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

[jma1009]

Hi Roger,

I think you have achieved an excellent result that you ought to be very satisfied with.

I admire your ‘thinking out of the box’ and experimentation.

Cheers,
Julian

[Roger]

Sept 20, 2023 19:38:41 GMT jma1009 said:

Hi Roger,

I think you have achieved an excellent result that you ought to be very satisfied with.

I admire your ‘thinking out of the box’ and experimentation.

Cheers,
Julian

Thanks Julian. It's just my way of using skills that I do have, to make up for the ones that I don't.

[doubletop]

Roger

I would say you should be extremely happy with that.

Do you plan to do the cab using the same method? For the front section the cab opening may provide an additional registration reference point, but the rear section could be a bit trickier with the steps. However, as you have your original CAD model doing the necessary cutouts in the masks should relatively easy. The problem would be the application of the masks.

Pete

[Roger]

Sept 21, 2023 8:55:33 GMT doubletop said:

Roger

I would say you should be extremely happy with that.

Do you plan to do the cab using the same method? For the front section the cab opening may provide an additional registration reference point, but the rear section could be a bit trickier with the steps. However, as you have your original CAD model doing the necessary cutouts in the masks should relatively easy. The problem would be the application of the masks.

Pete

Hi Pete,
Yes, I'll do the Cab and Bunker the same way. I'll probably 3D print something that registers with a feature on them and lets me place a masking tape  markers that have corresponding cuts on the mask. I did the Pannier Tanks that way, and it seemed to work ok.

The biggest issue is the fact that at least one Rivet gets in the way of the line. The plan is to cut the mask with the rivet missing. I've bought some Silicone Masking Fluid so that I can mask the Rivet separately with tape and then fill in the missing part with the fluid. Once that's set, I ought to be able to remove the Masking tape to leave the Rivet covered too. We'll see. I don't think the Vinyl Mask would stick well enough if I try to cover the rivet. It's sure to lift.

I'll use the same method of leaving registration dots, although I think I went a bit overboard with how many I used.

[doubletop]

Sept 20, 2023 7:59:30 GMT Roger said:

Sept 20, 2023 7:43:18 GMT doubletop said:

Plus one for that. Visions of a jackknife occurring and hours of work on the floor. Even without the possibility of the setup folding I do not think I would trust a workmate. Get yourself a hydraulic lifting trolley with some rails bolted on.

Pete

The WorkMate is going to be massively beefed up, I'm sure it will be fine in its rebuilt form. I'll definitely add a leg to the bridge though.

Sadly I don't have the space for anything like a lifting trolley, it has to be something that can be put away. The WorkMate is really useful for other things too, it's just feeble at the moment, like most modern things. They use as little metal in them as possible. Look as how skinny a 2 Ton jack is these days compared to how they used to be.

Roger

When the need has arisen to use the hydraulic lifter with a link span the same problem occurs. I just use a lashing strap from the furthermost rail of the link to the base of the table creating a triangle that prevents the table from jackknifing.

Pete

[Roger]

Sept 21, 2023 20:32:10 GMT doubletop said:

Sept 20, 2023 7:59:30 GMT Roger said:

The WorkMate is going to be massively beefed up, I'm sure it will be fine in its rebuilt form. I'll definitely add a leg to the bridge though.

Sadly I don't have the space for anything like a lifting trolley, it has to be something that can be put away. The WorkMate is really useful for other things too, it's just feeble at the moment, like most modern things. They use as little metal in them as possible. Look as how skinny a 2 Ton jack is these days compared to how they used to be.

Roger

When the need has arisen to use the hydraulic lifter with a link span the same problem occurs. I just use a lashing strap from the furthermost rail of the link to the base of the table creating a triangle that prevents the table from jackknifing.

Pete

Hi Pete,
This is the arrangement where the bridge meets the piece on the WorkMate. When it drops into place, it pulls the ends of the channel together, so there isn't a hinge there.


PXL_20230921_212617463 by Billy Roberts, on Flickr

Here's me supporting it from one end...

PXL_20230921_212646415 by Billy Roberts, on Flickr

... and this is trying to hinge it the other way.

PXL_20230921_212710210 by Billy Roberts, on Flickr

There's a little bit of slack, but that's all. It may be worth adding a couple of latches though, to make certain that the bridge can't lift off that end.
I could see that happening if I had a support in the middle of the bridge.

I've just designed a simple swinging latch that can bolt to the underside of the Channel on the bridge, such that you can only lift the bridge on and off when they are turned sideways. It's really simple, so I'll probably do that tomorrow.


I think the bridge needs a support near the car end rather than at the middle.

