Lever frame mk 2 and the locking frame

Discussions of the prototypes and how to model them. Show us how you do it.
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Tonycardall
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Re: Lever frame mk 2 and the locking frame

Postby Tonycardall » Fri Dec 13, 2019 4:32 pm

Are you able to post photos? It might be that I can't spot any issues which need heading off!

Howard,
I’ve just finished soldering up my first cam assembly et al and couldn’t wait to do a test fit it to see what I could learn before doing a second one.
Staggeringly it works rather well. I pictured my rough and ready trial and have attempted to show it in the normal and reversed positions.
I’m still waiting for the split pins to arrive.
3CEF2AF4-823E-4E7E-97C8-883B50AC0045.jpeg


Try to see past the sloppy untidy work.
I must say I am delighted and ready to proceed with the other four cams for this set before starting on the next 6 locking frames.

Work on the dog chart is going ahead reasonably well thanks to your tip about using Butts and loose nibs. I want to check a few things before posting my latest version.
I also have to get my head around how one locks another ‘when’ yet another is in a certain condition.

Still climbing that hill. Another positive; my PowerPoint are improving.
Regards,
Tony
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92F08D45-E556-4FB7-80D6-079BFB415018.jpeg

JFS
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Re: Lever frame mk 2 and the locking frame

Postby JFS » Sat Dec 14, 2019 9:31 am

That is looking first-rate Tony - believe me, if you can get that far and make it work, then you will make it all the way.

You will find (even when you have done a few) that the odd one or two tappets can turn out "stiff" - ie you feel a resistance for the first and last part of the lever travel. This (assuming the tappet and crosshead themselves are free in the frame assembly) is down to the two halves of the cam plates being misligned. Usually a samll tweak then will free things off. But it is important to find and eliminate any stiffness at each stage - obviously, there is a very fine line between too tight and a rattle fit...

Regarding the "when" - ie a "Conditional lock" - I will knock-up a couple of diagrams later and post them, but bear with me as we are a bit busy just now. Suffice to say for now that this is achieved using the pear-shaped "swinging pieces" you see in the fret. I don't want to frighten you off, but here is a photo of one of my frames in which you will see several and you will see that reversing the lever moves the swinger out of the way of a bridle allow the two halves to work independently when the lever is reversed. You can see that I have had to be a bit creative about how to fit them in, and you will several examples that look a bit horrible - but bear in mind that this is a very complex set of locking - you only need one! But you can at least see the principle and also see why it is necessary to plan up front for these things.

Wellington Locking levers 29_37.jpg


The important one to look at is the levers 2nd and 3rd from the right as these are the bog-standard examples to give you an idea.

Here is an extract for clarity - luckily it shows one lever Normal and one Reversed. You can see how a 12BA screw has been used as a pivot. You can also see that since it is on the bottom channel of locks, there is not too much fiddling to get the tappet(s) in and out. Otherwise you are constantly fitting and removing the things whilst building the frame!
Another small point is that the tray-side has to be cut to allow the thing to move and by cutting this in one place (using a slitting disc) and bending two "ears" down, it provides a guide to stop it falling out of the way.

Conditional locking.jpg
Conditional locking.jpg (84.65 KiB) Viewed 2075 times


I can post more later but have a go and see if you can solve the puzzle!

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Tonycardall
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Re: Lever frame mk 2 and the locking frame

Postby Tonycardall » Sat Dec 14, 2019 10:00 am

I don't want to frighten you off

Too late!!!!
Seriously Howard, thank you once again.
Last evening I finished the basic test fit of my first locking frame with all 5 levers in place. It’s a fiddly job but I managed so I’m happy. The postman brought my split pins this morning and so I hope to shortly do a full test with the tappets in place.

I think that it will be several weeks before I am in a position to start with bars, nibs etc. construction, but I am really tempted to do a trial with 31, 32 and 34 as that is a small self contained lock all within one frame. Mind you, if I do that I risk the possibility of finding that I need it in a different tray to facilitate a long locking run.
I’ll try to get my head around conditional locking and see if I can incorporate it into the chart.
Now..... I believe I am being called to put up the Christmas tree.
Tony

JFS
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Re: Lever frame mk 2 and the locking frame

Postby JFS » Sat Dec 14, 2019 10:16 am

... to give you a bit more of a clue - the locking here is a Distant Signal which can be cleared if any of three Homes is Off.

In this case 35 is Released by (36 OR 37 OR 38)

Cond L 1.jpg
Cond L 1.jpg (117.07 KiB) Viewed 2072 times


I am glad that you recognise it is not a quick job - a bit a planning up front makes it a lot easier in the long run!

