by some judicious use of needle files.

The part to the right of the hex has to be turned on the lathe, so that's not a problem.

It's a bit annoying, they were supposed to have got this all sorted out but it seems there are still major issues with the control.

It looks terrible, but the photo makes it look worse than it is. Let's see how it pans out before I decide to scrap it and start again.

20181008_221050 by Roger Froud, on Flickr

[Roger]

Ok, this looks like it's going to be scrap, the walls are too thin and they've broken through where the union pieces need to be Silver Soldered on.

However... I've spent the evening tracking down what's going on with the lost counts, and that seems to be down to the ESS acceleration settings in the backlash compensation table. Changing those to ten times the value I had resolved the issue so I'll do a few more tests and then have another go.

I think I need to make this slightly chunkier too, so it's a bit more robust.

[GWR 101]

Roger, as always I am impressed by your approach. Good luck with your proposed solution. Regards Paul

[Roger]

Oct 9, 2018 21:46:48 GMT GWR 101 said:

Roger, as always I am impressed by your approach. Good luck with your proposed solution. Regards Paul

Thanks Paul, I try to see scrapping something as an opportunity to make improvements rather than something overly negative. I've just spent a couple of hours reworking it so it now looks like this...


Overscale whistle branch by Roger Froud, on Flickr

... which hopefully looks pretty much the same as before.

The main changes are that the branch tubes are now 3.7mm diameter up from 3.1mm, the spacing between them is 1.5mm more and the nut is now captive on the whistle part, not the branch.
I've also increased the thread size to M5 x 0.5 (fine) from M4.5 and the hex has gone up from 5mm AF to 5.5 which is a bit thin on the sides. That might have to go up a bit too.

So it's not absurdly over scale, but it's enough to make it a lot more satisfactory for manufacturing and assembling as well as being stronger .

[Roger]

The mill is still playing up, so I'm been running more test programs in an attempt to find another simple program that displays the lost count issue I'm experiencing.

I have managed to machine these new clam shells though...

20181010_161424 by Roger Froud, on Flickr

This time I've added a pocket in the end so it can be attached to the Steel shaft without having to drill a hole as a separate operation.

20181010_164134 by Roger Froud, on Flickr

The assembly is wrapped up in Florist's wire, trapping some fine 55% Silver Solder against the joint.

This time, I've also wrapped a thick piece of 38% Silver Solder around the base so make that more secure when I have to re-heat it to attach the threaded top parts.

20181011_193812 by Roger Froud, on Flickr

This is now ready for machining the outside when the mill is up and running again. I could run it without backlash compensation, but I'm stubborn and would prefer to get the machine right first.

20181011_202000 by Roger Froud, on Flickr

[JonL]

I don't think there is anything wrong with being stubborn when its to do with getting things as they should be. Best of luck.

[92220]

Good luck Roger. You'll find a way I'm sure. Could you not get a piece of brass or copper tube and fill it with low temp soft solder and bend it up to the 'U' shape, then melt the solder out. It could then be silversoldered to a piece of brass/copper bar for holding it in the chuck, and forming stalk of the 'Y'?

Bob.

[Roger]

Oct 12, 2018 13:00:27 GMT 92220 said:

Good luck Roger. You'll find a way I'm sure. Could you not get a piece of brass or copper tube and fill it with low temp soft solder and bend it up to the 'U' shape, then melt the solder out. It could then be silversoldered to a piece of brass/copper bar for holding it in the chuck, and forming stalk of the 'Y'?

Bob.

Hi Bob,
The joining of the two parts isn't a problem so long as 55% Silver Solder is used. It's the higher temperature stuff that doesn't want to wick into the closely mated parts.

The Software Engineer is trying to figure out why the test program I sent him is causing lost counts. I think there may be two problems, I'm just trying to boil down a long program to find what part of it causes the problem on the long job I'm running. At least with an AC Servo, you can see the precise count of the current position, so it's possible to cross check that with what Mach4 thinks it ought to be. I don't think the Software developer has that facility, so this it vital information for him. Hopefully it will be resolved soon.

[Roger]

As an aside, I've attended a private steam event today and thoroughly enjoyed the balmy weather, spending most of the day in shirt sleeves.

I took along the axle weighbridge and we tried a few locomotives on it to see what they were like.

The two 0-4-0s were balancing across the corners with about half the weight being carried compared to the opposite corners.
The 0-4-2 was carrying almost twice the weight on the middle axle compared to the other driving axle and the pony truck.

I think we were all surprised at just how bad the imbalance was, considering these locomotives appear to work just fine. All very interesting.
It would be handy to have a way to clamp the load cells to the base plate in a variety of positions. I might bolt a couple of bars to the base plate to keep them lined up, that would be a help.

[Roger]

I've been running hours of test programs on the mill, trying to track down an elusive example of a lost count. That's now resulted in a very short test program that always shows the issue, so hopefully the software engineer for the ESS (Ethernet Smooth Stepper) module will now be able to find out what's going on.

While I've been doing that, I've turned my attention to the firebox cladding which has a 20mm corner radius on the top. The folder I made some time ago was made with a view to bending the radii on the side tanks, so it seemed sensible to use it for this too.

The tooling for this was originally going to be curved segments that were bolted to the clamping bar, but in playing around with it, a blindingly obvious solution came to mind.

Here is a 40mm diameter former being machined to length and a 12mm reamed hole put in the ends. It's one of those rare occasions where the stock won't pass through the mandrel. I've made a 30mm and 35mm one too, and they go through.

20181013_202622 by Roger Froud, on Flickr

Here I'm parting off to length, the end piece is supported on a 12mm dowel in the drill chuck until it's almost ready to come off. The DRO was set to 40mm when it first touched and I stopped when it got to 2mm, at which point I could twist it off by wringing its neck. It just stops it from chattering with such a long overhanging length acting like a tuning fork.

20181013_204300 by Roger Froud, on Flickr

And this is the final setup, with longer bolts to clamp it all down and a couple of spacers at the back for the cross clamp.

In case you haven't seen this before, the end plates of the folder are adjustable so that the centre line of the hinge can be raised and lowered to suit the material thickness and the radius of the bend. The pivot pins as loose, so you can slide them out to remove the forming roller.

Obviously, moving the pivot up means that the folding arm must be lowered by the same amount so it tracks the radius of the roller. The end plates are adjusted until then just nip the material and the folding arm is then set level with the base. The clamping bar on the top just stops the tooling and the piece you're bending from moving.

I don't know why I didn't think of this before, it's a much better way of doing the tooling for large radii.

20181014_113959 by Roger Froud, on Flickr

[JonL]

Bilmey. You don't do things by halves!