Building an Ace Kits "K"

[simond]

Brian,

Mine don't have a frame, they just sit on the track, but they aren't the same as Mike's either (though very similar).

The tops of the bearings have to lie on a plane parallel to the bottom plane, and they need to all be the same "wheelbase" too.

Maybe barking up the wrong tree on this one, but it's easy to check & eliminate.

Best
Simon

 

[oldravendale]

Thanks Simon. Clearly not the same rolling road, but the principle applies.

Here's my update on yesterday in the workshop:

Jim - location of axles all in the same running line is checked and confirmed, but see my response to Mickoo below.
Mick - chassis was, indeed, tail heavy by a couple of mm. Screw adjustments have been made and the screws temporarily locked in place while the chassis sits on a glass plate.
I've also taken on board your suggestion about trying a drive from the middle axle. I've not done it yet, as this will require the bearings for the middle axle to be filed back, but the evidence when running the chassis under finger power drive to the middle axle is that this will overcome the problem as no jamming occurs. This only seems to happen when driving the rear wheel set. And therein must lie a clue, although I don't know what that clue is! Centre drive is not the long term answer, I don't think, because checking the fit of the motor/gearbox against the scale drawing suggests that it will just foul the front of the firebox.
Yorkshire Dave - I've checked for slop in the hornblocks with coupling rods off, and there is actually very little.
Simon - Rolling road bearings/location/vertical and lateral position and as far as I can tell back to backs are all good.

So that's where I am at the moment. The chassis is on the shelf for a while for more consideration.

Many thanks for all the suggestions and help.

Brian

 

[Dikitriki]

The fact that it will work on the centre driver but not on the rear leads me to suspect that the issue is with the coupling rods.

Either they are not truly identical in wheelbase, or your ministrations have led to over-large holes which has much the same effect. The locking can be intermittent in such circumstances. I would bush the coupling rod holes and start again.

Good luck.

Richard

 

[oldravendale]

Hmmm. I've sort of come to that conclusion, Richard. It was one of the first things I thought of as I've been quite cavalier in opening up the holes in the coupling rods on the basis that they'd eventually work OK - certainly they are now much larger than I've ever had need to consider in the past.

I actually believe that these rods are identical, or at least were when originally assembled. I don;t believe that any of this can be put down to the Ace kit.

Thanks for the thought. Bushing the holes can't make the situation any worse!

B

 

[JimG]

Brian,

Can I raise another point, are you assuming that all the crankpins have the same throw and are accurately quartered? I could be calling down the wrath of David White here , but there might be a rogue wheel/crankpin that's causing the problem.

Jim.

 

[oldravendale]

Well, Jim, they look OK and I get a constant measurement from crankpins on each side. I'm more of the continuing opinion that this is all down to something I've done. It's an option to buy another axle/wheel set and see if the problem can then be solved but of it's not in the hardware that's an expensive test. It may, of course, help to preserve my sanity.

Brian

 

[mickoo]

Brian I think if you use the 40L then it'll fit in the firebox without impacting the front sheet. Given the woes so far encountered and the ones that lay ahead with bushing the rods, then I'd let sleeping dogs lie and drive on the middle axle and move on with life.

Regarding bushing the rods if your holes you have now are not accurately centred (due to them being opened out unevenly...it can happen) then your new bushes won't be either and you'll end up opening them again and be right back here.

I also haven't seen any reply to driving it on the track. I would do this before anything else and it doesn't even need to be on rails, any flat surface with flying leads to the motor will suffice. You may find that actually driving it will reveal no issues and all these planned remedials are not required.

MD

 

[oldravendale]

Thanks Mick.

When I get the body completed I'll be able to try it for real. If I can drive on the centre axle I agree that's the option. As for opening out the rods, that was done with a broach (I never use a drill for this), but I accept that some unevenness may have occurred.

I tried driving it with flying leads, but my old H & M controller sets it off like a rocket and my bench is limited to 2 metres. Worth another go, though. Ideally I want to see what happens with it running at very low speed. A light bulb moment has made me realise that I might be able to do that at club tonight with a superior controller. I'll try.

As ever I'll report when tests are completed.

B

 

[Tim Humphreys ex Mudhen]

Well, Jim, they look OK and I get a constant measurement from crankpins on each side. I'm more of the continuing opinion that this is all down to something I've done. It's an option to buy another axle/wheel set and see if the problem can then be solved but of it's not in the hardware that's an expensive test. It may, of course, help to preserve my sanity.

Brian

Rather buy another wheelset you could try swapping the axles front to back to determine whether locking up stays on the same axle or moves with the wheelset.
Tim

 

[oldravendale]

Here's my update.

Motor refitted on the rear axle. Test running on the club layout. Same problem as on the rolling road.

Next I'm going to put the chassis back on the chassis jig set up at the correct ride height. I'm expecting everything to be OK but.......

