60 degree v-bit issues--tear-out

(Cate) #1

I did a V-Carve with a flat area clearance in VCarve. The wood is some old maple (I think) from a 1960’s chemistry lab. I’m getting massive tear-out. Since I have to finish this job, just wondered if anyone has any tips or recommended tools on how to sand without disturbing the already-stained top. Last time (different wood, however) I did two coats of 1/2 lb shellac, but some of the stain chipped during the cut, so I didn’t do it this time.

The ram’s head is only 6" tall, to give you an idea of scale.

Thanks.

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(William Adams) #2

A sharp chisel and patience.

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(Luc) #3

If I was in your situation, my first try would be with my flex shaft rotary tool. You can get a relatively inexpensive one at Harbor Freight that works fairly well. They are used for power carving. I have an assortment of bits and rotary sanding attachments that would get into fairly small spaces. You can control the speed with a pedal that provides good control of the bits you use.

I hope this helps.

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(Jonathan Anderson) #4

I typically run my v-carving toolpaths twice to clean up the gunk left over from the first one like this.

This does look odd for maple since it is a finely-grained wood so I don’t typically get it looking like this. This looks like when I v-carve pine.

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(Neil Ferreri) #5

I’d try a brass wire brush first.

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(Dustin S Tilton) #6

I have a small set of files/rasps made for wood that work well for this. I especially like the flat one.

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(Gary Mitchell) #7

I’d bet you ran your end mill (flat clearance) first and then the Vbit looking at those pictures. It results in more end grain tear out.

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(Cate) #8

Thanks for all your tips. Answers:

  1. Just spent a long time with a chisel. Looks better, but not great.

  2. I can’t use a rotary tool because it will mess with the stained part - I had to stain it first for the contrast, but it really was fuzzy after it. I used the rotary tool on my test cut, sans stain, and it worked well.

  3. Ha - you are right - it’s pine, not maple. Oops. Still working on identifying wood species…

  4. Can’t do brass wire brush because I’m afraid of scratching the stain.

  5. Thanks for tip on the files/rasps.

  6. I did run the v-bit first…can’t imagine what would have happened if I had run the end mill first!

I did another project tonight on the remnants of the original board - slowed the speed on the v-bit and ran the v-carve tool path twice. I think it helped (emphasis on think) but it was still bad.

Then I did a quick v-carve on a small piece of project 1/2" pine from Lowes, and the difference was amazing (no fuzzy, no tear out). I’m blaming the original choice of material.

My friend who knows CNC keeps telling me to stop using pine, but until the 5 people I know who are asking for projects start paying…it will still be pine…

I do plan to try out some scrap pieces of maple and walnut just to see the difference and see if I am a convert.

Thanks again for your feedback!

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(Dennis Selander) #9

make yourself a toothbrush sander good for fine details
http://frugalwoodworking.com/reuse/detail-sander-toothbrush/

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(Luc) #10

In VCarve, you can specify to run a cleaning pass and you have a choice of the direction so you can run the cleaning pass .1in in reverse direction.

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(Michael) #11

Pine,
#302 .500 60° v bit
speeds set to 30 ipm, .225 dpp, .225 stepover, plunge 7.7
spindle set to 4-5 on Makita Router.
run time about 40 min.

This was drawn in Carbide Create as well as tool paths set.

Speeds are conservative but piece came out nearly perfect in on run.

Pictures are straight from machine.

Everyone is all about pushing the limits on speeds and feeds, which is great. but start low with your machine and pay attention to quality, once quality starts to suffer back down speeds and compare.

The sharpness of your bit can also effect these variables.

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(George J. Davis) #12

On your next project you may want to try and apply blue painters tape to help control the surface tearout.

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(George J. Davis) #13

Oh yea, before you run the cut! LOL!

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(Jonathan Anderson) #14

I’ve had issues with this getting stuck and gumming up my bit, especially with smaller bits. How do you get around that?

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(Cate) #15

I finally gave up on the scrap wood and bought an edge-glued pine panel at Lowes, and with the settings from mjmike69688, it came out much better, which proves it was the original wood. In a past experiment, I stained, then two coats of 1/2 lb cut shellac. Two was too much and there was a bit of flaking off of the stain, but I think one coat might be enough to strengthen the grain and prevent tearout. The good thing with shellac (so long as it is dewaxed) is that you can coat it with any finish - oil based, water based, lacquer. Planning to test the one-coat theory this weekend…with my new touch probe!!! I also got some scrap maple to try, so I might quit pine…

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(Michael) #16

I forgot to mention that when using really old wood like that it is very very dry. it has had a long time to cure, making it much harder than the same species freshly cut. In retrospect the same settings for your machine may not work for both old and new. If you still have some scrap of it try slower feed rates as well as less of a plunge (depth per pass) say maybe half and half, also try turning the spindle speed higher and see if this helps with tearout.

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