Making hexagonal/square bar, nuts and bolts, 1/2 round beading etc.

GrahamMc

Western Thunderer
Following Michael Motts suggestion about creating a thread for this subject in the Techniques section I'll start the ball rolling.
I had a need for quite a lot of hexagonal and square section of odd sizes in short lengths accurate to within a thou or so. In the end it was worth making a little jig for use in a lathe, photos below. It's just a piece of half inch steel square bar with three holes in it. One 3mm reamed hole right through (a good fit on 3mm stock rod), one tapped hole for the clamp screw that goes onto the aluminium setting section (left) and another tapped hole for the clamp (4mm threaded rod) that holds the workpiece in the guide hole.
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The two brass bits to the bottom right slide on to the rod, hex or square as required and are tightened on to it. The clamp sections were sawn off the top of a 13 amp plug prong and then soldered to a nut and a piece of square section with a hole in it. The aluminium section then tightens on the nut or square part to set the angle, see below. To change the angle just loosen off the aluminium clamp, rotate the workpiece and tighten again.

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I use it an ordinary toolpost and just screw down on to it.

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It's not too time consuming to make. All the holes are in the same plane and there are no critical measurements. You just need to get the workpiece hole parallel with a side to make setting up easy. IIRC I did it by mounting the square steel bar in the toolpost, putting that against a piece of ground bar in the lathe chuck to line it up and then drilled into the bar with a drill in the chuck. Once made it's very quick and easy to set up, a rod in the chuck and square off that to the side of the jig. It's worth it if you have a lot of this sort of thing to do.

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I use it with a milling cutter in a collet. No doubt a more refined jig could be made but it suffices for my needs. It's just as easily clamped in a vice on a milling machine. It's very easy to use, just insert a length of stock rod and shape as required.
As well as making short lengths of hexagonal or square stock it can also be used for making tiny lathe tools out of 3mm silver steel, for example for creating the groove between the square sections of some types of clack valve. Once the tool is made the jig can be used as the toolholder.
I tend to use it more for toolmaking than anything else at the moment but it was originally intended for the sort of work Giles is doing on things such as injectors. The jig was made for making longer lengths of bar to exact dimensions to be used in pattern making rather than for making representations of nuts or bolts for which there are easier ways.
 
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Giles

Western Thunderer
This is much more of a one-off bodge. Having a machine vise with a horizontal 'V', I simply soft-soldered two conveniently sized nuts onto some brass round stock on a flat surface, with 30mm or so sticking out. This was put into the vise as shown, which held it parallel and 'square'. To top surface was milled, the stock was then rotated 60 degrees in the vise, which recaptured it in exactly the same position, milled again, rotated and so on.

https://flic.kr/p/2nBiHZS
This gave nice crisp edges to the hex from which I made injector bodies

https://flic.kr/p/2nBdq6g
 

michael mott

Western Thunderer
This is another method for producing small hex nuts and bolts quickly. A piece of hex allen key the same size as the hex nut or bolt is first annealed then either drilled and tapped or turned and threaded (one can of course simply put a piece of threaded rod into the trilled and tapped hole) then the hex is re-hardened to act as a filing guide. A blank piece of threaded rod spun onto it and a few strokes of a No 4 flat file then a polish with a leather polishing stick.
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With practice one can also use a hex headed pin vice and just freehand the whole thing, by simply rotating the pin vice in the jaws of the vice, the flats of the filed nut will be oriented at 90 degrees to the flat faces of the pin vice but it doesn't matter the inportant thing is to only file on the forward stoke and lift it off and repeat count the strokes.

Michael
 

Overseer

Western Thunderer
Another method of making hex nuts or similar is to use a draw plate. Usually used by jewellery makers to make shaped wire draw plates can be purchased with a range of shapes in them. I bought this hex one from Frank Pike in Hatton Garden in about 1995. The smallest hole produces a hexagonal wire about 0.95mm across flats, starting with 1 or 1.1mm diameter wire. Using the smaller holes is straight forward, just grip the draw plate in a vice, file the end of the wire to fit through the hole, grip with pliers and pull firmly. Larger sizes take more force - larger vice and pliers.

