Jump to content
nick_bastable

Whats on your 2mm Work bench

Recommended Posts

Certainly a better reduction, Valentin, but it looks as though there is an interference between the motor and the worm and not much room for the worm shaft bearings.  Could you move the motor forward, putting the 16t and 30t gears on the other side of the worm, in between the two rear axles?  This would also keep the cab clearer of gears.   Just an arrangement that might be worth exploring.

 

Jim

  • Thanks 1

Share this post


Link to post
Share on other sites
1 hour ago, Caley Jim said:

[...] Could you move the motor forward, putting the 16t and 30t gears on the other side of the worm, in between the two rear axles?  This would also keep the cab clearer of gears.   Just an arrangement that might be worth exploring.

 

Jim

 

That, Jim, was my first thought when trying to change the overall reduction. Here we are:

 

 

boiler-gears-y.jpg

 

 

And I tried even this:

 

 

cab-gears.jpg

 

Or this, with pulleys, although a have to increase the spacing to about 6 mm as the smallest belt is about 4.5 mm inner diameter.

 

 

cab-pulleys.jpg

Edited by Valentin

Share this post


Link to post
Share on other sites

I'd say that the first one above would be your best option, provided there is clearance between the backs of the third driving wheels and the 30t gear.  You'll need an end elevation to check that.  You also need to make sure that you can fit a bearing at either end of the worm shaft,but that would appear not to be a problem.  Is it standard gauge?

 

Jim

  • Thanks 1

Share this post


Link to post
Share on other sites
55 minutes ago, Caley Jim said:

[...]Is it standard gauge?

 

Jim

 

Thanks for the feedback, Jim.

 

It's narrow gauge (2'6"):

 

 

764-421_CFF-Viseu.jpg

  • Like 1

Share this post


Link to post
Share on other sites
2 hours ago, Valentin said:

It's narrow gauge (2'6"):

In that case, I think you should do an end elevation to make sure that the 30t gear will clear the back of the wheels.

 

Jim

Share this post


Link to post
Share on other sites

I will do an end elevation anyway, but this may also work. I am thinking of a 7x15mm Tramfabriek motor with shafts at both ends so I can fit a flywheel.

 

 

boiler-gears-z.jpg

Share this post


Link to post
Share on other sites

Looking forward to seeing that. The same type I'm waiting to fire from Llanfair to Welshpool during the short time te engine spent on the WLLR.

Keith

Copy of PICT0110.JPG

  • Like 5

Share this post


Link to post
Share on other sites
5 hours ago, Valentin said:

I will do an end elevation anyway, but this may also work. I am thinking of a 7x15mm Tramfabriek motor with shafts at both ends so I can fit a flywheel.

That certainly takes the 30t gear well away from the driving wheels.  My tendency is always to go for the biggest reduction I can get in the space available.  If you can get a smaller primary gear and a larger secondary one, keeping the shaft centres much the same, then I would go for that.  I have no experience of brass gears vs other materials, so can't help there.

  • Thanks 1

Share this post


Link to post
Share on other sites
25 minutes ago, keitharmes said:

Looking forward to seeing that. The same type I'm waiting to fire from Llanfair to Welshpool during the short time te engine spent on the WLLR.

Keith

 

I wouldn't hold my breath, Keith.

 

I remember you emailed me that photo a while back; it's a shame the engine didn't meet the line's expectations. They're still in production, hauling logs from the forests in Romania. And also on some heritage railways.

Share this post


Link to post
Share on other sites

The end elevation shows that I can increase the overall reduction ratio.

 

 

end-z.jpg

Share this post


Link to post
Share on other sites
5 hours ago, Caley Jim said:

[...] My tendency is always to go for the biggest reduction I can get in the space available.  If you can get a smaller primary gear and a larger secondary one, keeping the shaft centres much the same, then I would go for that. [...]

 

Thank you, Jim.

 

After a bit of work I came up with this, which gives me an overall reduction ratio of 52:1. I could go with a 40 teeth secondary gear (instead of 38) which would give a 55:1 but I would really struggle to fit the motor and the clearance between the gear and the side frames would be very tight.

