Chuffer's Workbench

[Chuffer Davies]

49 minutes ago, richbrummitt said:

I’m so pleased that you decided to start a thread of your own (and that I found it). It’s hard to keep up with Wright Writes for the occasional posts that interest me.  
 

I hope that you and the family are all keeping well. 

 

1 hour ago, grob1234 said:

Looks fantastic Frank and a nice enjoyable account of what you’ve done to date.

 

Sadly my modelling time has been drastically reduced with my new work schedule but I live in hope of snatching a few hours at the bench from time to time.

Dear Tom/Richard,

its good to hear from you and thank you for your kind remarks.  I am fortunate that now I have retired I can at last spend as much time as I would like building models.    Its five years tomorrow since I left the bank and I haven't looked back since. 

 

I  well remember the years of full time work and bringing up a young family where grabbing an hour to model was a luxury and i was pleased if I could build a loco in less than two years.  What I did do in those days was have a set up where even if I could only escape for 10 minutes I could achieve something constructive in that time. 

 

Things do get easier as the children get older and your role will change from entertainer and child minder to taxi driver at which point you can grab modelling time between fares.... Of course when the grandchildren arrive to some extent its back to square one with school runs and baby sitting but that's a while yet for both of you. 

 

Look after yourselves.

 

Frank

 

P.S. The family are all well thank you. 

[gr.king]

On 09/01/2021 at 20:54, Chuffer Davies said:

...My preference is to use half round 0.7mm nickel silver wire.  My reason for using N/S is because I was advised in the past that paint adheres to it better than to brass...  

The wire can then be filed to shape.  I find that whilst filing it is best to stabilize the wire in the grove with a finger otherwise it will pull out and bend as the file is drawn across it.  It only takes a couple of minutes to file a length sufficient to complete the front or back of a GN cab's sides and roof, or the side of a tender.

 

I apologize for being a little late in commenting on the use of wire filed to half round, but I do remember trying the idea with brass wire and finding that once filed, every attempt to bend it simply caused it to snap. I assumed that work-hardening had occurred, perhaps a lot of cracking too. I never attempted to re-anneal the filed wire, simply giving up the idea as a bad job instead. Have others had success with brass wire, or the same failure that I had? Is Nickel Silver wire more resistant to to the problems that I encountered?

Edited March 12, 2021 by gr.king

[Chuffer Davies]

2 hours ago, gr.king said:

 

I apologize for being a little late in commenting on the use of wire filed to half round, but I do remember trying the idea with brass wire and finding that once filed, every attempt to bend it simply caused it to snap. I assumed that work-hardening had occurred, perhaps a lot of cracking too. I never attempted to re-anneal the filed wire, simply giving up the idea as a bad job instead. Have others had success with brass wire, or the same failure that I had? Is Nickel Silver wire more resistant to to the problems that I encountered?

Hi Graham,

Delighted you’ve found me.    
 

I’ve never had any problems with n/silver.  Have you ever tried buying half round brass from Eileen’s and bending that?  I know that trying to put a tight bend in brass wire often ends  in grief, and it becomes so soft when annealed it’s also a problem.  To be honest I tend to avoid using brass wire and prefer to use n/silver or phosphor bronze (especially for sand pipes). 
Frank

[Chuffer Davies]

I have at last managed to find an alternate source for the specific motor needed for my Dapol Mogul and so at long last I've been able to install the drive train.  It was not all plain sailing and installation required a couple of minor modifications, but otherwise the installation has been completely successful.  I am still awaiting delivery of a set of EM wheels from Ultrascale, the test model currently has a set of S4 wheels under it.  Once replaced I'll be able to complete the final build and give the model a proper haulage test.

 

One of the major challenges in creating these drive systems has been sourcing all the parts.  This is the 5th loco I've now built with the M-I-T system.  The first 4 used Neoprene tubing that I had bought for an experiment (from Branchlines - I think) at an Expo EM several years ago.  By the fifth loco I had run out and despite spending hours on the Internet had been unable to find a new source for the soft, thick walled tubing required.  Out of the blue, and I have no idea as to why this time I was successful, I have at long last found a source: Caldercraft Coupling Rubber 10 x 1.5-2.5mm x 50mm Part No: R1386 - Sussex Model Centre -SMC (sussex-model-centre.co.uk).  I estimate that one packet is enough for about 30 drive trains and so I should have enough for all the loco's I'm likely to build in the future. 

