Roxey Return Crank

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Hardwicke
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Roxey Return Crank

Postby Hardwicke » Thu Jan 26, 2023 6:58 am

Is it possible to use the Roxey Mouldings Return Crank on P4 wheels such as Gibson and Ultrascale? Shaman's might need the fitting adapting.
Ordsall Road (BR(E)), Forge Mill Sidings (BR(M)), Kirkcliffe Coking Plant (BR(E)), Swanage (BR (S)) and Heaby (LMS/MR). Acquired Thorneywood (GNR). Still trying to "Keep the Balance".

davebradwell
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Re: Roxey Return Crank

Postby davebradwell » Thu Jan 26, 2023 9:24 am

Perhaps if ew knew what a Roxey return crank was we might be more able to help.....

Gibson and Ultrascale wheels use different crankpin systems so the answer will likely be different in each case.

DaveB

Philip Hall
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Re: Roxey Return Crank

Postby Philip Hall » Thu Jan 26, 2023 10:38 am

The return cranks on the Roxey website are Markits ones, intended for
Romford axles. I have a vague feeling (might be wrong) that Mr Whittle (Barrowroad) of this parish may have used those on conversions, but only he can advise...

Philip

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45609
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Re: Roxey (Markits) Return Crank

Postby 45609 » Thu Jan 26, 2023 12:15 pm

AFAIK Robin uses the crankpins but discards the actual return crank from Markits because it is grossly overscale. As you say Phillip, Robin can confirm.

Morgan

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barrowroad
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Re: Roxey Return Crank

Postby barrowroad » Thu Jan 26, 2023 4:42 pm

I have used Markits return cranks converting a number of Bachmann RTR models notably the Jubilee and Patriot but also other models.
I only use the crank pin section of the pack and not the return crank as they are overscale for my purpose.
See my post in my 'barrowroad' workbench:-
viewtopic.php?f=139&t=6944
for details.
I now use Markits deluxe crankpins on the front and rear drivers and not the stainless steel ones used in this post.

Robin

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Hardwicke
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Re: Roxey Return Crank

Postby Hardwicke » Thu Jan 26, 2023 8:59 pm

Thank you all. I was taken by the four retaining bolts as the etched effort I have on a kit is rather ahem...lacking detail.
Ordsall Road (BR(E)), Forge Mill Sidings (BR(M)), Kirkcliffe Coking Plant (BR(E)), Swanage (BR (S)) and Heaby (LMS/MR). Acquired Thorneywood (GNR). Still trying to "Keep the Balance".

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Hardwicke
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Re: Roxey Return Crank

Postby Hardwicke » Thu Jan 26, 2023 11:09 pm

I can't really believe no one makes a decent return Crank.
Ordsall Road (BR(E)), Forge Mill Sidings (BR(M)), Kirkcliffe Coking Plant (BR(E)), Swanage (BR (S)) and Heaby (LMS/MR). Acquired Thorneywood (GNR). Still trying to "Keep the Balance".

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PeteT
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Re: Roxey Return Crank

Postby PeteT » Fri Jan 27, 2023 11:06 am

There is an Alan Gibson casting which is good, however I think the problem is that the return crank length is related to the throw so it isn't a one size fits all solution.

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grovenor-2685
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Re: Roxey Return Crank

Postby grovenor-2685 » Fri Jan 27, 2023 12:44 pm

The problem with return cranks, IMHO is having a reliable method of fixing them at the correct angle, Hornby and Bachmann do try but their solutions are usually sloppy. Most kit providers including AG and Ultrascale make no real attempt. The Markits de-luxe looked to be a possible solution spoiled by being noticeably oversize.
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davebradwell
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Re: Roxey Return Crank

Postby davebradwell » Fri Jan 27, 2023 1:00 pm

If the return crank is too chunky then the eccentric rods will slope inwards which looks strange. 00 wheels are too narrow so they need a hefty crank to avoid rods sloping out. Our coupling rods are usually further apart than the prototype anyway so with a chunky big end on the conn. rod it's easy to run out of room. I suppose the rtr conversions with their thin rods are easier.

