7mm J.p's Infinitely Sporadic Work Bench

lnerjp

Western Thunderer
Guess this is the area of the forum where I'll mainly hang out. I'll start with a thread on my 08 and bring it up to date over the next few days.



If you can build a F/S version of this kit then you can build a S7 version (am I the first? please speak up if you know of another S7 one), it only requires ninimal modifications. However the hardest bit is sourcing the axles, the current Slaters square ended outside crank axles afre not compatable with this kit, you require the Slaters old type D ended axles, which David Parkins now has all the remaining Slaters stock and they can be purchased from MMP. However the old type D ended axles where only ever available in F/S, so as I type this a freind with a lathe is making me some S7 axles. The only other modifications to the chasis is to move the brake blocks further out and to add two sets of spacers from Slaters plunger pick-ups packs to enable the pulungers to make contact with the now further appart wheels.

Slaters F/S wheels have been re-profiled by Christopher Makepeace and what a fine job he has made of them, the hubs required 0.6mm, which has cut into the spokes slightly in the centre of the wheel, but this is hidden by the hornblocks, so is not a problem.

The Chasis was built with Ball Bearings as a experiment, it is very free runing, this was achived by reaming out the etched holes and Aralditeing the bearings in place whilst the chasis was on a jig. Although I had to make some new compensation beams as the kit ones where too thin once I opneed them out and the centres had moved.

Further updates to follow.

 

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lnerjp

Western Thunderer
Their's 4 pictures, the largest being 140K. I suspect it will be me, rather than a technical issue, I'll read the Q & A section later tonight when kids are in bed.

J.P.
 
S

Simon Dunkley

Guest
lnerjp said:
If you can build a F/S version of this kit then you can build a S7 version (am I the first? please speak up if you know of another S7 one),
Simon Thompson built one a few years ago, and wrote about it in the Scale7 Newsletter. Not sure exactly when - I am no longer a member, and gave my backnumbers to a friend.
It has run on at least two of his layouts, including at Warley and Telford.
 

Dog Star

Western Thunderer
lnerjp said:
....  as I type this a freind with a lathe is making me some S7 axles.

Hi Jonpaul,

  You know that there is a problem with constructing an 08 in S7 as a consequence of Slater's change in design for the fitting of the fly-crank.  It is not just oil-burners which have problems.... the same issues are going to arise with any GWR outside-frame engine to S7 standards.  So please tell about the new axles...  how are the wheels to be retained and set to gauge?  how are the 08 cranks to be attached to the axle?

regards, Graham
 

28ten

Guv'nor
lnerjp said:
Their's 4 pictures, the largest being 140K. I suspect it will be me, rather than a technical issue, I'll read the Q & A section later tonight when kids are in bed.

J.P.
Additional options > Attach > Choose file
They done show up in preview as unlike phpbb they dont upload before you post.
 

lnerjp

Western Thunderer
Simon Thompson built one a few years ago, and wrote about it in the Scale7 Newsletter. Not sure exactly when - I am no longer a member, and gave my backnumbers to a friend.
It has run on at least two of his layouts, including at Warley and Telford.

Thanks Simon could have done with speaking to him when I was scratching my head over the axles, problems now hopefully all resolved.

Additional options > Attach > Choose file
They done show up in preview as unlike phpbb they dont upload before you post.

28ten, worked second time round, but didn't do anything different.


Graham, I can only comment on the MMP kit, other kits would have to be juged on a kit for kit basis, I did speak to Slaters and they informed me that the axles are designed for a Midland engine. The problem with the MMP kit is the thickness of the new moulded Slaters cranks, the kit is designed to use etched cranks which are 7 laminations of 10thou brass, which gives a total thickness of about 2mm, but cannot no longer be used due to the ends of the axles changing from a D shape to a square end. So you are now left with the new Slaters moulded cranks which are 4mm thick, the overall width of the axle has not changed and thefore the extra thickness is fouling where the hornblocks are, due to the class 08's being outside framed. This will occur either if you are building F/S or S7. As JLTRT are about to release a 08 kit, it will be very interesting to see if they use the new moulded Slaters cranks, and if so how they design the kit around them.



The Wheels are a press fit on the axle and the crank is secured by a small Allen screw.
J.P.
 

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djparkins

Western Thunderer
lnerjp said:
Thanks Simon could have done with speaking to him when I was scratching my head over the axles, problems now hopefully all resolved.

28ten, worked second time round, but didn't do anything different.


Graham, I can only comment on the MMP kit, other kits would have to be juged on a kit for kit basis, I did speak to Slaters and they informed me that the axles are designed for a Midland engine. The problem with the MMP kit is the thickness of the cranks, the kit is designed to use etched cranks which are 7 laminations of 10thou brass, which gives a total thickness of about 2mm, but cannot no longer be used due to the ends of the axles changing from a D shape to a square end.