 

Delivery time for wheels from Ultrascale is now quoted as being up to 6 months and so I probably have another couple of months to wait until I can at last complete this project but at least I now know I'm on the home straight.

 

[Chuffer Davies]

Despite my lack of posting for a while I have not been idol.  The most satisfying achievement in the last few months has been the final assembly of 5 locomotives that had been with Ian Rathbone for painting.  Some of these have already been displayed on Wright Writes, but for completeness I would like to present them here also.

 

In the order that they were originally designed and built therefore:

 

LNER Q2:

I have already described how I have retro-fitted my Motor-In-Tender (M-I-T) drive system to this model.  This was my first attempt at designing a complete locomotive kit as an alternate approach to scratch building which would have been the only other way to acquire a model of a Q2.  This model probably represents the ultimate in terms of my preferred approach to building models.  As well as the M-I-T, electrical pickup is by means of the American system, and the chassis is sprung to ensure all wheels are firmly planted for optimum current collection.  The icing on the cake is the working inside valve gear that was built to fill the very obvious void under the high mounted boiler.

 

This model is now available as a London Road Models kit.  

[Chuffer Davies]

The next models to go through final assembly have been the two J7's.  This was my 3rd attempt at locomotive kit design and on this occasion I opted for cosmetic valve gear between the frames.  Otherwise these models are basically the same as the Q2 in that they have M-I-T drive, American pickup and sprung chassis.  As with the Q2 the J7 is destined to be added to the LRM range of kits.

 

This model represents the GNR 1021 Series which was based on their standard goods engine design but with reduced diameter wheels (4' 8") to increase the haulage potential to cope with the steep gradients found in the West Riding of Yorkshire.  

 

 

The 2nd manifestation of a J7 represents its final form with a larger 4' 8" diameter boiler, the same as that found on the larger J3. 

 

[Chuffer Davies]

The fourth locomotive to be completed is the J1.  I found this far harder to design than either the Q2 or the J7 because of the curved footplate.  A key challenge was working out mathematically the length of the footplate so that it ended up the correct length once the curves had been formed in it.  I'm pleased to say I got this particular feature right first time, but unfortunately that wasn't true of some of the other components and it eventually took three visits to the etchers to get everything right.

 

This model has the same basic features as the Q2 and J7's but without any attempt to represent the valve gear.  

 

 

The fifth and final model to go through final assembly is my attempt at converting the Bachman GN Atlantic to EM using a replacement chassis of my own design.  I am really impressed by Bachman's rendition of the prototype.  On this occasion I decided that attempting to design the chassis for CSB suspension was a step too far for me and so the loco's chassis has been designed for compensation.  The motor is in the traditional location wholly within the firebox.  I have packed as much additional ballast into the model as possible.  

 

 

Since completing the final assembly of these models I have gone on to design two more complete kits: a J2 and a J52.  Both are now away at the etchers.  I hope that the J2 will eventually be offered to John Redrup for inclusion in the London Road Models catalogue. 

 

The J52 by contrast came about by accident.  I had already acquired a commercial kit for a J52 but was then advised by colleague that the kit had some dimensional errors and required some replacement parts for the tank and the cab side sheets to correct the anomalies.  So work started on drawing up the required components and this then led me to start thinking more deeply about how I wanted to assemble the superstructure so that I could have access to the inside of the cab for painting and subsequent installation of glazing and loco crew once painting was complete.  By the time I'd determined how many other parts needed modifying to achieve allow the cab to be removed from the footplate I decided the best way forward was to draw up artwork for the entire superstructure.  I then looked more closely at the chassis supplied with the kit.  There were two immediate problems with the kit chassis as supplied.  No provision had been provided for either suspension of compensation.  The leaf springs were underslung but the sub type of the J52 I wanted to model had the leaf springs above the axles and on view above the wheel splashers.   Yet again I came to the conclusion that it would be as easy to design a complete replacement chassis with CSB suspension built into the design, articulated coupling rods and correctly positioned leaf springs.  At that point I made a significant and happy discovery.  The frames of the J52 I'm modelling are identical to those of the J7 with the exception of the back of the frames because on the J52 they are extended to support the bunker.   I was therefore able to copy the CAD artwork previously prepared for the J7 and make a few minor modifications.  Job done!

