NSW 'B' class mogul

[Roger]

I'm not sure about the ones you mention. Maybe if you search for 2mm MDF you might be able to get that as another option. It's better if it's faced though, but at least that would be thin enough to be less likely to compress.
You might also search for "2mm board" or "backing board" which return quite a lot of search results of other options on the UK site. "Mount board" or "Grey board" also comes up with some possibilities. Ideally it should be dense and thin. I suppose you could go down to 1mm, it's only to give the cutter something to potentially cut into.

For sheet metal work I machine exactly to depth and use nibs on profles and go through an additional 0.5mm on the through holes where I can clean up without leaving a wafer.

[jon38r80]

Masonite is the Canadian/american trade name for what we call hardboard in the UK. its not quite thye same but near enough It has one smooth side and one rough where it is compressed against a platen whent its made. You used to be able to get it oiled with linseed oil to sort of waterproof it as well.

Melamine is usualy a thin surface on a cheaper substrate like MDF/chipboard/particle board but it can be got as solid sheet, very dense, hard wearing,tough they make toilet cubicle walls, worktops and stuff like that where you dont want water take up that you get with the cheaper faced mdf/chipboard types when the edges may get wet. Urinal splash backs get made out of it when an architect isnt being cheap.

Another alternative to use as a solid material under something you machine is plexiglas/acetate/perspex sheet or similar solid glazing type sheets. Sometimes a source of cheap offcuts will turn up , buying it to ruin it machining bits out of it is a bit expensive.

[steamer5]

Hi David,
You can get hardboard here in NZ, probably not worth the cost of getting it across the ditch.
As Jon says you can also get the same substrate with a surface for shower lining, well I think it’s still available, you can use it in other rooms BUT that’s very old school! Go to Bunnings & ask the guys in the building product area, if like here the guys are very helpful.


Cheers Kerrin

[Roger]

If you check out this link, you can see how makes PCBs in your neck of the woods. If they manufacture boards in house, they will use backing board behind every panel they drill, so they will have a ton of it going in the bin every day. It's worth getting cheeky and giving them a ring. The worst they can say is no. If it's anywhere close, I'd just turn up at the factory as tell them the story, a bit of charm and cheek goes a long way!

[steamer5]

Hi Roger,
David is in Australia!
There will be PCB guys there

Cheers Kerrin

[stevep]

Sundela is a soft fibrous material, often used for pin boards (notice boards which you attach posters with drawing pins - what the Americans call thumb tacks). It's often used as insulation, and I think as a baseboard material (mounted on a strong frame) for small gauge (e.g. OO) railways, as it absorbs the vibration.

[Jim]

It's also known as Caneite in OZ and it was made I think, from sugar cane fibre.

Jim

[Roger]

Nov 22, 2019 9:34:24 GMT stevep said:

Sundela is a soft fibrous material, often used for pin boards (notice boards which you attach posters with drawing pins - what the Americans call thumb tacks). It's often used as insulation, and I think as a baseboard material (mounted on a strong frame) for small gauge (e.g. OO) railways, as it absorbs the vibration.

That sounds like it's going to be too soft then.

[David]

I only mentioned Sundela to show the confusion arising from living in this hot, dry, dusty, drought-ridden, fire-prone place our ancestors saw on the one year in 100 it's habitable and thought was a good place to settle, and growing up reading magazines from the UK!

I've got an idea of what Sundela is now - I thought it was like what we call chipboard! So masonite is approximately hardboard, good to know. My bench has a 5 or 6mm masonite sacrificial top. It's pretty soft so it might not be exactly the same stuff. It is as Jon describes - smooth on one side with a pattern on the other and obviously pressed.

As to the loco I've decided to paint the frames and cylinders to try and show some real progress. I've spent a lot of time working on it recently but it doesn't look much different and I don't feel like I'm getting anywhere. I spoke to Barry about it yesterday and we have a plan.

The first thing is to take the cylinders apart and add the missing gaskets. I didn't put the Loctite 567 goo in when I first put it together because I assumed it wouldn't work and I'd have to take it all apart again. So the cylinder covers and steam chests and their covers all have to come off and get cleaned and have the goo put in. I'm also checking I didn't forget the o-rings for the piston rods and valve spindles.

The left side has been stripped, cleaned, checked, and is in the process of being reinstalled with just either side of the steam chest to have the goo added as it's assembled, and the valve timing to be checked in the middle of that process. The right side is off and ready to come apart sometime in the next few days.

