Worseter - update

[Jock67B]

Evening John et.al.

Pretty humbling to watch such engineering in miniature unfolding!

I'm enjoying this one, although my own engineering experience is at 'one-to-one', which looks a dam*ned sight easier than what is being attempted here!

Good luck fellows,

Kind regards,

Jock.

[Kempenfelt]

Morgan,

 

Thanks for the very useful insight to the problem of the live crank pins. Ultimately attempt one hasn't worked quite to plan and this has got me thinking too! How about a combination of the AGH and TR methods?

 

I like the idea of the Tufnol insulation between axle and wheel centre to prevent the axle from becoming live, but as you say the problem of insulating the live crank pins is a lot harder in 4mm compared to 7mm due to the sizes involved. Likewise Araldite has proven its bonding capabilities but has made life rather difficult when it comes the extracting the job from the jig. How about you Araldite the Tufnol insulation between the tire and a slightly modified, smaller diameter jig? I'd make the inside diameter of the Tufnol smaller than the required, but then bore out I/D afterwards as you were planning to do with the Araldite anyway. (The reduced I/D approach is what I've done when soldering bushes to 5" brakegear, then drilling and reaming out to size to finish) Hopefully this would result in a secure insulated ring to the inside of the tire and restrict the Araldite from coming into contact with the jig.

 

There are a few issues that spring to mind with this approach. Firstly this solution involves an additional stage in the sense of turning 10 Tufnol bushes. Secondly, could the I/D of the insulated tire be bored out sufficiently to maintain a scale thickness? Thirdly, would the Tufnol/Araldite combo withstand being bored out? (Although judging by your efforts I don't actually envisage this being a problem)

 

On the subject of you being "madder" than Ivan, I'm not sure I could ever bring myself to agree with that! :-p However you have certainly proved that you're up for a challenge and very proactive when it comes to putting ideas in to practice! Good luck with attempt number 2!

 

Best Wishes

 

Paul

[Porcy Mane]

I like the idea of the Tufnol insulation between axle and wheel centre to prevent the axle from becoming live, but as you say the problem of insulating the live crank pins is a lot harder in 4mm compared to 7mm due to the sizes involved. Likewise Araldite has proven its bonding capabilities but has made life rather difficult when it comes the extracting the job from the jig. How about you Araldite the Tufnol insulation between the tire and a slightly modified, smaller diameter jig? 

 

There are a few issues that spring to mind with this approach. Firstly this solution involves an additional stage in the sense of turning 10 Tufnol bushes. Secondly, could the I/D of the insulated tire be bored out sufficiently to maintain a scale thickness? Thirdly, would the Tufnol/Araldite combo withstand being bored out? (Although judging by your efforts I don't actually envisage this being a problem)

 

Paul,

Rick and I spent about an hour discussing this last night coming up with a similar solution. Peek rod :http://www.directplastics.co.uk/peek-rod or Tufnol rod:  http://www.directplastics.co.uk/tufnol-rod being used to turn up an insulating ring that would sandwich between tyre and wheel centre in the fashion of insulated Romfords.

The peek or tufnol would just be an added strengthener to the araldite "ring". As you say there is additional steps as well as cost and most of the Tufnol/Peek would be tuned to dust.

I've never seen Peek machined so don't know if its physical characteristics would allow a thin ring to be turned. Fortunately (for me) a 9F is well down on the priority list.

 

Nice pic of what to aim for.

BR 9F 92245, the last scrap loco at Barry! by Aron Stenning Photography, on Flickr

 

P

(Looks like you composed your reply after a Friday night clubbing. Good man.)

Edited February 14, 2016 by Porcy Mane

[45609]

Paul, Porcy,

 

Thanks for the input.  It is useful and worthy of consideration.  PEEK is a nice hard thermoplastic and easy to machine.  I saw it being done at a company I worked for more than a dozen years ago.  I'm pretty confident that the Araldite (proper 24 hour stuff) can be machined effectively provided I have a sufficient section to take a bite at.  I said in my previous post that there was a Plan B.  In actual fact it was Plan A but I thought that the 3D printed jig was worth a try for not much effort.  As it didn't work I've gone back to the original thinking and on Saturday morning made a simple single sided mould tool to enable me to make RTV silicone plugs.

