Converting a Dapol Class 22 to P4

User avatar
Captain Kernow
Posts: 480
Joined: Sat Jul 26, 2008 8:08 pm

Converting a Dapol Class 22 to P4

Postby Captain Kernow » Thu May 03, 2012 9:11 pm

There was quite a lot of debate on the Class 22 thread a while back about how one might convert it to EM or P4. I think that the EM gauge fraternity generally decided that the existing wheels could be pulled out slightly on their existing axles, and I hope that this has worked out for them.

This wasn't going to work in P4, and the original wheels could only have been used if they were turned down to P4 profiles. Some folk have suggested fitting P4 tyres to the existing Dapol wheels, and good luck to them, too.

The issue is that the Dapol Class 22 uses a split axle and associated pick up, as my photos will make clear. This means that the wheel tyres and axles have to be electrically connected. This wasn't a problem for Dapol, obviously, as they have mass produced a decent OO metal wheel for their model, which fits onto stub half-axles, that in turn fit into a central gear assembly.

Ultrascale considered doing a 'drop-in' wheel set for a while, but technical issues, which I understand were essentially associated with the fact that they didn't have an all-metal spoked wheel available, meant that they did not proceed with the project, although they do offer a bespoke wheel producing service for P4 modellers, albeit the price is very high and almost as much as the locomotive itself.

My method does use Ultrascale wheels, but an existing wheel from their range, namely a 3' 7" 10-spoked Southern tender wheel, which has one less spoke than the Class 22, but is the correct diameter. Each pair of wheels comes with a P4 axle.

Here is the Dapol motor bogie, with the keeper plate and one of the OO axles removed (I might add that despite being told how to remove the keeper plate by friends at DRAG, and the fact that it was 'easy', I didn't find it easy at all, and was in constant fear that I was going to break something with the amount of controlled force I was trying to apply at times). In the end, each keeper plate came away intact and without damage. The keeper plates are attached to the bogie side frames, as other photos will show.
22_001.JPG


22_002.JPG


22_003.JPG


22_004.JPG


22_005.JPG


The next activity involves creating an electrical pathway from the wheel rim, over the nylon wheel centre, to the half axle. I chose to solder a piece of 0.3mm brass wire over the outside front of one of the spokes. The theory was that when the wheel is hidden behind the bogie side frames and painted & weathered, you simply won't notice it, and it saves messing around with the rear of the wheel and the back of the flange.

22_009.JPG


22_010.JPG


What happens next was different for the first wheelset as compared with the other three, but the method adopted for the remaining 3 wheelsets was much easier and quicker, so..

22_011.JPG


Do NOT glue the other half axle in! The worm assembly is actually hollow right the way through, so if you are not using the split axle method, you could use a complete 2mm diameter axle with the worm assembly mounted centrally, but this would require seperate pick ups and more modifications to the Dapol motor bogies than I felt was necessary.

Next is the really barbaric bit. It you love the excellent and well-engineered finish of an Ultrascale wheel set, look away now....

22_012.JPG


A length of 0.3mm brass wire is then put into the groove on the rim, and soldered to the wheel rim. The wire should be pre-trimmed so that the opposite end reaches just as far as the opposite side of the axle hole (ie. reaches from the outer race of the rim, along one spoke, and across the width of the 2mm axle.

I would then recommend temporarily mounting each wheel in the other half axle and removing the surplus solder carefully. I filed most of the unwanted material off with a needle file, then mounted the wheel in the electric drill and used two grades of fine wet & dry paper, then a glass fibre pen.

22_013.JPG


It's then a matter of assembling the components to make a viable P4 wheelset. These photos were taken of the first wheelset.

22_015.JPG


22_016.JPG


22_017.JPG


22_018.JPG


What I did for the last three wheelsets, was to assemble the bearing, 1mm brass slieve and wheel to the axle already super-glued to the worm, solder the 0.3mm brass wire from that wheel rim to the steel axle, and then assemble the other side, bringing the whole lot carefully together using a GW Models wheel press and a back-to-back gauge.

22_019.JPG


22_020.JPG


22_021.JPG


22_022.JPG


22_023.JPG


22_024.JPG


22_025.JPG


22_026.JPG


OK, so it's not the most 'high-tech' of conversions, it's a bit 'Heath Robinson'ish' in fact, but it works, and it worked first time, so I'm happy with it, and when the bogie side frames are on you can't count the spokes, nor can you really see the bit of brass wire on each wheel either...
You do not have the required permissions to view the files attached to this post.
Tim M
Member of the Devon Riviera Area Group.

