From time to time, I have needed to turn a morse taper on a blank in order to make a chuck adaptor or similar and have been forced to indulge in the tedious process of setting the top slide of my ML7 to the correct angle and then even more tedious, attempt to turn the feed screw steadily in order to obtain a reasonable finish.

With the increasing availability of metric end mills, etc, on the surplus market and from the backs of lorries, the selection of metric tooling has grown of late and it became necessary to make a number of collets and end mill holders to suit – a taper turning attachment was obviously required

The attachment comprises a platform attached to the rear of the lathe bed which carries a slide adjustable to the angle of the required taper. A slider which runs on the adjustable slide is connected to the cross slide, with feedscrew removed and the cross slide is constrained to traverse at the angle of the taper as the saddle moves along the bed.

The Myford has a machined slot at the back of the bed with a series of 1/4” BSF tapped holes. The centre distance of these holes was measured with some difficulty, leaning over the bed, as 4”cc. A length of 2”x2”x1/4” angle was cleaned up with a fly cutter and carefully jig-drilled at 4” centres. To my disgust it did not fit – more careful measurement showed the holes to be at 4 1/16” centres.

The Myford attachment has a dovetail guide – since it was intended to fabricate from BMS flats a rectangular slide seemed more appropriate. A piece of 1 1/4” x 1/4” BMS was available in the scrap box but unfortunately it proved to be bent in both planes and also twisted – it took an afternoon and an evening with a scraper to correct it.

The slider was originally attached to the plate connecting to the cross slide with a solid pillar, in this form the saddle would travel only about an inch before it jammed. I could not discover the source of the misalignment and avoided the problem by dividing the pillar with a spigot and socket arrangement.

Back