3 1/2" 70025 Western Star

[Deleted]

I think ... fingers crossed ... This is NOW in the correct place. (I blame the cold weather and inferior whiskey ... deteriorates brain cells).

I am still coming to grips with what I have here while I wait for the words and music.

I have discovered that the axle boxes all have the needle bearing option in them.

Question ... is there an easy way to get the wheels off of the axles or are they on there for good?

Cheers

[uuu]

Have you any evidence of how the wheels are fixed? If they're glued on, then some heat to weaken the bond, then press out the axle, being careful to apply the force to the wheel boss, not the rim. If they're pressed on, they should press off. Beware of hidden fixings, screws pins etc.

BUT (and it's a big but), how are you going to get them back on in the same place?. If you have locating keys, then hurrah. Otherwise you'll need a quartering jig.

Are you planning to do one axle or all?

Wilf

[Deleted]

Hi Wilf, and Thank You for the response.

I would only be doing 2 wheels on the forward driving axle. The reason for maybe wanting to do that ... when turning that set of wheels there is a high spot. Once past that point the wheel is free again. As stated above, the axle boxes have the needle bearings in them and I'm thinking that perhaps the axle is misaligned or the boxes aren't bored square. Something is not as it should be and I would think that now would be a good time to fix it. I have a look and can see no set screw or evidence of glue. These were assembled in the 60's or 70's ... was crazy glue around then?

Cheers

Tom

[Deleted]

Hi Tom

Well done, this is the correct forum.....:)reading what you have said to Wilf, another possibility could be one of the rods is the wrong length between centre's causing it to bind at one of it's extremities, I would check that first, and check everything to drawings too.

Pete

[Deleted]

Thanks Pete ... nothing on the wheels, it has all been taken off ...



The person that started this engine passed away many years ago and in order to find out what stage it was at, I started over. Good job as it was just in "temporary assembly" mode with many fasteners missing, holes not threaded ect.

Cheers

Tom

[Deleted]

ah...ok....have you checked for run-out....my part built great northern had a wobble on it's driving axle which caused one wheel to foul the frame.... however on checking it was simply due to the suspension set-up...The builder had chocked up the wheels with small blocks of steel for normal riding height to run on air. Problem was one block had fallen out at some point and this caused the axle to be kinked over resulting in one wheel rubbing against the frames. It already had a very slight run-out which was greatly enhanced by this suspension mishap...worth checking

Pete

[Deleted]

Excellent thought (never crossed my mind).

Her That Allows Me To Play needs to be chauffeured somewhere, and when that chore is done, I will check it.

Thanks for the idea.

Tom

[Deleted]

I have checked the run out and I am quite sure that that is not the culprit.

But ... In order to check the run out, I secured the blocks in place as they would be in normal operation and the high spot seems to almost disappear.

At this point I am very tempted to leave as is. I don't really want to take a chance on breaking a wheel or getting it back in the wrong position. If it doesn't go away after some air running, I can still take it apart then.

Onward and upward ...

Tom

[Roger]

One thing that caught me out was when I had a tight spot at the front dead centre but not on the back dead centre. What's easily overlooked is how important it is for all the cranks to have the same throw. If you check the distance between the crank pins with them both forward and then both back, any difference is due to the crank throws being different. The only fix for this is to make a crank pin with an eccentric pin to get it to the correct radius.

[Deleted]

I will do all that measuring when I start to put the rods/arms on. I want to get the frame cleaned up and painted now so I can permanently mount the axle blocks and get them where they are supposed to be.

Thanks for all the replies.

Tom

[chris vine]

Hi Tom,

I looks like you have got yourself a grand project there. I hope you have a lot of fun with it.

When trying to find tight spots, it is amazing what you can discover by really watching closely as you turn things. EG if you watch the axleboxes, are they being made to wobble as the axle goes round.

Later when you put on rods, if there is a tight spot you may be able to see axle boxes being forced in the horns, or you will find that one rod can no longer be shoogled (good west coast of scotland word) as you get to the tight spot.

The most difficult locking up problem I ever came across was on a friend's locomotive which would suddenly lock up solid and slide along the track till it stopped. Nothing anywhere could be seen which could do this. Eventually, after a strip down, he found that there was a blow-hole in the back of the hub of one of the wheel castings. (he had cast them himself in a home-made foundry in a barn.) The blow-hole was of no importance at all, so the wheel was used.

However this did not take account of the possibility (very remote) that a screw in the frames would work loose and its head would sometime just jump into the blow-hole!!!

Solution, tighten up the screw a bit tighter this time...

Best wishes
Chris.

[Deleted]

Hi Chris,

That is exactly what is happening ... the axle boxes on that axle are being slightly moved around in the horns. If I tighten everything down to running position, then it is slight. I am thinking that perhaps the boxes on that axle were bored a wee bit off line, or got bored both at the same time, but got swapped around when installed.

I am waiting for some bits to finish off the frame, then I will paint it and start to put all this back. Then the fun will start.

At the moment I am mainly cleaning up things that had started to rust, and to file off some very sharp edges on wee fiddly bits.

I like shoogled ... it sounds distinctly Scottish, but I thought it might have something with the brewing trade. I usually feel a tad shoogled after a few wee drams of the amber liguid.

Cheers

Tom

[Deleted]

A question ... How accurate do the measurements need to be, particularly in all the linkage parts, in order for this engine to run fairly well?