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Not easy to photograph with the snappy camera.

The draw plate is good for making long lengths of hex that can be cut up into short lengths for inserting into cylinder covers etc. I would like a smaller diameter version but have never seen one available.
 

GrahamMc

Western Thunderer
It must get quite hard work when the dimension goes above a millimetre or so.

Indeed, but jewellers would normally anneal the wire/rod before drawing it down so making it much easier to pull. Much of the material hobbyists buy is in a work hardened condition after being drawn to that size. It's nice to work with but not suitable for drawing down again until annealed. The other thing jewellers do is use beeswax as a lubricant, just rub it along the wire/rod. Put those things together and it isn't so difficult. The holes are sized to make everything workable so you can move from size to size easily.
So, anneal first, then lubricate and give yourself the room to give a nice steady pull. The wire can easily end up twice the length it started on just one pull in the smaller sizes. After drawing it will be work hardened again making it less prone to unintended bending. HTH.

Edit. PS. Sorry forgot, mole grips/locking pliers help so you can concentrate on pulling rather than gripping and 1/2 round drawplates can be a useful cross section for beading etc.
 
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Ian@StEnochs

Western Thunderer
Another way to make 1/2 round wire fir beading is to roll it. I have a small set of pinch rollers, home made, from mild steel, they resemble a small mangle! The bottom roll is driven by handle and the top one forced against it by screws. There are a number of machined 1/2 round grooves in the top roll which shape the wire passed through. I have mostly used annealed copper wire to produce beading of whatever section I can turn in the roller. Brass does work but is harder to get to size and needs more passes and aneallings.
Sorry no photo but I am away from my workshop for the next fortnight.
Ian.
 

michael mott

Western Thunderer
I am going to pick up one of those draw plates in the morning from our local jewellery tool supplier. I have used a round plate in the past at my silver smith friends place, so this will be great.

Michael
 

michael mott

Western Thunderer
Today was delivery day I picked up my new drawplate, it was made in Italy. Range is 3mm to 1 mm
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First test with a bit of salvaged copper wire started in hole no 8 proceeded to hole number 13 the hex is .065" across the flats

Snipped off a bit and popped it into a small 3 jaw drill chuck I have set up to fit into the 1/2 inch morse taper draw collet for the Myford drilled a 1/32 hole in it and parted it off then turned down a shank and parted of the nominal bolt shape, If I cad do this with copper brass should be a breeze.
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I'll see how far i can take this.

Michael
 

michael mott

Western Thunderer
Well the brass in the smaller diameter was not quite a breeze, the difficulty is around an accurate enough chuck.
I pretty much reached the limit with the Myford using the chucks I have. The reason watchmakers have small precision lathes is even more apparent to me now.
The small nut in the front is .038" across the flats with a .019" hole the next size one up next to it is a scale 1 inch bolt in 1/32nd scale at .031" shaft with .054" across the flats. the styrene sole bar is 5/16 x 1/8th for comparison, now i can get back to working on the coach.

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Michael
 

michael mott

Western Thunderer
Using the 3 14 hole in the draw plate gives a nice hex that fits nicely into the 1/16th Myford collet chuck A .031 hole drilled into the end then parted off by slowly turning the headstock by hand and using the #08 jewelers blade in the jewelers saw the steel shaft in the tail-stock prevents the nut from taking flight never to be seen again (where all tiny bits fly away to)

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Michael
 

GrahamMc

Western Thunderer
Another way to make 1/2 round wire for beading is to roll it. I have a small set of pinch rollers, home made, from mild steel, they resemble a small mangle!....
Sorry no photo but I am away from my workshop for the next fortnight.
Ian.
Hi Ian, I'm sure I'm not the only one who would like to see this if you get the time....
 
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