There is absolutely nothing to be lost and everything to be gained by doing a trial with 31 etc. Bear in mind that you have spare tappets - so you can always move the lock later. And you will learn loads.

Another tip ( which I NEVER need to use... ) is this: there are lots of little bits which you saw out of the tappets to make the Ports. Always keep few ... They can be soldered back in - when you fill the gaps with solder and polish it all up, no one will ever know ...

Once you have got one working, you will be hooked :D

By the way - you mention the split pins - I tend not to fit these until everything is finished and tested - you need to shorten them to make thema a comfortable length, and once they have been opened out, they are a devil to re-fit. I therefore tend to use a bit of 0.7mm wire bent into an L shape as a temporary pin - you can see the levers above have been done that way. But for your trial, you might want to "finish" it properly so you learn the whole process.

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Tonycardall
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Re: Lever frame mk 2 and the locking frame

Postby Tonycardall » Thu Dec 19, 2019 6:10 pm

Once you have got one working, you will be hooked


Well, once again it isn’t up to Howard’s standard and it is the most simple lock possible but I am beaming from ear to ear. :D
F636B3B7-0B32-46E6-87C9-59A20D66A9A8.jpeg

It took a bit of tweaking but now works perfectly.
The delay since my last post was because I’ve been making up the second frame of 5. I figured that there was little point in moving ahead until I had satisfied myself that I could join frames together in good alignment.
Interestingly, the 6 that arrived a week ago, thanks to Jeremy’s good offices, are a different layout. They come in two etches instead of the single sheet of my first order. I imagined that this was to alleviate the problem of the mainframe becoming slightly bent during manufacturing and indeed it seemed pretty flat to me. However, when I examined the sheet I found that the version reference indicated that it was an earlier iteration.
I rather think I’d better return now to trying to create the dog chart. I had a break from it as it’s making my head boil. I suspect that I am trying to make it too basic and therefore taking up more tray space than I need if I used more ingenuity but without the experience I guess I’m not introducing the tricks that the experts have devised.
I’ll post my workings presently. I grew thick skin during my working life!
Thanks to those who have encouraged me to keep going.

Tony

JFS
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Re: Lever frame mk 2 and the locking frame

Postby JFS » Fri Dec 20, 2019 3:30 pm

Well, it looks pretty good to me Tony!!

You will get better at cutting the ports with a bit of practice, but - as I think you have found, the design is fairly tolerant of some innacuracy. Good job or we would all be struggling!

The split of the etch into two sheets is just to save on postage charges but actually, there is no physical change whatsoever to any of the bits, though the numbers of bits included has changed a bit to use the space economically. Noe I know that the new layout is "out there" I will update the destructions. The version numbers relate only to the drawing - not the design - but glad to know you are keeping an eye on me! :D

I have taken the liberty of attaching a Power Point which might be of help in drawing up the locking - sorry this is so late but I have only now had time to knock it together. You will see that it has the basic layout in the "Slide Master" so it does not get in the way also the tappets (which look awful) are done so that you can just select a "port" abd delete the bit of rectangle covering up a "pre-cut" port. I have also included some sample nibs etc which can be "grouped! to form a bridle - I use different colours for each channel. The dark blue nib is a "loose" one - not attached to a bridle, but driven by two others.

Locking Template.pptx
(310.45 KiB) Downloaded 32 times


I would mention that the "paper size" is too large to print out at A4 - to get round this, save it as a PDF, then open the PDF in Acrobat or some such. You can then either scale to fit page (which you could do in PowerPoint) or select the "tile" option and it will print it on multiple sheets.

Feel free to use or ignore as you see fit!

Best Wishes,

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Tonycardall
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Re: Lever frame mk 2 and the locking frame

Postby Tonycardall » Fri Dec 20, 2019 4:52 pm

Feel free to use or ignore as you see fit!

Howard,
Thank you. It looks extremely useful. I’m going to risk showing you how far I have got with my version of the dog chart having incorporated some of your expertise.
It is now at a stage where I’m finding it challenging to follow. :| However, I’m giving it a break whilst making up more frames. I’m on 3 of 7!
Once I have all seven completed I’ll return to it.
It will follow in a separate posting shortly as I’m using the wrong device to make the attachment at the moment.

