Tubalcain's Toolmaker's Clamp

[doug gray]

Here is a great little weekend project. These Toolmaker's Clamps are supper handy to have around the shop and are fun to make. I made a pair.


These are based on the video series by Tubalcain found here [ame="https://www.youtube.com/watch?v=1tRgONkbEdM"]YouTube[/ame]


and part two [ame="https://www.youtube.com/watch?v=SYWHjK22eVU"]YouTube[/ame]


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I have done up a drawing here http://www.dgphotoworks.com/tubialca...akersclamp.pdf
also available in the download area.




I started with the screws. There are two types of screws, they are virtually the same but have a couple of different features. Both types start with about 4 3/4" of 1/2" diameter stock.The first lathe operations are to centre drill one end and knurl about 1"on the other end. Tubalcain recommends a "pinch" type knurler and I agree completely. The push type
knurler I own is far to hard on the spindle bearings of my 1928 Southbend 13". Surprisingly even shallow knurling does provide quite a good grip on the screw head.





The next operation is to turn down thes screw shank to 5/16" diameter in preparation for threading. I chose to hold the work by the knurl in a collet and use a live centre in the tailstock.

Next we would like a small taper on the end of the screw stock to provide an easy start for the 5/16-24 UNF die. I found the easiest method was to use a file and a half centre.

The tailstock quill can be used to help ensure the die starts square to the screw shank. Just keep pressure on the die with the quill and turn the die handle by hand.

Once the die has started I re-installed the live centre and used my spindle handle to complete the threads. The spindle handle is a shop made device that clamps inside the spindle bore and provides an handle for threading. I was able to do two turns forward and a quarter turn back (to clear the chips) all the way, right up to the shoulder.

The photo below shows handles for the Southbend 13 and for my Taig lathe.

When the threading is complete the centre drilled end of the shank needs to be trimmed. Below is how I chose to hold the work. The threaded brass arbor is held in a collet and a jam nut created to lock the screw inposition.

collet arbor and jam nut in use

Next time I will startr on the jaws.