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From a 1912 Wolf, Jahn & Co. catalogue |
... and the original |
Dissasembled to show the replacement nut |
revised 15/07/09
This gadget is shown in the 1912 Wolf, Jahn & Co. catalogue and advertised for the larger larger lathes to go into the three-jaw chuck and hold 8 mm collets for small work. It is equally useful as a hand-held collet holder. I got it with a box of other pieces for WW-lathes. The tightening nut is missing and I have made a new one.
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From a 1912 Wolf, Jahn & Co. catalogue |
... and the original |
Dissasembled to show the replacement nut |
Quick-change tool post tend to be expensive, but useful items. The main body of the Leinen-made one cost EUR 90 net equivalent in 1996 according to my catalogue. The inserts would have set you back another EUR 60 each. So I decided to make my own; inspired by the Leinen design. I actually made two dove-tailed slots, but this is really unnecessary, as I found that I am turning it anyway to provide clearance etc.
If the repeatability of height-setting is all what you need, then there are simpler designs; for instance a round stud clamped into the T-slot and simple slotted holders sliding on it and being tightened down with a compression screw.
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Quick-change tool holder from 1996 Leinen catalogue. |
Drawing for shop-made qc tool post and inserts (not to scale) |
click on image for legend |
Good boring heads tend to be equally expensive. Also, I wanted one that is not too heavy for use on the small mills and that has not too much off-centre mass when extended. It is made of aluminium and fits onto an 8 mm arbor with a M8 thread. It is bored for 8 mm shank boring bars etc.
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Drawing for shop-made boring head (not to scale) |
Photographs of the original | ||
The Wolf,Jahn & Co. Model A milling machine has an integrated rotary table for indexing and it is convenient to hold workpieces upright in a collet or even a chuck. for this pruposes I made a non-indexing collet-holder that can be mounted in the centre of the rotary table. It can take ordinary split collets, wheel chucks, ring-chucks, or even the three-jaw scroll-chuck. The cone on top mimics the spindlenose on the lathe for this purpose. The collets are drawn in by a nut, which can be tightened by a bar.
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Drawing for shop-made upright collet holder (not to scale) |
Photographs of the original (still needs painting) |
Using various types of collets. Also shown is the tightening bar. |
The finished collet holder mounted on the Wolf, Jahn & Co. miller. On the right a six-jaw chuck is held in it. |
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