Tony

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Tonycardall
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Re: Lever frame mk 2 and the locking frame

Postby Tonycardall » Fri Dec 20, 2019 5:03 pm

Locking Table - 1.pptx
The chart thus far...
(79.72 KiB) Downloaded 27 times

JFS
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Re: Lever frame mk 2 and the locking frame

Postby JFS » Fri Dec 20, 2019 6:03 pm

Hello Tony,
That looks like a thoroughly good start and I can see that you have got a good grasp of how it all works - well done! It is true, unfortunately, that it does make your head hurt trying to think it all through!

I have had a QUICK look at your Powerpoint - but let me say I have not had a chance to go back to the locking table to double check.
My main comment would be that you could compress things together quite a lot. For example, your 32 locks ... bridle, which you currently have in the 5th tray could be moved up to the top one along with your 7 locks ... This would mean that they could share loose nibs on 23 and 26 and the lock on 7 could use the same 7 releases 6 port. Now you could also move the 2 locks ... bridle into the same tray as I don't think I see any conflict (I might later retract that statement!) but of course, you currently have that sharing ports with the EW locks on the 4 locks ... bridle, so that would mean moving both of them, along with the releases in the tray below. Given all that, I think it is better left as you have it not least as you have to worry about the condition lock on 4 - 4 locks 10 W 13R or somesuch if I remember rightly and therefore this move might not be worth it - not least because you are very unlikey to run out of space.

I have had a look at how to fit the conditional lock in and it is easy enough so don't worry about it for now - have a go at it and if you struggle, I will show you how when the rest is coming together.

This kind of Chinese puzzle is a bit the way of the job I am afraid but it is a very interesting excercise - at least to me!

A couple of tips - one is to label all the bridles and to "Group" the text with the bridle, its nobs and its pins - that way, you can easily see what does what just be selecting the text - this image shows you the idea (done in CAD rather than PPT but the principle still works)

Locking example.jpg


This image corresponds roughly with the photo of the locking I posted before.

A second tip is to keep successive versions (on different "slides" in PPT for example) that way, if you have to roll back a change - and you will run up blind alleys - it is easy to do so.

(a third tip you are already doing - go back to the metalwork to give yourself a break!!)

Hope that helps!

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grovenor-2685
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Re: Lever frame mk 2 and the locking frame

Postby grovenor-2685 » Fri Dec 20, 2019 6:56 pm

John,
Where does the 'nibs and bridles' terminology come from? Is it GWR practice? They did love having their own naming conventions. I, and the IRSE, have always known these as 'locks and bars'.
Regards

JFS
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Re: Lever frame mk 2 and the locking frame

Postby JFS » Fri Dec 20, 2019 10:31 pm

grovenor-2685 wrote:John,
Where does the 'nibs and bridles' terminology come from? Is it GWR practice? They did love having their own naming conventions. I, and the IRSE, have always known these as 'locks and bars'.
Regards


Hello Keith, Ignore the "John" - its Howard here!

I picked it up as one picks up habits, but I think the terms might orginate with Stevens. The GW called them "dogs" as far as I know, but I have heard a Western Region man use the term "bridle" - even though GW frames were called 5-bar ... etc. The chap from whom I picked up quite a bit unfortunately passed away last year. The problem I have with the term "lock" is that it more describes the result rather than the component - after all, some nibs create releases.

I could well imagine that there were as many terminologies as there were drawing offices...

Best Wishes,

JFS
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Re: Lever frame mk 2 and the locking frame

Postby JFS » Fri Dec 20, 2019 10:45 pm

Tonycardall wrote:Howard, yes please, suppliers of suitable piercing saw blades would be useful. Though, if I understand correctly, I don’t actually need to cut any more tube as the alignment jig is made and I should be able to use that for each of the drive mechanisms.
...
Tony


Tony,
Here is a supplier of piercing saw blades - and a million other useful things:-

https://www.cousinsuk.com/product/berge ... saw-blades

Although you have no more tube, I use the 6/0 and 4/0 blades for cutting ports, cutting bridles to length - in fact for almost everything. Such fine blades cut very accurately with a very narrow kerf. But they don't last long on thicker metal - I bought a gross a few years back; they are very cheap. But always buy the very best (Bergeon are good) as cheap ones never cut straight and break with just looking at them.

Best Wishes,

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Tonycardall
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Re: Lever frame mk 2 and the locking frame

Postby Tonycardall » Fri Dec 20, 2019 11:03 pm

Thank you Howard. I’m certain they will come in useful. Now that, through making the frames et al I’ve gained some confidence with metalworking skills, I may even venture into metal vehicle/loco kits once this project is over.
;)
Tony

JFS
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Re: Lever frame mk 2 and the locking frame

Postby JFS » Sat Dec 21, 2019 9:17 am

Tonycardall wrote: I may even venture into metal vehicle/loco kits once this project is over.


