Drilling a Square Hole

Okay TP45, what have you been smoking?

http://www.youtube.com/watch?v=305vRNoofr8

Good one .........

http://en.wikipedia.org/wiki/Watts_Brothers_Tool_Works

Oh yeah - their address is:

760 Airbrake Avenue, P.O. Box 335
Wilmerding, PA , 15148-1014

yes they would.

When my kids were young they each had a Spiro-graph set. I then used to keep them busy for hours drawing nice patterns on scrap paper.

Later when I became lazy I gave them an A3 pen plotter with a program on a XT and they could just punch in some numbers and draw whatever they wanted. I used a multi rod model where the cam ratio, length and side of each rod could be changed. Watching this plotter at work was even more addictive than CR4.

I am sure I saw some shapes that could pass as square holes.

My proposal for drilling a square hole is for the triangle rotor on a Wankel is replaced by a blade or a square cutter.

Maybe a laser on a CNC will be better.

Tanks Kris - Now do something with the corners.

Where and when can I place an order ?

Hee hee ! The cunning bit is that you also have a smaller set-up to refine the corners, then when you've done that you have an even smaller set-up and......

There is another way to refine the corners that can be done in two setups. Drill four small holes with a diameter twice the corner radius of the wobbler with the centerpoints at the theoretical corners of the square, then use your wobbler drill at the center of the square. You'll end up with a 3/4 round relief in each corner of the square. This will also serve to act to remove the stress riser that will result in a square corner.

The other thing you could do is to break the corners of the mating part.

how will you put the cutting edges for the drill in the wankel piston???

Wouldn't the cutting edge be on the end face similar to a slot drill or end mill?

hmmm.. so we have to use an open case wankel right.. i get the picture.. so we design the grill in the shape of a wankel piston and eccentrically mount it.. thats it.. thanks

Hiya, Hendrik,

How are things going on your side of the pond?

Are they still making the A3 Plotter? Who makes it? I've been looking for one for years. Any help would be appreciated.

Thanks

/Ari (Orpheuse)

I have an E size sheet fed inkjet Summagraphics that has never been used (stored in a container for ages.) that you or anyone else is welcome to come and get.

Ha ha ha.. lolz... if you really had been serious about this discussion try an electro discharge machining or electro chemical drilling.. or use wires.. i think you can do it with discharge machining... no traditional machine can do it..

I agree - a spark eroder for example does wonders but it is not effective on plastic or wood. The approximate result of traditional methods must sometimes be accepted because of economics.

By the way have a look at #2.

i can just say that an student of mechanical engineering student of our collage has Deon this thing. he has made an machine to drill a square hole and has also applied for its patent

if he had really done it without rounded edges then thats a really great thing.. i would like to know how and may be can at least get an abstract of his paper..

OK. An explanation.

The "Guests" got it. Several times in my work, I've wanted a square hole and couldn't figure out a way to do it (and, in fact, incorrectly argued that it couldn't be done!). Just recently I ran across the answer, less than ten miles of my home. Watt Brothers Tool in Wilmerding, PA has been making drills for square and hexagonal holes for about a century. Given their location, I assume they started to serve either Westinghouse Airbrake or Westinghouse Electric.

I ran across these fellows because of a recent book review which talked about a method for actually completely squaring the corners with a floating chuck. When I saw that I could make a pun, I posted.

Sparky was excluded since he is arguably the best Googler in our solar system and, with the time difference (NZ is either 10 hours behind or 2 days ahead of the US), he would have posted the answer first.

Being 2 days ahead he could have replied before you posted the question.

That's not so hard. My wife does that all the time.

I seen them as a kid, and didn't want to spoil the fun.

Kind of counter intuitive but cool.

Brad

Somewhere in the shop we have an EDM:

http://en.wikipedia.org/wiki/Electrical_discharge_machining

Amazing how precise it is.

Coincidentally, I plan to take a hike to Airbrake Falls, right now, with a little experiment I spun up in the cellar.

oh yeah.. my choice was EDM and there are sevral types too.. they all do magic man.. really kewl...

Liquid laser, laser, morticer all drill square holes depending on your definition of drill, but the politicians solution is much easier, redefine square and use any old drill.

Simon

If you wus a real man cat you'd drill a round hole and then file it square....
Then you'd post post pictures of your blistered hands.
I remember when I was a lad...blah...blah..once filed...blah..from ...London to Macclesfield...blach..blah...needle file....blah...nothing but...blah... and a piece of cheese.

Del (sorry I'm rambling ..it's a wet Sunday....)

Have you been on holiday? Someplace where they serve only whiskey and milk?

We used to Broach our components on hydraulic broaching machine for square holes, internal splines etc.

Been out laying pavers and posting concert pix on my web site, I see that del has broached the broaching subject...

My favorite source for this (rotary or wobble broaching)would be Somma tool :

http://www.sommatool.com/manuscripts/broaching.asp

These folks are personal friends and great tool makers.

milo

any of the following methods can be used

• punching - if the job is not thick & size of the hole is at least 1.5 t
• nibbling - suitable for thin sheets with large hole
• broaching
• EDM - spark erosion/ wire cutting
• laser cutting
• water jet machining

If drilling in masonry you could use an electrical box sinker.

A selection can be found here:

http://www.screwfix.com/cats/A237679/Drill-Bits/Electrical-Box-Sinkers

In woodworking, there is a attachment for a drill press that has a conventional twist drill rotating inside a square chisel/broach with windows cut in the sides for chip clearance. it is called a mortising attachment. Works fine for soft materials like wood or plastic. It would never do for steel unless you had some kind of hydraulic assist on the headstock feed.

I had heard of the wobbler drills for squares and hexes but had never seen one, and I'm not sure I ever knew who made them. Now I know... Thanks TVP45!

Square link.

More Rotary Broaching on YouTube.