That might give people a very wrong impression.  If you are modelling in F/S then our cranks CAN be used.  That is why I've purchased all of the old D ended axles from Slaters - in order to ensure that this is the case.  It should be clarified that only in S7 would you have a problem.

As regards other 08s, all published pictures of other 08 kits or RTR seem to show horn blocks that are too narrow.  That is why the boss on the inside face of the new Slaters O/S crank fouls our scale thickness horn blocks - thus requiring the use of our cranks & the D axles.

I hope this posting clarifies things for potential non S7 customers.

David Parkins,
Modern Motive Power
 

lnerjp

Western Thunderer
djparkins said:
That might give people a very wrong impression.  If you are modelling in F/S then our cranks CAN be used.  That is why I've purchased all of the old D ended axles from Slaters - in order to ensure that this is the case.  It should be clarified that only in S7 would you have a problem.

As regards other 08s, all published pictures of other 08 kits or RTR seem to show horn blocks that are too narrow.  That is why the boss on the inside face of the new Slaters O/S crank fouls our scale thickness horn blocks - thus requiring the use of our cranks & the D axles.

I hope this posting clarifies things for potential non S7 customers.

David Parkins,
Modern Motive Power

David, I wholeheartedly agree with you, I think we may have our wires a bit crossed, what I am trying to explain is that the etched cranks are designed for the kit and are suitable for either F/S or S7, and that is the reason that the new axles cannot be used, because the etched cranks will not fit the axle and the moulded plastic ones are unsuitable. I have edited my earlier post to make that clearer.

J.P.
 

Scale7JB

Western Thunderer
Hi JP..

Look forward to seeing this running soon.. I wouldn't mind one myself for my 'one day' late 50's western region layout..

JB.
 

Steph Dale

Western Thunderer
JP,

I can feel an 'oh crud' moment coming on.  I've got a feeling these new outside cranks will be a problem for a lot of kits.  Certainly I can't see how they could be fitted to any of the double-framed GWR prototypes easily...

Ho hum,  I can see that I'll have to 'play' when the time comes to use them.  ::)

At least the Southern didn't have many outside-framed rod-coupled locos, so I should be okay for a while!  :D

Steph
 

28ten

Guv'nor
Steph Dale said:
JP,

I can feel an 'oh crud' moment coming on.  I've got a feeling these new outside cranks will be a problem for a lot of kits.  Certainly I can't see how they could be fitted to any of the double-framed GWR prototypes easily...

Ho hum,  I can see that I'll have to 'play' when the time comes to use them.  ::)

At least the Southern didn't have many outside-framed rod-coupled locos, so I should be okay for a while!  :D

Steph

At least Martin Finney does the L/W cranks. and you can always use PGMS then loctite and pin the crank
 

Steph Dale

Western Thunderer
Cynric,

PGMS?  You've lost me...!  ???

It strikes me that  Loctite and a pin is probably a pretty good solution in this instance, though guaranteeing the quartering could be fun.  :scratch:

Steph
 

28ten

Guv'nor
Steph Dale said:
Cynric,

PGMS?  You've lost me...!  ???

It strikes me that  Loctite and a pin is probably a pretty good solution in this instance, though guaranteeing the quartering could be fun.  :scratch:

Steph
Sorry, Precision Ground Mild Steel. I always use it for AGH castings or homebrew axles  as you know it will be a precise fit in any reamed holes, or in ballraces.
 

Dog Star

Western Thunderer
Steph Dale said:
I've got a feeling these new outside cranks will be a problem for a lot of kits.  Certainly I can't see how they could be fitted to any of the double-framed GWR prototypes easily...
Steph

Steph, you might have noticed a comment from me earlier in the thread about this concern...  Slaters sent some of the new S7 axles to me about three months back and it was Jonpaul's queries on the S7 e-mail list, followed by a similar question on the 7mm Yahoo Group, which alerted me to the potential problem of the new axles.  As we are discussing an axle for an outside frame / outside crank engine the difference between FS B2B and S7 B2B is not of importance, we are concerned primarily with the overall length of the axle and with the way in which the outside cranks are affixed to the axle.

First the length...  the new design of axle is shorter than the old design - from what Jonpaul wrote in an e-mail to me the new axle is about 3mm shorter.  For the record, the length of an axle for a GWR outside frame engine is 7' 10.25", (reference is GWR drawing for valve motion of 3200, 3300 and 3400 engines and "Outline of GWR Locomotive Practice" by Holcroft).  Hence the length of an axle, to scale, ought to be pretty close to 55mm....  and that is about 1mm longer that the old axles.  The reason that the new axles are shorter than the old axles would seem to be that the new outside crank moulding is thicker than the previous design.

