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If you get a lot of marks, your router is probably not perfectly vertical. Also, an upcut spiral bit will leave a much cleaner bottom than a downcut. Not sure what you're using now.
Can't help you with the tools you're asking about.
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I know they're for aluminum, but they can be used for wood too, right?
I need to get something for area clearing pockets in and around 3D carvings that doesn't leave circle marks..
I'm thinking that this might be the hot ticket.. I guess I would just use them the same way as a regular spiral bit but increase the step over to account for the radiused edge, right?..
What about feeds and speeds? Same as similar sized spirals? How about longevity? Same as their wood counterparts?
After using it in wood, I could still use it for aluminum and vis versa?
[URL="http://www.cnczone.com/forums/cnc_wood_router_project_log/124543-mountaincrafts_router_plasma_build_thread.html"][U]4' x 8' CNC Wood Router Project[/U][/URL]
[U][URL="http://www.cnczone.com/forums/woodworking/135576-home_made_drum_sander.html"]Home Made Drum Sander Project[/URL][/U]
If you get a lot of marks, your router is probably not perfectly vertical. Also, an upcut spiral bit will leave a much cleaner bottom than a downcut. Not sure what you're using now.
Can't help you with the tools you're asking about.
Gerry
Mach3 2010 Screenset
http://home.comcast.net/~cncwoodworker/2010.html
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Although you might be successful using endmills on wood, the geometries are different and probably not ideal. Like Gerry said, I'd re-check that your z axis is perfectly plumb on both the x and y directions (I chuck a piece of 1/4" drill rod for this) Also make sure you have no backlash in the z keadscrew and no play in the lm bearings. You might have to slow your feed down and lower your doc slightly, as impressive as watching the machine move fast can be. You can also try tweaking the spindle speed during the cut with the SuperPID a couple hundred RPM up or down to find the "sweet spot." Finally you should ensure that your work is perfectly flat, against your table, and if not, add thin shims under the work to support it.
I agree, if you are getting circle marks its because your spindle is not properly trammed. you will not get a better result from another but.Originally Posted by ger21
I do not agree an up cut bit will give you a cleaner bottom in your pockets and a down cut, I always use a downcut bit for my pocket bottoms as it leaves a fuzz free top edge and a very nice bottom. If you are profiling through then an upcut for sure.
Also for cleaner bottoms I use a clean up pass of about 0.01 - 0.02".
I see what Mountaincraft is trying to do and I guess it *may* work. Even if the Spindle is perfectly vertical the sharp edges of the bottom clearing bit will leave a feather burr at the perimeter of the pocket bottom (assuming this is for V-carving). The radiused bit may avoid that but then probably the CAM software needs to know the exact shape of the radius bit. At the end you just got to try (and tweak) it.
These circle marks seem to be more pronounced with this single flute compression bit... I didn't really notice them before with the two flute upspiral.. but that tore up the top edges...
[URL="http://www.cnczone.com/forums/cnc_wood_router_project_log/124543-mountaincrafts_router_plasma_build_thread.html"][U]4' x 8' CNC Wood Router Project[/U][/URL]
[U][URL="http://www.cnczone.com/forums/woodworking/135576-home_made_drum_sander.html"]Home Made Drum Sander Project[/URL][/U]
Machine rigidity also plays a big role, if the tool can deflect it may tend to dig in an edge and leave the circle marks. Grab your bit or bottom of your router and see if you can move it slightly by hand.
Do the circle swirl marks happen more in one direction than the other? More in X or Y?
If there's a problem with deflection, I'd suspect either the bearing carriages need adjusting/tightening/maintenance, or more likely this old router, which the bearings don't sound that great to me..
I guess I'll have to try a few things, and sell a couple 'products' so that I can get a new router motor and some decent 3D and down spiral bits...
There also 'might' have been an issue with workpiece flex seeing as it was slightly cupped before I screwed it down...
I think I might have to get in the habit of adding a second finish path a few thousandths deeper to my projects to see if the issues persist... I don't mind the machine spending a little more time if it saves me time on the sanding side...
[URL="http://www.cnczone.com/forums/cnc_wood_router_project_log/124543-mountaincrafts_router_plasma_build_thread.html"][U]4' x 8' CNC Wood Router Project[/U][/URL]
[U][URL="http://www.cnczone.com/forums/woodworking/135576-home_made_drum_sander.html"]Home Made Drum Sander Project[/URL][/U]
For sure, the piece will "flop" around like a fish out of water, if it's not secured properly! I've gotten good results with straight flute, up-spiral, compression, and even down-spiral bits; though I do not like to use down-spiral bits for cleaning up pocket floors, since it's basically abrading the pocket floor with its negative rake, as opposed to cutting it. I've only got a rough pocket floor when my z goes out of tram..
With most hardwoods, I don't think you'll have a problem with the pocket floor, unless there's any kind of looseness, misalignment, or backlash anywhere in your z especially. Regardless of species, it's probably best to let the wood acclimate in your shop at least a few weeks before machining it.
Also, it's not a matter of making your finish pass a few thousandths deeper, it's making your rough pass a few thousandths shallower, so you can bring you finish pass to proper depth. Especially with your v-bits!
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