[Roger]

The latches on the Loading Bridge are held in by M5 screws. These will be secured with threadlocker when the Spring Washers arrive.

PXL_20230922_092423274 by Billy Roberts, on Flickr

I found a piece of 20x3mm Black Steel Strip, so I cut it in half and folded the ends over to make handles.

With the Latches in this position, they stop the rail from lifting up, so it's solidly attached to the rail that's mounted on the WorkMate.

PXL_20230922_203513914 by Billy Roberts, on Flickr

The Latches have to be turned through 90 degrees to lift the rail off.


PXL_20230922_203613330 by Billy Roberts, on Flickr


I'm much happier with the connection now, but I still want to add a support near the Car end in case the Bridge slips off the tailgate or the supporting wires give way.

[Roger]

I've just measured the pivot hole positions from the old WorkMate tubes and drilled both legs together. The clearances used are absolutely enormous, so I've tightened those up to something more sensible so there isn't so much play everywhere.


PXL_20230923_173238194 by Billy Roberts, on Flickr

After tacking up, the trial assembly works fine, and I won't bother adding the extra cross braces that I've cut because it's so rigid as it is.

I've printed some feet which I'll show later when it's a bit further on.

PXL_20230923_192104509 by Billy Roberts, on Flickr

[andyhigham]

I use a scissor lift with rails made from unistrut. At the club we have a similar lift.
20220122_145443 by Sigma Projects, on Flickr

[Roger]

Since there's not a lot of room under the footplate for two Whistles, their Servo valves and Steam Brake Cylinder, I decided to make the two Servo valves as a combined Duplex unit. That not only saves space, but also simplifies the plumbing because the inlet Steam connection can be shared instead of requiring a Tee.

This is the way up it will be mounted, ie with the Pilot feeds to the top and the bleed holes to the bottom. The inlet Steam is at the front and the two outlets are above each other on the side, pointing towards where the Whistles will be.


Duplex whistle servo valve by Billy Roberts, on Flickr

I've shrunk the overall thickness by 1mm compared to the prototype, and the valve element is shorter too.

I've also reduced the volume on the Pilot side of the Diaphragm so that it can fill the volume more quickly, and drain in the same way.

Sectioned duplex servo valve by Billy Roberts, on Flickr

The prototype had a hex on the inlet union because I didn't want to put an excessive force on the Silver Soldered joint.
However, on this design I needed to make the pocket big enough so that it broke into the Steam gallery on each side. by making the register for the fitting a rectangle shape, it can be Silver Soldered into position and be very strong, so I won't need a hex there. That makes it even more compact.

Sectioned servo valve inlet by Billy Roberts, on Flickr

Anyway, that will have less parts and be much neater than having two of them.

[Roger]

These are the new feet for the WorkMate...

PXL_20230923_070151735 by Billy Roberts, on Flickr

... which are flat bottomed on the inside.

PXL_20230923_070205673 by Billy Roberts, on Flickr

I spotted through the hole and tapped the tube M3 for the retaining screw.

PXL_20230926_100249701 by Billy Roberts, on Flickr

So it looks almost identical to the original one...

PXL_20230926_134949163 by Billy Roberts, on Flickr

... but when you lift it, the weight is about twice as much. It's massively strong and rigid, I reckon you could support the front of a car on it.

PXL_20230926_135005074 by Billy Roberts, on Flickr

I bought some of those 8mm Star retainers from eBay, which is what it had originally.

PXL_20230926_135050875 by Billy Roberts, on Flickr

Don't look too closely at the Welding or the Paint job, it's not great. It's good enough though.

PXL_20230926_135056639 by Billy Roberts, on Flickr

[Roger]

This is the body of the Duplex Whistle Servo Valve being made from a piece of 40mm diameter Brass bar.


PXL_20230926_093511674 by Billy Roberts, on Flickr

The Steam gallery and slots were machined with a 2mm cutter...

PXL_20230926_124930731 by Billy Roberts, on Flickr

... the M1.6 tapped holes added, then parted off long and faced off.

PXL_20230926_152020650 by Billy Roberts, on Flickr

The reverse side has M10 x 1 (fine) holes for the output fittings and the valve seats reamed to 6mm and countersunk 0.5mm deep.

PXL_20230926_183632320 by Billy Roberts, on Flickr

The body was then mounted on its side and the inlet details added...

PXL_20230927_094131398 by Billy Roberts, on Flickr

... at least that was what happened the second time around! The first time, I neglected to zero the Z-axis to the top of the body, and it annihilated the cutter and scrapped the job. Oh well, it doesn't happen that often.

PXL_20230927_094135511 by Billy Roberts, on Flickr

The inlet fitting was screw cut M7 x 0.75 (fine) for the Union and checked for the right fit...

