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Harold Hall

A few notes

Whilst I have stated above that the tool holder could be made using just a lathe I do include a drilling machine in that. However, it will be quicker, and a little easier to make, if a milling machine is available and I am therefore using one in the methods that follow. I will at the end, make some suggestions as to how tasks can be moved to either the lathe or the drilling machine.

 

The design and manufacturing methods have been chosen to minimise the need for precision, but whilst there are few dimensions that are critical there is a need for repeatability, the manufacturing methods have therefore been selected so as to easily achieve this aim.

 

Working Sizes

The tool holder has been made for use on a Myford Series Seven but will no doubt be suitable for other similar size lathes with only minor changes, if any. It would not though be overly difficult to scale it up, or down, for larger or smaller lathes should that be necessary. Some important dimensions will no doubt help the reader to determine if the holders as drawn will suit, or if changes will be necessary.

 

Lowest height of the cutting tool mounting surface.   5mm above the top slide

Amount that the Tool Holder can be raised. 7mm (easily increased)

Maximum cutter tool shank size. 12mm

The amount the tool holder can be raised can easily be increased by increasing the height or the Body and the Locating Key, or just the key. Screw H3 will also need to be increased in length. However, when using small shank sizes (6mm and 8mm) I have produced some spacers, 60 x 10 x 2mm, to place under them, avoiding the need to raise the holders beyond the limit .

 

If making them, then the first decision the reader will have to make is to decide how many holders are to be made. This being because it will be so much easier, and quicker, to make them all at the same time. Of course, it is far from impossible to make further holders at a later date should you find a need for more.  Personally, I would suggest 12 as a minimum number, being the number I have made. I would have made more but I still have the original base and holders that can be brought into use for the rarely used cutters.

 

Material

I would suggest that you use 230M07 steel (as per the drawings) for both the base and the holders as this is so much easier to machine than the more common square sections in 070M20.

      

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