 

Whilst I await delivery of the J2 and J52 metal from PPD I am filling my time with building a new test track shelf incorporating three B7 points made from the new British FInescale kits.  These kits incorporate 3D printed bases complete with chairs, a N/Silver casting for the frog and machined point blades.  Having previously hand built  points from C&L components these are a delight to build and make a superb end product that compares favourably with the C&L components.  Sadly the 3D printing process is unable to produce chairs with representation of the wooden keys but on a positive note the various specialist chairs found on a point are faithfully reproduced.   Assembly requires the rail to be cut to length and threaded through the chairs in the track base.  The cast frog is superglued in place and its precise positioning is controlled by integrated cast pegs that locate in holes printed into the track base.   I have hand built a 1:7 diamond crossing from C&L components to incorporate into the test track but had I been willing to wait a couple more months there will be a kit for the crossing coming out as well.   More to follow once I have finished laying the track and wiring it all up.

 

That just about brings you all up to date with my endeavours for now,  I will post some more updates as and when I get to grips with the J2. 

[Chuffer Davies]

Hello to all,

It amazes me how quickly time passes and it is now 5 months since I last posted to my blog.  I tend to spend an average of 3 hours every day designing or building models and so in 5 months I must have spent several hundred hours modelling, yet I have little to show for it compared to the likes of someone like Tony Wright who can turn a model around in significantly less than 100 hours.

 

The first update I would like to provide concerns the Mogul.  The EM wheel sets have now arrived from Ultrascale and I have been able to complete the build of the M-I-T chassis.  The model is not complete but I have been able to carry out a proper test run and haulage test to see whether I have actually delivered what I set out to achieve.

 

I am really pleased with the result. The model runs smoothly and quietly, is highly controllable across the speed range, and has far better haulage capacity than the out of the box model.   On test the loco hauled 28 kit built wagons up a 1:50 gradient on a 4' 6" radius without slipping and 40 wagons up the 1:100 gradient.  On the flat it hauled 50 wagons which was all I had available at club today.

 

 

The model now needs weathering, lamps, fire irons and crew and it will then be ready for revenue earning service on Hungerford.  Whether we ever actually get any more exhibition invites for Hungerford is an unknown but I live in hope, otherwise creating this model will have been for the enjoyment and challenge only.  

 

The other significant project I have been progressing since my last post in March is a J52 for our Clayton project.  The history surrounding this project has been strange indeed.  I first thought about building a J52 when I became aware that there was an etched kit sold under the Walsworth Models brand.   Soon after purchasing this my good friend Geoff Tiffany told me that he'd built one of these kits and had experienced all sorts of issues with the dimensions especially the shape of the saddle and the length of the bunker.  An examination of the kit confirmed what he'd told me which meant I would have to make the same corrections to mine.

 

I then researched which J52's had been allocated to Bradford shed and discovered that the main one had been one of 15 locomotives built for the GNR in 1896 by Neilson & Co.  These were based on Stirling's standard goods engine frame design with the leaf springs above the footplate.  In addition both the front and rear buffer beams had 9 inch wooden extensions.  The Walsworth kit did not include either of these features so further modifications would be required.  

 

With further modifications to allow the cab to be removed for painting and the installation of crew, it was evident that hardly any of the original kit would be used and so the decision was taken to retire the kit and draw up a new set of etches specifically suited to modelling the Neilson variant.    I also decided that this would be a bespoke EM gauge kit for Clayton (for me really)  so that I could avoid the additional research and effort required to design and test build a generic kit (in any of the popular 4mm/ft gauges),  that could be used to build a wider range of J52 variants as necessary for a commercial kit.

 

The model is still not quite finished as I'm awaiting a couple of replacement Gibson wheels and some castings from London Road Models, but its nearly there.  The basic features of the model are, split frame and CSB suspension.  A High Level 1320 motor sits vertically in the firebox and whilst the gearbox frame is included in the chassis's etch the gears are from a High Level Road Runner Compact+ gearbox.  The bunker, saddle/boiler and smokebox are filled with lead to maximise haulage.  