There's websites dealing with valve gear design for the live steamers and the return crank length is one of the easier bits to work out. Yes, it's dependent on the main crank throw so if your wheels aren't correct an adjustment will be desirable.

DaveB

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Horsetan
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Re: Roxey Return Crank

Postby Horsetan » Sat Feb 04, 2023 6:32 pm

Frankly a lot of Markits machined stuff is oversize. Might be alright in "S" scale or 7mm.
That would be an ecumenical matter.

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Hardwicke
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Re: Roxey Return Crank

Postby Hardwicke » Mon Aug 14, 2023 8:12 pm

Bought one at Railwells. The picture by Markits shows an LMS one with 4 bolts, but the packed ones only have 2. Fortunately the SR ones were correct for my need. I will be removing the overscale 00 bush.
IMG20230814210152.jpg

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Ordsall Road (BR(E)), Forge Mill Sidings (BR(M)), Kirkcliffe Coking Plant (BR(E)), Swanage (BR (S)) and Heaby (LMS/MR). Acquired Thorneywood (GNR). Still trying to "Keep the Balance".

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Hardwicke
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Re: Roxey Return Crank

Postby Hardwicke » Mon Aug 14, 2023 11:34 pm

Would it be possible to drill out the bush in a lathe and reduce the 00 depth? This way I keep the hexagon heads at the expense of losing the threaded spigot. What does everyone think?
IMG20230814211244.jpg
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Hardwicke
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Re: Roxey Return Crank

Postby Hardwicke » Wed Aug 16, 2023 3:56 pm

If I were to reduce the length of the Markits bush would it need retapping? The spigot end can fit into the 14BA crank pin hole and the other end turned or filed back. This way the beautiful four assembly bolts in the hexagonal head can be used again.
The only other overscale part is where the return rod fits. Normally on a model this is a rivet instead of a nut and thread. Should I re-use the threaded bolt or rivet it?
Ordsall Road (BR(E)), Forge Mill Sidings (BR(M)), Kirkcliffe Coking Plant (BR(E)), Swanage (BR (S)) and Heaby (LMS/MR). Acquired Thorneywood (GNR). Still trying to "Keep the Balance".

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Hardwicke
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Re: Roxey Return Crank

Postby Hardwicke » Fri Aug 18, 2023 1:49 pm

If only the Markits part was to scale. It's too big even for the 14BA crank pin
IMG20230818143153.jpg

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IMG20230818143626.jpg

I think I need a 14BA die to reduce the threaded spigot as it's too long and too large and tap the other end. Alternatively and probably easier is to make a new crank pin bush altogether, to the same design but to scale.
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Ordsall Road (BR(E)), Forge Mill Sidings (BR(M)), Kirkcliffe Coking Plant (BR(E)), Swanage (BR (S)) and Heaby (LMS/MR). Acquired Thorneywood (GNR). Still trying to "Keep the Balance".

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Hardwicke
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Re: Roxey Return Crank

Postby Hardwicke » Fri Aug 18, 2023 4:01 pm

As a 00 item it's exquisite though. Beautifully engineered.
Ordsall Road (BR(E)), Forge Mill Sidings (BR(M)), Kirkcliffe Coking Plant (BR(E)), Swanage (BR (S)) and Heaby (LMS/MR). Acquired Thorneywood (GNR). Still trying to "Keep the Balance".

Jeremy Suter
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Re: Roxey Return Crank

Postby Jeremy Suter » Fri Aug 18, 2023 5:36 pm

Hi Mike
It does look a very nice machining.
What is the diameter of the Crankpin end with a 10ba thread it looks about 3mm diameter and what is the throw?
With our wider back to back there is less room to make allowance with the valve gear. Will the Eccentric Rod not strike the milled nuts of the Eccentric Crank on the way past as they protrude further than the bearing surface of the crank, so you either need to inset it slightly or file them back.
Last edited by Jeremy Suter on Sat Aug 19, 2023 8:09 am, edited 1 time in total.
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nigelcliffe
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Re: Roxey Return Crank

Postby nigelcliffe » Fri Aug 18, 2023 7:46 pm

Those cranks are a nice bit of work, but they are strictly 00. Used on EM or P4 the whole valve gear gets out of line, and out of loading gauge as well.

