not sure if this is the right place to ask

Signed-In Members Don't See This Ad

trapper

Member
Joined
Jan 17, 2011
Messages
163
Location
united kingdom
:befuddled::befuddled::befuddled:I need to make a hexagonal recess in the end of a metal bar does anyone have any ideas how i can do this...... if it was wood or acrylic I could cope. I dont have suitable milling or casting facilities
 
Signed-In Members Don't See This Ad
Odd shaped holes -square, hex, etc- are usually accomplished with a broach.

An expensive tool to buy for only a single hole, but maybe you could find a local small machine shop to do it.

A more advanced way would be with EDM machining, something which is in the reach of hobbyists if you make your own (it isn't that hard to do it on a workable scale, try an Internet search). Again, you might find a small machine shop with the equipment to do it.

There's also the possibility of finding with a hex hole already in the end of it -maybe some kind of drive shaft- and using that.

Depending on the size and depth you need, you also might be able to drill and thread the end for an Allen head set screw and solder or braze that in place.
 
Last edited:
The answer will depend on the precision and tolerances needed, and the size.

If you can accept some rounding at the corners, a mill can remove metals but is limited by the mill diameter (which can be very small).
 
What is the metal bar made of? Steel?

I was thinking that, if it were softer than steel, you could drill a hole slightly smaller than the end result and drive an allen key into it as a punch. I have no idea if this would work, but the allen key is the only thing that I could think of that could make a hex hole.
 
What is the metal bar made of? Steel?

I was thinking that, if it were softer than steel, you could drill a hole slightly smaller than the end result and drive an allen key into it as a punch. I have no idea if this would work, but the allen key is the only thing that I could think of that could make a hex hole.


That would basically be the same as broaching it.

A regular broaching operation usually does it in several steps, each bing closer to the finished form, rather than in a single one.
 
Thanks for the thoughts so far guys, What I'm trying to do is make a section that can take micro tool bits....... these are 3.5/4mm across flats rather than apen or fountain pen set up the metal is copper,or brass or aluminium.
I'll let you know how I progress
 
Thanks for the thoughts so far guys, What I'm trying to do is make a section that can take micro tool bits....... these are 3.5/4mm across flats rather than apen or fountain pen set up the metal is copper,or brass or aluminium.
I'll let you know how I progress

Oh; That is much easier. Drill a hole in the end of the bar to hold the bit. Drill two small holes from the side and tap for set screws. Clamp the bit into the end of the bar with the set screws. You could also epoxy glue the bit into the end of the bar, but if it gets very warm, the glue could loosen. Soldering or brazing could also work.
 
Thanks Randy,
Simple is alway best I guess. But point well taken. Me thinks I have work to do tomorrow (yeah I know it's Sunday but what an excuse to avoid the mall and christmas shopping but don't tell her indoors!!!!! Merry Christmas
 
Broaching a hex update

Ok guys firstly thanks all for the responses.
This is how I'm progressing with the project.
I've decided to abuse some old allen keys, or is that wrenches,

What I am doing is maching crocodile teeth in the allen key across opposing flats. The allen key so cut is then being tapered (approx1.5-2 degrees toward the front of the tool. The teeth provide as it were castlelated cutters on opposing sides.

The tool is then held in the tailstock vis either a mandrel holder or a chuck.

The work piece will be held in the headstock chuck and drilled to fractionally under the af measurement of the tool.Without the lathe being
turned on The tool is forced through the softer metal workpiece so cutting the hex hole.:bulgy-eyes: Thats the theory:rolleyes: so time to try it will report back
 
Back
Top Bottom