4. 4-way toolpost                              Author - Derek Mackenzie

The attached file is for the tool post and its' mounting plate.

Various parts in this drawing were made from Tufnol so that I could use a multimeter (set to maximum resistance sensitivity) to detect when the tool touched the bar to be machined - in practice this has proved to be an unnecessary complication - I use the same technique on my mill where it has proved invaluable (the anodisation on the mill table effectively insulates the material to be machined from the milling cutter until they both touch).

The drawing shows a plunger in the tool post locating into one of 4 holes drilled in the baseplate to locate the tool post at 90 degree intervals. This has also proved an unnecessary complication - it did not work anyway, as I drilled in the hole in the tool post in the wrong place! I now use a piece of 1/8" x 1/2" x 2" mild steel held against the side of the tool post and the baseplate to locate it - simple and effective, as long as both are the same width.

The baseplate replaces the compound slide on the lathe using the same bolts and spacing.

The drawing is for a HobbyMAT lathe, some other lathes appears to use T-slots in the cross-slide - change the hole spacing to suit. Another thing that will almost certainly require changing is the tool height - adjust the baseplate thickness to suit.

I have found it very difficult to get tools back into an exactly identical position using this 4-way toolpost - it is fine as long as you require no more than 4 different tools! I have now replaced it with a Quick Change piston type toolpost, which gives me an unlimited number of tools - or at least limited to however many tool holders I care to make for it.