 

The first photo tonight shows the tool (made from steel) and a plug that has been cured in this mould.  The pink plug is actually the second one I have made.  The first being a bit rough because it was made with rubber that was past it's shelf life.

 

 

Nevertheless the first plug I made from the tool was sufficient to demonstrate that the method would work.  This photo shows the plug fitted to a tyre laid up with glue.  I have also laid up another tyre with glue just to see if the glue slump was going to be as big a problem as I had thought.  The silicone plug and the sheet of glass that the unplugged tyre is sat on was well coated with mould release compound.

 

 

After 30 minutes in the oven things looked interesting.  The glue had slumped far more than I thought it would and it was a pig to get off the glass, despite the mould release.  By contrast the other tyre was perfect and the plug flexed and peeled out without any damage.

 

 

 

It's now time to make up some more plugs so that I can glue up a few tyres at a time.  They will be reusable for a number of tyres so 5 or 6 plugs should be sufficient.  Of course waiting for silicone RTV to cure leaves you with time to do other things and so I have also been working on another part of this project.  More soon....

 

Cheers...Morgan

Edited March 4, 2016 by 45609

[Killybegs]

That looks very encouraging Morgan, excellent work as usual.

[45609]

Thanks John.  By the way I haven't got your wheels yet. I guess they will arrive this week.

 

The other thing I have started work on, whilst waiting for RTV silicone to cure, is the crank pins.  After discussing it with John we came to and agreement to use Markits deluxe crankpins.  The main reason for this is the donor Bachmann wheel centres have crankpin holes that are threaded 12BA so fitting anything smaller (Ultrascale 14BA crankpins was the first idea) would need the hole to be filled and re-drilled.  The Markits crank pins have a threaded 10BA shank that screws into the wheel so it should possible to open out the existing holes and tap them 10BA.  I’ll do this on the leading and trailing wheels but make a larger crankpin and bush, as per the prototype for the centre wheels using a 12BA screw.  The other good thing about the Markits product is that the slots on the pins and nuts make fitting them very easy. However, a couple of things need to be done to the crank pins to refine how they will work in the 9F wheels.

 

First I’ll show you a general picture of the lathe I’m using to modify the crank pins.  It was made during the second world war by the British Tabulate Machine (BTM) company and is a dead copy of a German Boley watchmakers lathe. I guess German made lathes were tricky to get hold of after 1939.  I picked it up a little while ago and it had never been used until I got it.

 

 

As manufactured the Markits crankpins sometimes show this problem.  The nut fails the seat fully because there is a slight radius at the bottom of the 14BA shank.  All the crankpins have been modified to slight undercut the diameter at the bottom.  The nut now goes fully home.

 

 

 

For the front leading crankpins the clearance behind the crosshead and coupling rod is going to be very tight so I have decided the wheel centre will need to be spot faced to recess the crankpin flange.  Also the nut heads need reducing in diameter slightly to sit flush within the coupling rod boss.  The trailing wheel crankpins only need to have the seating flange reduced in thickness.  I’ve taken them down to 0.25mm from just over 0.5mm. In the photo below the upper item is an example of the leading crankpin whilst the lower item is a sample trailing crankpin.  Obviously the nut length and flange thickness might need to be altered but I’ll leave that up to John when he is fitting the rods.

 

 

It’s been a busy weekend…..Morgan

[Kempenfelt]

Afternoon Morgan,

 

Hopefully not a silly question, but how do you ensure you get an even thickness of Araldite around the inside of the tire? I assume its down to careful placement of the rubber mould and tire, and to hope that neither slip when you're putting the whole assembly in the oven to cure?

 

Not quite clubbing this time Porcy, but I do find that generally the last few hours of the evening/early hours of the morning are the only real free time i get to write emails or responses! (This response is bucking the trend somewhat! )

 

Cheers

 

Paul 

[Porcy Mane]

Not quite clubbing this time Porcy, but I do find that generally the last few hours of the evening/early hours of the morning are the only real free time i get to write emails or responses! (This response is bucking the trend somewhat! )

 

As long as you are keeping the fleet afloat.

[Horsetan]

.... Bachmann wheel centres have crankpin holes that are threaded 12BA ....