David Knight
Posts: 813
Joined: Sun Jul 20, 2008 6:02 pm

Re: Converting a Dapol Class 22 to P4

Postby David Knight » Fri May 04, 2012 1:35 am

Tim,

Are the Dapol wheels of a substance suitable
for turning or are they plated zinc alloy?

Cheers,

David

User avatar
Captain Kernow
Posts: 480
Joined: Sat Jul 26, 2008 8:08 pm

Re: Converting a Dapol Class 22 to P4

Postby Captain Kernow » Fri May 04, 2012 7:52 am

davknigh wrote:Tim,

Are the Dapol wheels of a substance suitable
for turning or are they plated zinc alloy?

Cheers,

David

I doubt that it's suitable, David, although others have substituted a Gibson tread on the Dapol wheel centre.. - http://www.rmweb.co.uk/community/index. ... -class-22/
Tim M
Member of the Devon Riviera Area Group.

User avatar
Tim V
Posts: 2868
Joined: Tue Jul 29, 2008 4:40 pm

Re: Converting a Dapol Class 22 to P4

Postby Tim V » Fri May 04, 2012 8:25 am

Blimey Tim, shows what you can achieve with perseverance and no lathe....
Tim V
(Not all railways in Somerset went to Dorset)

User avatar
iak
Posts: 570
Joined: Thu Nov 05, 2009 10:28 am

Re: Converting a Dapol Class 22 to P4

Postby iak » Fri May 04, 2012 8:28 am

Very tasty sir 8-)
I shall have to read and cogitate on this - especially if the Dapol 21/29's follow the same drive format.
Unthinking respect for authority is the greatest
enemy of truth....
Albert Einstein


Perfection is impossible.
But I may choose to serve perfection....
Robert Fripp


https://www.facebook.com/groups/PadgateWorks/

David Knight
Posts: 813
Joined: Sun Jul 20, 2008 6:02 pm

Re: Converting a Dapol Class 22 to P4

Postby David Knight » Fri May 04, 2012 1:34 pm

Captain Kernow wrote:
davknigh wrote:Tim,

Are the Dapol wheels of a substance suitable
for turning or are they plated zinc alloy?

Cheers,

David

I doubt that it's suitable, David, although others have substituted a Gibson tread on the Dapol wheel centre.. - http://www.rmweb.co.uk/community/index. ... -class-22/


A very useful link Tim. I'm waiting for the 21/29 like Ian so no rush for the moment.

Cheers,

David

User avatar
Knuckles
Posts: 1262
Joined: Fri Nov 18, 2011 9:15 pm

Re: Converting a Dapol Class 22 to P4

Postby Knuckles » Fri May 04, 2012 5:07 pm

Ver interesting indeed. :) What you said about the keeper plate is kind of the same experience I had with the Heljan Hymek. Please answer a question though; what was the brass wire inside the wheel for? I've read it a few times but the penny is still in the money tree. :(
“He who dares not offend cannot be honest.” Thomas Paine

https://www.sparkshotcustomcreations.com/
Mostly 3D Printed Loco kits etc.

SCC Price list (7/4/22)
https://www.sparkshotcustomcreations.co ... e77d42.pdf

craig_whilding

Re: Converting a Dapol Class 22 to P4

Postby craig_whilding » Fri May 04, 2012 5:33 pm

Knuckles wrote:Ver interesting indeed. :) What you said about the keeper plate is kind of the same experience I had with the Heljan Hymek. Please answer a question though; what was the brass wire inside the wheel for? I've read it a few times but the penny is still in the money tree. :(


Makes the stub axles live which is how Dapol do the pickups (ie no wipers). In DCC i'd probably try to do a couple of spokes to get more cross section for the electric to go through though you do have multiple wheels as paths anyway.

User avatar
jjnewitt
Posts: 323
Joined: Sat Jan 02, 2010 5:04 pm

Re: Converting a Dapol Class 22 to P4

Postby jjnewitt » Fri May 04, 2012 9:22 pm

Nice work Captain. I like the way way you made the axles live, very neat.

Those close ups of the drivetrains are interesting. I hadn't seen the actual pickup arrangement before and it's good that they've used proper bearings on them. Hopefully the Westerns will be pretty much the same as these.

I've seen on forums a few attempts to convert the Dapol Class 22 to P4 and a lot of effort seems to be put into them simply to keep the split axle pickup arrangement. I can understand why people might like split axle pick ups but I wonder if it wouldn't save a lot of hassle simply to change the pickups to a more conventional system with wipers? I certainly wont be trying to preserve it in the Western. The idea of split axle sprung bogies makes my head hurt! :)

User avatar
Will L
Posts: 2516
Joined: Sun Jul 20, 2008 3:54 pm

Re: Converting a Dapol Class 22 to P4

Postby Will L » Fri May 04, 2012 9:35 pm

jjnewitt wrote:.. The idea of split axle sprung bogies makes my head hurt! :)


I don't know, I've always thought that CSBs and split axles pick-ups might work together quite well.

