Raglan Little John Mk.2 Bench Lathe - Post 4 - Present status as since June 2011

 (Updated, Feb 2013)

This is our Raglan Little John Mk.2 Bench Lathe. Its serial number is 1617. It is presently located at the Nuclear Engineering Department of the School of Mechanical Engineering at the National Technical University of Athens (NTUA). Date of manufacture is unknown and may be only estimated by the serial number to approximately 1949 or 1950. The lathe and some of its accessories were internally donated to the Nuclear Engineering Department by the Physics Department of NTUA in 1999. As far as it is known, this lathe has been in NTUA's premises since the 60's or even earlier. Between the 70's and the 90's the lathe was in storage because the Physics Department decided to replace it  with more modern equipment. Presently, and after some absolutely necessary maintenance, the lathe processes  light metal or acrylic pieces and it is being taken care of by Nick P. Petropoulos.
A front view of the lathe is depicted below:

1. Little John Mk.2 Bench Lathe on custom stand

Lathe custom stand is an original woodwork piece from the late 50's as per NTUA's equipment inventory and records. The stand might not have been designed for this particular purpose, however it serves the purpose quite well. The Little John has been securely bolted to the stand. A slight disadvantage is that, on this stand, the final height of the lathe  is something like 5-6 inches more than it should be for proper machining, when the machinist stands on the workshop floor. A palette -barely seen under the stand- has been employed to provide for a more appropriate working position of the machinist.

The lathe has not a gearbox for thread cutting; changewheel is employed for this purpose. The next figure presents the changewheel side of the head stock after some serious cleaning.

2. Headstock changewheel side

The black arrow on the photo indicates a gear that had to be replaced due to broken teeth. The gear was constructed gratis in external CNC works,  following the suggestions and connections of Dr. Th. Kostopoulos, NTUA's Machine Elements and Dynamics Professor. It has to be mentioned at this point that, practically (and unfortunately), no one cuts gears in imperial units in GREECE any more.

To our discomfort, it had been decided that the original Continuous Variable Transmission (CVT) of the lathe had to go. It was judged to be quite old to keep and maintain in working condition plus lathe has a lot of idle time, which makes it impractical to check CVT every other day. The picture below presents the new motor pivot system; view is  from the right.

3. New motor pivot system (view from the right)

The pivot system was assembled from simple materials, mainly 10mm thick metal plates, some 3/8" bolts and some hinges. Drilling, bench and filing work was necessary for  putting all these together and meet the scope. The internal lay-shaft assembly had to be dismantled and modified, but we managed with the assistance of the experienced senior machinist of the Physics Department Mr. K. Razakias (now retired). The modification was made so that a 3x3 pulley system using standard pulleys could be attached on the lay-shaft replacing the CVT. Pulleys and some adjusting machining were purchased at "Tsokas pulleys" in Piraeus, Attica (www.tsokas-machinery.gr). It goes without saying that all bearings were replaced. It should be noted that bearings equivalent to the originals still exist in the GREEK market at a reasonable cost of 40 to 50 EUR (*, see at the end of this post). It was chosen to use bearings with seals, in order to practically eliminate the need of lubrication. The fully assembled 3x3 pulley system is demonstrated below.

4. New 3x3 fully assembled pulley system

The pulley combination presented on the photo permits the lathe to run @ approx. 450 rpm. This is just OK for most applications in our Department. A closer look may be seen below.

5. Internal lay-shaft assembly close-up

Two more pulleys, with successive smaller diameters, to the left of the big one, cannot be seen. Moving the belt to the other two positions would allow for the lathe to run @ 750 and 1150 rpm respectively. Further note, that a part of the rear of the lathe headstock had to be cut, for the new arrangement; it was a lot of not-that-easy hand sawing. Some of the cutting was done using a small angle grinder. Pulley lay-shaft was put in place, just barely (no room for big movements in there). To do this, lathe was elevated using a workshop crane, so that to exploit the underneath free opening.

6. Leather belt for the pulley system

A leather T-belt was used for the power transmission. It is up to the task, however, plans are that it has to be replaced soon with a synthetic one. Following the above mentioned changes, belt protection lid had to be severely modified; it is not that protective anymore.

7. Belt protection lid

Other plans are that a Variable Frequency Drive will be employed to adjust rpm without too much of a fass.

8.  CVT adjusting lever still in place

The CVT adjusting lever was kept in place. Future plans are that it will be used for a transparent perspex chip shield.

9. Head and tail-stock paintwork visual

Left gear cover and tail-stock have been repainted by hand pretty close to original color . Cover and tail were the most weathered parts of all.

The following pictures add some visual of the whole system from other points of view.

10. Motor is original (3-P, 380V)

11. Other Little John view

12. Other Little John view

(*) contact me if you need more information on the two lay-shaft bearings


Rights and citations

Copyleft protects this post. This means that you may freely copy and distribute this content but please do not change it. If you, in the process, find that something in this post is inappropriate or wrong, please contact me at my e-mail. I would be more than happy to update the post. You are more than welcome to site this post in your own texts, blogs or whatever. If this is the case, please use more-or-less the following citation format:

Petropoulos, N.P., "Raglan Little John Mk.2 Bench Lathe - Post 4 - Present status as since June 2011", 2013; add URL; add access date.

Any citation will be much appreciated.