 

Not sure if, and when, this is going to materialize; for the moment, on my "workbench" are ten lengths of 45 x 145 x 3000 mm timbers for the next stage of the garage conversion. Hopefully I will finish it in time to be able to do more work on my GJLC entry...

side_38-12.jpg

end_38-12.jpg

  • Like 2

Share this post


Link to post
Share on other sites

Some of you Midland modellers have produced curved frame locos over the years and I'd be interested to learn how you managed to form the footplates. I bodged a sub-optimal but, as far as this project is concerned, adequate one for the model in the picture but I'd be interested to learn how others do things. Do you create a solid former and then press the footplate to that or, as I did, anneal a strip and overlay it over the frames soldering, pressing and curving from one end to the other? Some of the bends haven't ended up as clean as I'd have liked. 

IMG_20200207_110221.jpg

  • Like 4

Share this post


Link to post
Share on other sites

I form all the bends before soldering the footplate to the frames, it looks as though your curves over the axles are about right but the curves back to the footplate aren't sharp enough. This tends to leave a gentle curve where the shape should be flat.

  • Thanks 1
  • Informative/Useful 1

Share this post


Link to post
Share on other sites
1 hour ago, Michael Edge said:

I form all the bends before soldering the footplate to the frames, it looks as though your curves over the axles are about right but the curves back to the footplate aren't sharp enough. This tends to leave a gentle curve where the shape should be flat.

 

Thank you so much Michael and yup, that's exactly what has happened. More questions I am afraid.

 

  1. So do you form the bends on a 'whole' sheet of footplate material, attach to the frames and then remove the necessary cut outs for wheels etc?
  2. Are said bends formed by pressing annealed sheet on to a hard former that matches the frame profile whereby the metal assumes the correct shape?
  3. Or are you reliant on the skills of a lifetime to use bending rolls or similar in such a way that you can accurately coordinate the various curves of the mating surfaces without having to do too much tweaking when it comes time to solder up?  

From a 2mm perspective this attempt will pass muster as a test model but I want to be able to do it better for some future projects. Hence the input of the more experienced is truly appreciated. I prefer to bodge rather than making jigs but, if that is what needs to be done, I'll bite the bullet.

 

Andrew

IMG_20200207_193501.jpg

  • Like 2

Share this post


Link to post
Share on other sites

I don't usually anneal the sheet, I form one of the large radius bends (the ones over the axles) first - by hand round a suitable diameter bar, i.e. one somewhat smaller than the finished radius. Check the fit of this against the frame shape, then form the two smaller radius bends at each side, again by hand round a bar and check again. If the bends need moving slightly use smooth flat pliers to flatten the shape a bit and repeat. Same again for the other two. I don't work in 2mm scale myself, just 3mm and above but the techniques are the same, using appropriate thickness material - .010" n/s for 3 and 4mm, thicker for 7mm but sometime .010" steel in the latter scale. I do the same even if I have etched the footplate with bend lines in - this is a lot easier though.

I do have bending rolls but they aren't much use for this, wheel cut outs can be done before or after, it doesn't make much difference. When finally soldering up I do try to clamp the footplate on to the frames on the flat near to the sharper bends, holding with forceps is the usual way to do it. As you suggest after a few hundred locos it does get easier.

Share this post


Link to post
Share on other sites

I've built a lot more than that but most of them don't have awkward curvy footplates - fortunately.

  • Like 1

Share this post


Link to post
Share on other sites
10 hours ago, -missy- said:

First test run. Needs some tweaks but it seems ok (if a little noisy) I really needs a circle of track though.


J.


So when are you fitting sound to it? ;)

 

Seriously though, incredible work Julia! 
 

Tom. 

  • Thanks 1

Share this post


Link to post
Share on other sites

Lovely work Julia. A figure of eight track would be handy, even up the bedding in process.

 

Don

  • Thanks 1

Share this post


Link to post
Share on other sites
On 16/02/2020 at 13:52, -missy- said:

First test run. Needs some tweaks but it seems ok (if a little noisy) I really needs a circle of track though.

 

4mm gauge? That is tiny ! :good:

 

David

Edited by Kylestrome
  • Like 1

Share this post


Link to post
Share on other sites

All the clockwork locos I ever had, the key went in the side. Will you be writing up the mechanism for the magazine?

 

Nice work :)

  • Like 2
  • Agree 2
  • Funny 6

Share this post


Link to post
Share on other sites

Most recently on my workbench was......a bench! 
 

65A5910C-20F3-4F08-824E-E3324FF1B325.jpeg.905b5e027afffdd4259f7974a1030480.jpeg

 

Tom. 

  • Like 12

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.