A new lever frame design

[Terry Bendall]

Elsewhere on here Howard Bolton posted the following

"Some while back there was a discussion on the use of mechanical lever frames. Those who are interested in such things might be interested to see something I have posted on RMWeb here:-

http://www.rmweb.co.uk/community/index. ... try3106858

As I said there, I am happy to post further details if there is interest, but I should say here that for those who are contemplating such a path, we are well on track to having the necessary etches on sale from the Stores at Scalefour North in a couple of weeks time. Though I am not expecting traffic jams on the M1 as a consequence ...

Best wishes,

Howard"

I have the job of building one of these which will hopefully be finished for Scalefour North and with a bit more luck will have the locking frame that Howard has designed as well. I will try and post some pictures of the construction so far later. The sample will be on the Society stand.

Terry Bendall

[Le Corbusier]

Terry,

Am I right to assume it will be present at Scaleforum as well?

[JFS]

I think the short answer to your question Tim is "yes".

I know Terry is busy with lots of things so, without wishing to hi-jack his thread, perhaps I can give a bit of an intro to how this project came about and some of the "design principles" behind it. I can also post a few photos to which Terry can then add his own and his experience of putting the job together.

Firstly, as many here will know, for my own "Minories" layout, I built a 25 lever interlocked frame based around the SHAG frame which has been available from the stores for many years now. It is very nice and bar far the best available on the market at reasonable cost. However, it was never designed to have locking fitted, and although the finished job works well enough, it was a bit of a tussle to get it all to work nicely. Also, because of the way the 5-lever modules assembled together, it was not really suitable for "long" frames. Some years ago therefore I suggested that I might redesign it keep its basic features whilst addressing these shortcomings. That is as far as it it got until last year, I got involved with Jon Elliot's "Leeds City" layout - as described in the RMWeb thread above, and "volunteered to look at a mechanically locked frame (or two). This provided the necessary impetus to get on with the job.

The main issues needing to be tackled were these:-
For Locking:-
- improved accuracy to ensure reliability of the locking
- fixing to allow the locking table to be built up separately then bolted in place
- improved catch handle mechanism
- ability to fit and remove levers after the frame and locking have been assembled

For long frames:-
- ability to fit and remove levers for painting etc
- ability to join together and split apart 5-lever modules without any loss of accuracy of pitch
- means of fitting / removing electricl switches with breaking down the whole frame

To address some shortcomings in the existing design which those who have built them will have encountered
- the lack of "self-jigging" in the main frame
- the lever slots etched a bit too narrow (and a pain to open out!
- the need to make "spacer tubes" to space and align the levers along the pivot rod.
- the need to have one lever pivot rod the full length of the frame

The extent to which these objectives are both valid and have been achieved will be for others to say of course!

I should say that I have done my best to maintain full compatibility with the original frame in terms of appearance, dimensions "feel" etc. - you can put them side by side and they are hard to tell apart at a glance. Also, the locking - which will also be available from the stores - can still be fitted to the existing frame design - though it is a bit of a knife and fork job. So anyone half-way through building an existing frame is catered for.

Here are a few photos to show the "new" by comparison with the "original:-

The original SHAG frame

And my attempt at "improvement"

Hopefully - as improved...

The main things to notice are that the frame folds up in one piece and there is a base-plate which accommodates the pivot rod and spaces the levers out accurately. There are also various fixing holes to allow these five lever models to be joined and slit using nuts and bolts. Obviously, by splitting the five lever modes, the pivot rod can be slid out and the levers withdrawn from the top.

I have also added a slightly more sophisticated means of taking off a mechanical drive for both points and signals

Mech Drive Take off 1.jpg (371.72 KiB) Viewed 7912 times

I have also changed the way the electrical switches are fitted to place them outside the frame - this takes up more space, but it does mean that if - nay, when - a switch goes down on you, you have the possibility to replace it without having to break down the whole frame.

