email: tony@lathes.co.uk
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Mitsubishi HL300-Ua Lathe
If any reader has a Mitsubish lathe, or technical publications about them, the writer would be interested to hear from you


Apart form cuddly toys and marmalade is there anything that the giant Japanese Mitsubishi Group has not manufactured ? Amongst the company's machine-tool range in the 1960s was this 350 mm swing by 500 mm between centres (13.75" x 19.5") toolroom lathe of impeccable quality - a type of machine that would eventually finds its way down the second-hand supply chain into the workshop of the smaller jobbing engineer - or even that of the more ambitious home enthusiast.
292 mm wide (11.5") wide, the bed was not quite equal to the swing (the "test" of a toolroom-class lathe), but more than adequate to ensure a firm foundation for the 15.75" long saddle to run on.
With a 35 mm (1.375") bore, the headstock spindle ran in two Timken Type 0 precision tapered-roller bearings and a double-row, cylindrical-roller bearing and was rotated by three V belts, the pulley running in its own bearings with the drive transmitted through a keyway. Pressure lubricated from a large oil reservoir within the cabinet base, the headstock bearings were cooled by the constant flow of oil, the arrangement helping to combat any tendency for the spindle to expand when run at high speeds for prolonged periods. The nose of the spindle carried a No. 5 Morse taper bore (with a sleeve down to 3 Morse) and an external Cam Lock D1-5" fitting to mount chucks and faceplates.
Power came from a 5 h.p. 3-phase motor flange mounted to a speed change gearbox, the unit being mounted within the stand below the headstock. Gears were all hardened and ground, ran on shafts supported in anti-friction bearings and lubricated by a pressure pump. This remote mounting - a favourite ploy by the makers of better-class machine tools - was designed to minimise vibration from the transmission system and so aid in the task of producing the finest-possible turned finishes. The standard speed range spanned 55 to 2,500 rpm with optional higher and lower ranges of 70 to 3,200 rpm and 29 to 1330 rpm respectively. In addition to the speed-change levers on the font face of the cabinet stand, the spindle could be controlled from a switch, bracketed on the right-hand edge of the apron; moving the lever started the motor whilst a second touch stopped it through the application of a powerful electromagnetic brake.
Screwcutting and power feeds were provided by a totally enclosed, oil-bath lubricated gearbox with operation by dials--there was no sliding tumbler assembly - with thirty English pitches from 4 to 112 t.p.i., twenty-four metric from 7 to 0.25 mm pitch as well as MOD and DP available.
Substantially built, the carriage incorporated a double-wall apron which acted as an oil reservoir; an automatic pump, brought into action as the carriage moved, delivered lubricant to the apron gears and shafts, main bed ways and the sliding surfaces of the cross slide. An especially-powerful carriage lock was fitted, operated by a permanently installed lever on the right hand-side of the saddle. Power sliding and surfacing feeds were each engaged by their own lever - there being no need to operate a selector button - with each working through spring-loaded clutches - not unlike those fitted to, for example, to the American Monarch, Rivett 1020S and English CVA lathes.
To enable a large micrometer dial to be fitted (and the slide to be rotated through 360), the top slide casting was cranked up and a pair of gears used to connect the feed screw and handle - a system used a some other lathes including the well-known CZ-manufactured TOS SV-18R and its variants. A 4-way toolpost with both swivelling and indexing movements, was fitted as standard.
However, all was not perfect for, despite the wonderful quality - and no-compromise design evident elsewhere on the  machine - the tailstock was clamped to the bed by a self-hiding spanner acting on a single nut - though a useful option was offered of a hydraulically operated spindle.
Although a normal range of lathe accessories was offered, three and four-jaw chucks, faceplates and steadies, because the cross slide carried two T slots at its rear - an unusual fitting on a lathe of this size - it was possible to slide on and off a choice from two types of rear toolpost, and so enjoy (with the usual type of inverted tool), much easier parting off.
Hydraulic Copying was also available (with single, two, three and multi-cycle and in-feed attachments) that was unusual in having the slide unit mounted on the front, rather than at the rear of the carriage..

Mitsubishi HL300-Ua precision lathe 350 mm swing by 500 mm between centres (13.75" x 19.5")

Power came from a 5 h.p. 3-phase motor flange mounted to a speed change gearbox, the unit being mounted within the stand below the headstock.

With a 35 mm (1.375") bore, the headstock spindle ran in two Timken Type 0 precision tapered-roller bearings and a double-row, cylindrical-roller bearing and was rotated by three V belts - the pulley running in its own bearings with the drive transmitted through a keyway.

Unusual front mounting of the of the hydraulic copying (tracer) attachment in use


A clear illustration of the raised end of the top slide - designed to provide a usefully large micrometer dial and clearance to swivel over the cross slide dial. The two levers in the middle of the apron controlled the power sliding and surfacing feeds through individual, spring-loaded clutches - not unlike those fitted to certain American Monarch, Rivett 1020S and English CVA lathes.
The electrical switch on the right-hand side of the apron started the spindle and stopped it through an electromechanical brake.

Tailstock fitted with the option of hydraulic operation

Lever-operated two-way rear toolpost with adjustable screw stop.

Rear toolpost located in T-slots to the rear of the cross-slide

Heavy-duty 6-stud Cam Lock D1-5" Spindle nose fitting

Unusual cam-action "Work Driver"


email: tony@lathes.co.uk
Home   Machine Tool Archive   Machine-tools Sale & Wanted
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Mitsubishi HL300-Ua Lathe
If any reader has a Mitsubish lathe, or technical publications about them, the writer would be interested to hear from you