I had a set to do an EM conversion of a Hornby loco, didn't use them because of the size. Made my own crankpin so it could take the Hornby return crank and still be in the correct place.

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Hardwicke
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Re: Roxey Return Crank

Postby Hardwicke » Sat Aug 19, 2023 2:31 pm

Jeremy Suter wrote:Hi Mike
It does look a very nice machining.
What is the diameter of the Crankpin end with a 10ba thread it looks about 3mm diameter and what is the throw?
IMG20230819150847.jpg

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IMG20230819151626.jpg


IMG20230819151709.jpg

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IMG20230819150814.jpg

Will the Eccentric Rod not strike the milled nuts of the Eccentric Crank on the way past as they protrude further than the bearing surface of the crank, so you either need to inset it slightly or file them back.
IMG20230819151114.jpg
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Ordsall Road (BR(E)), Forge Mill Sidings (BR(M)), Kirkcliffe Coking Plant (BR(E)), Swanage (BR (S)) and Heaby (LMS/MR). Acquired Thorneywood (GNR). Still trying to "Keep the Balance".

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Hardwicke
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Re: Roxey Return Crank

Postby Hardwicke » Sat Aug 19, 2023 2:36 pm

Just to keep the photos paired..
IMG20230819151610.jpg

IMG20230819151626.jpg
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Ordsall Road (BR(E)), Forge Mill Sidings (BR(M)), Kirkcliffe Coking Plant (BR(E)), Swanage (BR (S)) and Heaby (LMS/MR). Acquired Thorneywood (GNR). Still trying to "Keep the Balance".

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Hardwicke
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Re: Roxey Return Crank

Postby Hardwicke » Sat Aug 19, 2023 2:37 pm

Scalefour News wasn't even out of it's bag...
Ordsall Road (BR(E)), Forge Mill Sidings (BR(M)), Kirkcliffe Coking Plant (BR(E)), Swanage (BR (S)) and Heaby (LMS/MR). Acquired Thorneywood (GNR). Still trying to "Keep the Balance".

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Hardwicke
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Re: Roxey Return Crank

Postby Hardwicke » Sat Aug 19, 2023 2:53 pm

Wider end of the crank
IMG20230819151709.jpg

IMG20230819151724.jpg
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Ordsall Road (BR(E)), Forge Mill Sidings (BR(M)), Kirkcliffe Coking Plant (BR(E)), Swanage (BR (S)) and Heaby (LMS/MR). Acquired Thorneywood (GNR). Still trying to "Keep the Balance".

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Horsetan
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Re: Roxey Return Crank

Postby Horsetan » Sun Aug 20, 2023 11:07 am

The more I look at that, the more it looks suitable for 7mm scale.
That would be an ecumenical matter.

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Hardwicke
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Re: Roxey Return Crank

Postby Hardwicke » Sun Aug 20, 2023 2:12 pm

Horsetan wrote:The more I look at that, the more it looks suitable for 7mm scale.

If only he did 3mm or 2mm cranks.
I'm not talking about the modellers themselves :D
Ordsall Road (BR(E)), Forge Mill Sidings (BR(M)), Kirkcliffe Coking Plant (BR(E)), Swanage (BR (S)) and Heaby (LMS/MR). Acquired Thorneywood (GNR). Still trying to "Keep the Balance".

Crepello
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Re: Roxey Return Crank

Postby Crepello » Mon Aug 21, 2023 10:23 am

I find it hugely frustrating that Markits invested a gobsmacking amount into a very sophisticated machine tool, produce a bewildering range of items which could make our lives easier, but for the fact that they are almost 'freelance' designs. "Inspired by" their prototypes I suppose.

As his range grew, I had wondered how he managed to do the prototypical research over such a broad canvas. That's left up to us, after which we may decide what we've bought isn't suitable after all.


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