Micro switch bracket

In terms of adding the locking (which has been developed based on experience of the Minories version), various fixing points have been created to allow nut and bolt assembly

The upshot of all this is that the locking can be built and tested as unit on the bench, then each five-lever frame unit bolted on and the levers added:-

Hopefully, that will give people a bit of an idea what it is all about, and prepare the background for Terry's experience of having to build the bloomin' things!

EDIT:- the link above does not work but this hopefully will:- http://www.rmweb.co.uk/community/index. ... try3108167

[essdee]

Howard,

Truly, a Work of Art.....

Brilliant..

Steve

[steamraiser]

A mechanical work of art. I look forward to seeing it.

Gordon A

[RobM]

+1.....
Rob

[Bernie]

Horological. Stunning.

[JFS]

Thanks for the kind comments chaps.

Just to mention that the Scalefour North chaps have managed to find a free demo bench for me to demonstrate the building of these things over the two days of the show. So anyone interested and who can make it to Wakefield can drop by to learn more - as if anyone needed an excuse to go to S4N

Since the etches will be on sale in the Stores, you will be able to buy your etches, bring them along and get some tips on building them up all in one weekend...!!!

That said, we are talking about April 14th, 15th which I note is now less than two weeks away, so I will need to get a wiggle on to finish the "instructions"...

Best wishes,

[David Thorpe]

Has a price been decided for these?

DT

[Philip Hall]

Howard,

These are beautiful things but also quite frightening when I think about the locking. I thought DCC was complicated...

Philip

[Colin Parks]

Hi Howard,

The lever frame is certainly going to be a success! Does the 'top take-off' clevis has the same throw as your trusty escapement units for point operation which you used on Minories? It looks as though it does. (That locking mechanism looks like something Alan Turing might have come up with!)

All the best,

Colin

[JFS]

Hi Howard,

Does the 'top take-off' clevis has the same throw as your trusty escapement units for point operation which you used on Minories?

Hello Colin,

You might not be surprised to learn that it exactly does - what a coincidence Though when the locking is fitted (as in your case ... ) that serves the same purpose as it uses the same hole in the lever and the drive take-off is the function of the rearward extension on the cam plates in the locking.

Very Best Wishes,

[JFS]

Has a price been decided for these?

Hello David,

Perhaps Jeremy will answer this more properly than me, but the answer is "yes" and - because there is more metal involved - the lever etches are slightly more expensive than the current version but against that, those on a tight budget no longer need purchase the turned handles as these are etched-in with the levers, though there is provision for them to be fitted as an optional extra.
Regarding the locking, as this is etched in 0.7mm N/S this is a bit dearer again on a per lever basis.

Best wishes,

[Colin Parks]

Hi Howard,

So the lever handles are to be shaped with a file etc.? Also, do the small springs on the levers come with the kit? Looks like I shall be ordering four of these units soon. The fact that locking can be added later is most useful.

All the best,

Colin

[JFS]

So the lever handles are to be shaped with a file etc.? Also, do the small springs on the levers come with the kit?
Colin

Hello Colin,

Yes and yes.

Building the locking is the most interesting bit - you won't want to put that off for long!

Very Best Wishes,

[Terry Bendall]

I have built two of the lever frames designed by SHAG and they go together very well. They also perform well in service. There is one which is part of the kit on the Society stand and those who try it at exhibitions are very complimentary about the quality of the finished product. I did not find any problems with assembling the design so every thing was square but then I have done quite a lot of this sort of work.

I saw Howard’s frame at the DEFine event in January and Howard asked if I would like to build one up with the locking frame which I was happy to do but otherwise I have not had any involvement in the development of the new design.

This is the etch for the frame. Made from 0.45mm thick nickel silver it gives a strong product

Frame folded.jpg (129.38 KiB) Viewed 7185 times

The basic frame folded up with the pivot frame for the levers in place. This locates on etched tabs. There are also tabs for the location of the top.

The formed top of the frame. There are separate strips to be soldered on each side of the slots which come later.

The underside of the top showing the etched grooves to assist in forming the top. The instructions suggest rolling this to shape using a piece of rod or wooden dowel on top of some magazines. I found this worked fairly well but it needed finishing wit the aid of a set of rolling bars. Possibly I needed to use a thicker pile of magazines.

