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Storebro Brucks
Öronmaskiner 185-GK lathe

Earlier Ornmaskiner Lathe


Manufactured during the 1950s and early 1960s by Storebro Brucks in Sweden, the Örnmaskiner 185-GK 7.25" (185 mm) centre height by 30", 40" or 60" (760 mm, 1000 mm, 1525 mm) between-centres lathe was a popular model both for toolroom and general workshop use.  Typical of this long-established  maker of fine quality tools (and reflecting design elements common to both its era and country of origin),  it was of absolutely conventional design but beautifully-made; marketin in the United Kingdom was by Startrite, a company well known for its own-make and factored bandsaws and drilling machines - but not precision centre lathes.
Braced by thin diagonal ribs, the deep V-and-flat ways bed was hand scraped and hardened as standard; a detachable gap section was optional and, when removed, allowed a piece of material 19.75" in diameter and just over 8 inches thick to be turned on the faceplate. The lathe was carried on a heavily-built, fabricated steel stand with a deep (non-removable) chip tray with one cupboard for tool storage and another to house the standard-fit coolant pump and tank.
Driven by 4 V-belts from a 2-speed, 2.5/3.5 h.p. motor bolted to an adjustable plate on the back of the bed (later models had a 5 h.p. Motor and a Poly-V belt), the headstock was of simple construction with the rather narrow hardened and shaved steel gears running in a splash oil bath that also fed the double-row roller bearings of the 1
9/16" (40 mm)-bore spindle. For the lathe's capacity and mass the chosen spindle nose size on early versions - an American long-nose taper in a L00 fitting - was really too small, and might be contrasted with the larger and more useful LO fitting of the (6.5-inch centre height) Colchester Student. Later versions of the lathe were upgraded to an L0 fitting. The eight spindle speeds were controlled by two concentric gear-change levers on the face of the headstock and an electrical (off/low/high) switch below and to the right of them; the speeds ran from a usefully low of 35 rpm to a rather slow maximum of 1055 rpm. Headstock spindle-speed electrical switchgear was neatly to hand, with the coolant push-button well out of easy reach on the tailstock-end face of the stand.
Carriage power feeds were driven by a separate slotted power shaft that turned a worm and wheel gear set; feeds were selected and engaged by a single control positioned centrally on the face of the apron with the longitudinal feed taken through a safety-over-load friction clutch.
From the headstock the drive down to the sliding-tumbler, Norton-type screwcutting and feeds gearbox went through a two-speed sliding gear (within the headstock), a tumble-reverse mechanism and a set of demountable changewheels. The box provided 36 inch pitches from 4 to 60 t.p.i and 11 metric from 0.5 to 7.7 mm without altering the changewheels - with a further 5 metric pitches available if one gear was changed. The 36 longitudinal feeds ranged from 0.00394" to 0.06299" and 36 cross feeds from 0.00197" to 0.0315" all per revolution of the spindle. The 1.125-inch diameter leadscrew was threaded 8 t.p.i and a thread-dial indicator was fitted as standard.
Although the cross slide was a proper full-length type (so obviating the uneven slide wear caused by the more common and cheaper half-length type) on some models instead of its thrust face being the usual solid fitting on the face towards the headstock the designers (unaccountably) used this to mount the push-screw adjusted gib strip; quite why they wanted to allow a proportion of the cutting forces to pass through screws onto a narrow (flexible) metal strip is a mystery. Other machines from Ornmaskiner have been found with the screws correctly fitted to the other side of the slide - and later models had tapered gib strips.
Fitted as part of the normal equipment supplied with the lathe (Model 185-GK/1) was a quick-change toolholder with a central block that fitted over a 4-way split boss that could be expanded by a tapered bolt (this system being used on earlier Ornmaskiner lathes as well. Although the standard toolpost was able to take three tools at once, another (slightly cheaper) option was an ordinary 4-way toolpost (again, fitting over the expanding boss). Both top and cross slide were fitted with "balanced" handwheels and rather-too-small zeroing micrometer dials.
With a set-over base. The tailstock had a 6-inch travel barrel with a No. 3 Morse taper, a useful micrometer dial fitted to the handwheel and could be locked to the bed with one turn of the rear-mounted handle.
In addition to the already-mention coolant equipment and quick-change toolpost the lathe was supplied with an SKF bearing rotating centre, 11.5-inch diameter faceplate, travelling steady, two dead centres, spanners, test certificate and an operator's handbook. Approximate weights for the various models were: 30-inch 1456 lbs;  40-inch 1624 lbs; 60-inch 1792 lbs..

Örnmaskiner 185-GK 

Visible in this picture are the cross slide gib-strip adjustment screws positioned, unaccountably, on its forward-facing thrust face.

The screwcutting gearbox provided 36 inch pitches from 4 to 60 tpi and 11 metric from 0.5 to 7.7 mm without altering the changewheels - with a further 5 metric pitches available if one gear was changed. The 36 longitudinal feeds ranged from 0.00394" to 0.06299" and 36 cross feeds from 0.00197" to 0.0315" per revolution of the spindle. 

As an alternative to the quick-change toolholder an ordinary 4-way toolpost could be supplied at a slight reduction in cost (Model 185-GK/2). Both top and cross slide were fitted with "balanced" handwheels and rather-too-small zeroing micrometer dials.

The headstock was driven by 4 V belts from a 2-speed 2.5/3.5 h.p. motor bolted to an adjustable plate on the back of the bed

The deep-section V-and-flat ways bed was braced by diagonal ribs, hand scraped and hardened as standard; a detachable gap section was optional and, when removed, allowed a piece of material 19.75" in diameter and just over 8 inches thick to be turned on the faceplate.


The internal construction was simple with the rather narrow hardened and shaved steel gears running in a splash oil bath that also fed the double-row roller bearings of the 19/16" (40 mm)-bore spindle.

Fitted as part of the normal equipment supplied with the Model 185-GK/1 was a beautifully made and very expensive quick-change toolpost by "Bergström", whose central block was, very handily, able to hold three tools at once.

This version has the cross-slide gib strip screws on the correct,
right-hand side of the slide. Later versions used a tapered strip



Earlier Ornmaskiner Lathe

Storebro Brucks
Öronmaskiner 185-GK lathe

E-MAIL   Tony@lathes.co.uk
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