PXL_20230926_202916381 by Billy Roberts, on Flickr

... before profiling the flange. That was made 0.1mm under size to leave room for the Silver Solder.

PXL_20230927_161704872 by Billy Roberts, on Flickr



PXL_20230927_162829431 by Billy Roberts, on Flickr



PXL_20230927_162839897 by Billy Roberts, on Flickr

The weight is to stop the part from coming away when the flux under it boiled. The places near to the joint were all protected with Tippex, including the whole of the thread and the inside passage.

PXL_20230927_164255395 by Billy Roberts, on Flickr

The little nugget of Silver Solder is all that was added.

PXL_20230927_164305103 by Billy Roberts, on Flickr

That flowed really nicely when it was Red hot.

PXL_20230927_164805623 by Billy Roberts, on Flickr

It still looked a mess after cleaning in the Ultrasonic Tank...

PXL_20230927_182822720 by Billy Roberts, on Flickr

... but a session with a wire brush made a big improvement.

PXL_20230927_204655169 by Billy Roberts, on Flickr

It's not worth the effort of getting a nice finish on the internal parts except for the bore and valve seat.

[Roger]

This is the Diaphragm Cover plate, with the M3.5 holes and O-ring pockets for the Pilot Steam Inlets, and the M1.6 holes with a 0.4mm Bleed hole in the bottom. I tapped the hole above those in case I need to make them into adjustable ones or insert a piece with a smaller hole. I think it's about right at 0.4mm, since 0.3mm was too small and 0.5mm just too big.


PXL_20230928_183217744 by Billy Roberts, on Flickr

That was parted off slightly long and faced off with a 10mm cutter this time. That was so I could touch the cutter down on the HSS parallels to set the Z-axis height to -3mm.

PXL_20230928_185541905 by Billy Roberts, on Flickr

After machining the clearance pockets for the Diaphragm Washers and M1.6 Centre bolt, I used a 45 degree engraving cutter to add a couple of 0.12mm deep grooves to help grip the Diaphragm. They look a lot deeper than they are.

PXL_20230928_201852607 by Billy Roberts, on Flickr

[Roger]

This is one of the Outlet fittings that holds the return spring and also gives access to unscrew the valve element. I screw cut the M10 x 1 (fine) thread and bored it first on the large end, leaving it on the stock so I can get hold of it in the mill to add the hex.

pxl_20230929_074719586 by Billy Roberts, on Flickr

Then it was parted off and mounted on my standard M10 x 1 mount so that the M7 x 0.75 (fine) Union end could be finished.

pxl_20230929_082324266 by Billy Roberts, on Flickr

This is the guide plate for punching the holes in the diaphragm.

pxl_20230929_194637166 by Billy Roberts, on Flickr

The 3mm centre holes were punched first...

pxl_20230930_085225071 by Billy Roberts, on Flickr

... against a piece of fibre board...

pxl_20230930_085230057 by Billy Roberts, on Flickr

... then bolted through and the outside cut with a Scalpel. The M1.6 bolt holes were then punched with a piece of 1.6mm Silver Steel that had a 1.6mm Carbide PCB drill spotted into the end of it. I don't bother to harden things like this that are only going to punch a few holes.

pxl_20230930_091326768 by Billy Roberts, on Flickr



pxl_20230930_092652763 by Billy Roberts, on Flickr

All the other parts were finished today, and the extra M1.6 Stainless bolts were cut to length.

pxl_20230930_180742229 by Billy Roberts, on Flickr

The end of the Valve element has a hex on it, rounded to accept the return spring. Here, the Valve elements have been bolted to the Diapragm, making sure that the 3mm diameter spacer in the middle is located in the hole in the diaphragm.

pxl_20230930_190815932 by Billy Roberts, on Flickr

And here's a video of the second test which seems ok. The other one worked fine, but the top one was weeping because the Valve element was slightly too long, and the Diaphragm was hitting the cover plate, preventing it from seating. I made a new Fluorosint Valve element with the shoulder 0.15mm further along, and that did the trick.

I tried the second valve with the second Pilot valve, but the Pilot valve stuck open. I'll have to take that apart and see where it's jamming.

pxl_20230930_205904497.ts by Billy Roberts, on Flickr

Anyway, the 0.4mm bleed hole seems about right, and the valve seems to operate crisply without too much delay opening or closing.

[Roger]

After a few tests and adjustments to the Duplex Whistle Servo Valve, I concluded that I need to allow for a little more travel in the Valve Element.

To that end, I've modified the design of the Diaphragm cover to give 0.2mm clearance above the Diaphragm, just to make sure that the Steam can always get above the edge of it. I was finding that it worked fine when cold but stuck closed when hot. That might just be because the Fluorosint has grown and used up all of the limited travel.

