Square holes

[firebird]

Hi

How do you, sorry, how does one make a square hole. 1/4 inch (6mm) and above I imagine drill a hole then file it out. I'm thinking 1/8 inch (3mm) and below???

Cheers

Rich

 

[greenie]

A broach is the normal method for thick material.
A punch is the easiest for thin material.
The preferred method is governed by the quantity of holes that are required.

 

[firebird]

Hi

I'm planning on making the small wheel handles on steam valves which require square holes. I wont be making that many so expensive tooling is not viable. You can buy them, not all that expensive but I would like to have a go myself.

Cheers

Rich

 

[Mcgyver]

filing works. for a really crisp job, the other method to consider is building it up. take a piece of round brass, mill out a slot at one end then solder a ceiling on it. you now have a square hole. if you carefully cut the slot so it was centre in a piece of round stock, put in a collet and turn the OD. part off, and solder or loctite into a matching hole you;ve made in the hand wheel. I've made square cutting progressive broaches, but it would be a challenge in this size. the other idea is make a single step broach that doesn't cut a full square but cuts four corners into the round bore, it'll work but won't like quite the same as a full square hole.

here's a pic of some home made broaches, sq one is 3/16 iirc

 

[4156df]

A method that uses the lathe crossfeed and a homemade broaching tool is described on this site:
http://www.modelenginenews.org/. Click "Resources" on the left column, then "How To ?", then "How to Broach Square Holes".
I've not tried this technique, but it looks like it would work.

Dennis

 

[firebird]

Hi

Thanks guys. Some good ideas to work with there.

Cheers

Rich

 

[tel]

The Forzit method works for the occasional job. Drill the round hole, file it out pretty close and then force a HHS toolbit of the appropriate size thru it. Bench vise will do a credible job of this. And for hex holes, a slice of Allen key, cut of square and with a little pilot turned on it will make a very tidy job.

 

[Cedge]

Here's a little tool I've been considering making from a spare bit of tool steel I have laying about.

It comes in 5/16 and 3/16 sizes from MICROMARK.COM

Steve

 

[raggle]

If I may jump in with my first post I would suggest the following. Drill the hole slightly oversize and grind a tiny shaper tool to hold sideways in the toolpost and rack in and out of the hole. Treat each corner as a separate cut, and if you used a 4-jaw when you drilled it a clamp on each jaw in turn provides easy indexing.

Needs a bit of ingenuity to set height and limit of the cut, but I'd think it was repeatable for short production runs. Once you've mastered that you're ready for keyways. I think the method is in Sparey's book "The Amateur's Lathe".

Ray

 

[BobWarfield]

How about a shaper attachment for your lathe to facilitate square holes and keyways?

I've always liked the idea. Here is one such:

It simply uses the compound together with a hand linkage so you can run the tool in and out repeatedly.

Cheers,

BW

 

[tel]

I made one of those years ago Bob. It works fine, but is a bit of a fiddle, as you have to strip the feedscrew out of the topslide to mount it. A better design is a smaller, self-contained one that carries it's own handle and simply clamps down in place of the tool holder. I'll big it out and take a pic at the first opportunity.

 

[old-biker-uk]

Here's some I made earlier (to quote a famous UK kids TV programme)

For the small handwheel I just pushed the broach through in the vice using a couple of short tubes as spacers.
This is the result for a triangular hole, 5/16" sides:-

.
The broach made for this was really too short with insufficient taper so the hole was made by a combination of broach & file.
The hole was for this centre hole divider.

Mark

 

[Mcgyver]

nice work as always Mark, you've got that Victorian flair

 

[Circlip]

So yer mate don't jump down me throat again Rich, If you get a piece of Silver Steel (Drill Rod) and machine it to the size of the square you need, turn a location spigot the same diameter of the root hole in the handwheel onto the end of it, harden and temper and squeeze it through the blank.
If you imagine the tool that Cedge has posted but using the end that's supposed to fit in the drill chuck as the cutting end, with a slight undercut.
Regards Ian

Turn a round peg to create a square hole :big:

DOH, sorry Tel, mines the English version.

 

[firebird]

Hi

I like that idea Ian. For a one off job that sounds the easiest. For a small run I like McGivers idea of milling a slot, filling in then parting off. When the time comes I'll try both ideas. Making up an attachment for the lathe looks good but I don't think it would get enough use to justify the time it would take to build one, maybe later.

Cheers

Rich

 

[tel]

nice work as always Mark, you've got that Victorian flair

He has, hasn't he. It's beautiful work.

 

[steamer]

I have a keyway slotter that fits on the tool post. I'll try to take a picture.


Dave

 

[baldrocker]

Ummm
How about a square file in a jigsaw.
BR

 

[4156df]

nice work as always Mark, you've got that Victorian flair

Beautiful work, Mark. I for one would really like to see a post on how you do your decorative brass turning.

Regards,
Dennis

 

[Circlip]

Rich, you would find more uses for the "Slotter" than you think. Regard it as a mini SHAPER. You also use it when making dial graduations
Regards Ian.