Widening back to backs

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ge_rik
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Widening back to backs

Post by ge_rik » Mon Mar 30, 2020 12:11 pm

If you look closely at the sequence in my recent video where the yard shunter at Peckforton shunts off a wagon from the train, you might have noticed the loco rocks a fair bit when it traverses the pointwork. I had to edit out where it derails consistently on the king point for the station. The problem seems to be that the back to backs are slightly too narrow and so where the gauge widens by a mm or so it drops off.

The wheels are firmly held in the frames and as they are made from mdf, trying to dismantle them would probably result in irrevocably delaminating the mdf. Can anyone advise as to whether, if or how I might be able to ease the b2bs while the wheels are in situ?

Here's a photo of the chassis during construction.
IMG_7327.JPG
IMG_7327.JPG (43.83 KiB) Viewed 6094 times
.

Rik
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Peter Butler
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Re: Widening back to backs

Post by Peter Butler » Mon Mar 30, 2020 1:14 pm

Rik, if the MDF is bonded with superglue I think there is a good chance it can be separated with a sharp blade in the joints. From the photograph it appears that the axles are dropped into the chassis and kept in place by the outer housings. If so you might be able to get them out?
A test piece of scrap MDF assembled in the same manner and then separated this way could be the answer.
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Re: Widening back to backs

Post by GTB » Mon Mar 30, 2020 1:28 pm

ge_rik wrote: Mon Mar 30, 2020 12:11 pm Can anyone advise as to whether, if or how I might be able to ease the b2bs while the wheels are in situ?
For 45mm gauge, the 16mm Society recommends a back to back of 40mm, a check gauge of 41.5mm and a wheel width of 6mm. Check gauge is the back to back plus the thickness of one flange. Wheelsets with those dimensions are supposed to work OK with commercial turnouts like LGB and Aristocraft.

If your wheels are to those dimensions, then you need to check the turnout, as it may be out of gauge.

Only way I can think of widening the B to B in-situ would be to make up a screw jack to force them apart. Basically a heavy bolt and matching nut with a slot in them so they can fit over the axle and press on the back of the wheels. The pulleys and gear don't make it easy, so you'd need a short one and a longer one, but if the wheelsets were assembled by pressing, or with Loctite, they'll require considerable force to move them.

Looking at the instructions, the chassis parts interlock, so the only way to remove the wheelsets without major damage would be to excavate the bottom of the axlebox covers carefully with a mini-drill to release the brass bearings, so the wheelsets can be removed.

Regards,
Graeme

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Re: Widening back to backs

Post by ge_rik » Mon Mar 30, 2020 6:25 pm

That's useful info, thanks chaps. Not sure I have the equipment or know-how to make a screw jack. I'm hoping I can jury rig something which will do the same job.
I'll investigate whether I can get the wheelsets out which might make the process easier

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Re: Widening back to backs

Post by GTB » Tue Mar 31, 2020 11:00 am

ge_rik wrote: Mon Mar 30, 2020 6:25 pm I'll investigate whether I can get the wheelsets out which might make the process easier
If you can get the axlesets out of the chassis it will be a lot easier. You can just support the wheel on the vice jaws and tap the axle end to adjust the B to B. Use a piece of brass, or a hardwood block, if you hit the axle end directly with a hammer there's a risk of mushrooming the end of the axle.

It would be worth asking David at HGLW how the wheels are fixed to the axles, ie. press fit, Loctite, etc.........

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Re: Widening back to backs

Post by philipy » Tue Mar 31, 2020 11:10 am

I can't help with the problem any more than others have said. However it has been in my mind since you first posted the underside picture, that sooner or later the drive band will need replacing and you'll have to get the wheelsets out, so finding a way to do that will potentially kill two birds with one stone.
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Re: Widening back to backs

Post by ge_rik » Tue Mar 31, 2020 5:34 pm

Thanks chaps. I think you're right, taking the wheelsets out will be the easiest way. I think Peter's right - if I remove the axle boxes on one side then the wheels should pop out.

The b2bs are presently 38.84mm and the check gauge is 40.28mm and the wheel width is 5.4mm. So, look like I need to ease them out a mm or so.

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Re: Widening back to backs

Post by Chris Cairns » Tue Mar 31, 2020 8:50 pm

Rik,

I pointed out this Topic to David Hippey (Mr HGLW) - if you get in contact with him he will sort you out. Thank You.

When I tried to remove one of these MDF axleboxes with a sharp knife it actually shred a little (like paper) but was still re-usable. My understanding is these HGLW wheel sets are assembled using Loctite 603.

Chris Cairns

(edited to update message from David Hippey).

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Re: Widening back to backs

Post by dhippey » Wed Apr 01, 2020 2:20 pm

As Chris mentioned - Just get in touch Rik
Quickest by phone, number on the website at http://www.hglw.co.uk/contact.html

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David H.
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Re: Widening back to backs

Post by ge_rik » Fri Apr 03, 2020 6:21 pm

dhippey wrote: Wed Apr 01, 2020 2:20 pm As Chris mentioned - Just get in touch Rik
Quickest by phone, number on the website at http://www.hglw.co.uk/contact.html

Regards,
David H.
www.hglw.co.uk
Thanks David
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Re: Widening back to backs

Post by ge_rik » Sun Apr 05, 2020 3:29 pm

Thanks to David's words of wisdom I have now managed to sort out my HGLW loco. When I tested her on all my pointwork it was only two points which were causing the problem. Sod's Law dictated that these happened to be the two points leading to the timber yard where the loco resides! I tried regauging the rails, but to no effect. However, after widening the B2Bs on the loco to 40.5mm she now runs through all my pointwork without the need for a curtsey!

How did I do it?

Following David's advice, I removed the axle boxes from one side with a craft knife, and then removed both wheelsets. I then applied some heat to one wheel on each axle to soften the Loctite. I was then able to move the wheel along the axle using gloved hands. The glue remained soft long enough for me to measure and tweak until the wheel was in the right position. After cooling down, wheelsets were re-installed and the axle boxes glued back into place. I'd say the whole process took no more than around 20mins.

Thanks David. I am now even more in awe of your marvellous kits and your after sales service.

Rik
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Re: Widening back to backs

Post by dhippey » Sun Apr 05, 2020 3:52 pm

We all look fwd to updated videos now Rik.
So pleased it was easily sorted. If you have any loctite it would be worth adding a drop to lock the wheels you adjusted as the heated glue may break down over time (or just leave it until it does and fix it then :D ).

Regards,
D.

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