Making Ball Handles.


This page explains one method for making ball handles like the one shown on the right. This example handle was a saddle lock for the ML7 lathe.

 

 

 

 

 

 

 

 

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To create a handle with the right proportions the diagram on the left can be used.

If the dimension of the larger ball is know (D), then the other dimensions can be calculated as a proportion of this.

Alternatively, if the length of the handle is known then the other dimensions can be calculated because the length is approximately three times the diameter of the large ball.

The other useful dimension is the one shown in green. This makes it easy to the get correct 20 angle for the lever.

 

 

 

 

 

 

 

 


  

In this example the lever length was 60mm and so the large ball at the base of the lever would be 20mm and the small ball 2/3rds of this.

As the lever was short it was made in 2 pieces with the small ball at the tip of the lever being a separate part screwed in place.

The first step was to chuck a blank piece of bar long enough to machine the large ball and the arm of the handle, plus a thread to attached the small ball.

A profiling and parting-off tool was used to recess a section of the bar. The reduced section was long enough to fit the head of the spherical turning tool. The larger diameter piece of bar on the end was left long enough to create the large ball. 

 

 

The other end of the bar was centre drilled.

 

 

 

 

 

 

 

 

The spherical turning tool was used to turn a 20mm sphere out of the end piece of the bar.

Using the ball turning tool

The finished ball

 

 

 

 

 

 

 

 

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A collet like the one shown on the left was used for the next few operations.

Again the dimension are given in terms of 'D' and are approximate. This design also assumes that with the small ball fitted to the handle, the total handle length still falls inside the chuck radius.

The length of the collet was designed to be a reference surface for the facing cut which would create the base of the handle.

 

 

 

 

 

 

 

 

The collet was used to chuck the sphere just turned and the free end was supported with a centre in the tailstock.

 

 

 

 

 

 

 

 

In this setting the arm of the handle was finished parallel to its largest dimension. Also the reduced section at the end was turned ready for a thread to attached the small ball.

If you have a taper turning fixture for your lathe then this can be used to taper the handle. If not then the top slide can be used, set over by about 2.

Finally in this setting the tail stock support was removed and a 32tpi thread was added to the reduced section.

 

 

 

 

 

 

 

 

The small ball was turned by taking a piece of bar large enough and drilling and tapping it to match the thread on the handle.

Then this blank was screwed on to a piece of threaded bar the ball turned to its final dimension.

To finished the ball it was placed in another simple collet and a flat turned to make it a snug fit on the handle.

 

 

 

 

 

 

 

 

The handle assembled

 

 

 

 

 

 

 

 

The handle was returned to the first collet and held by the larger end. In this setting a flat was turned and a hole drilled and tapped to take the clamping rod.

It was found that because the large ball was not exactly spherical the grip from the collet was not that strong, but with the chuck tightened firmed and using only light cuts, it was satisfactory.

 

 

 

 

 

 

 

 

The collet was designed so that in the Myford chuck it would provide both a datum surface for this facing cut and also provide the correct angle for the handle with the small ball resting against the face of the chuck.

 

 

 

 

 

 

 

 

To finished the handle it was fitted with a rod threaded to suit the Myford lock cam (5/16th BSF, 22tpi).

 

 

 

 

 

 

 

 

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