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In Focus: The MM305i Flange Facing Machine


The MM305i is the smallest of the Mirage internal mount flange facers. This pneumatically powered machine can be used for a wide range applications such as of flange facing, seal grooving, weld preparation and counter boring. Let’s take a closer look at the specification and how it works.

What flange sizes can the MM305i be used on?

The equipment supplied as standard can be used for machining of flange diameters from 2” up to 12”.  However, it’s also possible to reach diameters smaller than 2” using a bespoke tool attachment. (See our previous blog post).

Mounting and Installation

The standard base can be used when mounting into flange bores of up to 9”, but for smaller bores of less than 120mm diameter and down to 50mm, the supplied collet assembly should be used.

Installation of the standard base follows the same procedure as for other ID mount flange facers. Setting straps are used before the machine is clamped in top position and then adjusted using the jacking bolts. The setting straps are then removed before the machine is used.


Above: (Top) Base assembly shown with setting straps and (Bottom) the Collet assembly


The MM305i is supplied with 2 lead screws with pitches of 1.25mm and 1.75mm.  Each can be used with the Fine and Coarse feed settings to achieve the grooves per inch shown in the table below. An additional feed screw is available as an option to achieve an extra fine finish of 224 grooves per inch.


Boring Feeds

For boring operations, the machine can be used with the striker attachment which can be positioned either side of the star wheel. This enables the toolpost to be fed either down or up. This feature is used when machining RTJ faces.


Above: Striker attachment used for boring feed.

Options and accessories

Additional options and accessories include: a 1.5” collet base assembly, an end shaft turning kit and a Lens Ring Machining Kit.


As with all other Mirage flange facing machines, the MM305i can be used in a non-horizontal orientation by balancing the machine using the supplied counterweights.

Weights and swing diameter

Although robust in construction, at 16kg machine and 8kg base assembly are both light enough to be lifted and installed by hand.

How much space do you need?

To operate the machine, you will need sufficient space to accommodate the swing diameter of 15.4” (390mm).

For more information on the MM305i or to request a quotation, please get in touch with your nearest Mirage regional representative here.

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