Cutting an Hexagonal hole

[MuzzerParticipant @muzzer]

I recently got some prices for a rotary broach through Alibaba or AliExpress (I forget which). These are still prices you have to sit down for, so I reckon a workshop project would be well justified and really, they aren't exactly complicated.

However, rotary broaches aren't a form of black magic. The process mentioned at the start of this thread (forcing a sharpened and hardened hex key into a hole is achieving the same result. The difference is that rotary broaches are simply(?) applying all of the pressure to one cutting front at a time so that the required force at any time is ~1/6 of the total (for a hex). If your press (vise?) is man enough, you could avoid a lot of expense or making a rotary broach. You could always make a set of 2 or 3 that do the job in stages.

Murray

[MuzzerParticipant @muzzer]

I recently got some prices for a rotary broach through Alibaba or AliExpress (I forget which). These are still prices you have to sit down for, so I reckon a workshop project would be well justified and really, they aren't exactly complicated.

However, rotary broaches aren't a form of black magic. The process mentioned at the start of this thread (forcing a sharpened and hardened hex key into a hole is achieving the same result. The difference is that rotary broaches are simply(?) applying all of the pressure to one cutting front at a time so that the required force at any time is ~1/6 of the total (for a hex). If your press (vise?) is man enough, you could avoid a lot of expense or making a rotary broach. You could always make a set of 2 or 3 that do the job in stages.

Murray

[Involute CurveParticipant @involutecurve]

Like I said I could make a couple I have in he past, however I wanted to buy them they are 20 quid each in the US but postage is 40 odd!! I know some people live for making such things, over the past few years I've concluded I prefer to spend my time making stuff I can't buy easily/cheaply, So yes I could spend all day making them or I could go out on the bike, its summer its a no brainer……

looks like the postman is getting a few quid…again…….. lol

[peak4Participant @peak4]

Here's an alternative method, which would require a 5 sided "drill" bit.

I can recall seeing an article on this years ago in either EIM, ME or MEW, can't remember when, or which magazine.

https://www.youtube.com/watch?v=rjckF0-VeGI

Edited By peak4 on 11/06/2016 14:56:09

Edited By peak4 on 11/06/2016 14:56:57

[Charles hirstParticipant @charleshirst60928]

Jason:

That's nice. A technique to log into ze grey cells; now where did I leave ze grey cells. anybody got some spare ones?

Charles

[John ReeseParticipant @johnreese12848]

Cluckspring video of making a square broach. Start with hexagonal bar of tool steel to make a hex broach.

Alternative: start with a long allen wrench and grind the teeth with a toolpost grinder.

[John ReeseParticipant @johnreese12848]

I have tried a number of methods for making hex and square holes. I made and used a rotary broach similar to the Wobbly. I attempted to attach a link but could not find my original source. If anyone wants drawings in DWG or DFT format (Solid edge ST8 format) just send me a personal message and I will forward the files. It is a shank type tool for mounting in the tailstock of a lathe but could also be used in the spindle of a milling machine. I made it to accept 5/16" tools because drill blanks of that diameter are readily available. I just grind the shape fron pre-hardened material.

I have also used cut off allen wrenches to punch hex holes. I strongly suggest that when using that method you provide a guide to assure a square start. Sometimes I incorporated it into the part to be machined off later. Other times it was a separate piece held against the part. All that is needed for the guide is a short bore that the wrench will slide through. The biggest problem I had with using hex punches was removal of chips. I ground a concave surface on the end of my punch. That caused the chips to be directed toward the center of the hole where they met and effectively stopped the punch. (I was punching 9/16 into steel) It was necessary to back out the punch and clear the hole before proceeding. The deeper the hole, the more difficulty with packed chips. Also I founf there will be some breakout when the punch exits the hole.

[MuzzerParticipant @muzzer]

Posted by John Reese on 12/06/2016 17:46:06:

I have tried a number of methods for making hex and square holes. I made and used a rotary broach similar to the Wobbly. I attempted to attach a link but could not find my original source. If anyone wants drawings in DWG or DFT format (Solid edge ST8 format) just send me a personal message and I will forward the files.

Hi John

I don't have access to SE any more but if you could let me have the files I should be able to import them to SW or Fusion. It's one of those projects for the future but it may be more likely to happen if I can play about with it.

I'll PM you..

Murray

[“Bill Hancox”Participant @billhancox]

Posted by Oompa Lumpa on 06/07/2014 23:28:45:

I need to cut about a dozen Hexagonal holes, about 7mm across the flats. If it was just one, for a one off I would sacrifice an Allen key, but these need to be presentable.

Graham

A short while ago I picked up some of these at a local custom auto show. **LINK**

They are easy to use and many instructional videos are on You Tube. Apparently the product will not adhere to ferrous metals but will bond to non ferrous metals such as brass, copper al etc. The solidified material is quite tough.

One of the thoughts I have had about personal uses has been to make headless threaded fasteners. I have not tried this yet, but I see no reason why it should not work.
I thought of drilling a hole of appropriate size in the end of aluminum rod to precisely hold a hex key (or Torx bit) central to the hole. The next step would be to heat the rod with a propane torch and apply the alloy around the bit to fill the voids inside the hole. When cool one could remove the bit and tidy the job up on the lathe.

Just a thought. I know you are not afraid to think outside the box.

Cheers and best wishes to Ted

Bill

[Nick HulmeParticipant @nickhulme30114]

I've CNC pocketed Torx style pockets in fasteners, for hex you can modify the corners in CAD to clear the tool corners or even go for a form of "Flank Drive" where the flats of the tool do the work in the pocket,

– Nick

[BazParticipant @baz89810]

I have recently purchased a Hemmingway rotary broaching kit, cost of around £40, as with all their kits all you need is included and clear easy to follow drawings. Made the tool over a weekend and using silver steel broaches it works very well, only tried it on steel and brass with 1/4 hex, 3/16 square and 5/32 square broaches. Plan on using it for loco boiler fittings and also to make some BA box spanners. No connection to Hemmingway apart from being a satisfied customer.

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