 

 

      

Another couple of weeks finishing off the detailing and this will then (hopefully) be off for painting.

 

My next job will be to test build a J2 using the etches I designed last year.

 

Thanks for reading,

 

Frank  

Edited March 31, 2022 by Chuffer Davies
Re-instating Pictures

[grob1234]

Lovely sweet sound coming from the Mogul there Frank. Definitely no wasted effort for a loco that runs as sweetly as that one. Hungerford is a layout I would love to see, so I am very hopeful you will get an invite, and shows start to become more common. I'm also incredibly impressed with your etching. Very crisp.

 

3 hours a day modelling... I'm lucky if I manage 3 minutes! 

[Chuffer Davies]

29 minutes ago, grob1234 said:

I'm incredibly impressed with your etching. Very crisp.

 

3 hours a day modelling... I'm lucky if I manage 3 minutes! 

Hi Tom,

I can't take the credit for the crispness of my etches other than the selection of the company to use.  I am happy to recommend the services of PPD Ltd who can take the credit for the quality of the metalwork.  They are not the cheapest but the quality is always good. 

 

As to the amount of time I can spend modelling, that is down to the rewards of a well earned retirement, on going Covid isolating and a supportive wife.

 

Frank   

[dmurrell]

Frank,

The mogul looks like a great runner, very impressive. You mentioned some months ago that the chassis might become available as a commercial kit. Any news yet on when this might happen and if so who the supplier will be?

 

David

[Chuffer Davies]

6 hours ago, dmurrell said:

Frank,

The mogul looks like a great runner, very impressive. You mentioned some months ago that the chassis might become available as a commercial kit. Any news yet on when this might happen and if so who the supplier will be?

 

David

Hi David,

yes my understanding is that the plan to launch this as a commercial kit is still very much alive.  I don’t think it is my place to announce who is planning to launch it but I know they monitor this thread so they may choose to comment themselves.  
shouldn’t be too long now.

Frank

[Chuffer Davies]

With the J52 ready for painting I have been able to move on to the next project which is the test build of my prototype J2 etches designed earlier this year.  With regards the prototype the J2 is not that dissimilar to the J1, the main difference being that the J1 had slide valves whereas the J2 had piston valves with tail rods fitted to both the valves and the cylinders. The piston valves caused the centre line of the boiler to be raised, and the tail rods required the front of the footplate to be extended forwards to bring the end of the tail rods behind the buffers.  The rear of the J2's footplate was also extended backwards compared to the J1 but the rest of the frames and the footplate were the same on both the J1 and J2.  I have therefore been able to lift 50% of the CAD artwork for the J2 directly from the J1's which hopefully will reduce the risk of errors.   

 

So far I have assembled the frames (chassis) including the modified High Level gearbox for the M-I-T drive system.  One minor design error has surfaced (easily rectified)  with regards failing to provide a clearance slot in the ashpan's sides for the CSB pillars but otherwise all seems well.  I am pleased to say that the horn block spacing and wheel quartering has proved to be spot on.  I have the luxury of owning an Avonside chassis jig and given the number of models I need to build for Clayton I consider it to have been a sound investment.  The chassis follows my standard build approach: CSB suspension and American pickup (loco chassis live to the nearside).

 

I can't power up the chassis to test it out until I have built the tender's frames but I have made sufficient of these chassis to be confident that this one will work with a minimum of additional tweaking.  Here are some pictures of the frames as a reference for anyone building one of these models in the future as it is the intention to add the J2 to the LRM range of kits in due course.

 

 

I have just started the test build of the superstructure and will provide an update when I've either successfully built the superstructure or have hit a point in the build where I can't go any further because I've made a major blunder somewhere along the line.  Fingers crossed.....

 

Regards,

Frank

 

Edited March 31, 2022 by Chuffer Davies
Re-instating Pictures

[57xx]

That chassis looks fantastic frank.

