Cutting a hex head

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Whenever I contemplate making things with hex heads the formula I use is:

hexagonal stock = happiness

LOL Tim, VERY good point and strangely, one I hadn't thought of.

Thank you Bob I'll check it out.

What's this for? Do you have a lathe and mill? Do you have one of those inexpensive spin indexes?

The math: The distance across the poins of a hex is 1.1547 times the distance across the flats. The distance across the flats is 0.866 times the distance across the points.

I've made lots of special bolts/fittings with hex heads. If you are after a specific distance across the flats to fit a wrench, start with a round a few thou smaller than the distance across the points to avoid sharp points. Subtract distance across the flats from the diameter of the round and mill half that off at 0, 60, 120, 180, 240 and 300 degrees. You've got a hex head.

I could send you a couple pictures if that isn't clear.

Take a night school course to bring your math up to at least high school graduation level and you'll have all you need. What's more you'll wind up understanding where the formulae come from. Makes it much easier to remember.

Ted

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WAIT A MINUTE!! _Hex_ head, i.e., hexagon. Think of it as 6 equilateral triangles assembled around the center. Chord/flat = radius of circumscribed circle.

Bob

Whenever Im near a "drop" pile..thats the first stuff I zero in on.

Gunner

"To be civilized is to restrain the ability to commit mayhem. To be incapable of committing mayhem is not the mark of the civilized, merely the domesticated." - Trefor Thomas

I find "Engineering Formulas" by Kurt Gieck a good book - it is pages of pictures and the formulas. Other pages are tables of the various sciences - statics, dynamics, hydraulics, heat.... Geometry arithmetic.....

It is a bit much for general - it covers that and then much more. A small pocket book - hard cover. isbm 0-07-023203-2

Martin

I use the $50 indexer with the proper collet to hold the part, placing it in the Bridgeport vise horizontally. Zero indexer. Measure the diameter of your "head" of your part, assumption is that's it's round.. Subtract the required hex dimension. Divide remainder by two. Touch down on part with endmill turning to establish a relative zero. Cut a little off of at least two opposing sides of the head and remeasure to get a more accurate baseline. Zero knee and mill away , rotating indexer to new position each cut. When dimension is reached, remove part and lathe the corners off, or touch them on a belt sander if this is acceptable. Another way is to reset indexer and use the mill to nip the corners.

RJ

Subtract the diameter of the bolt from the distance across the flats of the hex size you want. Divide by two, which gives the step on one side from the shank to the flat of the hex. Mill two parallel surfaces where the hex will be to the number obtained earlier, a depth or step mic are handy for this. Now for how I cheat, take a large hex nut, set it in you mill vice (with one of the hex surfaces against the bottom of the vice, you may need to use parallels) and hold one of you new hex surfaces against the hex and clamp it in. Now it is set to machine at sixty degrees to form another flat on your hex. Repeat as necessary.

I know the guys who want to drag out their indexers and make a thousand calculations will blast me. BUT a hex bolt is not precise. Grab a bunch off the shelf and mic them, none are very accurate. Measure a variety of combination wrenches they are not close either. This is just a quick and dirty way to create a hex that will work. Neal

Yes but if you need a particular size, it's a lot easier to turn a 1" round into a 1/2" round than to turn a 1" hex into a 1/2" hex.

Ted

Which is why I try to keep a good supply of everything on hand.

Gunner, Master Scrounger "To be civilized is to restrain the ability to commit mayhem. To be incapable of committing mayhem is not the mark of the civilized, merely the domesticated." - Trefor Thomas

Indeed that is my rule. Always have plenty of....

Stuff.

All neatly catagorized, but, umm, Hmm.

Seems to be catagorized in a fairly random orientation. But it *is* stuff!!

Jim

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Ted