Chamfering Square Brass

[EmilioG]

I've been making these simple 3/4" square brass parts that I would
like to chamfer. What is the best way of doing this? See attached photo.
I'm using 8 mm SHCS on each end. These parts are 1 1/2" to 1 7/8" long.
AS you can see, these are not radii. A radius will leave sharp corners on a square part.
Lathe?
Thanks

 

[JimDawson]

I would use a lathe for the ends. The other edges could be done on a belt or disk sander if extreme accuracy is not required.

 

[mikey]

I would do the ends on a lathe, too. The sides could be done with a chamfer end mill in the mill if you need more precision for some reason.

 

[mzayd3]

I would do the whole thing on the lathe. Or do the chamfers have to be straight?

 

[ogberi]

I'm guessing you mean the ends of the square stock, and not the edges of the square stock (the square faces, not the rectangular ones). I'm also guessing that you'll be turning the part on the lathe, either in a 4 jaw chuck or in a square collet.

Looks like a darn good excuse to grind yourself a form tool.
If you're not terribly picky about how perfectly rounded the chamfer has to be, you could free-hand grind a lathe tool to the proper shape.

Or, if you have some non-hardened square tool steel, clamp it in the vice and use and endmill of the desired curve diameter to cut the curve. Grind your reliefs (tilting the workpiece a couple of degrees so the endmill cuts a slanted hole in it is a lot more accurate and faster), then harden, temper, and hone. Being brass, you can get away with no rake. Make sure you got a good hold on that tool in the toolpost. Form tools tend to want to chatter like *CRAZY*

If that doesn't work for you, you can grab a corner-rounding endmill in the toolpost and use it like a form tool. In a pinch, you can use a carbide router bit instead of the endmill. I'd be a little leery of the interrupted cut on a carbide tool, but it is brass, and a small effective diameter, so I wouldn't think chipping would be as big of an issue as it would with steel.

A ball turning jig is another option.

And last but not least, a belt sander would do it pretty darn fast too. But it'd be prettier if you use a form tool of some sort.

 

[EmilioG]

Thank you all.
I'd like to chamfer the long sides as well.
A good friend has agreed to do this work for me
since I don't have a lathe. The side chamfers and the ends
need to be symmetrical and straight. I'll learn from what he does
then try a few with scrap parts. Thanks.

 

[Wreck™Wreck]

It appears that you have a mill but not a lathe, use a boring head like so.

Cut blanks in saw.
Mill ends to length.
Set up a vice stop (or better yet mill a vice soft jaw to hold part), center spindle on part, drill and tap each end.
Grind HSS or carbide tool to desired angle, install in boring head and set a Z stop, chamfer each end.

Putting the chamfer on the corners of the square stock will be a fourth operation with a suitable milling tool, a 90 degree countersink would work fine. Deburr and you are done.

If you want to save time grinding the tool buy the correct diameter HSS or carbide round tool blank that already has the ends split from somewhere like McMaster and you will only have to grind the angle and relief as needed.