[Chuffer Davies]

As planned work has started on construction of the J2s superstructure.  The starting point is the footplate which, because of its complex curves, requires a cradle for its assembly.  Unfortunately I have identified some errors in the etches but the good news is that none of these have been terminal and I have been able to bodge my way around the mistakes to create a usable footplate.  Corrections have already been made to the CAD artwork, and because of these errors in due course I will need to test assemble a 2nd footplate to ensure that the changes in CAD have corrected the previous mistakes.

 

A key learning point has been a need to modify my expected build sequence.  I always thought that the front sandboxes would be awkward to assemble and this has proved correct but not in the manner expected.  The reverse curve at the back of the sandbox's top face was where I expected to come a cropper but in reality it was actually quite easy to form aided by half etched lines on the underside to indicate where the curve needed to be made.  The complication came with attaching the boxes to the footplate because the rear face of each box was obstructed by the dummy frames which had already been fitted.  Off came the frames, on went the sandboxes and then back on went the frames.  I must remember to update the assembly instructions....

 

 This is how the footplate looks at end of play today:

The footplate will remain in its cradle until I have fitted the cab after which it should be sufficiently rigid to allow the cradle to be removed.  I can then test fit the footplate to the frames to make sure that the splashers align with the wheels.  

 

Perhaps a detail worth noting are the knobs on the sandbox covers.  I have formed these from 1mm n/silver rod spun in a hand drill.  The neck of the knob was made with a fret saw after which the top of the knob was domed with a needle file before finishing off with some fine wet and dry.  Fixing the knobs in place was also awkward because despite being hollow I could not get my soldering iron bit inside the sandboxes to attach them.  Instead I drilled down through the top of each sandbox and right through the footplate underneath.  The knobs were made extra long so that they could then be soldered to the underside of the footplate instead.

 

Tomorrow work will start on the cab...

 

Thanks for reading,

Frank     

Edited March 31, 2022 by Chuffer Davies
Re-instating Pictures

[Chuffer Davies]

I received an email question today from a fellow EM gauge member with regards how I go about shorting out plastic centred wheels when building a split frame chassis.  Rather than just email him back I thought I'd post my explanation on here in case anyone else either will find this of interest or has an alternate approach worth sharing.

 

I am assuming that the questioner already has access to split axles and knows how to align the insulated gap to avoid shorts when mounting a gearbox.  My apologies in advance for the out of focus pictures.  I hadn't realised the problem until after I'd completed assembling my demonstration piece.

 

When I build tender locos I employ the so called American pickup system whereby the live chassis of the loco picks up from the nearside rail and the live chassis of the tender picks up from the offside rail.  The drawbar is used to carry current from one chassis to the other but is insulated at one end to avoid a dead short between the two chassis.  In these models I use etched shorting tags sourced from the EM Gauge Society's stores to short the rims of the wheels to the their axles.  This has been discussed in an earlier post near the bottom of page one of this topic.

 

 

The problem with these tags is that they don't like being disturbed so when used I ensure the wheel to which they have been attached remains permanently on the axle.  On a split frame chassis I need to be able to remove the axles several times during construction requiring me to remove at least one of the wheels on any given axle.  To facilitate this rather than use an etched tag I instead use very fine (36 swg) phosphor bronze wire sourced from Eileen's Emporium as follows:

 

The wheel is prepared by grinding two small hollows into the rim of the wheel directly opposite each other and 90 degrees from the crank pin.  I also cut a fine groove across the hub into which the wire will lay so as to allow it to lie flat against the back of the spokes.

  

I then attach a couple of clamps to the rim of the wheel to act as heat sinks whilst still leaving access to the hollows, and solder the wire across the back of the wheel.  The surplus wire and solder is removed and the back of the wheel cleaned to remove any flux residue.  This is particularly important with steel rimmed wheels.   Once attached the wire is cut at its centre using a scalpel blade.

 

 

The axle is now inserted in the usual manner at the same time forcing the ends of the wire down into the hub of the wheel.  To avoid potential problems with the soldered joint/s subsequently failing in use the right angled bend at the point the wire exits the wheel is accentuated using a small bladed screw driver. 

 

As and when the axle is removed the wire will remain embedded in the soft plastic of the wheel's hub and in my experience any subsequent insertion and removal of the axle will not dislodge the wire and electrical conductivity will not be compromised.

