This is only my second carve. Trying a coaster idea. This cut is in 1/4" oak. Did the perimeter with a quarter inch upcut. Did the engraving with a 60° bit.
Perimeter was 240 ipm at Makita speed 2. Engraving was the same speed but 80 ipm.
(Images go from rough cut to basic cleanup and sanding to mineral oil just to see what effect each had.)
I have some ideas for changes to settings and material but I thought I’d see if anyone here had feedback for me to try first.
Thanks!
Hi Scott,
For that delicate little part, you may want to slow down the feed and/or increase the speed. Idk what 2 corresponds to for Makita RPMs, but imaging it’s maybe 8-10k or so? I think your chip load may be a bit high given the speeds and feeds you mentioned for the profile/perimeter cut.
You could also consider a down cut bit to profile the edge, which could help with some of the chipping there.
Beautiful little engraving in the end! Not very experienced with V bits myself, but many here are and would have better input. Not too shabby for a 2nd project! Looking forward to what you post next.
Use a downcut for the profile. It wont have the tearout your seeing and personally i hate oak, but love cherry and maple due to the right grain structure… that’s just my preference
You said you did the carving with a 60° vbit… was it a profile? Maybe a vcarve instead (I’m looking at the 8).
I was going to try upcut. I knew that was a gamble. And I wondered if that tear out was because it was oak. I will try some maple and poplar. I don’t think I have anything else on hand.
I think I did the v cut as profile. Should be 0.020" deep.
I need to change the font to something that’s only single stroke
I think I read that speed 2 is something like 12,000 RPM.
Considering all that, do I still need to change the feeds if I switch material to something other than oak?
Oak is only part of the equation there… the bigger piece of the equation is the upcut. If you used an upcut on another wood variant, you would still have tear out, but it might be better contained. If you would have used a downcut it would have cut the fibrous straws downward as it moved. The upcut brings them up as it cuts breaking the top layer since they don’t have reenforecment.
I used upcut when hogging out material because it’s faster than downcut when wanting a clean top surface, and downcut or compression if the surface matters… if it’s getting a round over I’ll do upcut
Yeah, that makes sense. My question about speeds had more to do with the engraving. Is 60° at 80ips ok for only 0.020" deep in maple or poplar?
I don’t recall off the top of my head, but it doesn’t sound unreasonable… for 18k. What does the manufacturer recommend?
I haven’t made one project so kudos looking great!!
I almost always use downcut bits, that helps to eliminate the fuzzies. I get my downcut 30 degree, 60 degree, and 90 degree bits from:
www.cadencemfgdesign.com good prices and great service.
I need to get a 30° to try it. How deep do you go with that?
It would all depend on the the project. I would take a piece of wood similar to what you are going to use and run some test cuts.
@jscottsmith, what I found helpful was faster speeds/rpm and slower feeds when doing 15° bits. Higher RPMs provide better shearing. Slower feeds/IPM minimizes breaking off features—slightly different mechanism than tear out but looks the same int the end.
Another thing that helped me was using the v bit first then a clearing bit. This gives smaller features more support during the v as well as minimizing tear out from the clearing bit that crosses into fine lines.
At the beach right now so can’t see my specific feeds and speeds. iirc 20k RPM and 40 IPM. Normal chip load calculations are less useful for small diameter bits. A V at your depth qualifies as a small effective diameter in the cut.
Hope my experience helps.
(I know you said 60°. I think for this type of cut the principle is the same—RPMs as fast manufacturer says it’s rated and IPM just fast enough so it doesn’t burn 
)
I would suggest not having the design go all the way to the edges, hold it back some and use something other than oak.