Well, improving skills and building confidence is what this is all about - so very well done!

I did mean to comment about the process of joining frame units. I see from your photo that a number of the frame sides do not line up:-

tray sides.jpg


Don't beat yourself up about this - it is a feature of the etching technology but it is important to do something about this because it means that the spacing of the tray sides will not be consistent along their lengths and this will create inexplicably tight or slack locks.

The best way to treat the problem is to make up a little gauge, a shade under 5mm wide and also a short straight edge 55mm long (something like 30 thou plasticard is fine for both) and use these to tweak the tray sides with smooth jaw pliers to be straight and the correct spacing.
The other thing is that, at the time of assembly, it is worth very carefully, taking the sheet curl out after the tray sides are bent up and before they are soldered - again using your 55mm straight edge. The same is true BTW for the tappets - take the curl out before soldering.
Sheet curl and local over/under etching are unnaviodable and managing them is not a problem once we are all aware of it!

Just to say, please don't think for one second that I am criticising what you achieved with your first attempt - far from it - I would have to be honest and say that in the rush to get on, I have done a fair few a lot further from perfect than yours - and I can't use inexperience as an excuse :D

Also, I see that you have succeeded in using 0.8mm wire for your cap bars - well done for that - but you might find that on long bridles, they can make the lock stiff. Be aware of that and if you need to use - say - 0.7 or 0.6mm dia wire to ease things then no one will critcize and it will be no detriment to the job. And you certinaly do not need to fit every single one - as you will notice from my photo.

Good luck!

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grovenor-2685
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Re: Lever frame mk 2 and the locking frame

Postby grovenor-2685 » Sat Dec 21, 2019 11:22 am

Hello Keith, Ignore the "John" - its Howard here!

I had intended to write Howard but my fingers seem to have gone wrong, sorry. I have heard 'dog' used but nib is a new one on me. By my time in the drawing office we were drawing relay circuits so this mechanical stuff was just from book learning and a bit of maintenance experiencewhen it was the fitters lingo.
Rgds

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Tonycardall
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Re: Lever frame mk 2 and the locking frame

Postby Tonycardall » Sat Dec 21, 2019 11:53 am

Code: Select all

   this mechanical stuff was just from book learning   

Keith, what annoys me is that I didn’t have the same interest during my working days. I was Traffic Manager at Westbury and, in addition to the local stations, quarries, panel box etc. also had responsibilities for Bradford South Junction box at the time of its closure. If only I’d taken more notice.
Tony

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Tonycardall
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Re: Lever frame mk 2 and the locking frame

Postby Tonycardall » Sat Dec 21, 2019 12:05 pm

Just to say, please don't think for one second that I am criticising

As I said Howard, I have thick skin. No seriously, thank you. That is just the sort of advice that I need. I was aware that I’d made a mess of the tray thingies and intended to try to put them right later. Good idea to do it now.
In fact, what you didn’t see was the awful mess I made of fitting them. I clearly hadn’t followed the instructions properly. I had to remove some as they were out of line and I think that they got rather mangled during the process. The third frame went together much better as I took more time and care.
I reiterate that I am most grateful to you for taking the time to examine my progress. It really is most encouraging.
Regards,
Tony

JFS
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Re: Lever frame mk 2 and the locking frame

Postby JFS » Sat Dec 21, 2019 6:50 pm

Tonycardall wrote:

In fact, what you didn’t see was the awful mess I made of fitting them.


Well, it is where you end up that matters - even if the route takes you the long way round sometimes! If it is any consolation, I had one go wrong on me not long ago (after doing dozens of them) the reason came down to the tab and slots being slightly under etched - I can't blame the etchers for this as the rest of the sheet was fine - we are pushing the technology to its limits!
The only advice you already know - check and recheck before soldering.
I should also add that if you spot anywhere in the instructions that need extra explanation, please say so. I have already included some feedback (and some very helpful proof reading) by an early customer - and further aditions can always be made.

Just also to mention, that as spotty 14 year olds, two friends and I visited Westbury North and South boxes in 1969. (Middle had recently gone). In those days, BR management were very accomodating of interested boys and we got an official visit. On the Southern Region, we also got taken into Borough Market Junction and London Bridge during the rush hour - now that is an experience we will never forget! I doubt Network Rail would be so accommodating these days.