Second the fixing of the crank to the axle....  the old design of crank was a nylon moulding with a "D" shape hole, that crank was pressed onto the end of an axle (which had the corresponding "D" machined onto the axle).  The new design of axle has a square machined onto the axle and a tapped hole along the axle axis - just like the current method of retaining coupled wheels for inside frame engines.  To match the square on the axle the outside crank moulding has a brass insert which has been broached to fit onto the square...and the length of that insert is the reason why the overall length of the axle has been reduced.

I discussed this concern with David White at Slaters about three weeks back and I have provided David with information on the "outside frame" axle and the corresponding fly crank from the GWR drawings.  As of last week David had advised me that he now understands why there is a problem with the new axle design when used with kits which are not of Slater's manufacture, for example the MMP Class08 and probably all of the Finney GWR 4-4-0 kits.  I understand from David that he is considering the production of a revised axle design, whether or not that revision resolves the problem remains to be seen.

If anyone can see any other cocnerns with axles for GWR O/F 4-4-0 classes then I shall be very pleased to here of those concerns.

regards, Graham Beare
 

Steph Dale

Western Thunderer
Graham,

Thanks for your most lucid reply.  To be honest I had seen the discussion on the Yahoo group and asked a couple of the proponents follow up questions; I soon realised that in most of the cases those who had entered into the discussion hadn't actually seen one of the new axles and were merely offering up their opinions as facts.

The photos in this thread showing the new axle is what prompted my follow up as I could now see for myself where the problem was.  Your reply has done much to clarify the issues and I shall wait to see what Slater's propose.  In the meantime I shall try to pick up a couple of sets of the older-style axles if I see them for, although a Southern modeller, double-framed 4-4-0s weren't all that uncommon in the area I'm interested in.

I've also just ordered a copy of the Holcroft book you refer to; it was ?1 from an on-line bookseller!  It seemed silly not to.

Cynric,

Makes sense!  I'd probably be more likely to go for some thin-walled brass tubing for use with the pin and Loctite if I were left to my own devices!

Steph
 

28ten

Guv'nor
It might be a daft question, but why have Slaters changed the axle?
I have built a couple of  08's and the old style axle was no problem, I have one left to do for myself, so I had better check if I have any axles  :scratch:
 

Dog Star

Western Thunderer
28ten said:
It might be a daft question, but why have Slaters changed the axle?
I have built a couple of  08's and the old style axle was no problem, I have one left to do for myself, so I had better check if I have any axles.

This is supposition on my part...  the old style crank was a nylon(?) moulding and that moulding was a press-fit onto an axle which had a flat milled on one edge and, I presume, this combination had an element of imprecision in the wrong hands (or after removal and replacement of the crank).  The new design is the same as the current retaining system for coupled wheels, that is a socket-head, countersunk, screw to retain a broached brass insert onto an axle with a squared end.  The new design can be considered as a "better" engineering solution for retention of the crank, maybe not a better solution for some kits.

As to remaining supplies of the old style axles, see below.

Steph Dale said:
I shall try to pick up a couple of sets of the older-style axles if I see them for, although a Southern modeller, double-framed 4-4-0s weren't all that uncommon in the area I'm interested in.

MMP has purchased a significant number of the remaining Slaters D-axles for O/F engines presumably to assist those who have bought the Class 08 kit.  If the concern is for the GWR 4-4-0 O/F kits from Finney then you may succeed with a direct approach to David White as, I presume, there are likely to be some packets of 5'8" and 6'8" wheels with the old axles in the shrink-wrap.  Just remember to request the D-cranks at the same time.  None of that helps anyone who is modelling to the S7 standards as Slaters did not produce an O/F axle with the S7 B2B so in that case the only options are:-

[1] wait and see what happens next in Matlock;
[2] make your own axle (including the taper for the wheel seat);
[3] modify the new axles to replace the square end with a plain sleeve and make new cranks;
[4] take up kntting.

Steph Dale said:
I've also just ordered a copy of the Holcroft book you refer to; it was ?1 from an on-line bookseller!  It seemed silly not to.

Well done, I hope that you enjoy the book.  Holcroft was in the GWR DO with Churchward and later moved to a more southern influence at a later date.  I am not sure why this book has fallen below the radar which is a shame given that the content and style are very acceptable.  Apart from Holcroft and KJ Cook I am not aware of any other books about the design practices of the GWR where the author was involved with the development and maintenance of the engines.  Suggestions anyone?

regards, Graham
 

Ressaldar

Western Thunderer
28ten said:
It might be a daft question, but why have Slaters changed the axle?
I have built a couple of  08's and the old style axle was no problem, I have one left to do for myself, so I had better check if I have any axles  :scratch:

I think that it might have some connection with the JLTRT 08 that was announced at Telford.

regards

Mike
 
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