0-6-0 Mamod Locomotive.
Posted: Sun Dec 14, 2014 5:08 pm
Hi,
Miniature Steam Railway’s 0-6-0 a modified Mamod though I suspect not many original Mamod components were used.
A few evenings ago I re-read Peter Jones’s very interesting booklet titled Miniature Steam Railways. “A Brief History”. The booklet deals with the modifications done by Terry Shirley and Jim Wilson to Mamod locomotives imported into the USA.
Possibly their last prototype design was for a 0-6-0 Continental style locomotive. Peter has made a very good replica of this model. On the original MSR design the cylinders drove the centre axle; Peter sensibly drove the leading axle as per Mamod. MSR had problems with the valve events on their model as they used their standard cylinders and port block. Moving the axle further away from the cylinder trunnion to allow for the extra wheel meant that the cylinders moved through a smaller angle and the ports opened less or barely at all.
The model I have been playing with needed bits painting and a day or so drying time, so I thought I would work out what size ports would be needed to dive a Mamod 0-6-0 with centre wheel drive. So a drawing was done positioning the leading wheel close to the port block and the centre wheel as close to the leading wheel as practical. Doing this increased the standard Mamod cylinder trunnion to driving axle distance of 45mm to 67mm, this reduced the cylinders operating angle from 24 degrees to 17 degrees. The lower angle meant that the Mamod’s original steam ports of 2.2mm with lap are reduced to 1.6mm with no lap. This should work OK, so I started to make some frames to see how well it would work.
The drawings.
A new drilling jig was made using an old jig for making standard Mamod frames. A Mamod frames could have been used, only the holes that weren't to be altered were transferred to the new jig.
Another jig was made so that the angle of the cylinder port block and reversing block could be altered to suit the new position of the driving axle.
The port block jig is designed so that it can be used by lining up a centre line with the driving axle hole.
Old jig and the two new jigs.
Some recycled sheet steel were used to make some frames.
The frames will remain rectangular until it is seen how well they work.
A jig was used to position the steam and bolt holes for the cylinder using the driven axle hole as a reference.
The posion of the holes was checked.
Position of leading and driving wheels.
Frames to date.
The paint on the other project will be dry tomorrow so this playing will be put aside until some more free time becomes available.
Regards Tony.
Miniature Steam Railway’s 0-6-0 a modified Mamod though I suspect not many original Mamod components were used.
A few evenings ago I re-read Peter Jones’s very interesting booklet titled Miniature Steam Railways. “A Brief History”. The booklet deals with the modifications done by Terry Shirley and Jim Wilson to Mamod locomotives imported into the USA.
Possibly their last prototype design was for a 0-6-0 Continental style locomotive. Peter has made a very good replica of this model. On the original MSR design the cylinders drove the centre axle; Peter sensibly drove the leading axle as per Mamod. MSR had problems with the valve events on their model as they used their standard cylinders and port block. Moving the axle further away from the cylinder trunnion to allow for the extra wheel meant that the cylinders moved through a smaller angle and the ports opened less or barely at all.
The model I have been playing with needed bits painting and a day or so drying time, so I thought I would work out what size ports would be needed to dive a Mamod 0-6-0 with centre wheel drive. So a drawing was done positioning the leading wheel close to the port block and the centre wheel as close to the leading wheel as practical. Doing this increased the standard Mamod cylinder trunnion to driving axle distance of 45mm to 67mm, this reduced the cylinders operating angle from 24 degrees to 17 degrees. The lower angle meant that the Mamod’s original steam ports of 2.2mm with lap are reduced to 1.6mm with no lap. This should work OK, so I started to make some frames to see how well it would work.
The drawings.
A new drilling jig was made using an old jig for making standard Mamod frames. A Mamod frames could have been used, only the holes that weren't to be altered were transferred to the new jig.
Another jig was made so that the angle of the cylinder port block and reversing block could be altered to suit the new position of the driving axle.
The port block jig is designed so that it can be used by lining up a centre line with the driving axle hole.
Old jig and the two new jigs.
Some recycled sheet steel were used to make some frames.
The frames will remain rectangular until it is seen how well they work.
A jig was used to position the steam and bolt holes for the cylinder using the driven axle hole as a reference.
The posion of the holes was checked.
Position of leading and driving wheels.
Frames to date.
The paint on the other project will be dry tomorrow so this playing will be put aside until some more free time becomes available.
Regards Tony.