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Volstro Radial attachment

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Active Member
Active Member
Dec 8, 2016
Just to give some useful information on collet fitment for a Volstro Radial head attachment. Older models (fixed alignment arm) lock directly on most 3 3/8 inch spindle Bridgeport/clone vertical mills, newer models have a two part body ( bolt on alignment arm) can fit more spindle sizes with an appropriate sleeve. Older models are r8 arbor, newer models have a straight shaft that need an r8 collet installed in the mill. Four E25 collets 1/8 to 3/8 inch are standard. ER25 collets are similar enough to E25 collets to be substituted on these devices but need ER25 collar retaining nuts. E25 collets lack the groove and therefore locking/retaining ability of ER25 collets. Despite comments on another site, ER20 and ER16 will not fit my radial attachment
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