Subject to that being OK I'll swap the rear wheels for the front ones and see whether the problem moves. If so it has to be a wheel problem I guess.

Brian

 

[oldravendale]

Sorry Tim...... Great minds and all that.

I'd written my update before I saw yours, for which thanks.

Brian

 

[simond]

Any progress to report?

We're all waiting with bated breath!

Best
Simon

 

[oldravendale]

Sorry - garden duties, visitors and now I have instructions for some F7 locos to pick up from the printers and assemble, so some delay is inevitable.

However - Steph was here at the weekend and took a look. He's convinced that the rear hornblocks are not square (how he knows these things I'll never understand) so I've fired up the long bright mild steel ground rods to check in the bearings. In order to do that I'll have to strip the chassis down (again) and won't have time for a while. If Steph is correct I'll be , probably in that order.

A check of the squareness of the chassis/hornblocks has been suggested previously and you'll note above that I was proposing a check on the chassis jig as part of the next process. It just goes to show that an assumption regarding the most basic possibility for error is always worth checking.

Actually, when Steph told me what he thinks the problem is I was just going to put it right and say ....... nothing. Now I've let the cat out of the bag.

B

 

[mickoo]

Acknowledging there is a fault is the first step forward

 

[simond]

He acknowledged that about two pages back...!

 

[oldravendale]

Well, I managed to get a couple of afternoons in the workshop this last week. (Do I hear a chorus of "about b****y time?)

I spent two afternoons checking the axle centres, and found that the one Steph had marked up was one of the front hornblocks, not the rear, which is where all the problems appeared to have been. I made lots of measurements, checked stuff on jigs and actually spent a whole afternoon with the long ground steel rods trying to get a handle on where the problem lay. I should have just accepted that the man-boy guru got it right to start with (I still don't know how!), and the dimension which was awry was one of the front hornblocks.

The soldered joints around the hornblock were protected with water soaked bog paper (if you've not tried it the bog paper can hold a lot of water and can be moulded around any areas you want to protect) and the gas torch was applied. Having cleaned up the chassis and the hornblock both were reintroduced to one another on the jig and re-soldered. The result was exactly as before, as it was on the next try, so for some reason this hornblock is "floating" itself in to a position other than that where I set it up. Anyway, on the third attempt, and by applying a bit of bias during the soldering everything measured up quite reasonable.

So I reassembled the coupling rods and motor, and I now have a running chassis!

'Nuff said, and thank you Steph.

(Well, perhaps I should say that the problem has nothing to do with the kit and is all down to my reliance on a chassis jig......)

B

 

[richard carr]

So Brian are you saying that the chassis jig allowed the hornblock to go on in the wrong position ?

 

[oldravendale]

Exactly so, but I have to say that it's the first time I've had any problem. I also accept that it's probably down to my cack handedness.

I was surprised, however, that the problem hornblock consistently wanted to settle in the same (wrong) place. The back has been polished smooth so I'd not think that the hornblock has any tendency to rock. When located on the pins one side slid on and off without any problem. After soldering the problem bearing/hornblock the other side was tight on the pins, so it was immediately obvious that it was wrong. It took three goes to get it right, but it's right now and I've learned that it's necessary to take some care even when using a jig. I think my initial approach was rather cavalier, assuming that the jig would do the job for me and couldn't be wrong. On the basis of this experience I'll now take greater care and next time I build a chassis I'll still use the jig, but I'll make sure that the bearings slide off the pins easily before proceeding to the next stage.

Brian

 

[oldravendale]

Amazingly two days running in the workshop.

The chassis has now been on the rolling road for a couple of hours in each direction and runs beautifully.

My attentions now move on to the footplate. This is less than a perfect design IMHO.

Dimensionally this is pretty good (notwithstanding a questionable fit to the frames more of which later I suspect, once the footplate is complete). Unfortunately there is provision of sections of half etching, produced to make the subtle bending of the footplate easier - which they do not. They are very localised, and within areas of full thickness. These are best shown by reference to these pictures.



Of course the full thickness brass bends differentialy to the half etch, and now shows an uneven top surface. I think I can resolve this by careful use of car body filler and a file, but this really should not be necessary. The footplate now has the subtle curves of the prototype and the valances have been soldered in place.

The tops of the splashers are intended to be bent as attached to the splasher sides. This will doubtless give a short length of straight top to the splashers, so I am removing them and bending separately, then attaching to the splashers. I've started this process (photos to come) and it is working. The following two photos show the footplate as bent to shape but with the splasher tops still attached to the, as yet to be bent upright, splasher sides.


Forward!

Brian

 

[richard carr]

Funny isn't it, some ideas that are meant to help just don't work in practice, I wonder who designed this kit ?

Thats a shame about the chassis jig I was thinking of buying one as I have a few steam locos that I intend to build in the reasonably near future but I can't see the point if it lets you build in errors.

Richard