The assembly jig for the levers. A piece of melamine faced chipboard with two holes drilled using a drilling machine for the locating pins.

Two assembled levers. The bottom one is from the soldering and the top one has been cleaned up and polished. There is provision for fitting the turned steel handles sold by the stores but I chose to make use of the provision to file the end of the lever to shape. No problems with doing that and the end result is fine as far as I am concerned.

I have now finished the assembly of the frame. It certainly goes together well and works as well as the SHAG design. I can see the advantage of being able to remove a set of five levers for repairs and alterations and the design of the locking frame is very interesting and saves space. Building the locking frame may have to wait until after Scalefour North but I will see how things go.

Terry Bendall

[kelly]

Looks impressive Howard, but no surprise given your involvement I think

[JFS]

Many thanks indeed for this Terry

I have built two of the lever frames designed by SHAG ... I did not find any problems with assembling the design ...

Terry Bendall

Not too sure if the two frames you have built were joined together Terry, but just to stress that such problems as there are with the original design only start to show themselves on frames of 10 levers and more and only start to become insurmountable on frames longer than about 20 levers.

Of course, real signal boxes existed with as few as 3 levers (though I only know of one!) but, - break-section boxes apart - they were rare beasts with fewer than 10 levers. I managed to squeeze Minories into 25 levers, though the real railway would have used 35 including 4 spares.

Equally, most modelers will have better things to do with their modelling time than build lever frames - especially long ones

Best wishes,

[Jeremy Suter]

To all those interested in the price for Howard's units
The Lever Frame will be £26 and the Locking Frame will be £34. Stock should be available at Scalefour North.

[Alan Turner]

To all those interested in the price for Howard's units
The Lever Frame will be £26 and the Locking Frame will be £34. Stock should be available at Scalefour North.

And will they be available from the Stores thereafter?

regards

Alan

[JFS]

And will they be available from the Stores thereafter?

They will Alan - although they are not yet in the e-shop, I am sure an email to the stores will do the job.

Best wishes,

[JFS]

Just to mention that pending setting such things up on the Stores website, I have temporarily uploaded the "Assembly Guidance Notes" for both the Frame and the Locking to my own website. So anyone interested can download them to see what it is all about.

http://www.blockpostsoftware.co.uk/L_frame.html

Since they are quite lengthy, we will not be packing these with the kits - though paper copies will be available for those buying in person who do not have internet access.

Best wishes,

[martinm]

Howard,

Great stuff, nice to see the instructions!

BUT, where do you get your 1.4mm dia brass or N/S wire (for mechanical drive take-off if the optional locking is not to be fitted)?

I've had a quick trawl, but can't find a supplier.

Also, is it essential to use 8 BA, or could a metric be used?

regards,

martin

[Alan Turner]

Howard,

Great stuff, nice to see the instructions!

BUT, where do you get your 1.4mm dia brass or N/S wire (for mechanical drive take-off if the optional locking is not to be fitted)?

I've had a quick trawl, but can't find a supplier.

Also, is it essential to use 8 BA, or could a metric be used?

regards,

martin

Eileen's Emporium.

regards

Alan

[JFS]

BUT, where do you get your 1.4mm dia brass or N/S wire (for mechanical drive take-off if the optional locking is not to be fitted)?

Hello Martin,

That turns out to be a very good question, as I can't find any either. Because I have only used piano wire, I think I am guilty of making an assumption that an equivalent non-ferrous would be available - but the only thing I can find is an Albion Alloys tube and that is only thin wall. Although a coiled wire is available in brass.

That said, the diameter is only really critical if you are driving the locking - and for that it seems the piano wire is essential. For the mechanical drive take off, 1.2mm rod will be more than adequate - especially if you don't open out the etched holes too much.

Many thanks for spotting this and I will amend the notes when I am back home after S4N.

Edit: it should not be problem to substitute M2 threaded rod - though it might be slightly loose fit in the holes in the micro switches.

Best wishes,