While I was doing that, I decided to move the Pilot Inlet Fitting to a place where it wasn't as close to the other M1.6 bolts so it was easier to assembly. I also reduced the size of the Bleed hole to 0.35mm and moved it to the middle of the Diaphragm.

I've had to shorten the Inlet Fittings by 0.1mm to still fit in the cover without using some of the added clearance.

Duplex sectioned valve by Billy Roberts, on Flickr

Hopefully that will be finished tomorrow and I can give it another test.

[Roger]

I'm trying to fix the issue with the Whistle Servo Valve which happens when it's first used. When it's cold, the Valve pops open abruptly, but quickly closes. When it's hot, it works fine, but obviously that's not going to be satisfactory.

I've increased the gap shown on the 3D model by turning 0.5mm off the end of the outlet fitting. I might reduce the outside diameter of the valve slightly too. I got the impression that when the valve started to open, the restriction was causing the valve to get sucked into the tapered section of the fitting, causing it to open abruptly.


Increase clearance by Billy Roberts, on Flickr

I also realised that the large cold inside surfaces of the Valve were likely condensing the small amount of Steam, causing the Valve to close. I think the idea of exhausting water or Steam from the Valve at that end is sound. If the whole diaphragm and tube is full of condensate, it's going to take a lot more pressure to push that back up to the top valve than if it's disposed of near the Servo Valve.

So I've filled the tiny bleed hole in the Valve cover with Sealant, and used one of my Tee pieces with the tiny bleed hole up close to the Servo Valve.
The logic of this is that the Valve gets full of condensate, rather than have it being ejected through the hole in the cover. Once it's full, there will also be condensate between the bleed Tee that goes back into the valve when it's operated. The result should be that little if no Steam enters the Valve, so it doesn't cause it to shut immediately when it's cold.

These changes seem to have had the desired effect. The Pilot Valves still need a little work to make sure they don't stick, but it's good enough to move on to the next stage. I can come back to this later knowing it shouldn't need to be completely reworked.

PXL_20231017_092946013 by Billy Roberts, on Flickr

[flyingfox]

Greetings, on my 71/4 A3 for many years I have suffered "watery whistle", it has a long pipe run from the valve, which is of the PTFE "V" on a seat type, to the whistle under the cab floor. Result was a very odd sound, sometimes OK, more often not, which sounded about 1 in 3 times.
This year I fitted a small lightly sprung condensate drain valve just before the steam entered the whistle itself, under the cab floor, and the system is transformed. Strong positive note, always available.
I am sure you are on the right track to get rid of condensate.
Regards
Brian B

[steamer5]

The gent that got me into this game said your whistle valve needs to leak, let the steam thru to the whistle all the time, keeps the pipework heated so you dont have to clear the condensate first when you blow it.
Roger is there anyway that you could have the steam connected to the valve block but have a bleed in the void above the diaphragm to atmosphere? That way you would keep the valve block warm & any condensate would be ejected. This was chatted about this in Jims thread with his chime whistle, putting a auto drain on the bleed, same as on the cylinders may be another option?

Cheers Kerrin

[Roger]

Oct 18, 2023 7:04:25 GMT flyingfox said:

Greetings, on my 71/4 A3 for many years I have suffered "watery whistle", it has a long pipe run from the valve, which is of the PTFE "V" on a seat type, to the whistle under the cab floor. Result was a very odd sound, sometimes OK, more often not, which sounded about 1 in 3 times.
This year I fitted a small lightly sprung condensate drain valve just before the steam entered the whistle itself, under the cab floor, and the system is transformed. Strong positive note, always available.
I am sure you are on the right track to get rid of condensate.
Regards
Brian B

Thanks for the Brian, that might be useful on mine too. I'll keep that in mind if it isn't satisfactory.

[Roger]

Oct 18, 2023 7:57:18 GMT steamer5 said:

The gent that got me into this game said your whistle valve needs to leak, let the steam thru to the whistle all the time, keeps the pipework heated so you dont have to clear the condensate first when you blow it.
Roger is there anyway that you could have the steam connected to the valve block but have a bleed in the void above the diaphragm to atmosphere? That way you would keep the valve block warm & any condensate would be ejected. This was chatted about this in Jims thread with his chime whistle, putting a auto drain on the bleed, same as on the cylinders may be another option?

Cheers Kerrin

Hi Kerrin,
That certainly makes sense. I guess I could add a needle valve in the body, set to just leak the right amount. If the body was warm, I think it would heat all of it. An auto drain on both sides of the diaphragm might be in order.
I'll make sure there's enough room around the valve to give me options.