Square peg in a square hole

[WolfieParticipant @wolfie]

Ok heres one. How the hell do I drill a square hole??

 

A blind one too. OK I could see the method of putting a file through a round hole and filing it square but that ain’t gonna work for a blind hole.

[WolfieParticipant @wolfie]

[Gray62Participant @gray62]

I think the best way to go for this is with an EDM machine. There are many designs out there ranging from the simple to the ludicrously complex.

 

Another solution is to use a slotting device in your lathe, Hemingway do a kit for such a device and with a little ingenuilty one could be produced without castings.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Wolfe, there was an artical in ME issue 4285 vol 197 which you can view on the digital archives if you are a subscriber.

 

Regards Nick.

[NJHParticipant @njh]

Hi Wolfie

 

Go to All topics at the top of the page and enter “Square Hole” in the” keyword box” of the Search for: strip. You will find this subject has been discussed exhaustively!

 

Cheers

 

Norman

Edited By NJH on 04/02/2011 00:26:45

[chris stephensParticipant @chrisstephens63393]

Hi Wolfie,

First of, what do you need a square hole for? There is an easy method using inserts but it depends on the final use as to whether it will work for you.

chriStephens

[John OlsenParticipant @johnolsen79199]

Depends partly how big the hole is too. For nice small ones, you may be able to get away with drilling a round hole, then driving in a square cutter, made from a piece of HSS. Just grind the end a bit so that the corners stick out a little, then line it up and drive it down the hole. This should be OK up to about a quarter inch square. There will of course be a bit of a daggy bit left in the corners.

 

There is a technique with a sort of triangular drill guided by a square plate.The drill has to be in a floating holder so it can get into the corners. It can’t actually produce a perfect square but is close enough for practical purposes. I haven’t tried that one myself, but it has been in hte ME more than once over the years.

 

Then you can make a square hole that goes right through a round piece by filing, then braze the whole piece into a round hole in the job.

 

regards

John

[WolfieParticipant @wolfie]

I need to make something to wind a clock thats lost its key, so quite small.

 

Actually on reflection I don’t suppose it has to be blind… Mind you I don’t have any files that small.

Edited By Wolfie on 04/02/2011 08:05:10

[Anonymous]

If the part can be mounted in a lathe (which I guess a clock key could be) try a rotary broach:

 

http://www.littlemachineshop.com/products/product_category.php?category=1274803839

 

Caveat: Never used them myself!

 

Regards,

 

Andrew

[Michael Cox 1Participant @michaelcox1]

If you want to make a clock key then I think you could easily form it. For example, if the key is 2 mm square it has a circumference of 8 mm. Take a piece of thin wall tube with about the same internal circumference = 8mm/PI =2.5 mm. Tap a piece od 2 mm square bar into the tube and it should deform the tube to a square shape. It will be a tight fit and to remove it then gently hammer the external faces of the tube and the 2 mm bar should come out. Then braze or solder a handle on the square tube. You may have to anneal the tube during the forming operation to prevent it splitting.

I have made hexagonal steel sockets by this means – see:

http://mikesworkshop.weebly.com/nibbler.html

Hope this helps

Mike

[NJHParticipant @njh]

Ah Wolfie

 

I know it may go against the grain of this forum but for a clock key I wouldn’t consider making one. They are readily available in pretty much any size you may need and certainly for much less than you would pay for any specialised “square hole cutting tool”

 

Try here :-http://www.m-p.co.uk/

 

Regards

 

Norman

[DMBParticipant @dmb]

SMEE stand @ an XBN. possibly within last couple of years, they were demonstrating a method of making square holes in round bar. I think it involved milling out a `trench` down one side, deep enough to end up central in bar then filling in outer edge with a piece silver soldered in, leaving a square hole in the middle. This would `do` for larger jobs requiring strength. Just mentioning this for future ref if anyone needs a strong job, but above method with deformed tube should be sufficient for clock winding.

[chris stephensParticipant @chrisstephens63393]

Hi John,

That would be my little display that you saw.

 

Wolfie, have to agree with NJH, although easily made there are occasions when it is better to buy, unless you need an excuse to “play”. If you are going to play, as Clock keys are often made from Brass, drilling deep and filing would work well enough.

chriStephens

 

[Richard ParsonsParticipant @richardparsons61721]

The problem with drilling square holes is that the holes are not truely square. They have round corners’

[Ian S CParticipant @iansc]

A good many years ago I made a device for winding clocks that involved a quite large reduction ratio, and just today I was visiting the son of the chap I made it for, so I had a look to see how I had done it, and found that I had used the method advocated by chriStephens, the slot was either 5/32″ or 3/16″ cant remember which, doesnt matter now, but it worked well, the old boy had quite a number of clocks. He was an electrition, should have collected electric clocks, would have saved the winding.  Ian S C

Edited By Ian S C on 05/02/2011 10:51:52

[PolygonParticipant @polygon]

Wolfie, what size is your hole?

 

At Polygon Solutions Inc. we make a rotary broaching system which will create square holes with sharp corners in metal parts up to about 1″ diameter in through or blind holes. The tools work on lathes and mills, but will realistically only broach to a depth about 1-1/2 times the diameter.

 

Learn more at http://www.polygonsolutions.com or see our video:

 

http://www.youtube.com/watch?v=uTsPXFy7Xx0

 

Edited By Polygon on 07/02/2011 16:31:20

[NJHParticipant @njh]

Very interesting Polygon – but not a very cost effective solution  to produce just  one clock key!

Edited By NJH on 07/02/2011 16:57:44

Edited By NJH on 07/02/2011 16:58:05

[PolygonParticipant @polygon]

Great point! I tend to lean towards high production mentality. Some machinists have used the broaches by themselves as more of a punch or shaper. This gives you a precision form, but saves on the larger cost of buying the toolholder. I guess if you do small projects like this regularly the cost of the toolholder would make more sense.

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