 

Coincidentally the same size thread that Chris Pendlenton uses in all his builds.

[45609]

Hopefully not a silly question, but how do you ensure you get an even thickness of Araldite around the inside of the tire? I assume its down to careful placement of the rubber mould and tire, and to hope that neither slip when you're putting the whole assembly in the oven to cure?

 

Not a silly question Paul.  The mould tool has been made so that the rubber plug comes out as a very slight interference fit on the ID lip of the tyre.  This quick fag packet sketch should explain.

 

 

When I machine the wheel centres to fit the tyres I will ensure that there is no metal to metal contact between the ID lip and the centre.  The region around the balance weights will need the most attention but the prototype shows a significant gap here so it should be ok.

 

Cheers....Morgan

 

P.S.  Are you turning "septic"?  This is the correct way to spell tyre.  Perhaps all of these late nights are making you tired?  

[Killybegs]

While Morgan has been getting on with the 'engineering' side of things, I have been back working on the body today. Handrails have replacement finer knobs, I have reused the handrails themselves. Replacement pipework has been fitted and new regulator rodding has been fabricated and fitted. This also involved adjusting some of the pipework on the firebox and relocating the entry point into the cab.

 

I can now go ahead and fit the lead ballast in the boiler, after which I can fit the boiler bottom. Then I can start filling the gaps between boiler and footplate and set about fabricating and fitting the new sand box filler pipes.

 

[Killybegs]

Latest additions are the upstand on the footplate where it meets the boiler, general filling between footplate and other bits of bodywork, new feed pipes to sand boxes ans 'quarter lights' to the cab. Next job, ATC conduit and box.

 

 

 

 

 

 

 

Edited February 20, 2016 by Killybegs

[45609]

A little more progress to report from the wheel shop.

Having made a number of silicone plugs for the glue lay up of the steel tyres and done a couple more gluing trials I discovered that it was a little difficult to get a thin annulus of glue into the gap without the occasional air bubble getting trapped. I also realised that the thickness of glue with the Alan Gibson tyres as supplied was not going to really give me enough to machine out reliably with a decent lip at the front to set the tyre position axially. The solution has been to add a step into the process to bore out the steel tyres to increase the diameter by approximately 0.060" (1.5mm). To achieve this a set of "soft jaws" have been purchased for my lathe chuck. The "soft jaws" replace the "hard jaws" in the chuck and can be machined to accommodate the steel tyres for boring out.

The first photo shows the soft jaws in situ after machining the stepped recess into which the tyre will fit.



The next two photos show a tyre clamped in the chuck. In the first I've highlighted the bore and face that is to be machined by marking it with a black felt tip pen. The second photo makes it clear how the tyre is located by the outer face and the rim of the tyre. This ensures squareness and concentricity.





It is imperative to keep a good record of the lathe hand wheel positions when preparing the "soft jaws" so that you can then subtract the correct amount from these values and work out new positions to machine to create the new bore. My lathe doesn't have a digital readout (DRO) but sometimes it would make life a lot easier. My DRO is a set of pencil scribblings on the cupboard door above the lathe that develops as I progress through the job. I'm aiming for a 0.010" (0.25mm) lip and 0.750" (19.05mm) bore diameter. The next two photos are action shots...sort of. Whilst the lathe is more than capable of taking the 0.060" diameter cut in one go you need to be a wee bit careful as the grip of the chuck jaws is on the tyre rim. A heavy cut might just grab the tyre and spin it in the jaws. Best case the tyre gets the rim worn down by the spinning action. Worst case the tyre comes out completely and gets fired in your general direction. Either way this will scrap the tyre.





The final photo shows the finished article from this step.



The "soft jaw" set up will get used again shortly to machine out the Araldite to create a slightly smaller bore (aiming for 0.715" diameter and 0.020" step). In actual fact one set has already been done and I'll be showing these to John tonight. Two more sets of 9F tyres await their date with the Araldite.

More soon.....Morgan

Edited March 1, 2016 by 45609

[Killybegs]

A little more progress to report from the wheel shop.

