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circle cutter design
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=30159		 Page 1 of 1
Author:  Chris Ensor [ Tue Nov 30, 2010 7:21 pm ]
Post subject:  circle cutter design
I am modifying Tony Karol's design of the rosette cutter. I love the original design, but wanted it to plunge. What else, if anything, would you do to this new design?
Attachment:
rosette cutter.jpg


I should mention that the plunge posts between the upper and lower bases will have springs included. I just can't draw those on sketchup.
Author:  Terry Stowell [ Tue Nov 30, 2010 7:23 pm ]
Post subject:  Re: circle cutter design
dial indicator or scale of some sort
Author:  Rick Davis [ Tue Nov 30, 2010 7:35 pm ]
Post subject:  Re: circle cutter design
Since it's basically a copy of Bishop Cochran's, you might as well add a depth stop as he has. You can see his on the Allied Lutherie site -- the depth stop is just a 3/16" steel dowel running through a hole in the upper plate (with a knurled locking screw) down to the lower plate. With a plunge set up, it's pretty important. You'll also need a lock or two on the depth adjustment. Things vibrate.
Author:  Jimmy Caldwell [ Tue Nov 30, 2010 7:48 pm ]
Post subject:  Re: circle cutter design
Rick Davis wrote:
Since it's basically a copy of Bishop Cochran's, you might as well add a depth stop as he has. You can see his on the Allied Lutherie site -- the depth stop is just a 3/16" steel dowel running through a hole in the upper plate (with a knurled locking screw) down to the lower plate. With a plunge set up, it's pretty important. You'll also need a lock or two on the depth adjustment. Things vibrate.


I have one of Bishop's router bases along with a prototype binding cutter. They are both very precise, wonderful tools.
Author:  bluescreek [ Wed Dec 01, 2010 6:31 am ]
Post subject:  Re: circle cutter design
nice gadget .
Author:  Neil Gardiner [ Wed Dec 01, 2010 8:19 am ]
Post subject:  Re: circle cutter design
I think it should definitely have a WI FI port.
Author:  RustySP [ Wed Dec 01, 2010 10:26 am ]
Post subject:  Re: circle cutter design
LED lights like MicroFence has on their plunge base.
Author:  arie [ Wed Dec 01, 2010 10:59 am ]
Post subject:  Re: circle cutter design
imo
-replace the 4 guide pins with 2 larger ones mounted on the centerline. 4 are redundant and will create more drag.
-use linear bearings or bronze bushings with hardened pins.
-make a depth stop such as a 1/4"-20 screw (1 rev =.05)
-use thumb screw(s) to lock the depth in at the pins.
-use lexan for clarity
-use a bearing or bronze bushing on the pivot pin.
-radius or chamfer all edges and make sure the bottom is smooth or you'll scuff up the top plate of the guitar.

other then my .02, it looks good. show us some pix when you're finished [:Y:]
Author:  Chris Ensor [ Wed Dec 01, 2010 11:21 am ]
Post subject:  Re: circle cutter design
Thanks for all the great replys. I am considering the depth stop and am looking at lowering the plunge posts down to 3 rather than 4. I don't want to do 2 simply as a precaution against rocking. I am a little apprehensive about doing any sort of scale on it simply because If I change what size of bit I am using, it will no longer be accurate.

And heck, maybe I will even add LEDs and 4G wifi!
Author:  bluescreek [ Wed Dec 01, 2010 12:02 pm ]
Post subject:  Re: circle cutter design
I think you can take away the 4 but to maintain a good square base you will need 3 posts . That helps to control chatter .
Author:  Chris Ensor [ Thu Dec 02, 2010 7:13 am ]
Post subject:  Re: circle cutter design
Here are the newest changes. It now has three posts and a depth stop!
Attachment:
rosette cutter v2.jpg
Author:  bluescreek [ Thu Dec 02, 2010 7:30 am ]
Post subject:  Re: circle cutter design
there is one thing that you will need to do. You need to put stops on each leg. The vibration from the cutter will allow things to move and this can be counter productive when you are in the middle of a rout and things start to go off line . A single stop leg will not do it . Take that out and use wing nuts to make the unit stable .
Author:  TonyKarol [ Thu Dec 02, 2010 8:16 am ]
Post subject:  Re: circle cutter design
I think it will depend on what he makes it out of John .. mine is all UHMW plastic, and I only have one stop one my new one .. and its at the end piece which locks the threaded adjuster, not the one with the pivot pin - and the jig doesnt move at all. The threaded adjuster wont move unless you turn it, no matter what. UHMW has a natural compression remaining when you drill or tap it - use a 1/4 inch drilll for the 1/4 inch rod and see how tough it is to get the darn rod into the hole .. aluminum or lexan wont do that ....
Author:  Chris Ensor [ Thu Dec 02, 2010 10:56 am ]
Post subject:  Re: circle cutter design
I am liking the idea of using linear bearings for the plunge posts. Anyone know where I can find these for a good price. I found one local supplier, but they wanted $45 per bearing. I'm not willing to pay that.
Author:  Chris Ensor [ Thu Dec 02, 2010 10:58 am ]
Post subject:  Re: circle cutter design
Oh, and Tony, you should post pics of your new one. That sounds awesome!
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