MadModder

The Shop => Tools => Topic started by: No1_sonuk on May 12, 2011, 12:36:05 PM

Title: Corner Rounding Cutter
Post by: No1_sonuk on May 12, 2011, 12:36:05 PM

I'm after a corner rounding cutter with a wide offset (see attachment).
R can be 3/6" or 5mm.  The 25mm could go to 1".

I'll be using a 25mm end mill to cut a flat, then a concave radius, and need to round over the top.

Material being cut is aluminium.

Any suggestions on a source for such a cutter (preferably UK)?

Title: Re: Corner Rounding Cutter
Post by: spuddevans on May 12, 2011, 12:43:41 PM

I dont know of a cutter that would do both sides in one pass, but if you are able to make the rounding over in 2 passes you can use a carbide wood router bit to cut Ali, just up the rpms a bit. Rounding over router bits are available in many different radius'.



Tim

Title: Re: Corner Rounding Cutter
Post by: No1_sonuk on May 12, 2011, 12:58:09 PM

The point is it needs to swing at that radius to go round the corner.
See attachment - I want to round over the area in red.

Title: Re: Corner Rounding Cutter
Post by: Jasonb on May 12, 2011, 01:53:15 PM

Clamp it to a rotary table with the centre point of your corner located over the table ctr and then you can use any OD tool to roundover the curved part bu cranking the table through 90deg, the two straight runs can be done beforehand.

Trying to do it all with one cutter is likely to give a lot of chatter unless you have a heavy mill.

Jason

Title: Re: Corner Rounding Cutter
Post by: No1_sonuk on May 12, 2011, 02:25:27 PM

It's a good idea, but the radius is a couple of inches along a 13-inch workpiece.  That might be too much to be swinging about.
I also need to do it on the other side, and underneath - 4 places in total.

My mill is an SX3.

Title: Re: Corner Rounding Cutter
Post by: Jasonb on May 12, 2011, 02:44:05 PM

Even if it were in the middle you have plenty of throat depth to swing that size about, just make sure you set it up so the 11" end does not hit the column. As the bit being machined is close to the tabel ctr there should be no problem. It just needs some carefull setting up to ensure the centre of the curve is concentric to the table axis

Title: Re: Corner Rounding Cutter
Post by: djc on May 12, 2011, 03:36:30 PM

Buy a rounding over cutter of the correct radius, but any available diameter and mount it in a boring head. Adjust radius of boring head to suit.

Title: Re: Corner Rounding Cutter
Post by: No1_sonuk on May 13, 2011, 07:56:28 AM

Thanks, djc.
That is an option I had considered (and will probably use), but wanted to explore other options first.

Title: Re: Corner Rounding Cutter
Post by: Pete on May 13, 2011, 05:02:42 PM

http://www.use-enco.com/CGI/INPDFF?PMPAGE=170&PMITEM=890-8852

Are you looking for corner cutting endmills?

Title: Re: Corner Rounding Cutter
Post by: No1_sonuk on May 13, 2011, 05:58:35 PM

Yes, and no.
The cutter I'm after would have an o/d of 1 3/8 inches - not at all normal.