When that's all done I have to run it and look for leaks. Once any leaks are fixed I'll have to take the wheels and motion off other than the cylinders, piston rod/crossheads, and valve spindles which I have to be careful not to rotate. I went through that process not long ago when adding the left spring brackets. The brakes, drain operating rod and various other decorative bits are already off. Then clean it again and learn to paint.

While the valve gear is off I might give it a good clean and put thread lock on all the fasteners as they have shown a tendency to come undone when running. I may also check if I stamped numbers on everything because I'm watching another club member battle with the valve gear on one of his locos which didn't get numbered during construction.

[David]

Both sides checked, gooped, and back together. I adjusted the valve position on the right by one-half turn as it didn't seem to have equal travel as it was.

It was interesting to see how many mistakes I made making these parts. I thought I was well on my way to doing a good job by this point but the steam chests have two studs in different places and I wish I'd made proper studs rather than using 6BA threaded rod and gave bigger clearance holes for them. They're a real nightmare to work with. I got the orientation of the 'real' and 'dummy' bolts on the piston rod stuffing boxes exactly opposite to the instructions. I know there was a broken tap while doing one of the holes for a slidebar bolt so that bolt is pretty well cosmetic and an exhaust hole was drilled in the wrong place in one cylinder casting (misread a drawing, assuming the hole would be in the middle of a square cavity which I fixed by plugging and redrilling). Still, it all came apart and went back together.

I still have to put the inlet and exhaust manifolds back on. The inlet one is easy. The exhaust one is too aside from having to get o-rings into the right place. The manifold is captive in the frames over the cylinder castings and there is about 1.5mm to slide the o-rings in and get in the right place with no visibility... I'm not sure how I did it last time but one o-ring came out showing it obviously hadn't got to quite the correct location whereas the other one looked fine. Perhaps the cylinder castings need to be unbolted again so they can move a bit - meaning the valve rods, con-rods, and slidebars need to removed or freed up then reinstalled for the leak testing!

I'm looking forward to giving it another run and seeing if all the gasket goo makes a difference. There was air coming out from everywhere before.

[David]

A few wins and losses today looking for leaks. The biggest loss was having one of the cylinder drains shoot off because the thread in the cylinder is no good. It's the same one I stuffed up on the red train - the front right - so it seems I can't cut that thread. I don't want to take the cylinder off if I can help it. The only way I can think to fix it is to drill out and thread to a size where I can fit a plug which will then get drilled and tapped for the drain. I could have done without that. The red train has had this problem for 5 or 6 years and isn't fixed yet so you can see I'm not keen on the operation! I'll do the mogul cylinder when the motion is out and it can sit flat on the frame tops and is a bit lighter.

The wins were that none of the gasketed joints leaked and a leak at the exhaust flange was fixed by tightening the bolts a bit more than I'd like. Before the cylinder drain made its exit the engine ran very well needing about 25 or 30 psi to start but then running on 20 - 25 psi in both directions. I thought that was good, anyway.

The other loss was that the joints on the inlet manifold - like the exhaust - had to be soldered in-situ and it doesn't fit that well. I think I allowed too much for the contraction on cooling down so it's a bit too wide. I have to loosen one cylinder and motion bracket, fit and bolt the manifold on and then tighten things up again. At higher pressures there is a leak at the left hand inlet flange where it bolts to the steam chest. I tightened the bolts as much as I dared and it reduced but it didn't go away.

I also have to loosen the left cylinder to get the exhaust o-ring into place on that side due to not being able to lift the exhaust flange enough to get clearance so maintenance is going to be a bit painful on these manifolds. My fabrication skills aren't at the required level for the design and I really wish I'd made all the o-ring counterbores larger in diameter to make it easier to get them in place. Things I didn't know at the time!

The die block pin unscrewed itself again but luckily I felt the friction trying to move between forward and reverse before I went to restart the engine at some point and figured out what it was. That's why all those threads are going to get a good degreasing and threadlocking while the motion is out next time.

[David]

I took the inlet manifold off and wasn't happy with the look of the o-rings which had obviously been squashed in ways they should not be.

Checking the counterbores for the o-rings I found they were 12mm dia for a 1/2" o-ring.