 

I would stress the importance of using fine phosphor bronze wire.  I have tried using other materials but have found them too brittle with a tendency to snap when then axle is first forced into the wheel.  Thicker wire has a tendency to compromise the alignment of the wheel on its axle causing it to wobble.  Don't be tempted to use fuse wire, you will find out why the first time you get a dead short across the chassis.

 

If anyone else would like to share their approach to shorting out plastic centred wheels I would be interested to hear how they do it.

 

Regards,

 

Frank

Edited March 31, 2022 by Chuffer Davies
Re-instating Pictures

[Portchullin Tatty]

Hi Frank

 

I have two variants/observations on your approach.

 

Firstly, when soldering the wire to a steel rim, you do have to use a strong flux.  Carr's brown label - nothing else seems to keep the steel clean enough to allow the bond of solder.

 

Secondly, I have never got on with inserting the wire in the axle hole, I find that it makes the axle be a bit scew, either off centre or even less inclined to be perpendicular to the wheel.  Instead I adopt a trick taught to me by Bill Bedford.  Instead of two pieces use a single piece of fine wire and make a loop a little to big for the axle.  Solder each end as you do and leave the loop in the centre.

 

Once the axle has been inserted the loop can be tightened such that it touches the axle by simply pulling one of the ends and holding it with a bit of superglue.  In practise the wire is difficult to stop from touching the axle even if it is a bit bigger than I have described.

 

I do like your locos by the way!

 

 

Mark

[Chuffer Davies]

14 minutes ago, Portchullin Tatty said:

Hi Frank

 

I have two variants/observations on your approach.

 

Firstly, when soldering the wire to a steel rim, you do have to use a strong flux.  Carr's brown label - nothing else seems to keep the steel clean enough to allow the bond of solder.

 

Secondly, I have never got on with inserting the wire in the axle hole, I find that it makes the axle be a bit scew, either off centre or even less inclined to be perpendicular to the wheel.  Instead I adopt a trick taught to me by Bill Bedford.  Instead of two pieces use a single piece of fine wire and make a loop a little to big for the axle.  Solder each end as you do and leave the loop in the centre.

 

Once the axle has been inserted the loop can be tightened such that it touches the axle by simply pulling one of the ends and holding it with a bit of superglue.  In practise the wire is difficult to stop from touching the axle even if it is a bit bigger than I have described.

 

I do like your locos by the way!

 

 

Mark

Hi Mark,

thank you for posting and for your last statement in particular.  I completely agree with your comment regarding the use of brown label flux for steel rimmed wheels.    
Just so I’m clear in what you describe, does the loop turn through a full 360 deg, and is the wire still aligned so it is hidden completely by the spokes?  I’m just struggling to picture what you have described.

Frank

[Portchullin Tatty]

10 minutes ago, Chuffer Davies said:

Just so I’m clear in what you describe, does the loop turn through a full 360 deg, and is the wire still aligned so it is hidden completely by the spokes?  I’m just struggling to picture what you have described.

 

Hi Frank

 

Yes it is a 360 loop.

 

It is possible to hide the wire behind the spokes.  the slack is taken up behind the boss as you only need one decent piece of contact with the axle and in practise it is difficult to prevent it.

 

I am sorry I don't have any pictures at present, but the next time I do one I will take care to do so.

 

 

Mark

[gr.king]

Further to the theme of looping a single wire around the axle, I recently made a set of plastic-spoked wheels live to the axle by forming a wire loop a little too small for the axle so that it was a clench-fit when pushed over the axle. I then ran the straight bit behind a spoke and soldered the outer end to the rim, the end bent to 90 deg to lie along the rim to give more contact area for the solder. So long as the wire is supported it is possible to pull off and re-fit the wheel, the latter with the aid of a slight bevel around the end of the axle.

Edited October 6, 2021 by gr.king
Spelling mistake!

[5050]

I never have success in removing and refitting wheels such as Gibsons.  They become loose on the axle and, as well as losing quartering, slip inwards so losing the b-2-b. How do you get over this?

 

I make sure when building a chassis that I can remove axles, axleboxes and wheels intact as sets.