 

Having made a number of silicone plugs for the glue lay up of the steel tyres and done a couple more gluing trials I discovered that it was a little difficult to get a thin annulus of glue into the gap without the occasional air bubble getting trapped. I also realised that the thickness of glue with the Alan Gibson tyres as supplied was not going to really give me enough to machine out reliably with a decent lip at the front to set the tyre position axially. The solution has been to add a step into the process to bore out the steel tyres to increase the diameter by approximately 0.060" (1.5mm). To achieve this a set of "soft jaws" have been purchased for my lathe chuck. The "soft jaws" replace the "hard jaws" in the chuck and can be machined to accommodate the steel tyres for boring out.

 

The first photo shows the soft jaws in situ after machining the stepped recess into which the tyre will fit.

 

Bore tyre 1.jpg

 

The next two photos show a tyre clamped in the chuck. In the first I've highlighted the bore and face that is to be machined by marking it with a black felt tip pen. The second photo makes it clear how the tyre is located by the outer face and the rim of the tyre. This ensures squareness and concentricity.

 

Bore tyre 2.jpg

 

Bore tyre 3.jpg

 

It is imperative to keep a good record of the lathe hand wheel positions when preparing the "soft jaws" so that you can then subtract the correct amount from these values and work out new positions to machine to create the new bore. My lathe doesn't have a digital readout (DRO) but sometimes it would make life a lot easier. My DRO is a set of pencil scribblings on the cupboard door above the lathe that develops as I progress through the job. I'm aiming for a 0.010" (0.25mm) lip and 0.750" (19.05mm) bore diameter. The next two photos are action shots...sort of. Whilst the lathe is more than capable of taking the 0.060" diameter cut in one go you need to be a wee bit careful as the grip of the chuck jaws is on the tyre rim. A heavy cut might just grab the tyre and spin it in the jaws. Best case the tyre gets the rim worn down by the spinning action. Worst case the tyre comes out completely and gets fired in your general direction. Either way this will scrap the tyre.

 

Bore tyre 4.jpg

 

Bore tyre 5.jpg

 

The final photo shows the finished article from this step.

 

Bore tyre 6.jpg

 

The "soft jaw" set up will get used again shortly to machine out the Araldite to create a slightly smaller bore (aiming for 0.715" diameter and 0.020" step). In actual fact one set has already been done and I'll be showing these to John tonight. Two more sets of 9F tyres await their date with the Araldite.

 

More soon.....Morgan

 

Great stuff Morgan. Good to see you the other night and see the progress you have made with the wheels.

[Horsetan]

If this doesn't work, has anyone tried using resin for wheel centres? If so, what was the result?

 

It was just another mad idea that occurred to me as I was reading the updates last night - turning down the Bachmann 9F wheel centres, then trying to use them as masters in resin moulds......

[45609]

If this doesn't work....

 

 

Edited March 3, 2016 by 45609

[Kempenfelt]

If this doesn't work, has anyone tried using resin for wheel centres? If so, what was the result?

 

It was just another mad idea that occurred to me as I was reading the updates last night - turning down the Bachmann 9F wheel centres, then trying to use them as masters in resin moulds......

 

Ivan, I don't believe there is anything to suggest that Morgan's efforts wont succeed so i'm struggling to see the relevance of the resin wheel suggestion on this thread. Despite all the careful planning for such an experiment there's always the chance of coming across a small hiccup such as the characteristics of the glue in this circumstance. The role of any good engineer is to identify these problems and to provide a solution. I think Morgan's done a stella job of this having already explained the solution he's identified and to have provided the full story from trial to solution, I for one have found this extremely useful.

 

I always feel the tutor has done their job well when their explanation makes the process sound theoretically simple! With the steps provided above I feel could perform a similar operation, not sure I could've done it if I was just provided a set of 00 wheels and a set of tyres!

 

With regards to resin centres for wheels, perhaps its better that the question is asked in a dedicated thread? I wouldn't find it useful to interupt the current tutorial.

 

 

Kind Regards, and keep up the good work Morgan!

 

 

Paul

[Horsetan]

Ivan, I don't believe there is anything to suggest that Morgan's efforts wont succeed....

 

I didn't suggest that either, and Morgan's pointed video barb is a touch of an overreaction. I'm certainly not trying to rub him up the wrong way; the man suffers enough as it is.