The LHS steam chest came off again last night to have this counterbore increased to 12.8mm. I also rounded over the tops of the studs and ran a die over the threads again plus put a tap through the nuts in an effort to make it easier to get the nuts onto the studs in the limited space available between the steam chests and stop the nuts bringing the studs out with them when they're undone.

It was too late to test it by the time I'd finished and I should do the RHS beforehand anyway. Given the steam chest is coming off it's not that much more effort to take the cylinder casting out and try to fix the drain thread.

Pretty disappointing given I hoped to have the gasketing work done last weekend and perhaps be preparing to paint it by now.

[Jim]

Take heart David, we all encounter problems like that, it's part of the hobby and as an added benefit you learn all sorts of cunning ways to fix the problems.

Jim

[Roger]

Nov 26, 2019 22:17:42 GMT David said:

I took the inlet manifold off and wasn't happy with the look of the o-rings which had obviously been squashed in ways they should not be.

Checking the counterbores for the o-rings I found they were 12mm dia for a 1/2" o-ring.

The LHS steam chest came off again last night to have this counterbore increased to 12.8mm. I also rounded over the tops of the studs and ran a die over the threads again plus put a tap through the nuts in an effort to make it easier to get the nuts onto the studs in the limited space available between the steam chests and stop the nuts bringing the studs out with them when they're undone.

It was too late to test it by the time I'd finished and I should do the RHS beforehand anyway. Given the steam chest is coming off it's not that much more effort to take the cylinder casting out and try to fix the drain thread.

Pretty disappointing given I hoped to have the gasketing work done last weekend and perhaps be preparing to paint it by now.

'O' rings are very flexible, it's the compression on the section that matters, not the major diameters. You can get away with a lot as long as you get the right 'nip' on the section.

[David]

The RHS got a repeat of what the LHS suffered yesterday with the addition of the cylinder coming off and a plug pressed in for the cylinder drain. I tested the cylinder drain thread on a newly threaded hole in brass with the recommended tapping size and it was as loose as all get out so I went down 2 number drills and that gave a better fit. I used a 6mm endmill to open out the old threaded hole in the cylinder going down 5mm. I carefully turned down a 1/4" brass rod until it just went in and figured I'd need about 0.240" for a press fit based upon measuring that. I left the plug slightly long so I could file it down to have the drain in the correct orientation when it's done up. The fix has survived the first air test so I hope it will last. I think this might be an easier method than trying to tap a shallow blind hole.



The bad news is one of the studs on the RHS seems to have given up the ghost and isn't really pulling its weight athough there are enough of them this might be a big problem. Not sure if it's the stud or the hole it goes into and I can't take it out without removing the opposite steam chest cover as they're too long.

Adding to the fun is new very bad blow-by when the loco is in mid gear and whatever is causing it isn't getting moved on the motion of the valves when it's running so I'll have to take BOTH chests apart again and try and find it! Getting quite fed up with this detour and running out of Loctite 567 to boot.

Given the bad blow by in mid gear I didn't have the heart to check if the inlet is sealing properly with the larger o-ring recess.

There is also a squeak that's never been there before which I can't trace.

So aside from the (hopefully) successful drain fix I'm going backwards at a fairly rapid rate just now!

[Roger]

Nov 27, 2019 10:05:46 GMT David said:

The RHS got a repeat of what the LHS suffered yesterday with the addition of the cylinder coming off and a plug pressed in for the cylinder drain. I tested the cylinder drain thread on a newly threaded hole in brass with the recommended tapping size and it was as loose as all get out so I went down 2 number drills and that gave a better fit. I used a 6mm endmill to open out the old threaded hole in the cylinder going down 5mm. I carefully turned down a 1/4" brass rod until it just went in and figured I'd need about 0.240" for a press fit based upon measuring that. I left the plug slightly long so I could file it down to have the drain in the correct orientation when it's done up. The fix has survived the first air test so I hope it will last. I think this might be an easier method than trying to tap a shallow blind hole.



The bad news is one of the studs on the RHS seems to have given up the ghost and isn't really pulling its weight athough there are enough of them this might be a big problem. Not sure if it's the stud or the hole it goes into and I can't take it out without removing the opposite steam chest cover as they're too long.

Adding to the fun is new very bad blow-by when the loco is in mid gear and whatever is causing it isn't getting moved on the motion of the valves when it's running so I'll have to take BOTH chests apart again and try and find it! Getting quite fed up with this detour and running out of Loctite 567 to boot.

