Tubalcain's Toolmaker's Clamps

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


I have done up a drawing here http://www.dgphotoworks.com/tubialcainstoolmakersclamp.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.

 

[kvom]

Two of these clamps were my very first machining project at votech school. I had to single point the threads though. These are quite useful from time to time. I've been thinking about making some half-size ones.

 

[Hopper]

Nice little project and lovely old South Bend lathe you got there. I made a set of these at tech school 40 years ago and still use them today. Very handy for model sized work indeed. Another handy one is the toolmaker's vice, aka sometimes as a pin vice. It is basically the same thing but one jaw is left a couple inches longer on the back end, so it can be held in the standard bench vice while the small piece of work is gripped in the toolmaker's vice jaws for fine work to be performed.

 

[doug gray]

Continuing with the jaws…


The jaws are for the most part, straight forward drill and tap jobs. A letter “O” drill is a close clearance for 5/16” and a letter “I”drill is used to tap 5/16-24 UNF. Once the holes are drilled the angled nose can be layed out. Make sure the angled portion is layed out in the correct orientation to the holes.

A wooden jig is used to help position the jaws in the mill vice. The 16 degree angle is not critical but the jig will help ensure all the jaws are the same.

Once the jaws have been shaped we can turn our attention tothe clip. The clip is probably the most challenging part of the project. Thedrawing calls for 1/8” x ½” brass or steel, the closest thing my scrap box hadwas ½” x ½” aluminum.

When planning out how to machine these little clips Idecided to try the old face plate/crazy glue trick as per Myfordboy’s great videos. First I reamed some 3/8” holesin my stock.

next off to themill to shave the stock down to 1/8"

next I made a new surface plate for an old dog drive plate i have. I bored a 3/8" hole on centre in the surface plate. a 3/8" rod held in the tail stock allowed me to glue the work exactly on centre.

once the glue set I was able to bore the 1/2" diameter recess.

The glue held with no issues and yet the work pops right off when given a good stout wack. This was mt first time using the glue/face plate trick and I found it works great.




A little trim and the clips are ready for mounting.

that's all for now
Till next time

 

[Wizard69]

Nice work so far! What you really need to do is to make an entire set. I find smaller variants to be extremely handy.

 

[doug gray]

Thanks Wizard, this pair is fun to make .. not sure about a entire set.

 

[Wizard69]

Thanks Wizard, this pair is fun to make .. not sure about a entire set.

It can start to feel like production type work! I've just found that sometimes a tool makers style clamp that iron the smaller size is very handy!