 

It was merely an idea that occurred last night, that's why I asked.

[Mike G]

Morgan's pointed video barb is a touch of an overreaction.

 

Ivan

 

Did you have a bad day at the office? I thought it was funny and in no way barbed as you suggest. I thought you might have cut this process a bit of slack before casting doubt on the outcome.

 

Having seen these bits in the flesh I can see no reason why this won't work. However, this certainly isn't kitchen top modeling, it is engineering. And most engineers are...talented.   And yes I am jealous!

 

Mike

[Horsetan]

.... I thought it was funny and in no way barbed as you suggest.

I read between the lines.

 

...I thought you might have cut this process a bit of slack before casting doubt on the outcome.

 

Please refer to my previous post no.543 above. In no way have I said this won't work.

[Mike G]

If this doesn't work, 

 

?

[45609]

Maybe, Ivan, if you read the lines of your own post, in particular the first 4 words of post 540, you might appreciate why I posted what was intended to be a humorous reply. Obviously I must have misjudged your sense of humour but surely you'd forgive me for that considering how much you post on here (and else where) which you think is humorous. Having said that I accept, in your own words, "you are not trying to rub me up the wrong way" and that you appear to have redacted your comment that what I am doing "will not work". But to say that I must "suffer enough" in the very same sentence suggests that you are not content with the challenges that have come your way from Paul, Mike and now me? Please consider that last question to be rhetorical but if it is an incorrect assessment then you will prove that by modifying post 540 accordingly.

 

So, moving on, let me now reply to the 2 obvious questions you've raised in the last two weeks since I got more involved in John's thread. Also please remember that this is John's thread.

 

Q. Is this a one off job for John? A. No, I'm doing three sets.

Q. Have I tried using resin for wheel centres? A. No, because I consider it to be 1 structurally inappropriate, 2 more work for a less certain outcome and 3 infringing the copyright of the Bachmann product. However, if you fancied having a go yourself what is stopping you? The lack of response here and similar silence to the same question you subsequently put on the S4 web forum suggests to me that you might be able to do something innovative.

 

Morgan

Edited March 4, 2016 by 45609

[Mike G]

Ohh goodie..... I'm getting a set of wheels!

[barrowroad]

Maybe, Ivan, if you read the lines of your own post, in particular the first 4 words of post 540, you might appreciate why I posted what was intended to be a humorous reply. Obviously I must have misjudged your sense of humour but surely you'd forgive me for that considering how much you post on here (and else where) which you think is humorous. Having said that I accept, in your own words, "you are not trying to rub me up the wrong way" and that you appear to have redacted your comment that what I am doing "will not work". But to say that I must "suffer enough" in the very same sentence suggests that you are not content with the challenges that have come your way from Paul, Mike and now me? Please consider that last question to be rhetorical but if it is an incorrect assessment then you will prove that by modifying post 540 accordingly.

 

So, moving on, let me now reply to the 2 obvious questions you've raised in the last two weeks since I got more involved in John's thread. Also please remember that this is John's thread.

 

Q. Is this a one off job for John? A. No, I'm doing three sets.

Q. Have I tried using resin for wheel centres? A. No, because I consider it to be 1 structurally inappropriate, 2 more work for a less certain outcome and 3 infringing the copyright of the Bachmann product. However, if you fancied having a go yourself what is stopping you? The lack of response here and similar silence to the same question you subsequently put on the S4 web forum suggests to me that you might be able to do something innovative.

 

Morgan

 

Having donated/loaned one of my Bachmann 9Fs to Morgan in order for him to use the wheel set for this project I am more than confident in his engineering skills. I have seen Morgan's work on the wheels and believe it to be an elegant solution. I am looking forward to using them on a couple of 9Fs for my Bristol Barrow Road layout.

 

Robin

[Mike G]

Having donated/loaned one of my Bachmann 9Fs to Morgan in order for him to use the wheel set for this project I am more than confident in his engineering skills. I have seen Morgan's work on the wheels and believe it to be an elegant solution. I am looking forward to using them on a couple of 9Fs for my Bristol Barrow Road layout.

 

Robin

Just remember you're only getting one set :-) don't want you to be too disappointed

 

Mike

(From the hospital bed)