Milling Hexagons

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Ken I

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This is a hexagonal mount ER32 collet chuck I use for milling hexagons :-

HexMilling.jpg

I just open the vice rotate the hex shank and continue - accurate enough for spanner flats and hexagons. An a lot easier than mounting the dividing head or rotary table.

See also my thread on using such a cheap and nasty vice - with a bit of finessing.:
Cheap & Nasty Vice Made Good

Initially I wasn't very happy with the accuracy but there was nothing wrong with the chuck - it was my vice(s) soft jaws and lifting during clamping - once I had that sorted no further problems.
However if I am milling an accurate hexagon I will still clock each face for accuracy rather than relying on something that has been "moved" but for this sort of job is fine.

You can of course mount the hexagonal shaft in a 3-Jaw as a quick conversion to an ER-32 - but kinda negates any accuracy you might be hoping to achieve with a collet.

(I have a different collet chuck for my lathe so I've actually never tried to do this.)

See also my post from way-back on grinding small hexagonal thingummbobs :-

Grinding Hexagon Thingumybobs


Regards, Ken I
 
Last edited:
Just a further update :-
HexCollet.jpg

My "el-cheapo" vice does not hold it very well horizontally - so I added machined grooves to secure it by the corners.
The grooves are slightly down to pull it into the vice.
The qualifying spacer prevents the jaws from going out of alignment,
Works a charm

Regards, Ken I
 
I know these as Stevenson's collets. I use a depth stop on the vice to allow "same position" rotation. So far, they have worked well. As you say, quicker than a dividing head for basic jobs.
 
I've always wondered why they don't make twelve sided collet blocks for use in a milling vise, will probably make one and see how it works, one block handles both square and hex, and you don't have to try to clamp it on the points.
 
I've always wondered why they don't make twelve sided collet blocks for use in a milling vise, will probably make one and see how it works, one block handles both square and hex, and you don't have to try to clamp it on the points.
Six sided one will work as a twelve if you use the sides agains the vice walls on six of the cuts but use the six sides placed against the bottom of the vice for the other six cuts. Joe Pie taught me that.
 
They do manufacture 12 sided ER32 Collet Blocks ( Refer eBay item number:164033474721)
But I made my own.
 
Richard's set-up uses natural 90 degree machined surfaces of the vice to develop the new machined surfaces at the points of the hexagon. As accurate as the ground surfaces of the vice.
Aligning holes is less repeatable, unless perhaps with the use of screwed dowels? (a pair of dowels will form a datum at the tangent that touches both).
Clever! Thanks Richard.
Incidentally, to transfer the bottom surface of the vice to a higher position, I often use ground square carbide tools as spacers... They make excellent parallels that usually fit within the vice aperture.
K2
 
Well, I got my "extra" hex block back in July, and finally got around to putting it in the mill:

20231101 Dodecagon ER32 Block.jpeg


Now we'll see if I can keep track of what I'm doing when using it, or if I end up with a 10-sided hex!
 
I find a spin indexer a lot quicker as you don't have to keep repositioning the block in a vice, will also do 4, 8 & 12 sides. You can also leave the mill running as your hands don't come close to the cutter as they do when repositioning a block.
 
Yes, I have a SpinDexer, but the vise lives on the table and is already trammed and for putting a hex on just one part collet black are quicker. I never had issues with holding a hex block with the flats against the vise jaws and the point down, so this was mostly an exercise if calculating stock removal.
 

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