Given the bad blow by in mid gear I didn't have the heart to check if the inlet is sealing properly with the larger o-ring recess.

There is also a squeak that's never been there before which I can't trace.

So aside from the (hopefully) successful drain fix I'm going backwards at a fairly rapid rate just now!

Hi David,
Just a thought. Are the drills the wrong size or are they drilling over size? In other words, are the drills a loose fit in the hole they've just drilled? It's easy to end up with oversize holes if the drills are blunt or if you are drilling straight to the finished size in one go. I usually pre-drill to leave between 0.2mm and 0.3mm for the final size to clean up if it's important that it doesn't go oversize. 

[David]

All my small drills are cheap number sets so I'm sure they're drilling bad sizes. The most recent set seems to be blunt too which won't help but I didn't have them back when the cylinders were done. Most of the threads in the cylinders are pretty loose but I don't know if it's the male or female threads that are the problem.

If I have to take the steam chests off again to clean the port faces and valves I'll make another stud with the die quite open at one end to see if I can get one that fits.

MEW has recently published the design for a small drill sharpener which is on my to-do list. I already had a design in one of the Machinist's Bedside Readers but it looked like a pain to make. Maybe when the frames are painted I'll feel like I can afford a diversion, but probably not.

The one piece of good news since last nights posting is that the squeak seems to have been my bench! I noticed it again when I opened a drawer near where the loco is sitting and it went away when I clamped the sacrificial top down. So at least I don't have to chase that all through the wheels and motion.

[David]

Before taking everything apart I asked the expert if he'd have a look and listen and he said it's fine and I should take it apart and clean it. So that's good news! The amount of blowby in mid gear was normal and whatever there is when running, if any, isn't enough to worry about.

I'll give it one final test here with soapy water to check for leaks around the manifolds and see if I've fixed the inlet but other than that I'm hoping I can call this part of the detour done and take the wheels and motion off and give everything a good clean.

The dodgy stud will stay as is now the steam chest isn't coming off again. It has studs either side to to help out and it will be obvious which one needs fixing if I'm ever unfortunate enough to have to take the steam chest apart again.

Pretty relieved after nearly a weeks work that it hasn't gone wrong.

I did try to follow Julian's advice in the other thread and put a lot of oil down the exhaust and pumped it through by hand. Then I connected an air hose to it and you can imagine what happened. I did cover the exhaust but not well enough... even just cracking the air line to get it ticking over I got a good spray of oil up on my pristine white workshop ceiling.

[David]

The frames and various brackets, stretchers, and the pony truck have been cleaned. I put the motion brackets and rear brake hanger brackets back on so it will need another clean after the handling. I don't have the paint yet so can't move further.

Last night and this afternoon I made the loco cab steps. The plates they're mounted on were laser cut years ago and I lost one so made another from the same drawing on the CNC machine sometime in the last 12 months. It took a few goes to figure out the dimensions required for the step folds and a lot of filing afterwards on each one. I managed 1 in 3 hours last night and the other 3 took about that long today. Not being able to find any superglue I soldered the steps to the plates to keep them in place while drilling the rivet holes through. I've since cleaned up the solder you can see along the top of a step.

I will mount them after the frames are painted. I need the running boards mounted to the frames and drag beam to get the location right.

[Roger]

Nov 27, 2019 21:20:48 GMT David said:

All my small drills are cheap number sets so I'm sure they're drilling bad sizes. The most recent set seems to be blunt too which won't help but I didn't have them back when the cylinders were done. Most of the threads in the cylinders are pretty loose but I don't know if it's the male or female threads that are the problem.

If I have to take the steam chests off again to clean the port faces and valves I'll make another stud with the die quite open at one end to see if I can get one that fits.

MEW has recently published the design for a small drill sharpener which is on my to-do list. I already had a design in one of the Machinist's Bedside Readers but it looked like a pain to make. Maybe when the frames are painted I'll feel like I can afford a diversion, but probably not.

The one piece of good news since last nights posting is that the squeak seems to have been my bench! I noticed it again when I opened a drawer near where the loco is sitting and it went away when I clamped the sacrificial top down. So at least I don't have to chase that all through the wheels and motion.

To be honest, small drills are so cheap that buying each size ten at a time from eBay is usually what I do. I do sharpen some by hand though.