Roundover is it practial?

[knight_toolworks]

so far it has been more practical do to single and double sided roundovers on a router table. I have 20 sheets of ply to cut with 10 parts each only one side needs rounded over. I am debating on doing it on the cnc or the router table. it would requite a bit change on each sheet. I show about 15 minutes to roundover the parts. I don't thin kit would take much longer to do it on the table and I should get them done before the cuts are done.

[gabepari]

The only problem with roundover bits on the cnc are variations in material thickness with mess with your tool height. If you can live with an incomplete roundover (tool set too high) then it works ok, but using a laminate trim router with a roundover bit is mighty fast and you have more control over bit depth.

Gabe

[jhicks]

Steve, I agree with Gabe for the most part especially stock thickness BUT if you have a little wiggle room, you can buy plunge round overs with a longer cut length on the center. So we have made parts with a 1/2" round over and an extended 1/4" center plunge cutter.
Run the 1st pass a bit shallow say 1/4" to 3/8", then cut the rest through. depending on cutting length of the center straight cutting edge. I use a 480 depth for a .500 deep roundover to accomodate the top radius then sand the edge anyway on ply.
Magnate bits and others can make these bits for you to spec. They are common with folks using a Lagacy machine.
Just add enough straight to cut through without hitting the top with the edge of the roundover and you should be able to make it happen.
Good luck.

[bleeth]

Steve: If you have nothing else to do while parts are being cut out than watch then I would do the roundovers by hand. My overall production time would be least. On the other hand, since you have sanding to do anyway you could spend the time sanding. If all your parts are the same size I would do all my cutting and then set up a file to do the rounding over with a register location for the parts. Changing bits 40 times is a drag!!
(See my previous post about all I want for Christmas!!)

[Gary Campbell]

Dave...
I've been checking the mail every day!
Gary

[jhicks]

No real need to use a new registration point IF you cut to a part way through depth with a roundover then cut OUT with an identical diameter straight bit as the center of the round over on the outside of the very same vectors used with the roundover. In fact that partial depth pass with the roundover is a benefit if you like to leave an Onion skin for hold down. Even with a 5 minute bit change, it beats the router table or new registration and leaves time to sand while running.
check this site for standard and custom flat/round over plunge bits

http://magnate.net/index.cfm?event=showProductGroup&theID=41

Reference Bit #1269 as an example

[gabepari]

Jerry, I've used those on acrylic when I need a radius'd edge. Acrylic is a little more problematic to radius with a hand or table router.

Gabe

[knight_toolworks]

I think I will just do it on the router table. I could not do all the cutting with the above bits as one piece is only rounded on three sides. and there are holes to route too. it's pretty fast on the router table.

[bcammack]

We route profile edges on stone and engineered quartz countertops with the tops face-down and Z-zero being the tops of the Blick vacuum pods.

It's the only practical way I know of to account for variations in material thickness. That and we run a gauging wheel along the "underside" face of the profile edges to give a consistent edge thickness. This is in deference to the profile tooling, as too thick a piece puts a lot of strain on the "bottom" of the tooling's profile, milling excess thickness off.

From what you describe, I agree that routing on the ShopBot and profiling on a router table is the ticket. Let each do what it is best at without having to bother with tool changes or repeated tool setup.