Best Wishes,

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Tonycardall
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Re: Lever frame mk 2 and the locking frame

Postby Tonycardall » Tue Dec 24, 2019 5:03 pm

I should also add that if you spot anywhere in the instructions that need extra explanation, please say so. I have already included some feedback (and some very helpful proof reading) by an early customer - and further additions can always be made.


Howard, as I am working through the fourth frame of the seven I am working carefully and taking extra note of the instructions and making notes. Admittedly, it only takes me up to page 17. Hopefully, there will be attached a copy of the instructions with highlights and notes contained within.
As a person who has never carried out any metalwork before these notes will either be considered quite helpful or totally inappropriate.
If nothing else you should be able to use me as case study if hoping to sell the frames to totally inexperienced modellers!

Tony

4_Bar_VT_Locking_Assy_Guide -with notes.pdf
(1.48 MiB) Downloaded 31 times

JFS
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Re: Lever frame mk 2 and the locking frame

Postby JFS » Tue Dec 24, 2019 7:43 pm

Many thanks for that Tony - I have uploaded a revised version which includes the revision of the fret layout.

I am sure you will spot further issues - please feel free to let me know.

EDIT: I think I have sorted the references to 1.4mm wire but again please let me know what you think.

Best Wishes,

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Tonycardall
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Re: Lever frame mk 2 and the locking frame

Postby Tonycardall » Tue Jan 07, 2020 3:47 pm

go back to the metalwork to give yourself a break

Howard, Christmas over and I've finished making up the locking frames etc. Although it is not in your suggested sequence, I have coupled the lever frames and locking frames together. Just because I wanted to see how it all looks. It has also been useful to see how square things are. (or otherwise).
I had imagined that I would be replanting my lever frames and then fitting the locking frames to them. Having read through the detailed section on joining things up I can see what an error that would have been. So, shortly, I will follow the instructions for ensuring that all seven locking units are in perfect harmony prior to making the bridles, nibs etc. At least, as things are now, I know that all of the levers run smoothly and, via the cams and crossheads, move the tappets perfectly.
I am afraid that I am going to start from scratch with the locking chart/dog chart/plan … whatever. I found that I got into something of a muddle and so will restart using your blank sheets. I had wondered how I would achieve the miracle of lining up the rear bridles but, having looked again at your blanks I can see how all four are shown at the front. (I really do need to look at things several times before the penny drops).
Right then, forwards …. You may realise that even writing this note is further prevarication. :shock:
Regards,
Tony

JFS
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Re: Lever frame mk 2 and the locking frame

Postby JFS » Thu Jan 09, 2020 8:06 am

Hello Tony,

You seem to be following a good path here - a bit of thinking about the job goes a long way! You will find that there is a degree of tolerance in lining up the frames and locking trays, but the closer you get to perfect at each stage the better. The main thing to check when you have the frames and locking put together is that the cam plates are going full stoke and giving full movement to the crossheads - even a small lack of movement can cause stiff locks.

If I had a pound for every time I started again from scratch ...

Best Wishes,

Terry Bendall
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Re: Lever frame mk 2 and the locking frame

Postby Terry Bendall » Fri Jan 10, 2020 7:51 am

With apologies for diverting the thread...

JFS wrote:If I had a pound for every time I started again from scratch ...


I think this comment is true of much of what we do in our model making and should be an encouragement to those who are fairly new to the game. if those who are fairly experience - whatever the project is, sometimes have to stop and backtrack, or even start again, those with less experience should not worry. :)

Terry Bendall

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Tonycardall
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Re: Lever frame mk 2 and the locking frame

Postby Tonycardall » Fri Jan 10, 2020 9:36 am

those with less experience should not worry.

Thanks Terry. I find your thoughts both really encouraging and most timely. Trying to work out how to produce a locking chart that will physically work is causing me to divert anywhere other than going back to the job in hand.
Back to drawing board ....... again!
Tony

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Le Corbusier
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Re: Lever frame mk 2 and the locking frame

Postby Le Corbusier » Fri Jan 10, 2020 2:34 pm

In that sense the forum is a slightly misleading environment .... one doesn't tend to post until the work is at a level/standard where you are happy to show. But when you are reading other threads you are doing so from a position of a full knowledge of your own failings and issues.

Whatever anyone thinks about my own thread, it most certainly paints the best possible picture of my endeavours, because I don't post all the cock ups trials and tribulations :? So its like comparing real life to an idealised view ... great for inspiration perhaps but definitely not the whole picture :thumb
Tim Lee


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