As I clean up some of the parts I have been checking them against the plans. Some are bang on, some are out by a couple of hundredth's and some ar out by a thou or so.

Now, I am talking strictly about mating parts here, not general part profile measurements.

I am trying to get an idea of I need to remake.

I received an email this morning to say that the article reprints are on their way, so hopefully they will be here soon. I did get a complete bound set, but they had got wet and went a bit mouldy. Mould and I do not play well together and it usually wins so I bagged them and relocated to the garage for the winter. Hopefully the freezing temps will kill the mould and I will be able to look at some of the other articles in them.

Cheers

Tom

[Deleted]

Hi Tom


it's nice to get parts as accurate as possible however the most important thing is that they fit with each other. So if a con rod is short, is it because the distance between the crankpins is also short, as long as the two match it should work, even if the matching rod on the other side is a different size to it. The thing to bear in mind is that once you start chasing this error, correcting offending parts you may find yourself scraping everything and starting again. i had this same dilemma when stripping down Great Northern... there were many errors, the trick is discovering which one's you can leave alone. I left many and she ran pretty well once completed.

Pete

[Roger]

I think there's a lot to be said for trying to tie down accurate dimensions for as many things as possible to find where the biggest ones lie without the connecting rods in place.. Finding which axle is the most square to the frame for example and then using that reference to start mapping the axle spacing on both sides.
You can use a height gauge to test the crank pins in the low and high position on all 6 pins. Measuring inside and outside of connecting rods with calipers and taking the average works to find the centre distance even if the pins are different sizes.
It's hard to see where the errors are when looking at the whole assembly so I think it's valuable to check these things as absolute values before second guessing where the problems lie. The chances are that you'll guess wrong anyway.
Once you've done that, you can fit one sides rods and then use a height gauge to the pins on the other side to see it they are quartered relative to the other accumulated errors on the other side.
I did all of this and found that there was only one significant error, and having fixed that, it all worked fine. It took me the best part of two solid days to convince myself that all the measurements we telling me the truth. I probably triple checked everything before being sure. It's hard to take some of the measurements but it's worth the effort in my opinion.

[Deleted]

Thank You Pete and Roger.

I need to get a good height gauge anyway so that will be first on the list.  That, combined with the granite block will give me the proper measurements.

I strive to make my parts as accurate as I possibly can, and I am sure the original builder of this engine did as well.

I am treating this whole project as a massive learning curve, and so far I am not disappointed.

Cheers

Tom

[donashton]

I once took a look at a 3.5 Gauge 2-10-0. It was not particularly well made but had run for some years. Stripped to the chassis to renew rather sloppy bushes on the motion revealed that by naked eye viewing from above the 5 axles were at 5 different angles to the frames...by a long way! Stripping further, nearly all the bushes had obviously been made eccentric to find a reasonable fit. The new bushes were therefore made the same way and individually fitted (not by me I hasten to add).
After a few hours running in the rest of the engine was added and she ran again for years. Biggest trouble wasn't all that binding, but the fact that the wheel sets were made to run on 3.562" Gauge......or thereabouts. Didn't check the wheel diameters, but with 10 different wheels and a rough track nothing seemed in much distress at all, really.
Don.

[Roger]

You're most welcome Tom, this is my first locomotive and I'm starting from scratch although I've been in Engineering all my life. Making these particular parts as accurately as possible makes life so much easier when it comes to getting a smooth running chassis. Having said that, it's easy to get carried away and try to chase down everything to make it near perfect and that's not absolutely necessary either. It's getting your head round the magnitude of the errors and recognising what you can live with and what you can't that's the hard bit. I set myself a tough challenge by making all the bushes, axles and axleboxes with the absolute minimum of clearance. I know they will need more than I've got and they'll soon bed in and make their own clearances. I did it because I wanted to discover if there were any inaccuracies in the geometry. I reasoned that this is the worst case scenario and it was almost certain to bind up and I wasn't disappointed! I probably wouldn't have even noticed the error if I'd allowed sensible running clearances but it clearly wasn't right and it gave me the opportunity to do something about it.
Just one adjustment to the throw of one crank pin and it's nice and free without any tight spots on dead level track. It's a good starting point, but it's clear that some more clearance is going to be required else it's going to bind when things aren't perfectly flat.
What I'm trying to say is that you can go as far as you like getting things spot on and it's a good thing if they are. Whatever happens, you will need running clearances but those will end up smaller if you don't have to accommodate build inaccuracies on top, and the locomotive will run more like a watch than a bucket of spanners. The great thing is that they appear to be reasonably forgiving, so the chances are it will work well anyway.

[Deleted]

Thanks for that Don,

From what I have been able to check so far, all wheels are round, and square to the frame.

Another question ... In my browsing of this sight and many, many threads, I saw a home made tool for checking the distances between rod centers. It was an adjustable, slidy thing (technical term). I want to make one but can't quite remember what it looked like.

Cheers,

Tom

[Roger]

Nov 10, 2014 16:11:46 GMT @mealchips said:

Thanks for that Don,

From what I have been able to check so far, all wheels are round, and square to the frame.

Another question ... In my browsing of this sight and many, many threads, I saw a home made tool for checking the distances between rod centers. It was an adjustable, slidy thing (technical term). I want to make one but can't quite remember what it looked like.

Cheers,

Tom

Hi Tom,
You'll find my version of it here on the Wiki I started for SPEEDY

and more here in my photo album