Will

craig_whilding

Re: Converting a Dapol Class 22 to P4

Postby craig_whilding » Fri May 04, 2012 9:50 pm

jjnewitt wrote:I've seen on forums a few attempts to convert the Dapol Class 22 to P4 and a lot of effort seems to be put into them simply to keep the split axle pickup arrangement. I can understand why people might like split axle pick ups but I wonder if it wouldn't save a lot of hassle simply to change the pickups to a more conventional system with wipers? I certainly wont be trying to preserve it in the Western. The idea of split axle sprung bogies makes my head hurt! :)


It could be done if the sideframes were isolated maybe by soldering them to the main frame with double sided copperclad? Normal split chassis spacers would probably have issues with the bearing pads.

Mind I don't have issues with my sub £50 Dapol 22 as it was one without a motor and worms in so needs a new system anyway. One shame with the Dapol 22 is that the gear casing is quite large and square underneath spoiling the open nature of the prototype. I'd have hoped they could have come up with an inverted V of gears to avoid that.

User avatar
jjnewitt
Posts: 323
Joined: Sat Jan 02, 2010 5:04 pm

Re: Converting a Dapol Class 22 to P4

Postby jjnewitt » Mon May 07, 2012 6:10 pm

craig_whilding wrote:It could be done if the sideframes were isolated maybe by soldering them to the main frame with double sided copperclad? Normal split chassis spacers would probably have issues with the bearing pads.


I've had a think about it and have taken some paracetamol and it shouldn't be too difficult to do. Simply saw all the way down the middle! With appropriate non conductive material attached to the bogie spacers to provide the gap of course. You'd have to make sure that the bolster plate was insulated from the metal chassis block if it came into contact with it. You could attach the motor leads to the bolster plate as the current would pass through the secondary suspension and you wouldn't have any wiring to the bogie at all! Maybe I'll give it a go one day. Not sure how it would work on Ian's system though.

A sub £50 Dapol Class 22 sounds good Craig! Even without motor etc. I'll look forward to seeing how you go about motorising it.

Whilst thinking about split axle pickup on bogies I wonder if anyone who leans in that direction has "done a Dapol" on a Bachmann diesel? It shouldn't be too difficult as it has the brass bearings in the drivetrain to transmit the power through. The Bachmann drive gear could perhaps do with being a tiny bit wider to act as the sleeve but perhaps it would suffice? Just a thought.

User avatar
Simon_S
Posts: 134
Joined: Wed Aug 06, 2008 7:32 am

Re: Converting a Dapol Class 22 to P4

Postby Simon_S » Thu May 10, 2012 9:56 am

jjnewitt wrote:
craig_whilding wrote:Whilst thinking about split axle pickup on bogies I wonder if anyone who leans in that direction has "done a Dapol" on a Bachmann diesel? It shouldn't be too difficult as it has the brass bearings in the drivetrain to transmit the power through. The Bachmann drive gear could perhaps do with being a tiny bit wider to act as the sleeve but perhaps it would suffice? Just a thought.


That's pretty much what I did with my quick and dirty Bachmann 2EPB conversion: Bachmann 2EPB P4 Conversion

User avatar
jjnewitt
Posts: 323
Joined: Sat Jan 02, 2010 5:04 pm

Re: Converting a Dapol Class 22 to P4

Postby jjnewitt » Thu May 10, 2012 2:15 pm

Simon_S wrote:
jjnewitt wrote:Whilst thinking about split axle pickup on bogies I wonder if anyone who leans in that direction has "done a Dapol" on a Bachmann diesel? It shouldn't be too difficult as it has the brass bearings in the drivetrain to transmit the power through. The Bachmann drive gear could perhaps do with being a tiny bit wider to act as the sleeve but perhaps it would suffice? Just a thought.

That's pretty much what I did with my quick and dirty Bachmann 2EPB conversion: Bachmann 2EPB P4 Conversion


That's exactly what I had in mind! I hadn't seen your thread on the 2EPB. Nice work Simon. As I intimated in my previous post the only thing that worried me a little was if there was enough width on the drive gears for them to act as split axle sleeves but assuming you haven't had any issues with the driven axles(?) the answer must be yes.


Return to “Diesel and Electric Locomotives”

Who is online

Users browsing this forum: No registered users and 0 guests