[Chuffer Davies]

On 06/10/2021 at 10:13, gr.king said:

Further to the theme of looping a single wire around the axle, I recently made a set of plastic-spoked wheels live to the axle by forming a wire loop a little too small for the axle so that it was a clench-fit when pushed over the axle. I then ran the straight bit behind a spoke and soldered the outer end to the rim, the end bent to 90 deg to lie along the rim to give more contact area for the solder. So long as the wire is supported it is possible to pull off and re-fit the wheel, the latter with the aid of a slight bevel around the end of the axle.

This sounds like an equivalent method to the EMGS shorting tags but not sure how well they would stand up to having the axles removed multiple times.  Definitely worth considering though.

Frank 

[Chuffer Davies]

22 minutes ago, 5050 said:

I never have success in removing and refitting wheels such as Gibsons.  They become loose on the axle and, as well as losing quartering, slip inwards so losing the b-2-b. How do you get over this?

 

I make sure when building a chassis that I can remove axles, axleboxes and wheels intact as sets.

Hi,

I have had a similar experience to you with regards Gibson wheels becoming loser the more times they are fitted to an axle but not to the point that they have become unusable.  A critical requirement for me is to remove the burr from the axle's end before the axle is first inserted in a wheel.  I do this by spinning the axle in a mini drill and chamfering the end of the axle with fine wet and dry paper.  If not removed I find the burr can act like a blade and remove plastic from the centre of the wheel, both opening the hole and making it almost impossible to set the wheel square on the axle.  The second thing to note is that the plastic has a memory and so although it may feel loose when re-fitted it will try to return to its original size.  I find that if I go back later the wheel generally grips the axle more than when it was initially installed.  Finally, and equally importantly when I carry out final assembly I always Loctite the wheel to the axle.  I can't remember the last time a wheel so installed came loose other than when the centre boss has split which has happened a couple of times with Gibson wheels.  

 

Obviously I try to minimise the number of times a wheel is removed from an axle, probably half a dozen times maximum during the assembly of the frames, but I have never found the need to purchase a 2nd set of wheels because the first have become too loose. 

 

Regards,

 

Frank

[5050]

I also lightly countersink the wheels' axle holes with a large sharp drill (6mm?)  and make sure there is no 'swarf' in the hole before running a piece of rag with lighter fuel through the hole to degrease (does Colin use a release agent when moulding wheels?) it before using the same rag to wipe the end of the chamferred axle.  Wheels fitted to axles with a GW press.  However, I pack the rim and boss of the wheels in the press with thin plasticard (thickness depending on design of wheel) to try and ensure it is stable and won't rock when pressure is applied.  A very thin smear of Tacky wax holds it all in place whilst pressing.

 

All pretty normal procedures I guess but (so far at least!) with my removable axles I've not had any wheels come loose.  I tried to re-use some Sharman wheels a couple of years ago but they remained resolutely loose no matter what I tried.

[Chuffer Davies]

1 hour ago, 5050 said:

I also lightly countersink the wheels' axle holes with a large sharp drill (6mm?)  and make sure there is no 'swarf' in the hole before running a piece of rag with lighter fuel through the hole to degrease (does Colin use a release agent when moulding wheels?) it before using the same rag to wipe the end of the chamferred axle.  Wheels fitted to axles with a GW press.  However, I pack the rim and boss of the wheels in the press with thin plasticard (thickness depending on design of wheel) to try and ensure it is stable and won't rock when pressure is applied.  A very thin smear of Tacky wax holds it all in place whilst pressing.

 

All pretty normal procedures I guess but (so far at least!) with my removable axles I've not had any wheels come loose.  I tried to re-use some Sharman wheels a couple of years ago but they remained resolutely loose no matter what I tried.

You take a lot more care than I by the sounds of things.  I push the wheels on by hand rather than using a wheel press but have not had any problems despite this.  I admire that you design your frames to permit the wheels to be dropped out as a complete assembly but its something I have never felt the need for.  Once my models are built it is very rare for me to want to remove the wheels again but if I do then a quick twist of the wheel on the axle breaks the Locktite and off they come. 

 

Any idea whether the lighter fuel could be affecting the plastic?  I have never cleaned the holes in the wheels before pushing then onto the axles.  Could it be that lighter fuel softens the plastic permanently making the wheels more prone to becoming loose?

 

All very interesting...

 

Frank